Physogastric Queens Research Articles

Secretory oviducts contribute to the high egg-laying rate of physogastric termite queens (Isoptera: Termitidae)

Physogastric termite queens are characterized by a notorious enlargement of the abdomen triggered by an equal development of the ovaries. Other physogastry-related modifications have been reported on the fat body, cuticle, midgut, tracheal system, and hemolymph. Surprisingly, modifications on the lateral oviducts of these females, important sites for ovulation and egg transport, have received little attention. Here we took advantage of the high fecundity of physogastric queens in three termitid species to evaluate ovary development and also to compare the morphophysiological features of the lateral oviducts between early-mated and physogastric queens of Cornitermes cumulans. Older queens show well-developed ovaries, with numerous ovarioles connected to the lateral oviducts through pedicels. At these sites, several corpora lutea were observed, residual follicle cells from previous ovulation events. Such features were absent among early-mated queens and reflect then the maturity and ageing of the queens. Histological and histochemical analyses indicated that secretory activity of the lateral oviducts was also restricted to physogastric queens, in which proteins, but not polysaccharides, are secreted into the oviduct lumen. The likely function of these proteins, based on previous studies, is to lubricate the lateral oviducts and stimulate muscular contractions to the egg transport. The physogastry of termite queens is a notorious feature, characterized by several body modifications, especially concerning the ovaries. Our results shed light on the physogastry-related changes in the lateral oviducts of termite queens, as their increasing secretory activity is in agreement with the high number of eggs produced and transporting through these structures. Thus, such changes correspond to an important step allowing the high egg-laying rate shown by physogastric termite queens.

Composition of different castes in the subterranean termite Odontotermes horni (Wasmann) nest

An investigation was conducted at GKVK in Bengaluru, India, to study the composition of subterranean termite nests built by Odontotermes horni. The study revealed that eggs were found in groups on the primary depository, while nymphs of workers, soldiers, and alates were observed in the fungus combs. The nymphs formed most of the colony population, with workers being more numerous and dimorphic with major and minor forms. Soldiers were found to be associated with the workers as guards during various activities. The royal pair (king and queen) was situated in the royal chamber, with two queens and a king observed in one of the nests. The king and physogastric queen measured 12.6 and 61.5 mm in length, respectively. Adult alates were seen in the alate waiting chamber before emergence.

Lifespan prolonging mechanisms and insulin upregulation without fat accumulation in long-lived reproductives of a higher termite

Kings and queens of eusocial termites can live for decades, while queens sustain a nearly maximal fertility. To investigate the molecular mechanisms underlying their long lifespan, we carried out transcriptomics, lipidomics and metabolomics in Macrotermes natalensis on sterile short-lived workers, long-lived kings and five stages spanning twenty years of adult queen maturation. Reproductives share gene expression differences from workers in agreement with a reduction of several aging-related processes, involving upregulation of DNA damage repair and mitochondrial functions. Anti-oxidant gene expression is downregulated, while peroxidability of membranes in queens decreases. Against expectations, we observed an upregulated gene expression in fat bodies of reproductives of several components of the IIS pathway, including an insulin-like peptide, Ilp9. This pattern does not lead to deleterious fat storage in physogastric queens, while simple sugars dominate in their hemolymph and large amounts of resources are allocated towards oogenesis. Our findings support the notion that all processes causing aging need to be addressed simultaneously in order to prevent it.

Queen loss changes behavior and increases longevity in a stingless bee

The death of the queen can lead to behavioral changes in workers of eusocial bees that alter their longevity. Here, we investigated the behavior and longevity of workers in colonies of the neotropical stingless bee Scaptotrigona aff. postica in the absence of a mated queen. Eight colonies, four being queenright, and four with their physogastric queens removed (queenless), were used in experiments. Emerging workers were marked with different colors to obtain age cohorts. We observed external foraging activity, age of workers involved in cell construction and foraging, and worker longevity in all colonies for 100 days. Over time, queenless colonies presented a greater reduction in external activity than queenright colonies; older workers were more frequently observed participating in cell construction and foraging compared with queenright colonies, and worker lifespan in queenless colonies was about a third longer than that observed in queenright colonies. Our study demonstrates that orphaned workers of this species substantially alter their behavior, causing an increase in their overall longevity and workers starting to lay haploid eggs, allowing some direct reproduction by workers in the absence of a queen. For eusocial species, the loss of the reproductive individual is a critical period for colony survival. Our study shows, for the first time, how workers in a neotropical stingless bee species adapt their behavior during periods without a queen. We show that the longevity of workers of Scaptotrigona aff. postica from orphaned colonies on average increased by 33% compared with regular colonies. We also show that many foragers from orphaned colonies spend more time inside the nest building brood cells rather than participating in more risky foraging behaviors. Therefore, workers alter their behavior in the absence of an egg-laying queen; these changes cause a substantial increase of longevity of the labor force (i.e., workers), and consequently, a possibility that the nest survives until a new mated queen resumes oviposition. In case a new queen does not appear in the colony, males produced by egg-laying workers (which gain a direct fitness through direct reproduction) may spread the colonial genome, by mating with queens from other colonies.

The relationship between queen execution and cuticular hydrocarbons in stingless bee Melipona scutellaris (Hymenoptera: Meliponini)

In queenright colonies of stingless bees of the genus Melipona, workers recognize, attack, and kill young virgin queens. For Melipona scutellaris, we observed that virgin queens were executed when they were between 5 and 9 days old, while newly emerged queens were not attacked. The faster movements of old virgin in relation to newly emerged might be responsible for attacks. It has been also hypothesized that cuticular hydrocarbons are the source of the signal used by workers to recognize virgin queens. We investigated whether newly emerged, 8 days old virgin and physogastric queens of M. scutellaris have different cuticular hydrocarbon profiles. Cuticular hydrocarbons of three ages were compared using gas chromatography-mass spectrometry. The cuticular hydrocarbon profiles varied by reproductive status and age. Changes in the cuticular hydrocarbons in virgin queens during aging suggest that these compounds, together with change in movement, may play a role in the recognition of virgin queens by workers prior to regicide.

Parâmetros biométricos e produtivos de colônias em gerações de Melipona quadrifasciata anthidioides

This study aimed to analyze biometric parameters and productive stingless bee colonies mandacaia (Melipona quadrifasciata anthi-dioides) in consecutive generations. Sixty colonies from different regions of Bahia state were transferred to INPA boxes model. After 90 to 100 days the colonies were evaluated and divided, forming the first and later the second generation. In every generation the colony biometric measurement were evaluated (brood, honey and pollen pots), queen and glossa workers morphometry. The weight of physogastric queen and length of the glossa did not differ between generations. There were differences for the number of brood disks and between honey and pollen characteristics, with variability between generations. Thus biometric and productive parameters studied were directly influenced by environmental factors. However in subsequent generations the colonies showed environment adaptation demonstrating variability that can be exploited

Fat body, hemolymph and ovary routes for delivery of substances to ovary inMelipona quadrifasciataanthidioides: differences among castes through the use of electron-opaque tracers

The yolk protein precursor, vitellogenin (Vg), in bees is synthesized in the fat body trophocytes, delivered to the hemolymph and ultimately absorbed from there during the vitellogenic phase of oocytes in the active ovary. The routes tracing the material exchange that occurs between the trophocytes and the hemolymph, in addition to the transportation from the hemolymph to the ovarian follicles, were marked by alkaline phosphatase and lanthanum nitrate (LN). Active ovaries from nurse workers and physogastric queens, as well as inactive ovaries of virgin queens, were examined by transmission electron microscopy. The LN permitted better visualization of the routes of exchanges between the organs and the hemolymph. Both methods demonstrate the apparent differences between the phases of the ovary and the bee caste. In inactive ovaries of the virgin queens, the routes from the follicular epithelium to the oocyte remain closed; conversely, they are open in active ovaries of the nurse workers and physogastric queens. The differences between the methods and classes of bees are discussed.

Distribution, diversity, mesonotal morphology, gallery architecture, and queen physogastry of the termite genus Calcaritermes (Isoptera, Kalotermitidae)

An updated New World distribution of the genus Calcaritermes is given along with photographs and a key to the New World species outside Mexico. Calcaritermes recessifrons is found to be a junior synonym of Calcaritermes nigriceps. Except for Calcaritermes temnocephalus, pseudergates of the other seven studied Calcaritermes species possess a mesonotal rasp. The rasps suggest a role in propagation of microbes on gallery surfaces and microbial infusion below the wood surface. Calcaritermes temoncephalus is shown to have an unusually large physogastric queens for a kalotermitid and several species produce large eggs.

Queen Volatiles as a Modulator of Tetragonisca angustula Drone Behavior

Tetragonisca angustula mating occurs during the virgin queen nuptial flight, usually in the presence of a drone congregation area (DCA). The presence of virgin queen pheromone is considered the trigger for DCA establishment, although this has not been demonstrated experimentally. We established meliponaries, in different habitats, with T. angustula virgin queens during the main drone reproduction period. Eight DCAs were observed in urban areas, and all established outside or near colonies containing at least one virgin queen. The accumulation of drones in the DCAs occurred from 08:00 to 18:00h and over 3-35days. The number of drones in DCAs ranged from 60 to 2,000. In field trials, drones were attracted to virgin queens and also, unexpectedly, to physogastric queens. Volatiles collected from both virgin and physogastric queens elicited strong electoantennogram (EAG) responses from drones. Virgin and physogastric queen volatiles were qualitatively similar, but quantitatively different, in chemical composition. The queen's abdomen was the principal source of these compounds. Isopropyl hexanoate (IPH), the most abundant compound in virgin queen volatiles and one of the most abundant in physogastric queen volatiles, was identified as one of the compounds that elicited EAG responses and was demonstrated to attract drones in a field test.

Vitellogenin content in fat body and ovary homogenates of workers and queens of Melipona quadrifasciata anthidioides during vitellogenesis

Abstract Vitellogenin (Vg) is an egg yolk protein that is produced primarily in the fat body of most female insects. In the advanced social structure of eusocial honeybees, the presence of the queen inhibits egg maturation in the workers’ ovaries. However in the stingless bee Melipona quadrifasciata, the workers always develop ovaries and lay a certain amount of eggs while provisioning the brood cells with larval food during what is known as the worker nurse phase. The present work is a comparative study of the presence of Vg in homogenates of the fat bodies and ovaries of the nurse workers, and the virgin and physogastric queens of M. quadrifasciata. The presence of Vg was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting using Apis mellifera anti‐egg antibody. Vg was not detected in the fat bodies or ovaries of the workers, but it was found in the ovaries of virgin and physogastric queens and in the fat body of physogastric queens. The results are discussed, taking into account the reproductive state of the individuals and the other possible roles of Vg, such as a storage protein for metoabolism of other organs.

Olfactory attraction of Scaptotrigona mexicana drones to their virgin queen volatiles

Drone congregations are a ubiquitous phenomenon described in several species of stingless bees and extensively studied in the honeybee, Apis mellifera. In meliponaries of Scaptotrigona mexicana, it is usual to observe drones forming such congregations close to the nests, apparently waiting for a virgin queen for mating. We hypothesize that drones of this species, similarly to those of A. mellifera and the stingless bee Scaptotrigona postica, use olfactory signals to detect queens and evaluate their reproductive status. In both field and laboratory experiments, our results showed that S. mexicana drones were able to differentiate between virgin and physogastric queens. It seems that this ability to discriminate depends on the amount of 2-alcohols, since even though no differences were observed in the qualitative content between virgin and physogastric queens, these compounds were found in larger quantities in the virgin queens. Attraction is due to compounds found in the queen head, mainly 2-alcohols, where 2-nonanol is the most significant for drone attraction in field and laboratory bioassays and for eliciting a high drone antennal response.

Ultrastructural studies of the mandibular gland of Melipona quadrifasciata Lepeletier, 1836 (Apidae, Meliponini): a comparison between workers and queens

SummaryThe mandibular glands of workers and queens of Melipona quadrifasciata Lepeletier 1836 were studied in different functional states under transmission electron and light microscopy. In both castes, the glands consisted of a cluster of class III secretory cells and a small, thin-walled reservoir. The glands of queens were smaller than those of workers. The gland of workers were more developed in nurses, in which they consisted of secretory cells rich in smooth endoplasmic reticulum and lipid-like secretion. Among workers, the stored secretion seemed to be used only by foragers. In queens, the gland is more active in virgin than in physogastric queens, being the secretion likely composed mostly of proteins. Our results suggest that the secretion is mainly useful for foragers and virgin queens. Secretion appears to play a role in pheromone activity.

Modifications in the oviducts of workers and queens of Melipona quadrifasciata anthidioides (Hymenoptera: Apidae) with different ages

The study of morphological features of highly eusocial bees has helped to answer a series of questions concerning their biology. The labor division places the females into two castes, queen with reproductive function and worker with a wide variety of tasks. However, in different species and under different conditions, workers can develop ovaries and lay trophic eggs that are eaten by the queen or used to originate males. In this work, the development of the oviducts was monitored in workers and virgin queens of Melipona quadrifasciata anthidioides specimens of different ages to verify whether there is permanent sterility of these queens and workers due to aging. Lateral and common oviducts of virgin queens aged <7, 10, 15, 20, and 25days old, physogastric queens, nurse, and forager workers were analyzed for histology and ultrastructure. Although the structural organization of the lateral and common oviducts were very similar, differences in width of the cuticle and the degree of chromatin condensation were observed, indicating differences in the development of this organ of the reproductive system between the castes. It was also demonstrated that electron-lucent vesicles appear to be related to the formation of the cuticle that lines the oviducts. Because no cellular death characteristics were found, it can be inferred that the absence of mating of the queens as old as of 25days of age does not cause permanent sterility.

A new termite (Isoptera: Termitidae: Termitinae: Proboscitermes) from Tanzania

A new species of termite, Proboscitermes mcgrewi Scheffrahn, is described from soldiers, workers, and a physogastric queen collected along the northeastern shore of Lake Tanganyika. The new species differs from all other mandibulate termite soldiers in having a relatively large proportion of head capsule volume anterior to the mandibular articulations.

Chemical Signals in the Stingless Bee, Frieseomelitta varia, Indicate Caste, Gender, Age, and Reproductive Status

Chemical compounds on the cuticle are a rich source of information used during interactions among social insects. Despite the multitude of studies on these substances and their function in ants, wasps, and honeybees, little is known about this subject in stingless bees (Hymenoptera: Apidae, Meliponini). We studied the chemical composition of the cuticle of the stingless bee, Frieseomelitta varia, by gas chromatography-mass spectrometry (GC-MS), to investigate potential chemical variation among castes, gender, age, and reproductive status. We found differences in the cuticular hydrocarbon composition among workers, males, and queens, recording both qualitative and quantitative differences among individuals of different ages and gender. The cuticle of physogastric queens presented a chemical profile that was distinct from all other groups in the analysis, with high relative abundances of alkenes and alkadienes with 27, 29, and 31 carbon atoms. We discuss the possibility that these compounds signal a queen's presence to the colony, thereby initiating all vital worker-queen interactions.

Interaction and behavior of virgin and physogastric queens in three Meliponini species (Hymenoptera, Apidae)

We studied the behavior of virgin queens of the stingless bee species Schwarziana quadripunctata, Paratrigona lineata and Tetragona clavipes, investigating internal nest activities, including the cell provisioning and oviposition process. We made direct observation of queen behavior, with the aid of video filming. Forty-four virgin queens of S. quadripunctata were observed; one was larger and more attractive than the others. Miniature queens were more abundant than normal-size queens; both were found in prison chambers. Agonistic behavior between virgin and physogastric queens of P. lineata was observed during attempts at queen supersedure. After the disappearance of the physogastric queen and the appearance of a virgin queen in T. clavipes nests, the brood cells were sealed with pollen alone, but no egg. In all three species, the presence of one or more virgin queens appeared to make the colonies nervous, even though constant production of virgin queens is vital to the survival of the colony and is part of the colony cycle in these bees.

Pollen foraging in colonies of Melipona bicolor (Apidae, Meliponini): effects of season, colony size and queen number

We evaluated the ratio between the number of pollen foragers and the total number of bees entering colonies of Melipona bicolor, a facultative polygynous species of stingless bees. The variables considered in our analysis were: seasonality, colony size and the number of physogastric queens in each colony. The pollen forager ratios varied significantly between seasons; the ratio was higher in winter than in summer. However, colony size and number of queens per colony had no significant effect. We conclude that seasonal differences in pollen harvest are related to the production of sexuals and to the number of individuals and their body size.

Effect of delayed mating on spermathecal activation inMelipona quadrifasciata anthidioides(Hymenoptera, Apidae) queens

In this work, we examined the effect of delayed mating on spermathecal development in Melipona quadrifasciata anthidioides queens. The histology and histochemistry of the spermatheca of vir- gin queens zero, 15, 20, and 30 days old and physogastric queens were compared. There were no significant differences in the thickness of the epithelium and the volume of the spermathecal reservoir among virgin queens of different ages. However, physogastric queens had more voluminous spermathecae and thinner epithelia than virgin queens. The structure of the spermathecal glands was also influenced by mating. These findings suggest that mating leads to activation of the spermatheca and its glands.

Are orphan Scaptotrigona mexicana workers attracted to physogastric queens?

Are orphan Scaptotrigona mexicana workers attracted to physogastric queens?

Notas sobre a bionomia de Trichotrigona extranea Camargo &amp; Moure (Hymenoptera, Apidae, Meliponini)

Três ninhos de T. extranea, encontrados nas matas de igapó, na localidade de Samaúma, foz do rio Daraã (64°45'35" W, 0°27'7" S), AM, Brasil, são descritos e ilustrados. Este é o único lugar onde esta espécie é conhecida. Todos os ninhos estavam em ocos de ramos secos de "Tanimbuca" - Buchenavia suaveolens Eichler (Combretaceae). Dois deles compartilhavam o oco com ninhos de Frieseomelitta sp. e um era solitário. Um ninho continha 46 células de cria, 43 operárias adultas e uma rainha fisogástrica; o segundo, 240 células, 117 operárias, 25 machos e uma rainha fisogástrica; o terceiro, 260 células, 163 operárias, uma rainha fisogástrica e uma pupa de rainha. As células são construídas na forma de cacho, como em Friseomelitta, e as células de rainha são do mesmo tamanho e forma que as de operária. Não há potes de alimento - este é o único Meliponini que se conhece que não armazena alimento. Supostamente, esta espécie tem hábitos cleptobióticos. Rainhas e machos são também descritos.