94 research outputs found
More than royal food - major royal jelly protein genes in sexuals and workers of the honeybee Apis mellifera
No full textBACKGROUND: In the honeybee Apis mellifera, female larvae destined to become a queen are fed with royal jelly, a
secretion of the hypopharyngeal glands of young nurse bees that rear the brood. The protein moiety of royal jelly
comprises mostly major royal jelly proteins (MRJPs) of which the coding genes (mrjp1-9) have been identified on
chromosome 11 in the honeybee’s genome.
RESULTS: We determined the expression of mrjp1-9 among the honeybee worker caste (nurses, foragers) and the
sexuals (queens (unmated, mated) and drones) in various body parts (head, thorax, abdomen). Specific mrjp
expression was not only found in brood rearing nurse bees, but also in foragers and the sexuals.
CONCLUSIONS: The expression of mrjp1 to 7 is characteristic for the heads of worker bees, with an elevated
expression of mrjp1-4 and 7 in nurse bees compared to foragers. Mrjp5 and 6 were higher in foragers compared to
nurses suggesting functions in addition to those of brood food proteins. Furthermore, the expression of mrjp9 was
high in the heads, thoraces and abdomen of almost all female bees, suggesting a function irrespective of body
section. This completely different expression profile suggests mrjp9 to code for the most ancestral major royal
jelly protein of the honeybee.AB was supported by a fellowship of the Prorectorate
for Research and Young Academics of the Martin-Luther-University Halle-
Wittenberg. The DFG provided financial support for chemicals and supplies
(RFAM).http://www.frontiersinzoology.com/content/10/1/72am201
Sperm utilization pattern in the honeybee (Apis mellifera)
No full textQueen honeybees (Apis mellifera) mate with a large number of drones on their nuptial flights. Not all drones contribute equally to the queen’s offspring and the queen’s utilization pattern of spermatozoa from different drones has an important impact on the genetic composition of the colony. Here we study the consequences of sperm use for the fitness of the queen’s mates with microsatellite DNA-fingerprinting. Eight queens were instrumentally inseminated with semen of six or seven drones. Each drone contributed either 0.5 µl or 1.0 µl semen, respectively, and we analyzed both the impact of the insemination sequence and the amount of semen on
the sperm utilization. Our data show no significant effect
of the insemination sequence but a strong impact of the
semen volume of a drone on the frequency of his worker
offspring in the colony. This effect was not linear and the
patriline frequencies of the drones contributing larger
semen volumes are disproportionately enhanced. If these
observations are also valid for natural matings, drone
honeybees should maximize the number of sperm but not
apply specific mating tactics to be first or last male in a
mating sequence
Sperm numbers in drone honeybees (Apis mellifera) depend on body size
No full textThe effect of drone honeybee's body size on semen production was evaluated. In the same colonies, drones were either reared in drone cells (large drones) or in worker cells (small drones). Wing lengths (size indicator) and sperm numbers of small and large drones were compared. Small drones (~13% reduced wing size) produce significantly fewer spermatozoa (7.5 0.5 million) than normally sized drones (11.9 1.0 million spermatozoa). There is a significant positive correlation between sperm number and wing size within the small drones and in both groups combined. In the large group alone no correlation was found. The rearing investment per spermatozoon is lower for small than for normally sized drones because small drones produce more spermatozoa in relation to their body weight. Since colonies usually produce large drones, the enhanced investment must be outweighed by a mating advantage of large drones
Alleviating nanostructural phase impurities enhances the optoelectronic properties, device performance and stability of cesium-formamidinium metal–halide perovskites
No full textThe technique of alloying FA+ with Cs+ is often used to promote structural stabilization of the desirable α-FAPbI3 phase in halide perovskite devices. However, the precise mechanisms by which these alloying approaches improve the optoelectronic quality and enhance the stability have remained elusive. In this study, we advance that understanding by investigating the effect of cationic alloying in CsxFA1−xPbI3 perovskite thin-films and solar-cell devices. Selected-area electron diffraction patterns combined with microwave conductivity measurements reveal that fine Cs+ tuning (Cs0.15FA0.85PbI3) leads to a minimization of stacking faults and an increase in the photoconductivity of the perovskite films. Ultra-sensitive external quantum efficiency, kelvin-probe force microscopy and photoluminescence quantum yield measurements demonstrate similar Urbach energy values, comparable surface potential fluctuations and marginal impact on radiative emission yields, respectively, irrespective of Cs content. Despite this, these nanoscopic defects appear to have a detrimental impact on inter-grains’/domains’ carrier transport, as evidenced by conductive-atomic force microscopy and corroborated by drastically reduced solar cell performance. Importantly, encapsulated Cs0.15FA0.85PbI3 devices show robust operational stability retaining 85% of the initial steady-state power conversion efficiency for 1400 hours under continuous 1 sun illumination at 35 °C, in open-circuit conditions. Our findings provide nuance to the famous defect tolerance of halide perovskites while providing solid evidence about the detrimental impact of these subtle structural imperfections on the long-term operational stability.ChemE/Opto-electronic Material
Workers dominate male production in the neotropical bumblebee <it>Bombus wilmattae </it>(Hymenoptera: Apidae)
No full textAbstract Background Cooperation and conflict in social insects are closely linked to the genetic structure of the colony. Kin selection theory predicts conflict over the production of males between the workers and the queen and between the workers themselves, depending on intra-colonial relatedness but also on other factors like colony efficiency, sex ratios, cost of worker reproduction and worker dominance behaviour. In most bumblebee (Bombus) species the queen wins this conflict and often dominates male production. However, most studies in bumblebees have been conducted with only a few selected, mostly single mated species from temperate climate regions. Here we study the genetic colony composition of the facultative polyandrous neotropical bumblebee Bombus wilmattae, to assess the outcome of the queen-worker conflict over male production and to detect potential worker policing. Results A total of 120 males from five colonies were genotyped with up to nine microsatellite markers to infer their parentage. Four of the five colonies were queen right at point of time of male sampling, while one had an uncertain queen status. The workers clearly dominated production of males with an average of 84.9% +/- 14.3% of males being worker sons. In the two doubly mated colonies 62.5% and 96.7% of the male offspring originated from workers and both patrilines participated in male production. Inferring the mother genotypes from the male offspring, between four to eight workers participated in the production of males. Conclusions In this study we show that the workers clearly win the queen-worker conflict over male production in B. wilmattae, which sets them apart from the temperate bumblebee species studied so far. Workers clearly dominated male production in the singly as well the doubly mated colonies, with up to eight workers producing male offspring in a single colony. Moreover no monopolization of reproduction by single workers occurred.</p
Paternity skew in seven species of honeybees (Hymenoptera: Apidae: Apis)
No full textHoneybees (Apis) show an extremely polyandrous mating system. In general honeybee queens
mate with at least ten drones. The reproductive success of the drones is usually biased giving rise to
speculations of a first or last male advantage. Especially for A. andreniformis and A. florea a first male
advantage was hypothesized due to the peculiar anatomy of their male genitalia. We reanalyzed data from
the literature by using a sample size calibration method to survey the differences and similarities in paternity
skew among species in the genus Apis. The paternity skew among seven honeybee species differed
significantly, particularly due to the rare patrilines. The sorting algorithm, i.e. the ranking of the patrilines,
had, however, a considerable effect on the paternity skew pattern. The frequent patrilines appeared to be
similarly distributed in all tested species. As a consequence the proposed first male advantage in the dwarf
honeybees is not supported by empirical data
Multiple nuptial flights, sperm transfer and the evolution of extreme polyandry in honeybee queens
No full textThe honeybee, Apis mellifera, has an extremely polyandrous mating system, which often involves multiple nuptial flights by its queens. To understand the evolution of extreme polyandry, we investigated the cost of multiple nuptial flights in relation to potential benefits.We analysed, with eight DNA microsatellite loci, the paternity of worker offspring of naturally mated queens. Queens that were restricted to one nuptial flight, but may have taken additional nuptial flights if allowed to do so, had significantly fewer matings
than queens that started oviposition after a single nuptial flight. Furthermore, the number of sperm stored in a spermatheca increased significantly with the number of matings. We suggest that queens adjust their nuptial flight frequencies according to their mating success in their previous nuptial flights. The number of copulations seems to serve as a signal for the initiation of oviposition. In the light of these findings, we reconsider and discuss the significance of the sperm limitation hypothesis for the evolution of extreme polyandry in A. mellifera
Genetic structure of Balearic honeybee populations based on microsatellite polymorphism
No full textAbstract The genetic variation of honeybee colonies collected in 22 localities on the Balearic Islands (Spain) was analysed using eight polymorphic microsatellite loci. Previous studies have demonstrated that these colonies belong either to the African or west European evolutionary lineages. These populations display low variability estimated from both the number of alleles and heterozygosity values, as expected for the honeybee island populations. Although genetic differentiation within the islands is low, significant heterozygote deficiency is present, indicating a subpopulation genetic structure. According to the genetic differentiation test, the honeybee populations of the Balearic Islands cluster into two groups: Gimnesias (Mallorca and Menorca) and Pitiusas (Ibiza and Formentera), which agrees with the biogeography postulated for this archipelago. The phylogenetic analysis suggests an Iberian origin of the Balearic honeybees, thus confirming the postulated evolutionary scenario for Apis mellifera in the Mediterranean basin. The microsatellite data from Formentera, Ibiza and Menorca show that ancestral populations are threatened by queen importations, indicating that adequate conservation measures should be developed for protecting Balearic bees.</p
Extreme Food-Plant Specialisation in Megabombus Bumblebees as a Product of Long Tongues Combined with Short Nesting Seasons
No full text© 2015 Huang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. http://creativecommons.org/licenses/by/4.0/ The attached file is the published version of the article.NHM Repositor
- …
