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At least 109 records · Page 6Linked to original sources
PubMed2003

Male fitness of honeybee colonies (Apis mellifera L.).

Honeybees (Apis mellifera L.) have an extreme polyandrous mating system. Worker offspring of 19 naturally mated queens was genotyped with DNA microsatellites, to estimate male reproductive success of 16 drone producing colonies. This allowed for estimating the male mating success on both the colony level and the level of individual drones. The experiment was conducted in a closed population on an isolated island to exclude interferences of drones from unknown colonies. Although all colonies had produced similar numbers of drones, differences among the colonies in male mating success exceeded one order of magnitude. These differences were enhanced by the siring success of individual drones within the offspring of mated queens. The siring success of individual drones was correlated with the mating frequency at the colony level. Thus more successful colonies not only produced drones with a higher chance of mating, but also with a significantly higher proportion of offspring sired than drones from less successful colonies. Although the life cycle of honeybee colonies is very female centred, the male reproductive success appears to be a major driver of natural selection in honeybees.

Animals↗
PubMed1996

Common endocrine and genetic mechanisms of behavioral development in male and worker honey bees and the evolution of division of labor.

Temporal polyethism is a highly derived form of behavioral development displayed by social insects. Hormonal and genetic mechanisms regulating temporal polyethism in worker honey bees have been identified, but the evolution of these mechanisms is not well understood. We performed three experiments with male honey bees (drones) to investigate how mechanisms regulating temporal polyethism may have evolved because, relative to workers, drones display an intriguing combination of similarities and differences in behavioral development. We report that behavioral development in drones is regulated by mechanisms common to workers. In experiment 1, drones treated with the juvenile hormone (JH) analog methoprene started flying at significantly younger ages than did control drones, as is the case for workers. In experiment 2, there was an age-related increase in JH associated with the onset of drone flight, as in workers. In experiment 3, drones derived from workers with fast rates of behavioral development themselves started flying at younger ages than drones derived from workers with slower rates of behavioral development. These results suggest that endocrine and genetic mechanisms associated with temporal polyethism did not evolve strictly within the context of worker social behavior.

Aging↗
PubMed2001

Effects of western honey bee (Hymenoptera: Apidae) colony, cell type, and larval sex on host acquisition by female Varroa destructor (Acari: Varroidae).

Female mites of the genus Varroa reproduce on the immature stages of Apis cerana F. and A. mellifera L. Mites are found more often in drone brood than worker brood, and while evolutionary explanations for this bias are well supported, the proximate mechanisms are not known. In one experiment, we verified that the proportion of hosts with one or more mites (MPV, mite prevalence value) was significantly greater for drones (0.763 +/- 0.043) (lsmean +/- SE) than for workers (0.253 +/- 0.043) in populations of mites and bees in the United States. Similar results were found for the average number of mites per host. In a second experiment, using a cross-fostering technique in which worker and drone larvae were reared in both worker and drone cells, we found that cell type, larval sex, colony and all interactions affected the level of mites on a host. Mite prevalence values were greatest in drone larvae reared in drone cells (0.907 +/- 0.025), followed by drone larvae reared in worker cells (0.751 +/- 0.025), worker larvae reared in worker cells (0.499 +/- 0.025), and worker larvae reared in drone cells (0.383 +/- 0.025). Similar results were found for the average number of mites per host. Our data show that mite levels are affected by environmental factors (cell type), by factors intrinsic to the host (sex), and by interactions between these factors. In addition, colony-to-colony variation is important to the expression of intrinsic and environmental factors.

Animals↗
PubMed1994

Linkage analysis of sex determination in the honey bee (Apis mellifera).

A colony-level phenotype was used to map the major sex determination locus (designated X) in the honey bee (Apis mellifera). Individual queen bees (reproductive females) were mated to single drones (fertile males) by instrumental insemination. Haploid drone progeny of an F1 queen were each backcrossed to daughter queens from one of the parental lines. Ninety-eight of the resulting colonies containing back-cross progeny were evaluated for the trait 'low brood-viability' resulting from the production of diploid drones that were homozygous at X. DNA samples from the haploid drone fathers of these colonies were used individually in polymerase chain reactions (PCR) with 10-base primers. These reactions generated random amplified polymorphic DNA (RAPD) markers that were analyzed for cosegregation with the colony-level phenotype. One RAPD marker allele was shared by 22 of 25 drones that fathered low brood-viability colonies. The RAPD marker fragment was cloned and partially sequenced. Two primers were designed that define a sequence-tagged site (STS) for this locus. The primers amplified DNA marker fragments that cosegregated with the original RAPD marker. In order to more precisely estimate the linkage between X and the STS locus, another group of bees consisting of progeny from one of the low-brood viability colonies was used in segregation analysis. Four diploid drones and 181 of their diploid sisters (workers, nonfertile females) were tested for segregation of the RAPD and STS markers. The cosegregating RAPD and STS markers were codominant due to the occurrence of fragment-length alleles. The four diploid drones were homozygous for these markers but only three of the 181 workers were homozygotes (recombinants). Therefore the distance between X and the STS locus was estimated at 1.6 cM. An additional linked marker was found that was 6.6 cM from the STS locus.

Animals↗
PubMed2005

Caste, sex and strain of honey bees (Apis mellifera) affect infestation with tracheal mites (Acarapis woodi).

Worker honey bees from genetic strains selected for being resistant (R) or susceptible (S) to tracheal mites typically show large differences in infestation in field colonies and in bioassays that involve controlled exposure to infested bees. We used bioassays exposing newly emerged individuals to infested workers to compare the propensity for tracheal mites to infest queens, drones and workers from R and S colonies. In tests with queens, newly emerged R and S queens were either simultaneously confined in infested colonies (n = 95 and 87 respectively), or individually caged with groups of 5-20 infested workers (n = 119 and 115 respectively). Mite prevalence (percentage of individuals infested) and abundance (foundress mites per individual) after 4-6 days did not differ between R and S queens. In another test, five newly emerged drones and workers from both an R and an S colony, and a queen of one of the two strains, were caged in each of 38 cages with 20 g of workers infested at 60-96% prevalence. Infestations of the R queens (n = 17) and S queens (n = 19) did not differ significantly, but R workers had half the mite abundance of S workers, while R drones received about a third more migrating mites than S drones. In tests to evaluate possible mechanisms, removal of one mesothoracic leg from R and S workers resulted in 2- to 10-fold increase in mite abundance on the treated side, but excising legs did not affect infestation of the corresponding tracheae in drones. This suggests that differences in infestation between R and S workers, but not drones, are largely determined by their ability to remove mites through autogrooming. If autogrooming is the primary mechanism of colony resistance to tracheal mites, selection for resistance to tracheal mites using infestation of hemizygous drones may be inefficient.

Animals↗
PubMed1997

Expansion of the neuropil of the mushroom bodies in male honey bees is coincident with initiation of flight.

The mushroom bodies (MB), the insect brain structures most often associated with learning, have previously been shown to exhibit structural plasticity during the adult behavioral development of female worker and queen honey bees. We now show that comparable morphological changes occur in the brains of male honey bees (drones). The volume of the MB in the brains of drones was estimated from tissue sections using the Cavalieri method. Brains were obtained from six groups of drones that differed in age and flight experience. Circulating levels of juvenile hormone (JH) in these drones were determined by radioimmunoassay (RIA). There was an expansion of the neuropil of the MB that was temporally associated with drone behavioral development, as in female queens and workers. The observed changes in drones were maintained in the presence of low levels of JH, also as in females. These results suggest that expansion of the neuropil of the MB in honey bees is associated with learning the location of the nest, because this learning is the most prominent aspect of behavioral development common to all members (workers, drones, queen) of the honey bee colony.

Age Factors↗
PubMed2006

Mating system of the European hornet Vespa crabro: male seeking strategies and evidence for the involvement of a sex pheromone.

We describe details of the mate finding strategy of drones of the European hornet, Vespa crabro, and present evidence for the involvement of sex pheromones. Tests were carried out with free flying drones in natural habitats. Males patrolled the nest site itself, as well as nearby nonresource-based sites, without showing territorial behavior. Patrolling was restricted to sunny spots in the vegetation, and thus, the locations changed throughout the day. Drones were attracted to both caged gynes and to dead workers treated with gyne extracts, indicating the presence of a female-produced sex attractant. Treated workers also elicited copulation attempts by the attracted drones. Extracts from gynes, workers, and drones contained exclusively cuticular lipids, and the profile from gynes was much more diverse than that of workers and drones. The most striking differences observed related to the alkenes, monomethyl- and dimethylalkanes. The results provide a lead for potential attracting and copulation-releasing semiochemicals in V. crabro.

Alkanes↗
PubMed2004

High affinity HERG K(+) channel blockade by the antiarrhythmic agent dronedarone: resistance to mutations of the S6 residues Y652 and F656.

Pharmacological inhibition of human-ether-a-go-go-related gene (HERG) K(+) channels by structurally and therapeutically diverse drugs is associated with the 'acquired' form of long QT syndrome and with potentially lethal cardiac arrhythmias. Two aromatic amino-acid residues (Y652 and F656) on the inner (S6) helices are considered to be key constituents of a high affinity drug binding site within the HERG channel pore cavity. Using wild-type (WT) and mutant HERG channels expressed in mammalian cell lines, we have investigated HERG channel current (I(HERG)) blockade at 37+/-1 degrees C by dronedarone (DRONED), a non-iodinated analogue of the Class III antiarrhythmic agent amiodarone (AMIOD). Under our conditions WT I(HERG) tails, measured at -40 mV following activating pulses to +30 mV, were blocked with IC(50) values of approximately 59 and 70 nM for DRONED and AMIOD, respectively. I(HERG) inhibition by DRONED was contingent upon channel gating, with block developing rapidly on membrane depolarization, but with no preference for activated over inactivated channels. High external [K(+)] (94 mM) reduced the potency of I(HERG) inhibition by both DRONED and AMIOD. Strikingly, mutagenesis to alanine of the S6 residue F656 (F656A) failed to eliminate blockade by both DRONED and AMIOD, whilst Y652A had comparatively little effect on DRONED but some effect on AMIOD. These findings demonstrate that high affinity drug blockade of I(HERG) can occur without a strong dependence on the Y652 and F656 aromatic amino-acid residues.

Amino Acid Substitution↗
PubMed2006

Beyond 9-ODA: sex pheromone communication in the European honey bee Apis mellifera L.

The major component of the mandibular gland secretion of queen honeybees (Apis mellifera L.), 9-ODA ((2E)-9-oxodecenoic acid), has been known for more than 40 yr to function as a long-range sex pheromone, attracting drones at congregation areas and drone flyways. Tests of other mandibular gland components failed to demonstrate attraction. It remained unclear whether these components served any function in mating behavior. We performed dual-choice experiments, using a rotating drone carousel, to test the attractiveness of 9-ODA compared to mixtures of 9-ODA with three other most abundant components in virgin queen mandibular gland secretions: (2E)-9-hydroxydecenoic acid (9-HDA), (2E)-10-hydroxydecenoic acid (10-HDA), and p-hydroxybenzoate (HOB). We found no differences in the number of drones attracted to 9-ODA or the respective mixtures over a distance. However, adding 9-HDA and 10-HDA, or 9-HDA, 10-HDA, and HOB to 9-ODA increased the number of drones making contact with the baited dummy. On the basis of these results, we suggest that at least 9-HDA and 10-HDA are additional components of the sex pheromone blend of A. mellifera.

Animal Communication↗
PubMed2002

Effect of acaricide resistance on reproductive ability of the honey bee mite Varroa destructor.

The reproduction of pyrethroid-resistant Varroa destructor mite, a brood parasite of honey bees, was observed in Weslaco, Texas, and the results compared with known susceptible mite populations from other studies. Seven Apis mellifera colonies that had mite populations resistant to the acaricide Apistan were used. Pyrethroid-resistance was confirmed when only 17% rather than 90% of mites confined in dishes containing Apistan died after 12 h of exposure. The average number of eggs laid by resistant mites invading worker and drone cells was 4.4 and 5.4 respectively. This is similar to the number of eggs laid by susceptible mites in worker (4.4-4.8) or drone (4.7-5.5) cells. Also the average number of fertilised V. destructor female mites produced by resistant mites in worker (1.0) and drone (2.1) cells were similar to the number produced by susceptible mites in worker (0.9) and drone (1.9-2.2) cells. In addition, no major differences between the resistant and susceptible mite populations were observed in either worker or drone cells when six different reproductive categories and offspring mortality rates were compared. Therefore, it appears that there is little or no reproductive fitness cost associated with pyrethroid resistance in V. destructor in Texas.

Animals↗
PubMed2004

Identification of honeybee antennal proteins/genes expressed in a sex- and/or caste selective manner.

We identified three candidate proteins/genes involved in caste and/or sex-specific olfactory processing in the honeybee Apis mellifera L., that are differentially expressed between the antennae of the worker, queen, and drone honeybees using SDS-polyacrylamide gel electrophoresis or the differential display method. A protein was identified, termed D-AP1, that was expressed preferentially in drone antennae when compared to those of workers. cDNA cloning revealed that D-AP1 is homologous to carboxylesterases. Enzymatic carboxylesterase activity in the drone antennae was higher than in the workers, suggesting its dominant function in the drone antennae. In contrast, two proteins encoded by genes termed W-AP1 and Amwat were expressed preferentially in worker antennae when compared to those of queens. W-AP1 is homologous to insect chemosensory protein, and Amwat encodes a novel secretory protein. W-AP1 is expressed selectively in worker antennae, while Amwat is expressed both in the antennae and legs of the workers. These findings suggest that these proteins are involved in the antennal function characteristic to drone or worker honeybees.

Amino Acid Sequence↗
PubMed1992

Eye regionalization and spectral tuning of retinal pigments in insects.

The spatial and spectral properties of an eye can often be directly linked to the behaviour and habitat of the animal. In a honey bee (Apis mellifera) society, the drones use the well-developed dorsal part of the eye to detect the queen against the sky during her nuptial flight. Recently it has become clear that the dorsal area of the drone's eye serves its task by cleverly combining a number of optical mechanisms, thus achieving a high spatial acuity as well as a high sensitivity precisely in the wavelength range of interest--the ultraviolet to blue range. Since the various optical specializations in the drone eye have now been recognized, they can be traced in the eyes of other species: thus, the drone eye serves as a model to give a better understanding of the relationship between structure and function of compound eyes in particular, but also of visual systems in general.

Animals↗