The queen in relation to wax secretion and comb building in honeybees

Summary The role of the queen in relation to wax secretion and comb building in honeybees was analyzed with respect to queen status (mated, virgin and dead queens and queenlessness), and pheromones of the head and abdominal tergite of queens. Worker variables considered were colony size, percentage of bees bearing wax scales, wax scale weight, and weight of constructed combs.The amount of wax recovered from festoon bees and the percentage of festoon bees bearing wax were independent of queen status, the pheromones of queens and access to the queen. Colonies with full access to freely moving mated queens always constructed significantly more comb than those headed by virgin or dead queens as well as all permutations of caged and division board queens whose mandibular glands and/or abdominal tergite glands were operative or not.Despite pheromonal similarity of virgin queens to mated ones, colonies headed by virgin queens constructed as little comb as did queenless colonies. The bouquets of the mandibular glands did not differ significantly among queens nor was the amount of comb constructed correlated with pheromonal bouquet. Comb building is greatest among colonies having full access to freely moving queens but the stimulus for such building is not attributable to the 90DA, 9HDA and 10HDA components of the queen's mandibular gland secretions.     

Exocrine glands in the legs of the social wasp Vespula vulgaris

This study brings a survey of the exocrine glands in the legs of Vespula vulgaris wasps. We studied workers, males, virgin queens as well as mated queens. A variety of 17 glands is found in the different leg segments. Among these, five glands are novel exocrine structures for social insects (trochanter-femur gland, ventrodistal tibial gland, distal tibial sac gland, ventral tibial gland, and ventral tarsomere gland). Most leg glands are present in the three leg pairs of all castes. This may indicate a mechanical function. This is likely for the numerous glands that occur near the articulation between the various leg segments, where lubricant production may be expected. Other possible functions include antenna cleaning, acting as a hydraulic system, or pheromonal. Further research including leg-related behavioural observations and chemical analyses may help to clarify the functions of these glandular structures in the legs.     

Queen reproductive state modulates pheromone production and queen-worker interactions in honeybees

The mandibular glands of queen honeybees produce a pheromone that modulates many aspects of worker honeybee physiology and behavior and is critical for colony social organization. The exact chemical blend produced by the queen differs between virgin and mated, laying queens. Here, we investigate the role of mating and reproductive state on queen pheromone production and worker responses. Virgin queens, naturally mated queens, and queens instrumentally inseminated with either semen or saline were collected 2 days after mating or insemination. Naturally mated queens had the most activated ovaries and the most distinct chemical profile in their mandibular glands. Instrumentally inseminated queens were intermediate between virgins and naturally mated queens for both ovary activation and chemical profiles. There were no significant differences between semen- and saline-inseminated queens. Workers were preferentially attracted to the mandibular gland extracts from queens with significantly more activated ovaries. These studies suggest that the queen pheromone blend is modulated by the reproductive status of the queens, and workers can detect these subtle differences and are more responsive to queens with higher reproductive potential. Furthermore, it appears as if insemination substance does not strongly affect physiological characteristics of honeybee queens 2 days after insemination, suggesting that the insemination process or volume is responsible for stimulating these early postmating changes in honeybee queens.     

Dufour's gland secretion as a repellent used during usurpation by the slave-maker ant Rossomyrmex minuchae

In slave-making ants, the invasion of the host colony by newly mated queens is a critical stage. We studied the strategy used by Rossomyrmex minuchae queens to invade their host Proformica longiseta. Field observations revealed that queens enter the host nest unchallenged by the host workers in the vicinity of the nest entrance. Pre-usurpation queens were found to possess a highly inflated Dufour's gland, which considerably reduces in size after successful usurpation. Chemical analysis of these queen glands revealed tetradecanal to be the major product in pre-usurpation Rossomyrmex queens, but to be almost absent in queens that have been adopted by P. longiseta. We consequently hypothesized that tetradecanal is a repellent that is used by queens to prevent host worker aggression. We tested its repellent effect by attempting to deter starved, highly motivated workers from a droplet of honey. Tetradecanal indeed proved to be highly repellent both to host worker P. longiseta and non-host worker Formica selysi. It was even more powerful than limonene, a reported general ant repellent. These results are consistent with the hypothesis that R. minuchae queens use Dufour's gland secretion as a weapon during nest usurpation. The general use of tetradecanal as a defensive compound, and its seemingly non-specific repellent effect on ants, indicate that it may act as a general ant repellent. Its adoption by R. minuchae queens thus provides them with an efficient defensive and offensive chemical weapon during their long and risky search for new host nests.     

Multiple functions of fire ant Solenopsis invicta mandibular gland products

Alarm pheromones of social insects are best known for their role in the defence and maintenance of colony integrity. Previous studies with the fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae) demonstrate that the mandibular glands of workers (sterile females) and male and female sexuals produce an alarm pheromone, 2‐ethyl‐3,6‐dimethylpyrazine. The function of alarm pheromones in worker ants is well understood and divergent from the function of these compounds in the winged sexual forms. The present study quantifies the amount of pyrazine in the mandibular glands from male and female alate sexuals, as well as queens. Pyrazine production in female alates starts in the late pupal stage and increases until they reach mating flight‐ready maturity; however, after mating flight participation, the pyrazine level declines by >50%. Interestingly, mature male alates lose >85% of their mandibular gland pyrazine during mating flight activity. The results of the present study indicate that male and female sexuals use mandibular gland secretions for mating flight initiation and during mating flights. Furthermore, the ontogeny of mandibular gland products (pyrazine as the marker) from newly‐mated queens to mature colony queens shows a more than two‐fold increase in the amount of pyrazine by 6 months after mating. However, this is followed by a decline to trace amounts in mature colony queens (>2 years old), suggesting a function for mandibular gland products during colony development. Multifunctional use of social insect pheromones is well documented and data are reported in the present study suggesting new roles for mandibular gland products in fire ants.     

Induction of balling in worker honeybees (Apis mellifera L.) by “stress” pheromone from Koschewnikow glands of queen bees: Behavioural,structural and chemical study

• 1.1. The Koschewnikow glands (KG) of honeybee queens are composed of type III glandular units; secretions are emitted from ducts that open onto the entire surface of the intersegmental membrane.
• 2.2. Secretory activity is characterized by the appearance of dense granules containing mainly glycoproteins, stained by periodic acid-thiocarbohydrazide-silver proteinate, extracted by pronase. In one-yearold mated queens, the gland degenerates. Secretory products originating from mitochondria are likely to be only carriers of pheromonal compounds.
• 3.3. Topical treatment of worker bees (“pseudoqueens”) with EtOH extracts of queen Koschewnikow glands induced typical queen balling behaviour in workers of a bee colony.
• 4.4. Twenty-eight compounds including acids, alcohols, alkanes and alkenes (C₈H₁₆C₄₃H₈₈) were characterized by gas liquid chromatography-mass spectrometry in queen KG extract. None of them is present in worker alarm pheromone which is secreted from worker KG.

     

Avoid mistakes when choosing a new home: Nest choice and adoption of Leptothorax ant queens

In ants, mating and colony founding are critical steps in the life of ant queens. Outside of their nests, young queens are exposed to intense predation. Therefore, they are expected to have evolved behavior to accurately and quickly locate a nesting place. However, data on the early life history of female reproductives are still lacking. Leptothorax gredleri is a suitable model organism to study the behavior of young queens. Reproductives can be reared under artificial conditions and readily mate in the laboratory. After mating, L. gredleri queens have the options to found solitarily, seek adoption into another colony, or return into their natal nest. In this study, we investigated the decision-making processes of female sexuals before and after mating. In particular, we tested whether female sexuals use chemical cues to find their way back to the nest, studied if they prefer their own nest over other nesting sites and followed the adoption dynamics of mated queens over 8 weeks (plus hibernation and spring). We showed that female sexuals and freshly mated queens spent more time on substrate previously used by workers from their own colony and from another colony than on a blank substrate. This discriminatory capability of queens appears to be lost in old, reproductive queens. Nest choice experiments showed that female sexuals and freshly mated queens can distinguish their own nest while old mated queens’ do not. When reintroduced in their maternal colony, young queens were readily adopted, but a few weeks later aggression against young queens led to their emigration from the maternal nest and eventually also death.     

Population and colony structure and morphometrics in the queen dimorphic harvester ant, <Emphasis Type="Italic">Pogonomyrmex pima</Emphasis>

The North American seed-harvester ant Pogonomyrmex (Ephebomyrmex) pima displays a dimorphism that consists of winged (alate) and wingless (intermorph) queens; both types of queens are fully reproductive. Microsatellite allele frequencies and a mitochondrial phylogeny demonstrate (1) alate and intermorph queens represent an intraspecific wing polymorphism, and (2) an absence of assortative mating and inbreeding by males. Surveys at our field site in southcentral Arizona, USA, demonstrated that only one type of queen (intermorph or dealate) occurred in each colony, including those excavated during the season in which reproductive sexuals were present. Colony structure appeared to vary by queen type as most intermorph colonies contained multiple mated queens. Alternatively, dealate queen colonies rarely contained a mated queen. Our inability to find mated dealate queens in these colonies probably resulted from difficulty in excavating the entire colony and reproductive queen, especially given that these colonies were only excavated over one day. A morphometric analysis demonstrated that intermorph queens are intermediate in size to that of workers and alate queens, but that intermorph queens retain all of the specialized anatomical features of alate queens (except for wings). Some colonies had queens that foraged and performed nest maintenance activities, and these queens sometimes accounted for a significant portion of colony foraging trips. Dissections revealed that these queens were uninseminated; some of these queens produced males in the laboratory. Received 24 October 2006; revised 1 December 2006; accepted 8 December 2006.     

Antimicrobial defense shows an abrupt evolutionary transition in the fungus-growing ants

Understanding the relative evolutionary importance of parasites to different host taxa is problematic because the expression of disease and resistance are often confounded by factors such as host age and condition. The antibiotic-producing metapleural glands of ants are a potentially useful exception to this rule because they are a key first-line defense that are fixed in size in adults. Here we conduct a comparative analysis of the size of the gland reservoir across the fungus-growing ants (tribe Attini). Most attines have singly mated queens, but in two derived genera, the leaf-cutting ants, the queens are multiply mated, which is hypothesized to have evolved to improve colony-level disease resistance. We found that, relative to body size, the gland reservoirs of most attines are similar in size but that those of the leaf-cutting ants are significantly larger. In contrast, the size of the reservoir did not relate with the evolutionary transition from lower to higher attines and correlated at most only slightly with colony size. The results thus suggest that the relationship between leaf-cutting ants and their parasites is distinctly different from that for other attine ants, in accord with the hypothesis that multiple mating by queens evolved to improve colony-level disease resistance.     

Chemical Profiles of Two Pheromone Glands Are Differentially Regulated by Distinct Mating Factors in Honey Bee Queens (Apis mellifera L.)

Pheromones mediate social interactions among individuals in a wide variety of species, from yeast to mammals. In social insects such as honey bees, pheromone communication systems can be extraordinarily complex and serve to coordinate behaviors among many individuals. One of the primary mediators of social behavior and organization in honey bee colonies is queen pheromone, which is produced by multiple glands. The types and quantities of chemicals produced differ significantly between virgin and mated queens, and recent studies have suggested that, in newly mated queens, insemination volume or quantity can affect pheromone production. Here, we examine the long-term impact of different factors involved during queen insemination on the chemical composition of the mandibular and Dufour''s glands, two of the major sources of queen pheromone. Our results demonstrate that carbon dioxide (an anesthetic used in instrumental insemination), physical manipulation of genital tract (presumably mimicking the act of copulation), insemination substance (saline vs. semen), and insemination volume (1 vs. 8 µl) all have long-term effects on mandibular gland chemical profiles. In contrast, Dufour''s gland chemical profiles were changed only upon insemination and were not influenced by exposure to carbon dioxide, manipulation, insemination substance or volume. These results suggest that the chemical contents of these two glands are regulated by different neuro-physiological mechanisms. Furthermore, workers responded differently to the different mandibular gland extracts in a choice assay. Although these studies must be validated in naturally mated queens of varying mating quality, our results suggest that while the chemical composition of Dufour''s gland is associated with mating status, that of the mandibular glands is associated with both mating status and insemination success. Thus, the queen appears to be signaling both status and reproductive quality to the workers, which may impact worker behavior and physiology as well as social organization and productivity of the colony.     

Functional morphology of the postpharyngeal gland of queens and workers of the ant Monomorium pharaonis (L.)

Eelen D., Børgesen L.W. and Billen J. 2006. Functional morphology of the postpharyngeal gland of queens and workers of the ant Monomorium pharaonis (L.). —Acta Zoologica (Stockholm) 87 : 101–111 The postpharyngeal gland (PPG) is unique to ants and is the largest exocrine gland in their head. In queens of the pharaoh's ant, Monomorium pharaonis, the gland contains approximately 15 finger‐like epithelial extensions on each side and opens dorsolaterally in the posterior pharynx. In these ants the PPG morphology varies considerably according to age and mating status. The epithelial thickness increases with age and reaches a maximum at 3 weeks in both virgin and mated queens. A considerable expansion of the lumen diameter occurs in both groups between 4 and 7 days. Virgin queens release their secretion into the gland lumen from an age of 7 days, whereas mated queens accumulate large amounts of secretion in their epithelium. The increasing epithelial thickness, together with the increasing lumen diameter, the presence of numerous inclusions in the epithelium and the release of secretion, are indicative for increasing gland activity. The gland ultrastructure indicates involvement in lipid metabolism and de novo synthesis of lipids. The PPG of workers consists of 12 finger‐like tubes at each side. There is a significant difference in epithelial thickness between nurses and repletes and between nurses and foragers. We suggest the PPG serves different purposes in pharaoh's ants: it is likely that the PPG of workers and virgin queens is used to feed larvae. In mated queens the gland probably plays a role in providing the queen with nutritious oils for egg production. The PPG may also function in signalling species nestmate and caste identity, as well as in the reproductive capacity of the queens.     

Host queen killing by a slave-maker ant queen: when is a host queen worth attacking?

A new colony of the slave-making ant Polyergus breviceps is initiated when a newly mated gyne invades a host nest and kills the resident queen. This process seems to result in chemical camouflage of the invading gyne and allows her to usurp the position of colony reproductive. Young, recently mated Formica gynes, however, are not attacked. To determine whether worker and/or immature presence is the basis for aggression, we placed eggs, larvae, pupae and workers from mature F. gnava queens with newly mated F. gnava queens and observed the responses of introducedP. breviceps queens. Because no newly mated gyne was attacked, we tested newly mated F. gnava queens (1) once they had produced eggs, (2) when the offspring reached the larval, pupal and callow stages of development, and (3) every 2 weeks until aggression ensued. Eventually all F. gnava queens were attacked but only 29 weeks after having mated. Thus, although offspring are the ultimate benefit from attacking an established F. gnava queen,P. breviceps queens detect mature queens using another time-dependent feature that is reliably indicative of reproductive status. The similarity of host queen hydrocarbon profiles, often correlated with reproductive status in other ant species, suggests that other compounds reflect queen fecundity and produce a kairomonal effect, or that another cue signals host queen and colony suitability. Our findings indicate P. breviceps gynes have evolved to respond aggressively to a host gyne cue that appears long after mating, preventing attacks on gynes without the workers necessary for colony founding.Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Fatty Acids of Extractable and Bound Lipids of Rhodomicrobium vannielii

Cells of Rhodomicrobium vannielii grown at 29 C in a lactate-containing medium were extracted at room temperature with organic solvents. The extractable fraction contained the bulk of the simple lipid (1.87% of cell dry weight) and complex lipids (phospholipids, 4.2%; sulfolipid, 0.01%), coenzyme Q (0.09%), and pigments (carotenoids 1.2%; bacteriochlorophyll, 1.9%). The cell residue contained the bound lipids (nonpolar fatty acid fraction, 1.86%; polar hydroxy fatty acids, 0.49%). The residue also contained poly-β-hydroxybutyric acid (0.2%), which was extracted in boiling chloroform. In both the simple and complex lipids, vaccenic acid (11-octadecenoic acid) was the largest single component (approximately 90% in each fraction). The fatty acids of the bound lipid contained 35% vaccenic acid, even- and odd-numbered saturated and unsaturated straight-chain fatty acids, cyclopropane-, branched-, and α- and β-hydroxy fatty acids. The extractable lipids contained only straight-chain saturated and unsaturated even-numbered fatty acids. Nearly 60% of hydroxy fatty acid fraction was α-hydroxydodecanoic acid (24%) and β-hydroxydodecanoic acid (34.5%). Coenzyme Q was crystallized and identified as Q₉ on the basis of melting point and chromatographic properties. Q₁₀ had been previously reported.     

The behaviour of queen honeybees and their attendants

Abstract. The behaviour of queen and worker honeybees (Apis mellifera L.) was observed using small colonies in observation hives. Workers paid more attention to queens which had been mated for 2 months or more than to those which were newly mated; virgin queens received least attention. Queens received most attention when they were stationary and least when they were walking over the comb; virgin queens were most active. Queen cells had as many attendants as virgin queens and queen larvae were inspected almost continuously. The queen pheromone component 9–oxo-trans-2–decenoic acid stimulated 'court' behaviour when presented on small polyethylene blocks, but workers responded aggressively to complete extracts of queens' heads. Both the heads and abdomens of mated queens received much attention from court workers but the abdomens were palpated by more workers for longer and were licked much more. The queens' thoraces were least attended. Abdominal tergites posterior to tergite glands were licked for longer than those anterior to the glands. Only worker bees very near to the queen reacted to her and joined her 'court'.
No evidence was found of a diel periodicity in the behaviour of a queen or her 'court'. During the winter the queen's court was smaller than in summer and she walked less and laid fewer eggs. When colonies were fed with sucrose syrup in winter, their queens laid more eggs and workers reared more brood but there was no change in the attention received by the queens.
The implications of these findings for the secretion and distribution of queen pheromones are discussed.     

Observation on the composition and biosynthesis of egg wax lipids in the cattle tick,Boophilus microplus

The biosynthesis of wax lipids by Gené's organ, the egg waxing organ in ticks, was investigated. Gené's organ, a complex dermal gland system, applies a superficial wax layer to the eggs during oviposition which prevents desiccation and is essential for egg viability. The detailed anatomy and histology of the three gland cell types are unambiguously described. Serial sectioning of ticks showed that all three gland cell types are capable of contributing to the egg wax. The wax synthetic ability of these three gland types was characterized. The composition of wax lipids extracted from the surface egg wax, and from the three types of wax gland dissected from ovipositing ticks, was analysed using thin-layer and gas-liquid chromatography. Injection of ovipositing ticks with radiolabelled acetate resulted in the incorporation of the label into wax lipids by gland cells of Gené's organ. The egg wax was a complex mixture of long-chain alkanes and fatty acid esters. The gland cells contained a greater proportion of shorter chain alkanes than were present in the egg surface wax. Some unsaturated long-chain fatty acids were present, and these were more abundant in the gland cells than in the surface wax of oviposited eggs, suggesting that oxidation occurs after oviposition. The results confirm that the tubular glands, acinar accessory glands and lobular glands of Gené's organ all contribute to the egg waxes, although the lipid components differed in relative abundance. The results are also consistent with alkane synthesis from fatty acids in Gené's organ by a chain-elongation-decarboxcylation pathway.     

Mating Triggers Queen Elimination by Workers of Japanese Harvester Ant (<Emphasis Type="Italic">Messor aciculatus</Emphasis>)

During reproduction, ant colonies produce winged queens. These new queens usually leave the nest to mate and can then establish a new nest. If the new nest is close to an existing colony, it will be in competition with the existing colony. Therefore, workers will kill any mated queens they find outside the colony during the reproductive season. In this study, factors that might determine whether workers eliminate queens were investigated. Mating status (mated or unmated), colony origin (same or different to tested workers) and mating partners (inbred or outbred) of the queens of Japanese harvester ants (Messor aciculatus) were manipulated and the workers’ behavior towards the queens was observed. Mated queens were always attacked by workers, though this was not affected by either colony origin or mating partners. These results suggest that mating status triggers elimination of queens by workers, and that the colony origin and mating partner are unlikely to be important roles in elimination of queens.     

Lipoidal Components of Bacterial Lipopolysaccharides: Nature and Distribution of Fatty Acids in Aerobacter aerogenes

The fatty acid distribution of Aerobacter aerogenes was studied by comparing the fatty acid composition of the lipoidal component of the endotoxin (lipid A) with the fatty acids of the readily extractable native lipids and total cellular fatty acids. The results for total cellular fatty acids and readily extractable native lipids were generally similar, but both quantitative and qualitative differences exist. In addition, profound differences between these two fractions and lipid A were observed. These differences included fewer fatty acids and lower concentrations of unsaturated and cyclopropane fatty acids in the lipid A. Hydroxy fatty acids persisted in the lipid A. The significance of these differences with respect to mammalian toxicity of endotoxins is discussed.     

Variability in fatty acids and fatty aldehydes in different organs of two prosobranch gastropod mollusks

The distribution of fatty acids and fatty aldehydes of total lipids in mantle, foot and digestive gland of two prosobranch gastropod mollusks, Bellamya bengalensis and Pila globosa, from India were studied. The individual volatile compounds, e.g., acids and aldehydes, were separated by serially coupled capillary columns with different polarity stationary phase and identified by gas chromatography-mass spectrometry. Saturated fatty acids were the main components and vary from 48–60%, monoenic are 18–30%, while polyunsaturates vary between 21–33%. The digestive glands of both the snail species contained cyclopropane fatty acids, not previously reported in gastropods.     

Comparative morphology of cephalic exocrine glands among castes of the black ant Lasius niger

The glandular system is crucially involved in main aspects of ant social life. The function of glands has been primarily studied in the workers (the non-reproductive individuals in a colony). In contrast, little information is available on queens (the reproductive females in a colony) or males in spite of the obvious functional differences between these castes. Here we report a comparison of the general morphology of the mandibular, propharyngeal and postpharyngeal glands between the three castes of the black ant Lasius niger. The analysis clearly shows that all these cephalic glands differ in relative size between castes and suggests a link between gland structure and its behavioral role in queens, workers and males. In particular, males present a hypertrophied mandibular gland. This is consistent with the fact that these glands might be the source of the sex pheromone in this caste. By contrast, queens exhibited the most developed postpharyngeal glands. This is consistent with the production of particular cues by queens for workers to help them to distinguish between reproductive and non-reproductive females. Finally, the propharyngeal glands were most developed in the worker caste and of similar relative size in males and queens. Their function is still enigmatic.     

Task-related variation of postpharyngeal and cuticular hydrocarbon compositions in the ant Myrmicaria eumenoides

In the ant Myrmicaria eumenoides we investigated postpharyngeal and cuticular hydrocarbons. At eclosion the glands contained almost no hydrocarbons and there were no lipid inclusions in the glandular epithelium. During the first 3 weeks of adult life the amount of hydrocarbons in the gland increased until day 5, and then remained constant while the lipid content in the epithelium increased steadily. Intracolonial hydrocarbon compositions were not uniform. Compositions of post-pharyngeal and cuticular hydrocarbons in individual ants varied simultaneously, but in different manner depending on the tasks of the ant (brood-tenders, foragers, scouts). Variations on the cuticle were greater than in the gland, but they were strongly correlated. Independent of ants' age and task, cuticular hydrocarbon compositions were dominated by alkenes and alkadienes. Task-specific differences in cuticular compositions were mainly in the amount of alkenes (high in foragers) and alkadienes (high in brood-tenders). Variation of hydrocarbons was low in ants up to 10 weeks old. Thereafter, ants fell into two groups: (1) ants that did not change their hydrocarbons and remained in the nest, and (2) ants that changed their hydrocarbon compositions and became foragers. These results contribute to an ongoing discussion of the dynamic relationship between post-pharyngeal and cuticular hydrocarbons.