Factors influencing seasonal absconding in colonies of the African honey bee,Apis mellifera scutellata

Summary This study investigated the effects of colony growth and development, food storage, foraging activity and weather on the migration behavior of African honey bees in the Okavango River Delta, Botswana. Four observation colonies were studied during the honey bee migration season (November–May), at which time the availability of blooming species was reduced. Two of the colonies (colonies 1 & 2) migrated during the study period, while the remaining two (colonies 3 & 4) did not. During the 4–6 weeks preceding the onset of migration preparations, colonies 1 & 2 exhibited increasing population sizes, high levels of brood production with low brood mortality, relatively large stores of food, and increasing mass. In contrast, the populations of colonies 3 & 4 did not increase, brood-rearing activity was erratic and lower, brood mortality was higher, food stores became depleted and colony mass declined. Both colonies 3 & 4 ceased rearing brood, and colony 3 died of starvation. Colony foraging activity was examined by monitoring waggle-dance activity 2–3 days each week. For 4–6 weeks before the onset of migration in colonies 1 & 2, daily foraging areas and mean daily foraging distances became increasingly large and variable. Colonies 3 & 4 exhibited foraging patterns similar to those observed for colonies 1 & 2 preceding migration. There was no clear association between 7 weather parameters examined and migration behavior. These data suggest that migration is influenced by an interaction of intra-colony demographics, food reserves and foraging patterns. Migration may be feasible only for those colonies that possess (1) a population of appropriate size and age structure to compensate for the natural attrition of older workers during the emigration process, and (2) sufficient food reserves for long-distance travel and the establishment of a new nest. Changing foraging patterns may reflect a deteriorating foraging environment, which may trigger the onset of migration preparations, provided that colony demographics and food reserves are conducive. Colonies that show decreased brood production, higher brood mortality and reduced food stores may be incapable of migrating, even when experiencing deteriorating foraging conditions. Rather, such colonies may have a greater chance of survival if they attempt to persist in a given area.     

Nocturnal dispersal by femaleAcarapis woodi in honey bee (Apis mellifera) colonies

Comparisons were made between the infestation levels of the honey bee tracheal miteAcarapis woodi (Rennie) in newly emerged honey bees (Apis mellifera L.) exposed for 12 h during the daytime or nighttime in mite-infested bee colonies. Bees exposed during the night harbored a significantly higher number of mites (718) when compared with the daytime bees (88 mites) (n=14 day/night cycles utilizing 33 colonies). On 4 days of an 8-day study, three test colonies were closed during the daytime to eliminate foraging flights. Thus equal numbers of bees were present in the colonies during the day and night sample periods. These 4 flightless days were compared to 4 free-flight days and mite dispersal rates were not significantly different. Additionally, the movement of bees on the combs of four glass-walled observation hives was quantified on 10 days at 0800, 1200, 1600, 2000, 2400 and 0400 h. Bee movement at 2400 and 0400 h was significantly lower than the other observation times. Movement of host bees may be one factor involved in the increased nighttime mite dispersals. These findings do not support the hypothesis that the absence of foraging bees during the day reduces the bee to bee contact time, thus reducing mite dispersals between host bees. Differential diurnal activity levels between host bees and mite parasites was demonstrated. The exact role of host-bee behavior and/or mite behavior in the nighttime dispersal patterns observed, remains for further investigation.     

Hox genes in the honey bee Apis mellifera

Hox genes are known to control the identity of serially repeated structures in arthropods and vertebrates. We analyzed the expression pattern of the Hox genes Deformed (Dfd), Sex combs reduced (Scr), Antennapedia (Antp), and Ultrabithorax/abdominal-A (Ubx/abd-A) from the honey bee Apis mellifera. We also cloned a cDNA with the complete coding region of the Antennapedia gene from Apis. Comparison with Antp proteins from other insect species revealed several regions of homology. The expression patterns of the isolated Hox genes from Apis showed that the original expression patterns of Dfd, Scr, and Antp appear between late blastoderm and early germ band stage in a temporal and spatial sequence. Each of them shows up as a belt, spanning approximately two segment anlagen, Dfd in the anterior gnathal region, Scr in the posterior gnathal and anterior thoracic region, and Antp in the thoracic region. Following expansion of the Antp domain in the abdomen as a gradient towards the posterior, Ubx/abd-A expression appears laterally in the abdomen. During gastrulation and in the germ band stage the domains of strong expression do not overlap any more, but touch each other. After gastrulation the borders of the expression domains partly correlate with parasegment and partly with segment boundaries. Laterally, gaps between the domain of each gene may show no expression of any of the genes examined. Received: 30 August 1999 / Accepted: 28 April 2000     

Waggle dance behavior associated with seasonal absconding in colonies of the African honey bee,Apis mellifera scutellata

Summary Waggle dance activity associated with seasonal absconding (migration) was investigated in two colonies of the African honey bee. Prior to absconding, waggle dances regularly communicated distances up to 10–20 km from the nests. However, compared to waggle dances observed during nonabsconding periods, those occurring prior to migration were less associated with food sources, occurred during periods of little or no flight activity, and exhibited great variability in the communication of distance by consecutive waggle runs of individual bees. It is therefore unlikely that migration dances communicated the locations of, or stimulated immediate recruitment for, specific foraging or nesting sites. Rather, the dances may have functioned to establish a general route of travel. The majority of migration dances observed were oriented in an easterly direction, and upon departure both colonies traveled towards the E-SE. The orientation of migration dances occurred independently of the directions communicated by waggle dances associated with past foraging success or the sampling of alternate foraging areas. Migration dance orientation may have been affected by prevailing wind directions, because during the migration period winds blew primarily from the east. However, it is unlikely that wind direction was the only factor influencing migration dance orientation. The lack of immediate flight activity associated with migration dance performance suggests the dances may have gradually prepared colonies for migratory movement by conveying a message to fly for a long, but unspecified distance in a certain direction. Waggle dances associated with migration may therefore function differently from those associated with foraging and nest site selection, which convey both the distance and direction to specific locations.     

Life history strategy of the honey bee,Apis mellifera

Summary The feral honey bee queens (colonies) of central New York State (USA) show a K-type life history strategy. Their demographic characteristics include low early life mortality, low reproductive rate, long lifespan, high population stability and repeated reproductions. Identifying the life history strategy of these bees reveals the general pattern of selection for competitive ability, rather than productivity, which has shaped their societies. Selection for competitive power explains the adaptiveness (compared with alternatives found in many other insect societies) of the large perennial colonies, infrequent but expensive offspring, and efficient foraging which characterize the social organization of these bees.     

Selection for outbreeding in Varroa parasitising resistant honey bee (Apis mellifera) colonies

Parasitism is expected to select for counter‐adaptations in the host: driving a coevolutionary arms race. However, human interference between honey bees (Apis mellifera) and Varroa mites removes the effect of natural selection and restricts the evolution of host counter‐adaptations. With full‐sibling mating common among Varroa, this can rapidly select for virulent, highly inbred, Varroa populations. We investigated how the evolution of host resistance could affect the infesting population of Varroa mites. We screened a Varroa‐resistant honey bee population near Toulouse, France, for a Varroa resistance trait: the inhibition of Varroa's reproduction in drone pupae. We then genotyped Varroa which had co‐infested a cell using microsatellites. Across all resistant honey bee colonies, Varroa's reproductive success was significantly higher in co‐infested cells but the distribution of Varroa between singly and multiply infested cells was not different from random. While there was a trend for increased reproductive success when Varroa of differing haplotypes co‐infested a cell, this was not significant. This suggests local mate competition, through the presence of another Varroa foundress in a pupal cell, may be enough to help Varroa overcome host resistance traits; with a critical mass of infesting Varroa overwhelming host resistance. However, the fitness trade‐offs associated with preferentially co‐infesting cells may be too high for Varroa to evolve a mechanism to identify already‐infested cells. The increased reproductive success of Varroa when co‐infesting resistant pupal cells may act as a release valve on the selective pressure for the evolution of counter resistance traits: helping to maintain a stable host–parasite relationship.     

Chill sensitivity of honey bee, Apis mellifera, embryos

Improved methods for preservation of honey bee, Apis mellifera L., germplasm would be very welcome to beekeeping industry queen breeders. The introduction of two parasites and the emergence of an antibiotic resistant disease have increased demands for resistant stock. Techniques for artificial insemination of queens are available, and semen has been cryopreserved with limited success. However, cryopreservation of embryos for rearing queens would mesh well with current practices and also provide drones (haploid males). Eggs at five ages between twenty-four hours and sixty-two hours were exposed to 0, -6.6, and/or -15 degrees C for various times, and successful hatch measured. Honey bee embryos show chill sensitivity as do other insect embryos, and the rate of chill injury increases dramatically with decrease in holding temperature. The 48 h embryos in both groups showed the greatest tolerance to chilling, although 44 h embryos were only slightly less so.     

Seasonal patterns of foraging activity in colonies of the African honey bee,Apis mellifera scutellata,in Africa

Summary Seasonal foraging patterns were investigated using six observation colonies maintained in the Okavango Delta, Botswana. Pollen collection, flight from the hive, and recruitment for pollen and nectar sources occurred throughout the 11 months of the study. However, the distribution of foraging activity throughout the day changed seasonally. Colonies emphasized recruitment for pollen sites throughout most of the year. Brood production occurred in all months except May, and there was a significant, positive correlation between the proportion of recruitment activity devoted to pollen sources and the amount of brood comb in the colonies. The seasonal foraging patterns ofscutellata in the Okavango were similar to those of Africanized honey bees in the neotropics. The extended foraging season and emphasis on pollen collection may be associated with the high swarming rates and migrational movements of tropical honey bees.     

Microbiology of feces of the larval honey bee,Apis mellifera

Methods for collection and microbiological examination of feces of larval honey bees, Apis mellifera, are described. Feces collected on sterile agar were inoculated onto selective media, some of which were acidified to approximate more closely the pH of larval food and the larval gut. A total of 104 microbial isolates were obtained from fecal collections of 20 larvae, although the feces of 4 of these larvae contained no detectable microbes. Microorganisms isolated in order of frequency were Bacillus spp., Gram-variable pleomorphic bacteria (Achromobacter eurydice?), molds (primarily Penicillia), actinomycetes, Gram-negative bacterial rods, and yeasts. It appears that larvae can become inoculated with microorganisms which are found in adult bees and pollen from ingestion of contaminated food. However, evidence for a constant symbiotic microflora which could contribute significant amounts of biochemicals to larvae is lacking.     

A quantitative study of worker reproduction in queenright colonies of the Cape honey bee, Apis mellifera capensis

Reproduction by workers is rare in honey bee colonies that have an active queen. By not producing their own offspring and preventing other workers from producing theirs, workers are thought to increase their inclusive fitness due to their higher average relatedness towards queen-produced male offspring compared with worker-produced male offspring. But there is one exception. Workers of the Cape honey bee, Apis mellifera capensis, are able to produce diploid female offspring via thelytokous parthenogenesis and thus produce clones of themselves. As a result, worker reproduction and tolerance towards worker-produced offspring is expected to be more permissive than in arrhenotokous (sub)species where worker offspring are male. Here we quantify the extent to which A. m. capensis workers contribute to reproduction in queenright colonies using microsatellite analyses of pre-emergent brood. We show that workers produced 10.5% of workers and 0.48% of drones. Most of the workers' contribution towards the production of new workers coincided with the colonies producing new queens during reproductive swarming.     

Oxidative enzyme systems of the honey bee,Apis mellifera L

1. Oxidative dissimilation has been studied in enzymes from the honey bee. Using mitochondria isolated from the thoraces, complete oxidation of most of the TCA cycle members has been shown. 2. The presence of the acetate-activating enzyme, citrate-condensing enzyme, isocitric dehydrogenase, alpha-ketoglutarate dehydrogenase, glucose-6-phosphate, and 6-phosphogluconic dehydrogenase has been demonstrated and the cofactor requirements established. 3. The oxidation of isocitric acid has been shown to be either non-specific for the D- or L-isomer, or the presence of a racemase is indicated. 4. The presence of the pentose cycle is indicated in the soluble portion of the thoracic homogenate.     

Inheritance of thelytoky in the honey bee Apis mellifera capensis

Asexual reproduction via thelytokous parthenogenesis is widespread in the Hymenoptera, but its genetic underpinnings have been described only twice. In the wasp Lysiphlebus fabarum and the Cape honey bee Apis mellifera capensis the origin of thelytoky have each been traced to a single recessive locus. In the Cape honey bee it has been argued that thelytoky (th) controls the thelytoky phenotype and that a deletion of 9 bp in the flanking intron downstream of exon 5 (tae) of the gemini gene switches parthenogenesis from arrhenotoky to thelytoky. To further explore the mode of inheritance of thelytoky, we generated reciprocal backcrosses between thelytokous A. m. capensis and the arrhenotokous A. m. scutellata. Ten genetic markers were used to identify 108 thelytokously produced offspring and 225 arrhenotokously produced offspring from 14 colonies. Patterns of appearance of thelytokous parthenogenesis were inconsistent with a single locus, either th or tae, controlling thelytoky. We further show that the 9 bp deletion is present in the arrhenotokous A. m. scutellata population in South Africa, in A. m. intermissa in Morocco and in Africanized bees from Brazil and Texas, USA, where thelytoky has not been reported. Thus the 9 bp deletion cannot be the cause of thelytoky. Further, we found two novel tae alleles. One contains the previously described 9 bp deletion and an additional deletion of 7 bp nearby. The second carries a single base insertion with respect to the wild type. Our data are consistent with the putative th locus increasing reproductive capacity.     

Antennal hygroreceptors of the honey bee,Apis mellifera L.

Summary Antennal hygroreceptors of the honey bee, Apis mellifera L., have been investigated electrophysiologically and the sensillum containing these receptors with SEM. Moist and dry hygroreceptors have been identified along with a thermal receptor in a specialized coeloconic sensillum. This sensillum comprises a cuticular, shallow depression (diameter; 4 ) having a central opening (1.4–1.5 m) and a mushroom-shaped protrusion (1.4–1.5 m) from the opening. The head of the protrusion is irregular in shape and is not perforated. This sensillum has been thus far referred to as a sensillum campaniformium (Dietz and Humphreys 1971), henceforth, it is referred to as a coelocapitular sensillum.The responses of both moist and dry hygroreceptors are of a phasic-tonic manner. Both receptors are antagonistic with respect to their responses to humidity; one responds with an increase in impulse frequency to rising humidity, the other to falling humidity. The humidity-response relationship is independent of stimulus flux.     

The relationship between comb age and performance of honey bee (Apis mellifera) colonies

A study on the relationship between the age of comb and the activity of the hybrid Carniolan honey bee colonies in collecting pollen activity, worker brood production, colony strength, and honey yield was conducted. In comparison to colonies with combs aged 4-years, colonies with combs aged 1, 2 and 3-years significantly exceeded in the number returning workers, number returning workers with pollen loads, rate of storing pollen, rate of worker brood production, and size of colony population. Colonies with combs aged 1, 2 and 3-years produced significantly more honey than colonies with combs aged 4-years (5.25, 4.90 and 4.65 kg/colony vs. 4.45 kg/colony, respectively). It can be concluded that the foraging rate, gathering and storing pollen, brood production, colony population size, and honey yield significantly depended on the age of combs. Beekeepers can replace old combs with new ones to increase brood and honey production.     

Nest characteristics and recruitment behavior of absconding colonies of the African honey bee,Apis mellifera scutellata,in Africa

Absconding behavior was investigated in a naturally occurring population of honey bees in the Okavango River Delta, Botswana. Fifty percent of all colonies excavated in the field between October and December had abandoned the nest or were preparing for absconding, suggesting that an absconding season began in the Delta in October or November. However, the factors influencing absconding during this period were unclear, and there were no distinct differences in nest characteristics of the absconding and nonabsconding colonies. Waggle dance activity in observation colonies preparing for absconding was not used to preselect a specific nest site prior to departure. However, in two of the three colonies examined recruitment activity indicated the general direction of colony travel. The distances indicated by these dancers ranged between 6 and 16 km. Since these distances were three to four times greater than those communicated by dancers in nonabsconding colonies, workers from absconding colonies may sample potential forage or nest sites well outside their regular foraging range.