Anita M. Collins

Sperm storage and antioxidative enzyme expression in the honey bee, Apis mellifera

Honey bee (Apis mellifera) sperm remains viable in the spermatheca of mated female honey bees for several years. During this time, the sperm retains respiratory activity, placing it at risk of the damaging effects of reactive oxygen species common to many biological processes. Antioxidative enzymes might help reduce this damage. Here we use quantitative real‐time RT‐PCR to establish gene‐expression profiles in male and female honey bee reproductive tissues for three antioxidative enzymes: catalase, glutathione‐S‐transferase (GST) and superoxide dismutase (SOD1, cytosolic). Catalase and GST showed ten‐ to twenty‐fold transcript increases in the sperm storage organs of mated queens vs. unmated queens, whereas SOD1 levels are high in both mated and unmated queens. Male reproductive and somatic tissues showed relatively high levels of all three antioxidant‐encoding transcripts. All three enzymes screened were higher in mature males vs. young males, although this effect did not appear to be confined to reproductive tissues and, hence, need not reflect a role in sperm longevity. Furthermore, antioxidative enzyme transcripts remained present, and apparently increased, in male tissues long after sperm had matured and seminal fluid was produced. We also found measurable levels of catalase transcripts in honey bee semen. The presence of catalase transcripts in both reproductive tissues and semen in bees suggests that this enzyme might play a key role in antioxidative protection.

Colony defense by africanized and European honey bees.

Africanized and European honey bee (Apis mellifera) populations showed quantitative differences in colony defensive behavior. Africanized bees responded faster and in much larger numbers than European honey bees and produced 8.2 and 5.9 times as many stings during two different experiments. Times to react to alarming stimuli were negatively correlated with the number of bees responding and to the total number of stings. The number of bees responding was significantly correlated to the total number of stings only for the Africanized population.

Proteomic analyses of male contributions to honey bee sperm storage and mating

Honey bee (Apis mellifera L.) queens mate early in life and store sperm for years. Male bees likely contribute significantly to sperm survival. Proteins were extracted from seminal vesicles and semen of mature drones, separated by electrophoresis, and analysed by peptide mass fingerprinting. Computer searches against three databases, general species, honey bees and fruit flies, were performed. Spectra were used to query the recently generated honey bee genome protein list as well as general species and fruit fly databases. Of the 69 unique honey bee proteins found, 66 are also in Drosophila melanogaster. Two proteins only matched honey bee genes and one is a widespread protein lost from the fly genome. There is over‐representation of genes implicated in the glycolysis pathway. Metabolism‐associated proteins were found primarily in the seminal vesicle. Male accessory gland proteins as identified in Drosophila rarely had orthologs among proteins found in the honey bee. A complete listing of gel spots chosen including honey bee genome matches and Mascot searches of MALDI‐TOF results with statistics is in the Supplementary table. MALDI‐TOF spectra and more complete Mascot peptide mass fingerprinting data are available on request. Supplementary figs 1–3 show the stained protein gels.

Bioassay of compounds derived from the honeybee sting

Nine compounds identified from honeybee,Apis mettifera L., sting extracts and one compound identified from the honeybee mandibular gland were evaluated in a standardized laboratory test for their effectiveness in eliciting an alarm response from caged honeybees. Two,n-decyl acetate and benzyl alcohol, were judged ineffective as alarm pheromones. The remaining eight—2-nonanol, isopentyl acetate,n-butyl acetate,n-hexyl acetate, benzyl acetate, isopentyl alcohol, andn-octyl acetate from the sting and 2-heptanone from the mandibular gland-produced responses of similar frequency and strength.

Chemistry of the Sting Apparatus of the Worker Honeybee

SummaryVolatile compounds present in extracts of the sting apparatus of foraging worker honeybees were analysed by gas chromatography and mass spectrometry. Eight acetates were detected, including n-butyl, isoamyl, n-hexyl, n-octyl, n-decyl, and benzyl acetate. These esters were accompanied by isoamyl alcohol, 2-nonanol and benzyl alcohol, as well as a series of aliphatic hydrocarbons.

A Model of Honeybee Defensive Behaviour

SummaryA model of defensive behaviour by an individual honeybee (Apis mellifera) is presented. The behavioural sequence involves four basic steps: alerting, activating, attracting and culminating. The model accommodates both genetic and environmental variation.

Male reproductive parasitism: a factor in the africanization of European honey-bee populations.

Africanized drone honey bees (Apis mellifera) migrate into European honey-bee colonies in large numbers, but Africanized colonies only rarely host drones from other colonies. This migration leads to a strong mating advantage for Africanized bees since it both inhibits European drone production and enhances Africanized drone production.

Alarm responses caused by newly identified compounds derived from the honeybee sting

Twelve compounds identified from honeybee,Apis mellifera L., sting extracts were evaluated in a standardized laboratory test for their effectiveness in eliciting an alarm response from caged worker honeybees. Two-1-decanol and phenol-were judged ineffective as alarm pheromones. The other ten-1-butanol, isopentyl acetate, isopentyl alcohol, 1-hexanol, 2-heptyl acetate, 2-heptanol, 1-octanol, 1-acetoxy-2-octene, 2-nonyl acetate, and 1-acetoxy-2-nonene-produced alarm responses of similar speed and intensity. Three non-sting-derived compounds-β-ionone, methyl benzoate, andtrans-cinnamaldehyde—caused weak or no responses, indicating that the responses were not simply a reaction to concentrated odoriferous substances.

Survival of Honey Bee (Hymenoptera: Apidae) Spermatozoa Stored at Above-Freezing Temperatures

Abstract The development of practical techniques for the storage of honey bee, Apis mellifera L., semen would significantly improve our ability to breed for desirable genotypes and maintain genetic diversity in populations. Artificial insemination of queens has been possible for some time, but the semen used is usually freshly collected, or held for <1 wk at room temperature. I examined the limitations of spermatozoal survival at nonfrozen temperatures. Pooled, diluted semen was stored in sealed capillary tubes at room temperature (25°C) or in a refrigerator set to 12°C, for periods up to 1 yr. Survival of spermatozoa was assayed by a dual fluorescent staining technique using SYBR-14 and propidium iodide stains, which readily distinguishes live and dead cells. No significant loss of viable spermatozoa occurred within the first 6 wk. Between weeks 6 and 9, the percent live spermatozoa fell from 80 to 58%, and remained at that level until after 39 wk. By week 52, samples at room temperature, but not at 12°C, fell to 18.9% live spermatozoa. Nonfrozen storage of honey bee semen has potential for short-term preservation of germplasm, however several factors need to be studied further to optimize survival rates.

Performance of honey bee (Apis mellifera) queens reared in beeswax cells impregnated with coumaphos

SUMMARY The sublethal effects of coumaphos on developing queens were investigated. Young honey bee larvae were transferred into beeswax cups containing known concentrations (0 to 1000 mg/kg) of coumaphos. The cups with larvae were placed in queenless colonies for rearing and 10 days later acceptance was determined by recording mature queen cells. The queen cells were placed in small mating colonies for 21 days, when the queens were collected after being rated for commercial acceptability. The queens were then either introduced to production colonies and monitored for six months or dissected to determine mating success. All but one queen failed to develop at 1000 mg/kg of coumaphos, and greater than 50% of cells were rejected at 100 mg/kg coumaphos. The queens that were reared were lighter in weight as pre-emergence pupae. The effects on other characters related to queen performance are discussed. The presence of coumaphos in queen rearing cells can reduce the number of queens still functioning in colonies at six months by as much as 75%.