91 research outputs found
Acoustic communication in insect disease vectors
No full textAcoustic signalling has been extensively studied in insect species, which has led to a better understanding of sexual communication, sexual selection and modes of speciation. The significance of acoustic signals for a blood-sucking insect was first reported in the XIX century by Christopher Johnston, studying the hearing organs of mosquitoes, but has received relatively little attention in other disease vectors until recently. Acoustic signals are often associated with mating behaviour and sexual selection and changes in signalling can lead to rapid evolutionary divergence and may ultimately contribute to the process of speciation. Songs can also have implications for the success of novel methods of disease control such as determining the mating competitiveness of modified insects used for mass-release control programs. Species-specific sound "signatures" may help identify incipient species within species complexes that may be of epidemiological significance, e. g. of higher vectorial capacity, thereby enabling the application of more focussed control measures to optimise the reduction of pathogen transmission. Although the study of acoustic communication in insect vectors has been relatively limited, this review of research demonstrates their value as models for understanding both the functional and evolutionary significance of acoustic communication in insects.Peer reviewe
Acoustic signals in the sand fly <it>Lutzomyia (Nyssomyia) intermedia </it>(Diptera: Psychodidae)
No full textAbstract Background Acoustic signals are part of the courtship of many insects and they often act as species-specific signals that are important in the reproductive isolation of closely related species. Here we report the courtship songs of the sand fly Lutzomyia (Nyssomyia) intermedia, one of the main vectors of cutaneous leishmaniasis in Brazil. Findings Recordings were performed using insects from three localities from Eastern Brazil: Posse and Jacarepaguá in Rio de Janeiro State and Corte de Pedra in Bahia State. The three areas have remnants of the Brazilian Atlantic forest, they are endemic for cutaneous leishmaniasis and L. intermedia is the predominant sand fly species. We observed that during courtship L. intermedia males from all populations produced pulse songs consisting of short trains. No significant differences in song parameters were observed between the males of the three localities. Conclusions L. intermedia males produce acoustic signals as reported for some other sand flies such as the sibling species of the Lutzomyia longipalpis complex. The lack of differences between the males from the three localities is consistent with previous molecular studies of the period gene carried out in the same populations, reinforcing the idea that L. intermedia is not a species complex in the studied areas and that the three populations are likely to have similar vectorial capacities.</p
Copulatory courtship song in Lutzomyia migonei (Diptera: Psychodidae)
No full textLutzomyia migonei is a vector of leishmaniasis with a wide distribution in South America, which could favour population differentiation and speciation. Cryptic species of the Lutzomyia longipalpis complex, the widely distributed sand fly vector of visceral leishmaniasis in Latin America, have previously been shown to display distinct copulation songs. We found that Lu. migonei males also produce a song during copulation. This "lovesong" presents short trains (6-8 pulses) with an inter-pulse interval around 26 ms and is potentially involved in cryptic female choice and insemination success
Copulatory courtship song in Lutzomyia migonei (Diptera: Psychodidae)
No full textLutzomyia migonei is a vector of leishmaniasis with a wide
distribution in South America, which could favour population
differentiation and speciation. Cryptic species of the Lutzomyia
longipalpis complex, the widely dis- tributed sand f ly vector of
visceral leishmaniasis in Latin America, have previously been shown to
display distinct copulation songs. We found that Lu. migonei males also
produce a song during copulation. This “lovesong” pres-
ents short trains (6-8 pulses) with an inter-pulse interval around 26
ms and is potentially involved in cryptic female choice and
insemination success
Acoustic signals in the sand fly Lutzomyia (Nyssomyia) intermedia (Diptera: Psychodidae)
No full textBackground: Acoustic signals are part of the courtship of many insects and they often act as species-specific
signals that are important in the reproductive isolation of closely related species. Here we report the courtship
songs of the sand fly Lutzomyia (Nyssomyia) intermedia, one of the main vectors of cutaneous leishmaniasis in
Brazil.
Findings: Recordings were performed using insects from three localities from Eastern Brazil: Posse and
Jacarepaguá in Rio de Janeiro State and Corte de Pedra in Bahia State. The three areas have remnants of the
Brazilian Atlantic forest, they are endemic for cutaneous leishmaniasis and L. intermedia is the predominant sand fly
species. We observed that during courtship L. intermedia males from all populations produced pulse songs
consisting of short trains. No significant differences in song parameters were observed between the males of the
three localities.
Conclusions: L. intermedia males produce acoustic signals as reported for some other sand flies such as the sibling
species of the Lutzomyia longipalpis complex. The lack of differences between the males from the three localities is
consistent with previous molecular studies of the period gene carried out in the same populations, reinforcing the
idea that L. intermedia is not a species complex in the studied areas and that the three populations are likely to
have similar vectorial capacities
Molecular and Biochemical Markers for Investigating the Vectorial Roles of Brazilian Sand Flies
No full textIdentification of the sex chromosome system in a sand fly species, Lutzomyia longipalpis s.l.
No full textIn many animal species, sex determination is accomplished by heterogamety i.e., one of the sexes produces two types of gametes, which
upon fertilization will direct the development toward males or females. Both male (“XY”) and female (“ZW”) heterogamety are known to
occur and can be easily distinguished when the sex-chromosomes are morphologically different. However, this approach fails in cases of
homomorphic sex chromosomes, such as the sand fly Lutzomyia longipalpis s.l. (Psychodidae, Diptera), which is the main vector of visceral
leishmaniosis in Brazil. In order to identify the heterogametic sex in L. longipalpis s.l., we did a whole-genome sequencing of males and
females separately and used the “Y chromosome Genome Scan” (YGS) method to find sex-specific sequences. Our results, which were
confirmed by PCR, show that L. longipalpis s.l. has XY system. The YGS method can be especially useful in situations in which no morpho logical difference is observed in the sex-chromosomes or when fresh specimens are not readily available
Reproductive isolation between sympatric and allopatric Brazilian populations of Lutzomyia longipalpis s.l. (Diptera: Psychodidae)
No full textLutzomyia longipalpis s.l., the main vector of Leishmania chagasi in Latin America, is a species complex although the exact number of siblings is yet unknown. In Brazil, the siblings differ in male copulatory courtship songs and pheromones that most certainly act as pre-zygotic reproductive barriers. Here we analysed the reproductive isolation between three allopatric and two sympatric populations of Lu. longipalpis s.l. from Brazil. The results indicate a strong copulatory and pre-mating isolation between the three allopatric populations. In addition, the results also indicate a stronger pre-mating isolation between the two sympatric siblings than between the three allopatric ones, suggesting a role for reinforcement in the speciation of the Lu. longipalpis s.l. complex
<i>L. longipalpis</i> male reproductive system: the ejaculatory pump.
No full text<p><b>A)</b> LM detail of the cuticular ejaculatory pump (EP) and the two aedeagal filaments (AF). Note the external genitalia, or terminalia (Tn), formed by modification of the eighth, ninth and tenth abdominal segments. <b>B)</b> LM transversal section of the ejaculatory pump (EP) showing the central cuticular duct (CD); HG: Hind gut; SV: seminal vesicle. <b>C)</b> LM longitudinal section of the ejaculatory pump (EP) showing well-developed muscle fibers (M) surrounding a central cuticular duct (CD). Below is a longitudinal section through the seminal vesicle (SV) at the point of insertion of a <i>vas deferens</i> (to the right), showing the two consecutive seminal vesicle cell layers with different granule types (black and white arrows). <b>D)</b> TEM transversal section of the ejaculatory pump (EP) showing the muscle fibers (M) with mitochondria (Mi) surrounding the cuticular duct (CD) <b>E)</b> TEM detail of the muscle fibers (M) with mitochondria (Mi). <b>F)</b> TEM detail showing the disposition of the muscle fibers (M); The thin outer sheet is disposed transversally. Mi: mitochondria.</p
Reproductive isolation between sympatric and allopatric Brazilian populations of Lutzomyia longipalpis s.l. (Diptera: Psychodidae)
No full textLutzomyia longipalpis s.l., the main vector of Leishmania chagasi
in Latin America, is a species complex although the exact number of
siblings is yet unknown. In Brazil, the siblings differ in male
copulatory courtship songs and pheromones that most certainly act as
pre-zygotic reproductive barriers. Here we analysed the reproductive
isolation between three allopatric and two sympatric populations of Lu.
longipalpis s.l. from Brazil. The results indicate a strong copulatory
and pre-mating isolation between the three allopatric populations. In
addition, the results also indicate a stronger pre-mating isolation
between the two sympatric siblings than between the three allopatric
ones, suggesting a role for reinforcement in the speciation of the Lu.
longipalpis s.l. complex
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