CR Biologies

Hugo Bellin

C. R. Biologies 342 (2020) 247–278
Contents lists available at ScienceDirect
Comptes Rendus Biologies
www.sc iencedi rec t .com
Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles
Talk summaries
Résumés des interventions
Session I. Insects as model organisms in
biology
1
How flies contribute to the
discovery of human diseases
and their pathogenic
mechanisms
Hugo Bellin
Howard Hughes Medical Institute, Baylor College of Medicine,
Houston, TX, USA
E-mail address: hbellen@bcm.edu
An area of research that has developed rapidly in the past five
years is the use of Drosophila to facilitate the diagnoses of rare
human diseases. The technical developments in sequencing
human genomes using whole exome (WES) or whole genome
sequencing (WGS) have completely changed the landscape of
human genetics. It is estimated that there are approximately 30
million people in the US and 400 million worldwide with rare
diseases. Many of the patients who have these diseases undergo
a diagnostic odyssey and remain undiagnosed for many years.
By sequencing their genomes and those of their relatives we
can now discover genetic variations in patients that are rare
or ultrarare. However, considering that there are many poly-
morphisms in the population, assessing which variant(s) is/are
related to the observed symptoms has remained a challenge.
This is precisely where model organisms can contribute and
Drosophila is now playing a prominent role in this strategy.
Although there are nearly 4,000 genes annotated in OMIM, the
pace of gene discovery has not shown any evidence of slowing
down in the past few years.
The NIH launched the Undiagnosed Diseases Network (UDN)
four years ago. Its goal is to enroll patients with undiagnosed
diseases and try to determine their causes, which are typically
genetic in origin. The patients who are enrolled are the most
challenging cases in medicine, and 12 clinical sites, a sequenc-
ing center, a metabolomics core and two Model Organisms
Screening Centers (MOSC) are supported to develop diagnoses.
To date, over 3,000 patients have applied and about 30% of the
accepted patients have been diagnosed by combining clinical
phenotyping, WES or WGS of the proband and 2–3 mem-
bers of the family, and performing functional studies in a
model organism. The MOSC Drosophila Core at Baylor College
of Medicine (BCM) has played a prominent role in this ven-
ture and has provided critical data for many human genetic
diseases [1]. The MOSC at BCM has also collaborated with the
Center for Mendelian Genomics to assess variant function using
Drosophila and facilitate the discovery of new human disease-
causing genes.
The first project discussed in this presentation was driven by
WES of a patient and his parents and the discovery of a de novo
point mutation in ACOX 1 (Acyl-CoA oxidase 1). ACOX1 encodes
the rate-limiting enzyme in very-long-chain fatty acid (VLCFA)
 -oxidation, and produces H2O2 in peroxisomes [2]. The
proband was diagnosed at age 11 and now uses a wheelchair
at age 18. Another patient with the same point mutation was
diagnosed at age 9 and is now comatose at age 15. By studying
the function of the ACOX1 gene in flies using strains devel-
oped in my lab, we showed that homozygous loss-of-function
mutations cause lethality and an autoimmune phenotype in
which the animals activate their cellular and humoral immune
responses. A comparison with the vertebrate literature sug-
gests that autoimmunity may also be the main reason infants
with an ACOX1 deficiency die at a very young age, prior to the
age of 5.
We then created flies with the patient’s point mutation and
observed a very different phenotype. Flies eclosed and died
within one or two days but were able to survive, fly, mate,
and live for extended periods of time when kept on food with
a potent antioxidant, N-acetylcysteine. This is consistent with
the fact that ACOX1 produces ROS in peroxisomes and that the
point mutation is a gain-of-function mutation. However, we
were surprised by the potency of the suppression. In addition,
just expressing the variant in Drosophila wrapping glia but not
any other tissue, is sufficient to kill animals, showing that the
toxicity is mainly due to an expression of the mutant protein in
glial cells. Importantly, expressing catalase in glia suppresses
this lethality. We were therefore able to demonstrate that fly
ACOX1 is indeed abundantly expressed and mostly restricted
to wrapping glia.
We then turned to rats and showed that ACOX1 is abun-
dantly expressed in Schwann cells (not in neurons). In addition,
expression of the patient de novo mutation kills cultured
Schwann cells and the antioxidant AD4 fully suppresses cell
1631-0691/
248 Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278
death. Finally, nerve biopsies of the patient, who suffered
severe axonal loss, showed that surviving Schwann cells are
morphologically (TEM) and functionally aberrant (electrophys-
iology). This prompted the physicians to provide the patient
with high doses of N-acetylcysteine and this new treatment is
associated with a clear improvement in motility.
A second project was driven by a forward mutagenesis screen in
Drosophila in which we previously identified variants in the fly
Ankle2 gene. We discovered that loss-of-function mutations of
the human ortholog of ANKLE2 cause microcephaly in a child
[3]. We then discovered, in collaboration with Nevan Krogan
and Priya Shah, that a Zika virus protein, NS4A, interacts with
and inhibits Ankle2 [4,5]. Our studies in Drosophila combined
with human genetic studies allowed us to uncover a pathway
that implicates several genes associated with primary micro-
cephaly in human.
We identified five additional microcephaly patients with
variants in ANKLE2 and showed that these variants act as
loss-of-function alleles in flies. Our data show that Ankle2 is
an ER-localized protein essential for proper ER and nuclear
envelope structure. Mutations in Ankle2 affect cell division,
spindle alignment, and localization of asymmetric determi-
nants including the proteins of the Par complex. Ankle2
strongly interacts with the nuclear kinase Ballchen, the
homolog of human VRK1, an established microcephaly locus.
Ankle2 mutants fail to maintain Ballchen/VRK1 in the nucleus,
and we propose that this leads to a “gain-of-function” phe-
notype where Ballchen/VRK1 can ectopically interact with
targets that it normally does not interact with. This results in
severely reduced aPKC phosphorylation, which has previously
been shown to have reduced kinase activity. The Ankle2 path-
way also physically and genetically interacts with L(2)gl, an
inhibitor of aPKC activity, which is consistent with the observed
aPKC defects noted in Ankle2 mutants. Finally, we show that
expression of NS4A, which binds to and inhibits the function
of Ankle2, phenocopies Ankle2 mutant defects in neuroblasts,
and these defects can be rescued by modulation of the Ankle2
pathway [3] (Link et al., 2019).
Our work highlights an important pathway required for proper
human brain development: ANKLE2 and VRK1 are both asso-
ciated with microcephaly; a member of the Par complex has
been linked to brain defects in mice; and LLGL1, the homolog of
L(2)gl, maps to the critical region of Smith Magenis Syndrome, a
disease associated with microcephaly. Furthermore, we identi-
fied many novel variants associated with microcephaly in many
of the human homologues of the fly genes described in this
study.
Disclosure of interest The author declares that he has no com-
peting interest.
References
[1] H.J. Bellen, M.F. Wangler, S. Yamamoto, The fruit fly at the
interface of diagnosis and pathogenic mechanisms of rare
and common human disease, Hum. Mol. Genet. [submitted].
[2] H. Chung, M.F. Wangler, P.C. Marcogliese, J. Jo, T.A. Raven-
scroft, S. Sadeghzadeh, et al., Loss of peroxisomalACOX1
induces autoimmunity whereas a de novo gain-of-function
variant induces elevated ROS and Schwann cell loss [in
preparation].
[3] S. Yamamoto, M. Jaiswal, W.L. Charng, T. Gambin, E. Karaca,
G. Mirzaa, et al., A Drosophila genetic resource of mutants to
study mechanisms underlying human genetic diseases, Cell
159 (2014) 200–214 [PMCID: PMC4298142].
[4] P.S. Shah, N. Link, G.M. Jang, P.P. Sharp, T. Zhu, D.L.
Swaney, et al., Comparative flavivirus-host protein inter-
action mapping reveals mechanisms of dengue and Zika
virus pathogenesis, Cell 175 (2018) 1931–1945 [PMCID:
PMC6474419].
[5] N. Link, H.L. Chung, A. Jolly, M. Withers, B. Tepe, B.R.
Arenkiel, et al., ANKLE2, a target of Zika virus, controls asym-
metric cell division of neuroblasts and uncovers a novel
microcephaly pathway, Biorxiv (2019) [611384].
https://doi.org/10.1016/j.crvi.2019.09.002
2
Drosophila research: From the
genome to the proteome
Markus Affolter
Departement Biozentrum, University of Basel, Switzerland
E-mail address: markus.affolter@unibas.ch
Starting from 1900, Drosophila melanogaster has been studied in
the laboratory by scientists interested in many different aspects
of animal development, physiology, and evolution. Over much
of this more than hundred year period, genetic analyses have
been at the basis of most studies, also those who led to the
Nobel prices attributed to scientists working with Drosophila.
More recently, fluorescent proteins and optogenetic tools have
been added to the ever-expanding genetic toolbox allowing for
a better understanding of basic cellular processes underlying
complex developmental processes.
Even more recently, a novel approach is being added to the
toolbox. Small protein binders can be used to directly tar-
get and manipulate proteins in their native environment, in
cells of the living organism. The development of numerous
antibody- and non-antibody-based scaffolds of protein binders
(Fig. 1) has allowed the rapid identification of such small bind-
ing domain, recognizing virtually any target protein of interest.
Such binding molecules can then be functionalized in many dif-
ferent ways, allowing for acute and direct protein manipulation
Fig. 1 A–H: Different protein binder scaffolds that can be used
in developmental biology studies (see [1]).
Fig. 2 Protein binders can be expressed as functionalized pro-
teins in vivo (see [2]).


How flies contribute to the discovery of human diseases and their pathogenic mechanisms

Vincent Doublet

Toby Doyle

Isobel Refoy

Sophie Hedges

Claire Carvell

Mark J.F. Brown

Lena Wilfert

258 Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278
Disclosure of interest The author declares that she has no
competing interest.
References
[1] F. Müller, Ituna and Thyridia: A remarkable case of mimicry
in butterflies, Proc. Entomol. Soc. Lond. (1879), xx–xxix.
[2] M. Elias, M. Joron, Mimicry in Heliconius and Ithomiini but-
terflies: the profound consequences of an adaptation, Bio
Web of Conferences 4 (2015) 00008.
[3] M. McClure, C. Clerc, C. Desbois, A. Meichanetzoglou, M. Cau,
L. Bastin-Héline, et al., Why has transparency evolved in
aposematic butterflies? Insights from the largest radiation
of aposematic butterflies, the Ithomiini, Proc. Biol. Sci. 286
(2019) 20182769.
https://doi.org/10.1016/j.crvi.2019.09.010
Session III. Social insects and other
10
Supergene, sex and sociality
Laurent Keller
Faculté de biologie et médecine, Département d’écologie et
évolution, Groupe Keller, Lausanne University, CH-1015,
Lausanne, Switzerland
E-mail address: laurent.keller@unil.ch
Intraspecific variability in social organization is common, yet
the underlying causes are rarely known. I will show that the
existence of two divergent forms of social organization in six
ant species is under the control of a pair of heteromorphic
chromosomes that have many of the key properties of sex
chromosomes. In particular, this social chromosome contains
a large (13 megabases) region in which recombination is com-
pletely suppressed via three large inversions (Fig. 1). These
findings highlight how genomic rearrangements can maintain
divergent adaptive social phenotypes involving many genes
acting together by locally limiting recombination.
Fig. 1 Fine scale mapping and BAC-FISH analysis of social
chromosome.
Disclosure of interest The author declares that he has no com-
peting interest.
Further reading
T. Schwander, R. Libbrecht, & L. Keller. Supergenes and complex
phenotypes, Curr. Biol. 24 (2014) R288–R294.
J. Wang, Y. Wurm, M. Nipitwanttanaphon, O. Riba-Grognuz, Y.-
C. Huang, D. Shoemaker & L. Keller. A Y-like social chromosome
causes alternative colony organization in fire ants, Nature 493
(2013) 664-668.
A.C. LeBoeuf, R. Benton & L. Keller, The molecular basis of social
behavior: models, methods and advances, Curr. Opin. Neurobiol.
23 (2013) 3-10.
https://doi.org/10.1016/j.crvi.2019.09.011
11
Termites: Soil engineers for
ecological engineering
Pascal Jouquet1,∗, Ajay Harit2, Sougueh Cheik1,3,
Saran Traoré4, Nicolas Bottinelli 1,3
1 UMR iEES-Paris, Centre IRD, Bondy, France
2 School of Environmental Sciences, Mahatma Gandhi University,
Kottayam, Kerala, India
3 Soils and Fertilizers Research Institute, Dong Ngac, Tu Liem,
Hanoi, Vietnam
4 UFR-ST, Université Nazi Boni (UNB), Bobo, Burkina Faso
∗ Corresponding author.
E-mail address: pascal.jouquet@ird.fr (P. Jouquet)
This communication assesses advances in our knowledge of
the beneficial influences of termites on ecosystem functioning
and services. Termites are amongst the main macroinverte-
brate decomposers in arid and semi-arid environments and
exert additional impacts through the creation of biostructures
(mounds, galleries, sheetings, etc.) with different soil physical
and chemical properties. Unfortunately, the positive ‘or bright’
role of termites is often overshadowed by their dark side, i.e.
their status as pests threatening agriculture in the tropics (635
vs. 164 articles referenced in WoS with termites and either pest
or ecosystem engineer as keywords. Source: WoS, April 2019).
Termite impacts on soil properties and water dynamics can
be differentiated at four different scales: (i) at the landscape
scale, where termites act as heterogeneity drivers; (ii) at the
soil profile scale, where termites act as soil bioturbators; (iii) at
the aggregate scale, where they act as aggregate reorganizers;
(iv) and last, at the clay mineral scale, where they can act as
weathering agents [1].
In this communication, two examples of ecosystem services
provided by termites are given.
The first describes the positive impact of termites on water
infiltration and nutrient guidance at small scale through the
production of foraging galleries in soil [2] and how this activity
can be used to improve agro-ecosystem functioning in arid and
semi-arid environments [3].
The second example deals with the construction of mounds and
sheeting by termites in “natural” environments [4] and how
these “patches of biodiversity and fertility” can be used in the
lower Mekong Basin to reduce food insecurity and to provide a
better access to health [5] (Fig. 1).
Finally, the perception of termite mounds in Southern Indian
rural environments (Fig. 2) is discussed and used as example
of the cultural services that can be provided by termites in
some circumstances. The story of Valmiki, the author of the
Ramayana, is explained and used as a parable for highlighting
the interconnection between the “bright” and “dark” sides of
termites, and more generally that to get the bright we also need
the dark.
Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278 259
Fig. 1 Termite mounds are conspicuous features of paddy
fields in Laos and Cambodia. Their soil is used as amendment
because it is enriched in organic matter and clay while its ani-
mal and plant diversity are used by the population as source
of food or medicine (Miyagawa et al., 2011) (Photo: P. Jouquet,
Cambodia, 2008).
Fig. 2 Termite mound made by Odontotermes obesus in South-
ern India (Photo: P. Jouquet, 2016). The offerings and the
statuette show that termite mounds are used as a means to
express one’s devotion to Shiva.
Disclosure of interest The authors declare that they have no
competing interest.
References
[1] P. Jouquet, N. Bottinelli, R.R. Shanbhag, T. Bourguignon, S.
Traoré, S.A. Abbasi, Termites: the neglected soil engineers
of tropical soils, Soil Sci. 181 (3/4) (2016) 157–165.
[2] S. Cheik, N. Bottinelli, M.T. Tran, T.T. Doan, P. Jou-
quet, Quantification of three dimensional characteristics of
macrofauna macropores and their effects on soil hydraulic
conductivity in northern Vietnam, Front. Environ. Sci.
(2019), http://dx.doi.org/10.3389/fenvs.2019.00031.
[3] E. Roose, V. Kabore, C. Guenat, Zai practice: a West African
traditional rehabilitation system for semiarid degraded
lands, a case study in Burkina Faso, Arid Soil Res. Rehab.
13 (4) (1999) 343–355.
[4] P. Jouquet, E. Chaudhary, A.R.V. Kumar, Sustainable use of
termite activity in agro-ecosystems with reference to earth-
worms. A review, Agron. Sustain. Dev. 38 (2018) 3.
[5] S. Miyagawa, Y. Koyama, M. Kokubo, Y. Matsushita, Y.
Adachi, S. Sivilay, N. Kawakubo, S. Oba, Indigenous utiliza-
tion of termite mounds and their sustainability in a rice
growing village of the central plain of Laos, J. Ethnobiol.
Ethnomed. 7 (2011) 24.
https://doi.org/10.1016/j.crvi.2019.09.012
12
Using contact networks and
next-generation sequencing for
wildlife epidemiology
Vincent Doublet ∗,1,2, Toby Doyle2, Isobel Refoy2,
Sophie Hedges2, Claire Carvell3, Mark J.F. Brown4,
Lena Wilfert2,5
1 Institute of Evolutionary Biology, University of Edinburgh, UK
2 College of Life and Environmental Sciences, University of Exeter,
Penryn Campus, UK
3 NERC Centre for Ecology & Hydrology, Wallingford, UK
4 Royal Holloway University of London, School of Biological
Sciences, UK
5 Institute of Evolutionary Ecology and Conservation Genomics,
University of Ulm, Germany
∗ Corresponding author.
E-mail address: vincent.bs.doublet@gmail.com
(V. Doublet)
Horizontal transmission of infectious diseases is strongly
determined by the contact network between hosts [1]. Envi-
ronmental and ecological variables that define the probability
of contacts between individuals, such as food resource quality
and quantity, have been largely neglected in models studying
the dynamics and epidemiology of wildlife diseases.
In this work, we used pollinators and their pathogens to study
the role of contact networks in a natural multi-host pathogen
community. In agricultural landscapes, wild flowers are the
most important food resources of insect pollinators such as
bees and flies. To boost yields of agricultural crops and ensure
pollinator conservation, the UK Environmental Stewardship
scheme prompted farmers to grow pollinator-friendly wild
flower margins along their fields (Fig. 1). Wild flower margins
(Fig. 1) have proven to be efficient to increase both density and
diversity of bees in agricultural areas, and to increase pollina-
tion success of surrounding crops.
As the rate of disease transmission should increase with host
density, we hypothesize that the success of wild flower margins
may generate hubs for pathogen exchange within the bee com-
munity. Several recent studies have illustrated the frequent
transmission of infectious diseases between managed and wild
bees, potentially via the shared use of flowers [2]. However,
the environmental and ecological drivers of disease dynamics
between pollinators remain uncharacterised [3]. To understand
the role of flower density and diversity for bee disease trans-
mission, we reconstructed high-resolution plant–insect visitor
networks from flower visitation data collected in ten farms in
Southern England (five farms participating in the scheme vs.
five control farms), as well as a record of bee pollen collec-
tion to describe the resource bees were exploiting (pollen vs.
nectar).
When analysing the plant–pollinator networks, we found that
flower density and diversity strongly define pollinator density
and foraging behaviour, and influence the structure of indi-


Using contact networks and next-generation sequencing for wildlife epidemiology

Angela E. Douglas

Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278 259
Fig. 1 Termite mounds are conspicuous features of paddy
fields in Laos and Cambodia. Their soil is used as amendment
because it is enriched in organic matter and clay while its ani-
mal and plant diversity are used by the population as source
of food or medicine (Miyagawa et al., 2011) (Photo: P. Jouquet,
Cambodia, 2008).
Fig. 2 Termite mound made by Odontotermes obesus in South-
ern India (Photo: P. Jouquet, 2016). The offerings and the
statuette show that termite mounds are used as a means to
express one’s devotion to Shiva.
Disclosure of interest The authors declare that they have no
competing interest.
References
[1] P. Jouquet, N. Bottinelli, R.R. Shanbhag, T. Bourguignon, S.
Traoré, S.A. Abbasi, Termites: the neglected soil engineers
of tropical soils, Soil Sci. 181 (3/4) (2016) 157–165.
[2] S. Cheik, N. Bottinelli, M.T. Tran, T.T. Doan, P. Jou-
quet, Quantification of three dimensional characteristics of
macrofauna macropores and their effects on soil hydraulic
conductivity in northern Vietnam, Front. Environ. Sci.
(2019), http://dx.doi.org/10.3389/fenvs.2019.00031.
[3] E. Roose, V. Kabore, C. Guenat, Zai practice: a West African
traditional rehabilitation system for semiarid degraded
lands, a case study in Burkina Faso, Arid Soil Res. Rehab.
13 (4) (1999) 343–355.
[4] P. Jouquet, E. Chaudhary, A.R.V. Kumar, Sustainable use of
termite activity in agro-ecosystems with reference to earth-
worms. A review, Agron. Sustain. Dev. 38 (2018) 3.
[5] S. Miyagawa, Y. Koyama, M. Kokubo, Y. Matsushita, Y.
Adachi, S. Sivilay, N. Kawakubo, S. Oba, Indigenous utiliza-
tion of termite mounds and their sustainability in a rice
growing village of the central plain of Laos, J. Ethnobiol.
Ethnomed. 7 (2011) 24.
https://doi.org/10.1016/j.crvi.2019.09.012
12
Using contact networks and
next-generation sequencing for
wildlife epidemiology
Vincent Doublet ∗,1,2, Toby Doyle2, Isobel Refoy2,
Sophie Hedges2, Claire Carvell3, Mark J.F. Brown4,
Lena Wilfert2,5
1 Institute of Evolutionary Biology, University of Edinburgh, UK
2 College of Life and Environmental Sciences, University of Exeter,
Penryn Campus, UK
3 NERC Centre for Ecology & Hydrology, Wallingford, UK
4 Royal Holloway University of London, School of Biological
Sciences, UK
5 Institute of Evolutionary Ecology and Conservation Genomics,
University of Ulm, Germany
∗ Corresponding author.
E-mail address: vincent.bs.doublet@gmail.com
(V. Doublet)
Horizontal transmission of infectious diseases is strongly
determined by the contact network between hosts [1]. Envi-
ronmental and ecological variables that define the probability
of contacts between individuals, such as food resource quality
and quantity, have been largely neglected in models studying
the dynamics and epidemiology of wildlife diseases.
In this work, we used pollinators and their pathogens to study
the role of contact networks in a natural multi-host pathogen
community. In agricultural landscapes, wild flowers are the
most important food resources of insect pollinators such as
bees and flies. To boost yields of agricultural crops and ensure
pollinator conservation, the UK Environmental Stewardship
scheme prompted farmers to grow pollinator-friendly wild
flower margins along their fields (Fig. 1). Wild flower margins
(Fig. 1) have proven to be efficient to increase both density and
diversity of bees in agricultural areas, and to increase pollina-
tion success of surrounding crops.
As the rate of disease transmission should increase with host
density, we hypothesize that the success of wild flower margins
may generate hubs for pathogen exchange within the bee com-
munity. Several recent studies have illustrated the frequent
transmission of infectious diseases between managed and wild
bees, potentially via the shared use of flowers [2]. However,
the environmental and ecological drivers of disease dynamics
between pollinators remain uncharacterised [3]. To understand
the role of flower density and diversity for bee disease trans-
mission, we reconstructed high-resolution plant–insect visitor
networks from flower visitation data collected in ten farms in
Southern England (five farms participating in the scheme vs.
five control farms), as well as a record of bee pollen collec-
tion to describe the resource bees were exploiting (pollen vs.
nectar).
When analysing the plant–pollinator networks, we found that
flower density and diversity strongly define pollinator density
and foraging behaviour, and influence the structure of indi-
260 Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278
Fig. 1 Example of wild flower margin in one of our site. Photo:
Vincent Doublet.
rect ‘contact networks’ among pollinators (via the use of flower
species). Particularly, we found flower diversity to be posi-
tively correlated with the reduction of niche overlap between
insect species. This response of insect pollinators suggest that
wild flower margins with high plant species richness may
reduce insect competition for resources, and potentially reduce
the risk of inter-specific disease transmission by supporting
diverse diet for insects exploiting different flowers.
To test the effect of plant diversity on pathogen dynamics in
bees, we sampled pollinators on these farms and character-
ized their virome by deep transcriptome sequencing. We are
now combining these environmental data to virus discovery in
order to reveal the impact of the agri-environmental scheme on
viral dynamics. Ultimately, we aim to identify environmental
(flower density, agricultural practices) and ecological factors
(plant taxa, insect community assemblage) that significantly
enhance the transmission of plant and pollinator viral diseases
within our model to eventually improve agricultural practises
and wildlife management.
Disclosure of interest The authors declare that they have no
competing interest.
References
[1] M.E. Craft, Infectious disease transmission and contact
networks in wildlife and livestock, Phil. Trans. R. Soc. B. 370
(2015) [20140107].
[2] M.A. Fürst, D.P. McMahon, J.L. Osborne, R.J. Paxton, M.J.F.
Brown, Disease associations between honeybees and bum-
blebees as a threat to wild pollinators, Nature 506 (2014)
364–366.
[3] R. Manley, M. Boots, L. Wilfert, Emerging viral disease risk
to pollinating insects: ecological, evolutionary and anthro-
pogenic factors, J. Appl. Ecol. 52 (2015) 331–340.
https://doi.org/10.1016/j.crvi.2019.09.013
13
Microbial nutrient factories in
insects on extreme diets
Angela E. Douglas
Department of Entomology, Cornell University, Ithaca, NY, USA
E-mail address: aes326@cornell.edu
Insects are renowned for their capacity to specialize on a
wide diversity of diets, many of which are nutrient-poor or
nutritionally unbalanced. For example, various insects feed
through the life cycle on wood, vertebrate blood, plant sap and
other extreme diets that are variously deficient in vitamins,
sterols and essential amino acids. These insects circumvent
the fundamental “rules” of animal nutrition because they
possess symbiotic microorganisms that overproduce the lim-
iting dietary nutrients. Many associations between insects and
microorganisms are evolutionarily ancient and involve the
exquisite coevolution of metabolic function in the insect and
microbial partners, including the restructuring of microbial
metabolism as nutrient factories for the host (Fig. 1). These
insects include major pests and vectors of animal, human and
crop disease agents. Their dependence on specific microor-
ganisms offers novel routes for the control of these globally
important insect pests.
Fig. 1 Metabolic networks in xylem feeding insects.
Disclosure of interest The author declares that she has no
competing interest.
Further reading
N.Y.D. Ankrah, B. Chouaia, A.E. Douglas, The cost of metabolic
interactions in symbioses between insects and bacteria with
reduced genomes. mBio 9 (2018) e01433-18.
N.Y.D. Ankrah, A.E. Douglas, Nutrient factories: metabolic func-
tion of beneficial microorganisms associated with insects.
Environ. Microbiol. 20 (2018) 2002–2011.
A.E. Douglas, The multi-organismal insect: diversity and func-
tion of resident microorganisms, Annu. Rev. Entomol. 60 (2015)
17–34.
https://doi.org/10.1016/j.crvi.2019.09.014
Session IV. Interaction with other organisms
14
The insect reservoir of diversity
for viruses and antiviral
mechanisms
Jean-Luc Imler
Unité “Modèles insectes d’immunité innée” (M3i), Institut de
biologie moléculaire et cellulaire du CNRS, Université de
Strasbourg, France
E-mail address: jl.imler@ibmc-cnrs.unistra.fr
Insects originated more than 400 million years ago and have
undergone since then an extraordinary diversification, asso-
ciated with many spectacular innovations, such as flying or
establishment of social societies. They have colonized all ter-
restrial ecosystems, and are exposed to a broad range of
pathogens, including viruses, bacteria, fungi, and parasites. Like
all animals, insects rely on innate immunity to control infec-
tions. Innate immunity is the first layer in host-defense in
animals. It involves receptors sensing the presence of infec-
tious microorganisms and triggering signaling that leads to the
expression of genes coding effector molecules, which concur to
counter the infection. In vertebrates, a subset of genes induced
encode cytokines and coreceptors that activate a second layer


Microbial nutrient factories in insects on extreme diets

Kris Wyckhuys

262 Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278
Drosophila C Virus (DCV) and Cricket Paralysis Virus (CrPV)
in Drosophila. By contrast, the other components of the path-
way, including the regulatory subunit of the IKK kinase,
NEMO, do not appear to play a role in the resistance to infec-
tion by these viruses. Among the genes regulated by IKK
in virus-infected flies, we identified two genes involved in
the resistance to viral infection. The first one is the homo-
logue of the mammalian factor STING (Stimulator of Interferon
Genes), and we could show that it acts upstream of IKK and
Relish in a new signaling pathway (Fig. 2). The second one
encodes a new antiviral factor, that we called Nazo (meaning
“enigma” in Japanese) [3]. The STING-IKK -Relish signaling
cassette controls inducible expression of Nazo in response to
viral infection. Nazo results from a duplication of the gene
CG3740 in Drosophila species from the Sophophora subgenus. Of
note, CG3740 is not upregulated by viral infection, and ectopic
expression of the gene has no effect on replication of DCV or
CrPV, unlike expression of Nazo, which results in strong sup-
pression of viral replication. The discovery of Nazo provides
an excellent opportunity to decipher the genetics by which a
cellular gene acquires a new function in antiviral immunity.
Furthermore, the characterization of its mode of action against
picorna-like viruses may reveal novel angles of attack against a
family of viruses that include many serious human pathogens
(e.g., poliovirus).
In summary, the fantastic diversity of insects extends to the
viruses they carry, and to the genetic mechanisms they evolved
to control these viruses. This biodiversity provides a unique
opportunity to extend the repertoire of known antiviral mech-
anisms and to identify weak spots in the replication cycles of
viruses.
Disclosure of interest The author declares that he has no com-
peting interest.
References
[1] M. Shi, et al., Redefining the invertebrate RNA virosphere,
Nature 540 (2016) 539–543.
[2] E.R. Aguiar, et al., Sequence-independent characterization
of viruses based on the pattern of viral small RNAs produced
by the host, Nucl. Acids Res. 43 (2015) 6191–6206.
[3] A. Goto, et al., The kinase IKK regulates a STING- and NF-
 B- dependent antiviral response pathway in Drosophila,
Immunity 49 (2018) 225–234.
https://doi.org/10.1016/j.crvi.2019.09.015
15
Cassava mealybug biological
control delivers multi-faceted
societal benefits
Kris Wyckhuys
China Academy of Agricultural Sciences, China
E-mail address: kagwyckhuys@gmail.com
As core component of sustainable intensification, biological
control constitutes a tailor-made solution for the long-term
management of both endemic and invasive pests. Here, draw-
ing upon the example of the cassava mealybug (Phenacoccus
manihoti; Hemiptera), we illuminate the myriad benefits of
insect biological control.
In 2008, the above mealybug invaded Asia, where it inflicted
a 27% drop in aggregate cassava production and triggered
a 260% surge in starch prices. Mealybug-induced shocks in
Thailand’s cassava output were offset by a 300,000-ha expan-
sion of the agricultural frontier–accompanied with major
loss of intact tropical forest. Mealybug outbreaks were per-
manently resolved through the release of the neotropical
wasp Anagyrus lopezi (Hymenoptera). This minute parasitoid
effectively suppressed P. manihoti at a continent-wide scale,
restored food security, and delivered pest control services
worth US$ 200–700/ha. This same parasitic wasp had pre-
viously averted famine for ∼ 20 million people in Africa.
Our work emphasizes how beneficial (pest-controlling) insects
help meet food production needs while benefiting farmers’
pockets, global commodity trade, and the environment.
Disclosure of interest The author declares that he has no com-
peting interest.
Further reading
K.A. Wyckhuys, W. Zhang, S.D. Prager, D.B. Kramer, E. Delaquis,
C.E. Gonzalez, W. Van der Werf, Biological control of an invasive
pest eases pressures on global commodity markets, Environ.
Res. Lett. 13(9) (2018) 094005.
K.A.G. Wyckhuys, A.C. Hughes, C. Buamas, A.C. Johnson,
L. Vasseur, L. Reymondin, J.-P. Deguine, D. Sheil, Biologi-
cal control of an agricultural pest protects tropical forests,
Commun. Biol. 2 (2018); https://doi.org/10.1038/s42003-
018-0257-6.
K.A. Wyckhuys, P. Wongtiem, A. Rauf, A. Thancharoen, G.E.
Heimpel, N.T. Le, M.Z. Fanani, G.M. Gurr, J.G. Lundgren, D.D.
Burra, L.K. Palao, Continental-scale suppression of an invasive
pest by a host-specific parasitoid underlines both environ-
mental and economic benefits of arthropod biological control.
PeerJ., 6 (2018) e5796.
https://doi.org/10.1016/j.crvi.2019.09.016
16
Insects and their microbial
partners: The Drosophila case
study
François Leulier
Institute de génomique fonctionnelle de Lyon, École normale
supérieure de Lyon, University of Lyon, France
E-mail address: francois.leulier@ens-lyon.fr
Metazoans establish reciprocal interactions with their com-
mensal bacterial communities. Despite recent progress, a
clear view of the physiological benefits associated with
host/microbiota relationship remains elusive. Hence the
molecular mechanisms through which the microbiota exerts its
beneficial influences are still largely undefined. In this line, we
aim at deciphering the molecular dialogue governing the mutu-
alistic interaction between intestinal bacteria and their host. To
Fig. 1 Lactobacillus plantarum (associated with blue food and
feces) colonizes the host intestine (in both adults and larvae)
and is transmitted vertically to progenies (note the contami-
nation of an egg being laid) and promotes larval growth (note
the size difference of L. plantarum associated individuals (lar-
vae with blue intestine) vs. non colonized larvae (no blue in
the intestine) when grown for six days on a low nutrient diet).
© François Leulier.
Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278 263
this end, we are using a genetically tractable gnotobiotic ani-
mal model: Drosophila melanogaster, which is mono-associated
with one of its natural dominant commensal, Lactobacillus
plantarum (Fig. 1). We are developing multiscale functional
approaches to identify the mechanisms that underlie their
mutualistic relationship, which results in the promotion of host
juvenile growth upon chronic undernutrition. Our approaches
aim at identifying both the bacterial and host genetic networks
required to sustain their mutualistic relationship.
Disclosure of interest The author declares that he has no com-
peting interest.
Further reading
M.E. Martino, P. Joncour, R. Leenay, H. Gervais, M. Shah, S.
Hughes, B. Gillet, C. Beisel, F. Leulier, Bacterial Adaptation to
the Host’s Diet Is a Key Evolutionary Force Shaping Drosophila-
Lactobacillus Symbiosis. Cell Host Microbe 24. Published online
28 June 2018, 10.1016/j.chom.2018.06.001.
G. Storelli, M. Strigini, T. Grenier, L. Bozonnet, M. Schwarzer,
C. Daniel, R. Matos, F. Leulier, Drosophila Perpetuates Nutri-
tional Mutualism by Promoting the Fitness of Its Intestinal
Symbiont Lactobacillus plantarum, Cell Metab. (2017), doi:
10.1016/j.cmet.2017.11.011.
R.C. Matos, M. Schwarzer, H. Gervais, P. Courtin, P. Joncour,
B. Gillet, D. Ma, A.L. Bulteau, M.E. Martino, S. Hughes, M.P.
Chapot-Chartier, F. Leulier, d-Alanylation of teichoic acids
contributes to Lactobacillus plantarum-mediated Drosophila
growth during chronic undernutrition, Nat. Microbiol. (2017),
doi: 10.1038/s41564-017-0038-x.
https://doi.org/10.1016/j.crvi.2019.09.017
17
What five insects told us about
how a native plant copes with
real-world problems
Ian Thomas Baldwin
Max Planck Institute for Chemical Ecology, Jena, Germany
E-mail address: baldwin@ice.mpg.de
Five native insects have taught us about traits that are essential
for the survival of a native tobacco plant, Nicotiana attenu-
ata, which lives in the Great Basin Desert of the USA. The
five insects come from different feeding guilds, attack different
tissues at different developmental stages and have revealed dif-
ferent traits that are essential for plant survival. For example,
this plant recognizes attack from a specialized Lepidopteran
herbivore (Manduca sexta) by the particular chemistry of the
herbivore’s saliva, and uses this recognition to tailor a compli-
cated 6-layered defense response that involves a remodeling of
the plant’s transcriptome, metabolome and proteome, as well
as some of its life history traits. The plant traits revealed by the
remaining four insects will be described below, and how these
insects will be used as high-through-put (HTP) screeners of
large plantations of transformed and recombinant inbred lines
of this native plant, to reveal the function of genes required for
survival in nature. Insects are some of the best plant biologists
on our planet and it behooves plant biologists to rediscover the
lost art of natural history discovery to take advantage of the
unique skill-sets of insects.
The plant and its insect herbivore community
Nicotiana attenuata (coyote tobacco: Solanales: Solanaceae) is
a diploid tobacco native to the Great Basin Desert of North
America. It enjoys a unique position scientifically, because hun-
dreds of transgenic lines have been studied over the past two
decades to understand the fitness consequences of precisely
defined changes in gene expression for plants growing in their
native habitats. For more than 30 years, the plant has been an
ecological model system to study the complex plant-mediated
interactions that occur in nature and to elucidate the genetic
basis of traits important for the Darwinian fitness of plants.
The choice of this diploid, largely selfing plant as a model sys-
tem is grounded in its natural history and unusual germination
behavior. Dormant seeds, survivors of decades or even cen-
turies of microbial challenges in soil, germinate synchronously
into the nitrogen-rich, competition-free environments that are
commonly found after fires. Dense N. attenuata populations
then develop, in which plants are exposed not only to intense
conspecific competition, but also to attack from as many as
34 different herbivore and pathogen taxa that colonize these
post-fire populations from adjacent unburned areas.
These are the ecological conditions in which agriculture
started, as slash-and-burn agriculture, and are the conditions
that all our crops face. However, most crop taxa have not origi-
nated from post-fire adapted native species and are unlikely to
be pre-adapted to the conditions of the agricultural niche. By
understanding the specific traits that this native tobacco plant
has evolved to optimize its fitness in the post-fire environment
in which it times its germination and growth from long-lived
seedbanks, we hope to learn what will be required to make our
crop plants more self-sufficient, less dependent on agricultural
inputs.
Nicotiana attenuata hosts a diverse insect herbivore community
that includes several specialists on the Solanaceae: Corime-
laena extensa (Hemiptera: Thyreocoridae), Epitrix hirtipennis,
and E. subcrintia (Coleoptera: Chrysomelidae), two sympatric
sibling species of Trichobaris, T. compacta, and T. mucorea
(Coleoptera: Curculionidae), Tupiocoris notatus, (Hemiptera:
Miridae), Manduca quinquemaculata, and M. sexta (Lepidoptera:
Sphingidae) as well as the generalist herbivores Spodoptera
spp. (Lepidoptera: Noctuidae), Trimerotropis spp. (Orthoptera:
Acrididae), and Oecanthus spp. tree crickets (Orthoptera: Grylli-
dae) and the opportunistic generalist herbivores Empoasca spp.
(Hemiptera: Cicadellidae) and Heliothis spp. (Lepidoptera: Noc-
tuidae). Geocoris pallens is a common predator of herbivores on
N. attenuata.
Five of these insects (four herbivores and one predator) have
proven to be very useful in eliciting and responding to plant
traits, characteristics that make them very useful as High-
Through-Put (HTP) screeners and sentinel insects for large
forward-genetic Recombinant Inbred Line (RIL) populations
that will be described after these five insects are introduced.
The herbivores: Manduca, Empoasca, Tupiochorus, and Tri-
chobarus spp
Manduca spp. The tobacco and tomato hornworms (M. sexta
and M. quinquemaculata) have evolved an unprecedented
capacity to detoxify the signature defense metabolite of the
genus, Nicotiana, namely: nicotine. These nicotine-adapted
larvae excrete the vast majority of the nicotine that they ingest
with their food, but also co-opt a small fraction of the ingested
nicotine for their own defense [1]. M. sexta larvae are found
on N. attenuata plants because the adult moths oviposit while
nectaring on the flowers. Hence, this insect plays dual roles in
the lives of N. attenuata plants, as a devastating herbivore dur-
ing the larval stages and as an important pollinator as an adult,
vectoring gametes among the spatially separated plant popu-
lations that occur after fires, likely adding important genetic
diversity to the seeds that must survive the decades of dor-
mancy in the seed banks. Attack from these nicotine-adapted
larvae is specifically recognized by the plant, when fatty acid
amino acid conjugates (FACs) in the larval oral secretions
are introduced into wounds when the larvae feed. This FAC-
mediated recognition by the plant results in a six-layered suite
of defense, avoidance, and tolerance responses (summarized
in an iBiology talk available at https://www.ibiology.org/
plant-biology/studying-plants-ecological-interactions-
genomics-era-story-nicotiana-attenuata/#part-2), which
engages all aspects of the plant’s physiology. As such, Manduca
larvae are ideal elicitors of ecologically important plant phe-
notypes and these phenotypes can be elicited by introducing
larval oral secretions into plant wounds, a treatment that
can be readily accomplished in a HTP manner for the large
numbers of plants in a MAGIC population.
Empoasca spp. These piercing-sucking leafhoppers “eavesdrop”
on the jasmonate (JA)-mediated signaling capacities of their
host plants, preferentially selecting those hosts that are defi-
cient in jasmonate accumulations [2]. Given that JA signaling
mediates the vast majority of plant defenses, it is particularly
intriguing that this natural phenotyping “bloodhound” specif-


Cassava mealybug biological control delivers multi-faceted societal benefits

Rosaria Scudiero

Mariailaria Verderame

Chiara Maria Motta

Vincenzo Migliaccio

Palma Simoniello

HSP70 localization in Podarcis siculus embryos under natural thermal regime and following a non-lethal cold shock

Mouna Lamaoui

Abdelghani Chakhchar

Raja Benlaouane

Youssef El Kharrassi

Mohamed Farissi

Said Wahbi

Cherkaoui El Modafar

Uprising the antioxidant power of Argania spinosa L. callus through abiotic elicitation

Nadia Hanniche

Ouanassa Saadi-Brenkia

Anna Maciejewski-Duval

Saida Lounis

Abdelkader Bougrid

Mounira Bendjelloul

Structural study and expression of the androgen receptors during the reproductive cycle in the Harderian gland of the male Meriones libycus

François Leulier

Insects and their microbial partners: The Drosophila case study

Olivier Dangles

Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278 267
Un dernier aspect concerne le venin des parasitoïdes et le
potentiel d’évolution de la composition de ce venin en fonction
de paramètres abiotiques (température) ou biotique (résis-
tance de l’hôte, espèce ou souche hôte). Ainsi, un protocole
d’évolution expérimentale a été utilisé comme résumé ci-
dessous pour tester l’influence de la souche et espèce hôte
sur l’évolution de composition du venin. Deux souches de
L. boulardi différant par leur virulence et leur venin ont été
croisées dans les deux sens pour produire une F1 puis une
descendance F2, qui a ensuite été élevée en différents réplicas
et parallèlement sur des souches de D. melanogaster, D. yakuba
et D. simulans. L’expérience a été analysée en F3, F7 et F11 en
étudiant le taux de virulence du parasitoïde (réussite) et la
composition du venin. La méthode utilisée pour cette dernière
analyse a été développée et publiée en 2015 (Mathé-Hubert
et al., Mol. Ecol. Res.). Elle s’appuie sur la migration individu-
elle du venin et l’analyse des gels obtenus avec une méthode
semi-automatique à l’aide de Phoretix 1D. Elle permet d’obtenir
des bandes de référence calibrées et de produire un jeu de
données donnant l’intensité de chaque bande pour chaque indi-
vidu, cette intensité étant corrélée à la quantité de protéines.
Les résultats montrent une rapide augmentation de la viru-
lence du parasitoïde sur l’hôte de sélection et de la composition
du venin selon l’hôte et la génération. Trois à quatre généra-
tions suffisent pour observer des changements significatifs.
Les données suggèrent aussi un trade-off pour la virulence et
la composition du venin entre D. melanogaster et D. yakuba
(un changement dans un sens sur une espèce est corrélé à un
changement dans l’autre sens sur l’autre espèce). Enfin, il est
possible d’identifier les bandes dont le changement d’intensité
est responsable de l’évolution du venin sur un hôte donné.
On voit ainsi que toutes les bandes dont l’intensité a changé
sur D. yakuba sont spécifiques de cette espèce, montrant que
les protéines sélectionnées le sont également. En synthèse,
le venin évolue rapidement en fonction de l’hôte. En termes
de lutte biologique, des parasitoïdes locaux pourraient ainsi
s’adapter à un nouvel hôte invasif. Par ailleurs, l’élevage de par-
asitoïdes pour cibler un hôte donné se fait parfois sur un hôte
alternatif, ce qui peut induire une adaptation à cet hôte et un
échec ensuite sur l’hôte ciblé. En tous les cas, l’étude du venin
devrait permettre d’identifier les souches les plus efficaces et
de mener des contrôles qualité avant lâchers sur le terrain.
Déclaration de liens d’intérêts L’auteure déclare qu’elle n’a
pas de liens d’intérêts.
Pour en savoir plus
C. Kim-Jo, J.-L. Gatti, M. Poirié, Drosophila cellular immunity
against parasitoid wasps: a complex and time-dependent
process, Front. Invert. Physiol. 10 (2019) 603, doi:
10.3389/fphys.2019.00603.
A. Lacovone, N. Ris, M. Poirié, J.-L. Gatti, Time-course anal-
ysis of Drosophila suzukii interaction with endoparasitoid
wasps evidences a delayed encapsulation response compared
to D. melanogaster PLoS One 13(8) (2018) e0201573, doi:
10.1371/journal.pone.0201573.B. Wan, E. Goguet, M. Raval-
lec, O. Pierre, S. Lemauf, A-N. Volkoff, J.-L. Gatti, M. Poirié,
Venom atypical extracellular vesicles as interspecies vehicles
of virulence factors involved in host specificity: the case of a
Drosophila parasitoid wasp, Front. Immunol. 2019 (2019); doi:
10.3389/fimmu.2019.01688.
H. Mathé-Hubert, J.-L. Gatti, D. Colinet, M. Poirié, T. Malausa,
Statistical analysis of the individual variability of 1D pro-
tein profiles as a tool in ecology: an application to parasitoid
venom, Mol. Ecol. Res. 15(5) (2015) 1120-1132, 10.1111/1755-
0998.12389.
https://doi.org/10.1016/j.crvi.2019.09.019
19
When a bacterium fights
arboviruses
Luciano A. Moreira
Fiocruz Institute, Belo Horizonte, Brazil
E-mail address: luciano.andrade@fiocruz.br
Arboviruses or arthropod-borne viruses, such as dengue, Zika
and chikungunya represent a huge burden for tropical and sub-
tropical human populations. It has been estimated that, every
year, 390 million new cases of arboviruses occur in 128 coun-
tries and 3.9 billion people are at risk.
Vector control strategies are based on mechanical destruc-
tion of mosquito breeding sites and application of insecticides,
which, due to continuous and massive usage of different chem-
icals, have been contributing to the development of insect
resistance in many countries. Based on this complex scenario,
novel and sustainable strategies are urgently needed, which
can be used in an integrated control program by the gov-
ernments of affected countries. Biological control strategies,
involving mosquito pathogenic or pathogen-interfering orga-
nisms such as fungus or bacteria are possible, environmentally
friendly, candidates.
Wolbachia is an intracellular bacterium present in more than
60% of all insect species, worldwide. It manipulates the repro-
duction of insects, in order to be successfully maintained in
the system, through a mechanism called cytoplasmic incom-
patibility, or CI. When Wolbachia-infected males mate with
uninfected females, no progeny is produced. On the other hand,
females can mate with either infected or uninfected males and
will produce eggs, most frequently, 100% Wolbachia-infected,
the so-called, vertical transmission (Fig. 1). This mechanism,
among others caused by Wolbachia, promotes reproduction
advantage towards infected insects. Although present in sev-
eral mosquito species, the bacterium was never found in Aedes
aegypti, the main vector for dengue, Zika, and chikungunya,
worldwide. In the laboratory, back in 2005 in Australia, WMP
researchers were able to introduce a specific strain of this bac-
terium, into Aedes aegypti embryos, after having isolated it
from the fruit fly, Drosophila melanogaster. After this successful
transinfection, it has been discovered that, when the bacterium
is present in the mosquito, viruses do not replicate well, there-
fore reducing their transmission ability. This strategy does not
involve any kind of genetic modification.
An example of translational research
The World Mosquito Program (WMP) is a not-for-profit initia-
tive, working to protect the human population from mosquito-
borne diseases. WMP proposes an innovative method of
releasing Aedes aegypti mosquitoes into the environment with
Fig. 1 Representation of crosses between Wolbachia-infected
and uninfected mosquitoes, showing the mechanism of cyto-
plasmic incompatibility: when infected males mate with
uninfected counterparts, they produce no progeny.
268 Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278
the Wolbachia microorganism, which reduces the ability of the
mosquito to transmit dengue, Zika, and chikungunya. The Wol-
bachia method is safe, natural, and self-sustaining, and has the
potential to achieve significant public health impact in areas
endemic to these viruses.
WMP was formerly known as “Eliminate Dengue: Our Chal-
lenge.” The name has been changed due to rapid global program
expansion and also to reflect that the method works against
several diseases, not just dengue. WMP is active in 12 countries:
Australia, Vietnam, Indonesia, Pacific Islands (Fiji, Vanuatu,
Kiribati, New Caledonia), India, Sri Lanka, Colombia, Mexico,
and Brazil, and discussions are at an advanced stage with sev-
eral others. In Brazil, it has been conducted since 2012 by the
Fundação Oswaldo Cruz (Fiocruz), based in Rio de Janeiro.
The aim of WMP is to perform controlled releases of Aedes
aegypti containing Wolbachia, so there will be a gradient
substitution of local the Aedes aegypti population by Aedes
aegypti with Wolbachia. This is possible, through both the CI
mechanism and the vertical transmission, guaranteeing the
self-sustainability of the method.
Steps of Wolbachia Method
To achieve the goal of substitution of the local population of
Aedes aegypti with Aedes aegypti with Wolbachia, the actions of
WMP are divided into three main stages. (i) In the Community
Engagement phase, project teams interact with the population
and institutions (health clinics, schools, community leaders) for
disseminating information about the initiative. At this stage,
surveys are conducted to measure understanding and accep-
tance of the local population about the method. In addition,
a Community Reference Group is set up, a local committee
who monitors all actions taken in the locality, and communi-
cation channels are established with the community, including
telephone, e-mail, face-to-face interactions, and social media.
(ii) After the Community Engagement phase and community
approval begins the release of Aedes aegypti mosquitoes with
Wolbachia. Mosquitoes are bred in the Fiocruz insectary, which
has similar humidity and temperature characteristics as those
that mosquitoes encounter in the external environment. Adult
releases happen in the early hours of the morning and are
made by car. In some regions, this work is done on foot, by
health surveillance agents and community health agents of
the municipal governments of Rio de Janeiro and Niterói. (iii)
Monitoring of the Aedes aegypti population in these areas ini-
tiate during mosquito releases. Traps are installed in homes or
commercial establishments that voluntarily provide a location
for the traps. Weekly, technicians go to these sites to collect
mosquitoes. At the project facilities, the captured mosquitoes
are separated, identified and the Aedes aegypti are sent to the
Diagnostic Laboratory, where they are checked individually.
This analysis aims to identify the DNA of Wolbachia bacteria in
the mosquito organism and is an indicator of the establishment
of the local mosquito population with Wolbachia.
Large-scale expansion
WMP began preparative studies in Brazil in 2012 and ethical
and regulatory approvals. In 2014, releases began in the pilot
areas, Jurujuba, in Niterói-RJ, and Tubiacanga, in the city of
Rio de Janeiro. The last releases of mosquitoes at these sites
were carried out in January 2016, and since then monitoring
has revealed Wolbachia’s establishment of more than 90%. In
November 2016, large-scale expansion began for 28 neighbor-
hoods in Niterói, to protect 270,000 people.
In Rio de Janeiro, large-scale releases began in August 2017,
with the plan of reaching 19 neighborhoods, where 0.9 mil-
lion people live. Concomitantly with community engagement,
mosquito release and monitoring activities, an epidemiological
study is underway to measure the impact of our work in reduc-
ing disease transmission. Preliminary results show already a
reduction on the incidence of dengue, Zika, and chikungunya
in areas where Wolbachia is present.
Through a partnership with the city of Belo Horizonte, WMP
Brazil will start activities in an pilot area with 60,000 inhabi-
tants, probably in late 2019.
Regulatory and ethical approvals
For pilot projects, regulatory and ethical approvals were
granted in 2014. The Temporary Special Registry (Registro
Especial Temporário–RET–, in Portuguese) was granted after
evaluating the project simultaneously by three governmen-
tal areas: National Agency of Sanitary Surveillance–ANVISA–,
Ministry of Agriculture, Livestock and Supply–MAPA–, and
the Brazilian Institute of Environment and Renewable Natural
Resources–IBAMA. Ethical approval was also granted in early
2014, following a thorough evaluation by the National Commis-
sion for Research Ethics (CONEP). For the large-scale expansion,
all the regulatory documents have been renewed.
In February 2016, the Ministry of Health recommended the
Wolbachia method as promising in vector control in response
to Zika’s national emergency. This recommendation was rein-
forced in March of that year by the World Health Organization
(WHO) through its Vector Control Advisory Group (VCAG).
Funding
The project has been historically financed in Brazil by the
Ministry of Health, with an in-kind contribution from Fiocruz
and, internationally, by the Bill and Melinda Gates Foundation,
through Monash University, Australia. The municipalities of Rio
de Janeiro and Niterói provided an important contribution with
local infrastructure and human resources.
Disclosure of interest The author declares that he has no com-
peting interest.
Further reading
L.A. Moreira, I. Iturbe-Ormaetxe, J.A. Jeffery, G. Lu, A.T. Pyke,
L.M. Hedges, B.C. Rocha, S. Hall-Mendelin, A. Day, M. Riegler, L.E.
Hugo, K.N. Johnson, B.H. Kay, E.A. McGraw, A.F. van den Hurk,
P.A. Ryan, S.L O’Neill, A Wolbachia symbiont in Aedes aegypti
limits infection with dengue, Chikungunya, and Plasmodium,
Cell 139(7) (2009) 1268–1278.
H.L. Dutra, M.N. Rocha, F.B. Dias, S.B. Mansur, E.P. Caragata, L.A.
Moreira. Wolbachia Blocks Currently Circulating Zika Virus Iso-
lates in Brazilian Aedes aegypti Mosquitoes, Cell Host Microbe.
19(6) (2016) 771–774.
S.L. O’Neill, The Use of Wolbachia by the World Mosquito Pro-
gram to Interrupt Transmission of Aedes aegypti Transmitted
Viruses, Adv. Exp. Med. Biol. 1062 (2018) 355–360.
https://doi.org/10.1016/j.crvi.2019.09.020
20
Ecosystem services provided by
insects for achieving sustainable
developmental goals
Olivier Dangles
Département “Écologie, biodiversité et fonctionnement des
écosystèmes continentaux” (ECOBIO), Montpellier, France
E-mail address: olivier.dangles@ird.fr
Ecosystem services underpin all dimensions of human well-
being. As a consequence, it is crucial to integrate ecosystem
services into strategies for achieving Sustainable Develop-
ment Goals (SDGs). Because insects and other invertebrates
have profound and well-identified influences on many ecosys-
tems services (e.g., pollination and biological control) and
SDGs (e.g., crop pest and disease vectors), insect research and
development have a great potential to address current global
challenges. We argue that time is ripe to put more efforts in
developing integrated research on the ecosystem services pro-
vided by insects, as they may result in solutions to achieve
many SDGs. We provide evidence of insects’ utility to address
global challenges and propose a framework of the needed shift
in the perception of insects from enemies to allies, providers of
ecosystem services, and then to solutions to achieve SDGs. We
further advocate that making a place for SDG-relevant research
on insects’ ecosystem services requires transforming existing
academic knowledge into application-driven science, a poten-
tial upscaling of local solutions and socio-economic relevance.
Disclosure of interest The author declares that he has no com-
peting interest.
https://doi.org/10.1016/j.crvi.2019.09.021


Ecosystem services provided by insects for achieving sustainable developmental goals

Anna-Bella Failloux

Insects: Friends, foes, and models/Insectes : amis, ennemis et modèles / C. R. Biologies 342 (2020) 247–278 269
Session V. Vector insects and transmission
of diseases
21
Do we have to get rid of
mosquitoes to eliminate
malaria?
Markus Gildenhardt , Elena Levashina ∗
Vector Biology Unit, Max Planck Institute for Infection Biology,
Berlin, Germany
∗ Corresponding author.
E-mail address: levashina@mpiib-berlin.mpg.de
(E. Levashina)
Malaria is a local disease with global impact. The fitness of
vector-borne Plasmodium parasites, the causative agents of
malaria, is closely linked to the ecology and evolution of its
mosquito vector. Ongoing adaptive radiation and introgression
diversify mosquito populations in Africa. However, whether
the genetic structure of vector populations impacts malaria
transmission remains unknown.
We discuss below new approaches that gauge the contribution
of mosquito species to Plasmodium abundance in nature, with a
particular focus on time-series analyses in the context of popu-
lation genetics and epidemiology [1]. Our data highlighted the
importance of focusing vector control strategies on mosquito
species that drive malaria dynamics.
Using time-series collections and the econometric approach
Granger causality, we demonstrated that the abundance of
Plasmodium-infected mosquitoes in a field site in Mali was
driven by only one of the two sympatric vectors (Fig. 1). This
mosquito species carried a susceptible allele of the known
antiparasitic gene TEP1 [2,3], and until now it was resistant to
colonization efforts and, therefore, is not the target of current
gene drive applications.
Extending such studies to other key components of vecto-
rial capacity and epidemiological and parasitological surveys
should ultimately identify patterns, tipping points, and gen-
eral laws that describe dynamics, emergence, and resurgence
of mosquito-borne diseases.
Fig. 1 Granger causality.
Disclosure of interest The authors declare that they have no
competing interest.
References
[1] M. Gildenhard, E.K. Rono, A. Diarra, et al., Mosquito
microevolution drives Plasmodium falciparum dynamics,
Nat. Microbiol. 4 (6) (2018) 941–947.
[2] S. Blandin, S.-H. Shiao, L.F. Moita, C.J. Janse, A.P. Waters, F.C.
Kafatos, et al., Complement-like protein TEP1 is a determi-
nant of vectorial capacity in the malaria vector Anopheles
gambiae, Cell 116 (2004) 661–670.
[3] S.A. Blandin, R. Wang-Sattler, M. Lamacchia, J. Gagneur, G.
Lycett, Y. Ning, et al., Dissecting the genetic basis of resis-
tance to malaria parasites in Anopheles gambiae, Science 326
(2009) 147–150.
https://doi.org/10.1016/j.crvi.2019.09.022
22
Human activities and climate
change in the emergence of
vector-borne diseases
Anna-Bella Failloux
Arboviruses and Insect Vectors Laboratory, Department of
Virology, Institut Pasteur, Paris, France
E-mail address: anna-bella.failloux@pasteur.fr
Because of human population expansion and activities,
arthropod-borne viruses (arboviruses) have increased in
importance during these last decades. Arboviruses are main-
tained by alternate replication in both vertebrate hosts and
arthropod vectors. Successful transmission relies on a complex
life cycle in the vector, which starts when a competent arthro-
pod ingests an infectious blood meal from a viremic vertebrate
host. Following an extrinsic incubation time during which the
virus replicates in the vector midgut, followed by systemic viral
dissemination to the salivary glands, the vector can transmit
the virus to a new naïve host. Whereas they typically cause self-
limiting, acute infections in their vertebrate hosts, arboviruses
establish persistent infections in their vectors.
Arboviruses are typically maintained within an enzootic cycle
between wild animals and vectors. As human populations
encroach on regions where these diseases are endemic,
spillover transmission to humans and domestic animals can
lead to large-scale disease outbreaks affecting millions of peo-
ple. Dengue, chikungunya, Zika, and yellow fever mainly use
humans as amplification hosts. Extensive urbanization com-
bined with increased commerce and travel give rise to the
mosquitoes Aedes aegypti and Aedes albopictus, both highly
adapted to the human environment. The high densities of these
human-biting mosquitoes that proliferate in highly populated
cities made the bed to explosive outbreaks of arboviral dis-
eases. As insects are ectothermic organisms, climate change
may affect the geographical distribution of vectors, with con-
sequences on the transmission of arboviruses.
Yellow fever (YF) is a good example of an emerging arbovirus,
as it illustrates three main steps in the emergence: (i) introduc-
tion of a new pathogen in a new environment causing urban
outbreaks, (ii) spillback of this pathogen into the wild initiating
an enzootic cycle, and (iii) the spillover of this pathogen from
an enzootic cycle to initiate an urban cycle (Fig. 1).
YF (YFV, Flavivirus, Flaviviridae) is a disease endemic to tropical
regions of Africa and South America. There are seven lineages:
five in Africa and two in America. Each year, 200,000 cases and
30,000 deaths were reported. In 2016, YFV emerged in Angola
and imported cases were detected outside Africa, posing the
threat of emergence of this virus outside Africa and Americas
(Amraoui et al. Euro Surveill 2016).
YFV was introduced into the New World during the slave trade,
causing devastating outbreaks in several American countries,
including cities like New York City and Boston. Once Carlos
Finlay and Walter Reed had demonstrated that the YFV was
transmitted by a mosquito, Ae. aegypti, eradication campaigns
of the vector were initiated, leading to the control of YF.
In Brazil, Ae. aegypti was eradicated in 1954. YF disappeared
from cities and only persisted in a sylvatic cycle where YFV
circulated between zoophilic mosquitoes (Hemagogus and
Sabethes) and non-human primates. Using experimental infec-
tions, we showed that the zoophilic mosquitoes (Hemagogus
leucocelaenus and Sabethes albiprivus) were able to transmit
YFV at very high rates (Couto-Lima et al. Sci Rep 2017). With
the relaxation of control measures in Brazil, Ae. aegypti was
reintroduced in 1967 and Ae. albopictus in 1986. We showed
that Ae. aegypti and Ae. albopictus were highly susceptible to
YFV. We also demonstrated that using a protocol of experi-


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