Mating Flight Research Articles

Development of germline progenitors in larval queen honeybee ovaries.

Honeybees (Apis mellifera) are a keystone species for managed pollination and the production of hive products. Eusociality in honeybees leads to much of the reproduction in a hive driven by the queen. Queen bees have two large active ovaries that can produce large numbers of eggs if conditions are appropriate. These ovaries are also active throughout the long lives of these insects, up to 5 years in some cases. Recent studies have indicated that the germline precursors of the adult honeybee queen ovary are organized into 8-cell clusters, joined together by a polyfusome; a cytoplasmic bridge. To understand the origin of these clusters, and trace the development of the honeybee queen ovary, we examined the cell types and regionalization of the developing larval and pupal queen ovaries. We used established (nanos and castor), and novel (odd skipped) gene expression markers to determine regions of the developing ovary. Primordial germline cells develop in the honeybee embryo and are organized into ovary structures before the embryo hatches. The ovary is regionalized by larval stage 3 into terminal filaments and germaria. At this stage, clusters of germline cells in the germaria are joined by fusomes and are dividing synchronously. The origin of the 8-cell clusters in the adult germarium is therefore during larval stages. On emergence, the queen ovary has terminal filaments and germaria but has not yet developed any vitellaria, which are produced after the queen embarks on a nuptial flight. The lack of germaria, and the storing of germline progenitors as clusters, may be adaptions for queen bees to endure the metabolic demands of a nuptial flight, as well as rapidly lay large numbers of eggs to establish a hive.

The dual coding of a single sex pheromone receptor in Asian honeybee Apis cerana

In Asian honeybees, virgin queens typically only mate during a single nuptial flight before founding a colony. This behavior is controlled by the queen-released mandibular pheromone (QMP). 9-oxo-(E)-2-decenoic acid (9-ODA), a key QMP component, acts as sex pheromone and attracts drones. However, how the queens prevent additional mating remains elusive. Here, we show that the secondary QMP component methyl p-hydroxybenzoate (HOB) released by mated queens inhibits male attraction to 9-ODA. Results from electrophysiology and in situ hybridization assay indicated that HOB alone significantly reduces the spontaneous spike activity of 9-ODA-sensitive neurons, and AcerOr11 is specifically expressed in sensilla placodea from the drone’s antennae, which are the sensilla that narrowly respond to both 9-ODA and HOB. Deorphanization of AcerOr11 in Xenopus oocyte system showed 9-ODA induces robust inward (regular) currents, while HOB induces inverse currents in a dose-dependent manner. This suggests that HOB potentially acts as an inverse agonist against AcerOr11.

To house or oust: Honey bee (Apis mellifera) colonies can evaluate and evict drones of low quality

Across the animal kingdom, males advertise their quality to potential mates. Males of low reproductive quality, such as those that are sick, may be excluded from mating. In eusocial species, there is some evidence that reproductive females gauge the quality of their mates. However, males often spend much more time with non-reproductive females when being raised or when returning from unsuccessful mating flights. Do non-reproductive workers evaluate the quality of male reproductives? Here we address this question using male honey bees (Apis mellifera), called drones, as a model. We generated immune-challenged drones by injecting them with lipopolysaccharide and tested: 1) do workers evict immune-challenged drones from their colony, 2) do cuticular hydrocarbon (CHC) profiles, body size, or mass change when drones are immune-challenged, and 3) are these changes used by workers to exclude low quality males from the colony? We found that an immune challenge causes changes in CHC profiles of drones and reduces their body mass. Workers selectively evict small and immune-challenged drones who, themselves, do not self-evict. This work demonstrates that some eusocial males undergo an additional layer of scrutiny prior to mating mediated by the non-reproductive worker caste.Significance statementMales of some species must advertise their quality to mates but, in the case of eusocial species, must they also advertise their quality to nestmates? By manipulating honey bee male quality, we found that small and immune-challenged drones are evicted from colonies overnight. Workers may not use a drone’s cuticular hydrocarbon profile to make this assessment. This is a new example of social immunity expressed against adult males and an example of worker involvement in reproductive decisions.

Mechanisms for polyandry evolution in a complex social bee

Polyandry in social Hymenoptera is associated with reduced within-colony relatedness and increased colony-level ecologic fitness. One explanation for this sees increasing within-nest genetic diversity as a mechanism for improving group task efficiency and colony competitiveness. A queen on her mating flight captures nearly 90% of her breeding population’s allele potential by her tenth effective mating (me ~ 10 males). Under this population allele capture (PAC) model, colony fitness gains track mating number in an asymptotic manner, leveling out after about the tenth mating. A supporting theory we call the genotype composition (GC) model sees genetic novelty at mating levels higher than the me ~ 10 asymptote, the hyperpolyandry zone, resulting from unique genotype compositions whose number are potentially infinite. Colony fitness gains under the GC model will track mating number in a linear manner. We set up field colonies with Apis mellifera queens each instrumentally mated with 1, 2, 4, 8, 16, or 32 males, creating a polyandry gradient bracketing the qualitative divide of me ~ 10, measured tokens of colony level fitness, and collected observation hive data. Our results lead us to conclude that (1) ancestral colony traits fundamental to eusociality (cooperative brood care) respond to mating level changes at or below me ~ 10 in a manner consistent with the PAC model, whereas (2) more derived specialized colony phenotypes (resistance to the non-native parasite Varroa destructor) continue improving with increasing me in a manner consistent with the GC model. By either model, (3) the mechanism for increasing colony fitness is an increase in worker task specialisms and task efficiency.Significance statementPolyandry is a female’s practice of mating with many males, storing their sperm, and using it to produce genetically diverse offspring. In complex social bees, a queen captures nearly 90% of her breeding population’s diversity potential by her tenth mating; however, queens in nature routinely mate with many more than ten males. We tested two models that, together, explain how social bee colonies ecologically benefit from queen mating numbers ranging from 2 to potential infinity. A population allele capture (PAC) model focuses on colony fitness gains at mating numbers at or below 10, and we provide evidence that it was at these polyandry levels that significant gains were made in an ancestral eusocial trait, cooperative brood care. A genotype composition (GC) model focuses on colony fitness gains at higher mating numbers, and we believe these gains are centered around more recently evolved ecologic specialisms such as parasite resistance.

How the Choice of Habitat and Sampling Technique Affects Biodiversity Knowledge: The Case of Cylindromyrmex (Hymenoptera, Formicidae) in the Atlantic Forest

The Atlantic Forest is a biodiversity hotspot, and myrmecologists broadly study its numerous habitats. Even so, much of its biodiversity remains to be discovered, and the choice of collection methods and habitats to be explored directly affect the results obtained, especially in the case of species with cryptic habits, such as Cylindromyrmex ants. The ant subfamily Dorylinae has 11 genera registered in the Neotropics, with Cylindromyrmex Mayr, 1870 being a lineage to the region. The present study reports new records of three Cylindromyrmex species in 13 municipalities located in the Atlantic Forest in southeastern Brazil. It also describes the effect of sampling techniques and habitats on species records. The 78 examined herein specimens belong to the species C. brasiliensis Emery, 1901, C. brevitarsus Santschi, 1925, and C. longiceps André, 1892, and were collected manually or with Malaise traps. Records are distributed along the Espírito Santo state, with a tendency towards higher records in municipalities with mountainous habitats. All records in this region of the Atlantic Forest are associated with the hottest months and with the highest rainfall, suggesting a possible preference for nuptial flights in the summer. Most records of the three Cylindromyrmex species occurred in forested areas (93%), whereas few records belong to urban areas (7%). Although manual collections and Malaise traps are not widely used in research or surveys of ant diversity, these techniques could potentially reveal essential findings for ant ecology.

Penjadwalan Kompetisi Sepak Bola Liga PSN Ngada Menggunakan Algoritma Honey Bee Mating Optimization

Soccer scheduling is one of the key factors so that the competition can be done well or not. Poor scheduling will affect the condition of the team that will compete, because a poor schedule will prevent the team from preparing their team well for the next match. For this research, we will discuss a system that can determine scheduling and also discuss issues that must be resolved in the big phase 10 PSN Ngada competition that uses a competition system. In this study, we will use the marriage honey bee optimization algorithm, this algorithm was chosen because it is easy to use and can produce quite good scheduling. This algorithm allows the formation of scheduling that avoids predetermined boundaries of combinations that have been formed, which have passed the process of mating flights, crossover, mutations and queen selection. This cycle will continue to run until it reaches the specified and choose scheduling with the best fitness value.

Queens Survival during Pleometrosis in Monogynous and Polygynous Ant Species (Hymenoptera, Formicidae)

The objective of this study is to examine the survival rates of queens in pleometrotic groups of two ant species: Lasius paralienus Seifert, 1992 (a monogynous species) and Solenopsis fugax (Latreille, 1798) (a polygynous species). The study was conducted in 2020 and 2021 in Odesa, Ukraine. After the nuptial flight, 45 gynes of S. fugax and 64 of L. paralienus were captured. Solenopsis fugax were seated in groups of 5 (9 experiments in total), L. paralienus in groups of 5 (8 experiments) and 3 specimens (8 experiments). For L. paralienus, the effect of pleometrotic group size on the queens was tested. Maximum duration of the experiment was 115 days for S. fugax and 293 days for L. paralienus (until only one queen remains or the number of queens does not change significantly). The number of queens (alive, dead and killed), workers and brood were counted once a week. There were no significant differences in mortality between groups of 3 and 5 queens of Lasius paralienus ants (p = 0.06). The period of main queen mortality occurs shortly after founding of the pleometrotic group. Mortality continues to rise after the emergence of a group of 10–30 workers until only 1 queen remains in group of Lasius. When L. paralienus queens died naturally, the average number of workers was 7.5, the average number of larvae was 3.32 and the average number of pupae was 5.16. However, when they died due to fights, the average number of workers was 23.89, the average number of larvae was 8.89 and the average number of pupae was 13.89. In the case of S. fugax, when queens died naturally, the average number of workers was 5.43. A comparison of the total queen mortality in the pleometrotic groups of the two ant species showed that most queens survive in the polygynous S. fugax, whereas all but one die in the monogynous Lasius.

Ecological comparison of native (Apis mellifera mellifera) and hybrid (Buckfast) honeybee drones in southwestern Sweden indicates local adaptation.

Honeybee drones' only known task is to mate with a virgin queen. Apart from their mating behaviour, their ecology has been little studied, especially in comparison to honeybee females. Previous knowledge is primarily based on short-term direct observations at single experimental hives, rarely, if ever, addressing the effect of drones' genetic origin. Here, Radio Frequency Identification Technology was utilised to gather drone and worker bee lifetime data of Apis mellifera mellifera and Apis mellifera x (hybrid Buckfast) colonies over one mating season (spring and summer) with the ultimate goal to investigate differences at subspecies level. This technique enabled continuous monitoring of tagged bees at the hive entrance and recording of individuals' movement directions. The results confirmed that spring-born drones survive longer than summer-born drones and that they generally live longer than worker bees. Drones' peak activity occurred in the afternoon while worker bees showed more even activity levels throughout the day. Earlier orientation flights than usually reported for drones were observed. In summer, mating flights were practiced before reaching sexual maturity (at 12 days of age). Differences were found between Apis m. mellifera and Buckfast drones, where Apis m. mellifera showed later drone production in spring, but significantly earlier first activities outside the hive in summer and a later peak in diurnal activity. Additionally, Apis m. mellifera flew more in higher light intensities and windy conditions and performed significantly longer flights than Buckfast drones. The observed differences in drone ecology indicate the existence of a local adaptation of the native subspecies Apis m. mellifera to environmental conditions in southwestern Sweden.

The function of wing bullae in mayflies (Insecta: Ephemeroptera) reveals new insights into the early evolution of Pterygota

BackgroundMayflies are basal winged insects of crucial importance for the understanding of the early evolution of Pterygota. Unlike all other insects, they have two successive winged stages, the subimago and the imago. Their forewings feature so-called bullae, which are desclerotized spots in the anterior main veins. Up to now, they have been considered to play a major role in wing bending during flight.ResultsWe investigated bullae by multiple methods to reveal their structure and arrangement and to gain new information on the evolution of insect flight. Bullae are mostly present in the anterior negative wing veins, disrupting the otherwise rigid veins. High-speed videography reveals that mayfly wings do not bend during flight. Likewise, different arrangements of bullae in different species do not correlate with different modes of flying. Observations on the moulting of subimagines unravel that they are essential for wing bending during the extraction of the imaginal wing from the subimaginal cuticle. Bullae define predetermined bending lines, which, together with a highly flexible wing membrane enriched with resilin, permit wing bending during subimaginal moulting. Bullae are only absent in those species that remain in the subimaginal stage or that use modified modes of moulting. Bullae are also visible in fossil mayflies and can be traced back to stemgroup mayflies of the Early Permian, the 270 million years old Protereismatidae, which most probably had bullae in both fore- and hind wings.ConclusionsBullae in mayfly wings do not play a role in flight as previously thought, but are crucial for wing bending during subimaginal moulting. Thus, the presence of bullae is a reliable morphological marker for a subimaginal life stage, confirming the existence of the subimago already in Permian Protereismatidae. A thorough search for bullae in fossils of other pterygote lineages may reveal wheather they also had subimagines and at what point in evolution this life stage was lost. In mayflies, however, the subimago may have been retained due to selective advantages in connection with the transition from aquatic to terrestrial life or due to morphological requirements for a specialized mating flight.

Are LED lights driving the massive nuptial flight swarm of the tramp ant Technomyrmex albipes?

AbstractWhereas most economic and ecological impacts of tramp ant species stem in large part from numerical dominance and exacerbated aggressiveness of workers, those imposed by alate (winged) ants have been rarely described. In the present study, we report an unprecedented massive alate swarming (i.e., mating flight) event in southern Taiwan by a tramp ant species, Technomyrmex albipes (Smith) (Hymenoptera: Formicidae), that triggers immediate pest management responses, and examine factor(s) that potentially contribute to the remarkably high number of alates. We monitored the seasonal activities of T. albipes workers and phenology of alate swarming, attempting to link the worker foraging dynamics with swarm ontogeny. As it was argued that recent streetlight fixtures converted from high‐pressure sodium to light‐emitting diode (LED) may serve as a major cause of the massive swarming, alates' light color preference was investigated. Sex ratio of trapped alates was also assessed to test whether sex‐specific light preference exists in T. albipes. We showed that foraging intensity of workers increased in the spring, peaked in May, and was followed by the nuptial flight season that began in August and lasted for 4 months. The phenological pattern is consistent with the colony dynamics in many other ant species. Although the two light preference experiments did not yield the same results, T. albipes alates overall preferred lights with shorter wavelengths in the active trapping, partially supporting the argument of white LED streetlights contributing to the massive flight. The sex ratio of trapped alates was overall female‐biased, suggesting female alates are disproportionally produced and/or more sensitive toward lights.

Phylogenetic analyses of Reticulitermes (Blattodea: Rhinotermitidae) from California and other western states: multiple genes confirm undescribed species identified by cuticular hydrocarbons.

Subterranean termites in the genus Reticulitermes Holmgren 1913 are among the most economically important wood-destroying pests in the western United States. Yet, there remains uncertainty regarding the taxonomy and biology of the species in this genus. The 2 species described as having distributions in this region are the western subterranean termite, Reticulitermes hesperus Banks, and the arid land subterranean termite, Reticulitermes tibialis Banks. Taxonomic studies utilizing cuticular hydrocarbon (CHC) profiles, agonistic behavior, flight phenology, and mitochondrial DNA (mtDNA) suggested that R. hesperus is a species complex comprised of 2 or more sympatric, yet reproductively isolated species. To further delineate these taxa, we examined multiple genes from samples of Reticulitermes collected in the western United States. Alates collected after recent spring and fall mating flights, as well as previously collected workers, were subjected to CHC phenotyping and DNA sequence analyses that targeted mitochondrial cytochrome oxidase subunit II (COII), mitochondrial 16S rRNA, and nuclear Internal Transcribed Spacer 1 and 2 (ITS1 and 2). Phylogenetic analyses conducted also included published sequences of other putative western Reticulitermes species. Results suggest that at least 5 species of Reticulitermes may be present in California and that Reticulitermes in Arizona consistently group into multiple clades, including samples previously identified as R. tibialis in a sister clade. These analyses further support the species status of qualitatively different CHC phenotypes and that alates swarming in spring vs. fall are reproductively isolated species.

Co-Occurrence of Wing Deformity and Impaired Mobility of Alates with Deformed Wing Virus in Solenopsis invicta Buren (Hymenoptera: Formicidae).

Deformed wing virus (DWV), a major honey bee pathogen, is a generalist insect virus detected in diverse insect phyla, including numerous ant genera. Its clinical symptoms have only been reported in honey bees, bumble bees, and wasps. DWV is a quasispecies virus with three main variants, which, in association with the ectoparasitic mite, Varroa destructor, causes wing deformity, shortened abdomens, neurological impairments, and colony mortality in honey bees. The red imported fire ant, Solenopsis invicta Buren, is one of the most-invasive and detrimental pests in the world. In this study, we report the co-occurrence of DWV-like symptoms in S. invicta and DWV for the first time and provide molecular evidence of viral replication in S. invicta. Some alates in 17 of 23 (74%) lab colonies and 9 of 14 (64%) field colonies displayed deformed wings (DWs), ranging from a single crumpled wing tip to twisted, shriveled wings. Numerous symptomatic alates also exhibited altered locomotion ranging from an altered gait to the inability to walk. Deformed wings may prevent S. invicta alates from reproducing since mating only occurs during a nuptial flight. The results from conventional RT-PCR and Sanger sequencing confirmed the presence of DWV-A, and viral replication of DWV was confirmed using a modified strand-specific RT-PCR. Our results suggest that S. invicta can potentially be an alternative and reservoir host for DWV. However, further research is needed to determine whether DWV is the infectious agent that causes the DW syndrome in S. invicta.

The Potential of Instrumental Insemination for Sustainable Honeybee Breeding.

Mating control is crucial in honeybee breeding and commonly guaranteed by bringing virgin queens to isolated mating stations (IMS) for their nuptial flights. However, most breeding programs struggle to provide sufficiently many IMS. Research institutions routinely perform instrumental insemination of honeybees, but its potential to substitute IMS in breeding programs has not been sufficiently studied. We performed stochastic simulations to compare instrumental insemination strategies and mating on IMS in terms of genetic progress and inbreeding development. We focused on the role of paternal generation intervals, which can be shortened to two years with instrumental insemination in comparison to three years when using IMS. After 70 years, instrumental insemination yielded up to 42% higher genetic gain than IMS strategies-particularly with few available mating sites. Inbreeding rates with instrumental insemination and IMS were comparable. When the paternal generation interval in instrumental insemination was stretched to three years, the number of drone producers required for sustainable breeding was reduced substantially. In contrast, when shortening the interval to two years, it yielded the highest generational inbreeding rates (up to 2.28%). Overall, instrumental insemination with drones from a single colony appears as a viable strategy for honeybee breeding and a promising alternative to IMS.

Collecting young nests of Atta spp. is more efficient to establish laboratory colonies than collecting founder queens after nuptial flights

Collecting young nests of Atta spp. is more efficient to establish laboratory colonies than collecting founder queens after nuptial flights

Seasonal differences in the timing of flight between the invasive winter moth and native Bruce spanworm promotes reproductive isolation.

The European winter moth, Operophtera brumata L. (Lepidoptera: Geometridae), was accidentally introduced to North America on at least 4 separate occasions, where it has been hybridizing with the native Bruce spanworm, O. bruceata Hulst, at rates up to 10% per year. Both species are known to respond to the same sex pheromones and to produce viable offspring, but whether they differ in the seasonal timing of their mating flights is unknown. Therefore, we collected adult male moths weekly along 2 transects in the northeastern United States and genotyped individuals using polymorphic microsatellite markers as males of these 2 species cannot be differentiated morphologically. Along each transect, we then estimated the cumulative proportions (i.e., the number of individuals out of the total collected) of each species on each calendar day. Our results indicate that there are significant differences between the species regarding their seasonal timing of flight, and these allochronic differences likely are acting to promote reproductive isolation between these 2 species. Lastly, our results suggest that the later flight observed by winter moth compared to Bruce spanworm may be limiting its inland spread in the northeastern United States because of increased exposure to extreme winter events.

In vitro Studies on the Biology and Predatory Potential of Commonly Occurring Ant Species in a Selected Agro-ecosystem of the Himalayan Range, India

Four commonly occurring species of queen ants were collected after their nuptial flight from an agroecosystem in Lehri Sarail village of Himachal Pradesh (31°32’03.9”N 76°38’57.7“E) using light traps. Queens named HAC1, HAC2, HAC3, and HAC4 were placed individually in a test tube with water sources. Once the queen started laying eggs, and a few workers emerged, they were transferred to an artificial formicarium. HAC1 and HAC2 were identified as Camponotus compressus, while HAC3 and HAC4 were identified as Polyrhachis thompsoni and Pheidole minor, respectively. In the study period of one year between July 2020 and July 2021, offspring from all colonies were found to be workers. HAC1, HAC2, and HAC4 produced dimorphic workers, the majors and minors. Studies on colony establishment, biology, and behavior were carried out with colonies from HAC1, HAC2, and HAC3, while a colony from HAC4 failed to establish. All species showed similar types of colony founding, nesting, brood management, necrophorosis, and hibernation. C. compressus showed higher fecundity, while percent hatchability was higher in P. thompsoni. Percent pupation and adult emergence were higher in C. compressus and lower in P. thompsoni. P. thompsoni was observed to be more aggressive with a high predation rate, followed by C. compressus. P. minor showed aggressiveness initially but was unable to incapacitate the host larva. Understanding ant biodiversity, biology, behavior, predatory potential, etc., will allow us to use the native ants in the agroecosystem as biological control agents. Methods of rearing ants under the artificial setup described here enable laboratory culturing of ants with biocontrol potential and using ants as model organisms to study the bio-efficacy of agrochemicals and pharmaceutical drugs.

Effect of Light Intensity on the Colony Development of <i>Lasius japonicus</i>（Hymenoptera: Formicidae）

In this study, we examined the effect of light intensity on colony development regulation in Lasius japonicus Santschi. Queens were collected soon after their nuptial flight in Okayama, Japan. They were reared under 16L-8D（16 h light, 8 h dark）and 12L-12D at 25°C with four light intensity conditions: 50, 200, 800, and 3000 lux. The queens started oviposition soon after collection. Thereafter, the larvae, pupae, and workers emerged under the 50–800 lux conditions； however, the hatching and larval development were suppressed under 3000 lux conditions, especially under the long-day photoperiod. Light intensity was also measured under the shelters where queens were found soon after their nuptial flight. Under the shelters, the median light intensities were between 2.4 lux and 1070.5 lux, which was low enough for the queens to develop colonies. These results suggest that queens start colony founding at places with low light intensity. The queens also likely control the rate of colony development by responding to the light intensity of the surrounding environment.

Honeybee queen exposure to a widely used fungicide disrupts reproduction and colony dynamic

Pollinators have to cope with a wide range of stressful, not necessarily lethal factors limiting their performance and the ecological services they provide. Among these stressors are pesticides, chemicals that are originally designed to target crop-harming organisms but that also disrupt various functions in pollinators, including flight, communication, orientation and memory. Although all these functions are crucial for reproductive individuals when searching for mates or nesting places, it remains poorly understood how pesticides affect reproduction in pollinators. In this study, we investigated how a widely used fungicide, boscalid, affects reproduction in honey bees (Apis mellifera), an eusocial insect in which a single individual, the queen, fulfills the reproductive functions of the whole colony. Boscalid is a succinate dehydrogenase inhibitor (SDHI) fungicide mainly used on rapeseed flowers to target mitochondrial respiration in fungi but it is also suspected to disrupt foraging-linked functions in bees. We found that immature queen exposure to sublethal, field relevant doses of boscalid disrupted reproduction, as indicated by a dramatic increase in queen mortality during and shortly after the nuptial flights period and a decreased number of spermatozoa stored in the spermatheca of surviving queens. However, we did not observe a decreased paternity frequency in exposed queens that successfully established a colony. Queen exposure to boscalid had detrimental consequences on the colonies they later established regarding brood production, Varroa destructor infection and pollen storage but not nectar storage and population size. These perturbations at the colony-level correspond to nutritional stress conditions, and may have resulted from queen reduced energy provisioning to the eggs. Accordingly, we found that exposed queens had decreased gene expression levels of vitellogenin, a protein involved in egg-yolk formation. Overall, our results indicate that boscalid decreases honey bee queen reproductive quality, thus supporting the need to include reproduction in the traits measured during pesticide risk assessment procedures.

Long-term sperm storage in eusocial Hymenoptera.

In internally fertilizing species, sperm transfer is not always immediately followed by egg fertilization, and female sperm storage (FSS) may occur. FSS is a phenomenon in which females store sperm in a specialized organ for periods lasting from a few hours to several years, depending on the species. Eusocial hymenopterans (ants, social bees, and social wasps) hold the record for FSS duration. In these species, mating takes place during a single nuptial flight that occurs early in adult life for both sexes; they never mate again. Males die quickly after copulation but survive posthumously as sperm stored in their mates' spermathecae. Reproductive females, also known as queens, have a much longer life expectancy, up to 20 years in some species. Here, we review what is currently known about the molecular adaptations underlying the remarkable FSS capacities in eusocial hymenopterans. Because sperm quality is crucial to the reproductive success of both sexes, we also discuss the mechanisms involved in sperm storage and preservation in the male seminal vesicles prior to ejaculation. Finally, we propose future research directions that should broaden our understanding of this unique biological phenomenon.

Virgin queen behaviour and controlled mating in the stingless bee Tetragonulacarbonaria (Meliponini)

Improving knowledge of virgin queen behaviour and mating biology in stingless bees (Meliponini) is an important step towards artificial selection programmes for managed colonies. Here we study the Australian stingless bee Tetragonulacarbonaria to (1) describe the behaviour of queens from eclosion until egg-laying, and (2) assess whether young queens can be reared and mated under constrained conditions. We extracted mature virgin queen cells of T.carbonaria from large colonies and reared them in queen maturation boxes containing a limited number of workers (“micro-colonies”). Queen behaviour followed a typical pattern with three phases: a period of high activity and wing-flapping on top of the brood (5 ± 2 days of age), attempts to leave the colony for the nuptial flight (12 ± 3 days of age), and oviposition (20 ± 6 days of age). In total, 71% (68 of 95) of queen cells hatched in our maturation boxes and 57% (39 of 68) survived to mating age, with some observed to be actively killed by workers within the first week of life (8 of 68; 11%). For a subset of our queens, we performed controlled matings (either with or without CO2 narcosis) by presenting constrained females to males in mating aggregations, allowing one male to mate (deposit mating plug) and then returning queens to their box. In the absence of CO2 narcosis, 30% of queens mated this way were subsequently found to have sperm in their spermathecae, indicative of a successful mating (5 of 17). The remaining 70% however contained no sperm, despite the presence of the male mating plug. Amongst queens that were CO2 narcotized before and during the controlled mating, none had sperm in their spermathecae (0 of 12), though most went on to activate their ovaries following the mating and lay male (haploid) eggs. Together, these trials indicate that controlled matings with T.carbonaria are possible, but suggest that queens may need to actively accept mating for successful sperm transfer.