Siriwat Wongsiri

Polyandry in the genus Apis, particularly Apis andreniformis

Abstract Using four polymorphic microsatellite loci, we found that four Apis andreniformis queens collected in Thailand each mated at least 10–20 times, producing an average relatedness, gww, of workers of 0.30 ± 0.007, and an average effective number of matings of 9.1 ± 2.2. The degrees of polyandry and intra-colonial genetic relatedness in A. andreniformis are similar to those in A. mellifera, slightly more than in A. florea, and up to 6 times less than in A. dorsata. We argue that while presently favoured hypotheses for the evolution of polyandry in monogynous social insects may adequately explain the evolution of up to five or six matings, they are inadequate to explain the extreme polyandry (10–60 matings) observed in Apis. One alternative possibility is that colony fitness is a non-additive function of the fitness of individual subfamilies. Such behavioral over-dominance may mean that queen fitness is increased by high levels of polyandry, which increase the probability of desirable combinations of worker genotypes occurring in one colony. The special attributes of honey bees which may lead to behavioral over-dominance include colony aggregation (which may increase the incidence of disease), and frequent long-distance migration.

Comparative biology of Apis andreniformis and Apis florea in Thailand

The existence of two species of dwarf honey bees has only recently generally been accepted. Since they coexist in many locations, this leads to the question of how they differ so that they can both be present. This article presents a comparison of the biology of these species, particularly as they occur in Thailand. We do this to highlight what we do not know about these two very similar species, as well as what we do know.

Social parasitism by workers in queenless and queenright Apis cerana colonies.

We examined worker reproduction in queenless and queenright Apis cerana colonies to determine if they are parasitized by workers from other nests. The results demonstrate that 2–6% of workers in queenright colonies are from another nest (non‐natal), but these workers are not statistically more likely to have activated ovaries than natal workers, and are therefore unlikely to be active parasites. However, in queenless colonies we found a significant difference between the proportion of non‐natal (72.7%) and natal (36.3%) workers with activated ovaries. Non‐natal workers also had significantly higher reproductive success than natal workers: 1.8% of workers were non‐natal, but these laid 5.2% of the eggs and produced 5.5% of the pupae. Unlike A. florea, the proportion of non‐natal workers does not increase in queenless nests.

Levels of polyandry and intracolonial genetic relationships in Apis florea

DNA was extracted from worker and drone pupae of each of five colonies of the dwarf honey bee Apis florea. Polymerase chain reactions (PCR) were conducted on DNA extracts using five sets of primers known to amplify microsatellite loci in A. mellifera. Based on microsatellite allele distributions, queens of the five colonies mated with at least 5–14 drones. This is up to 3 times previous maximum estimates obtained from sperm counts. The discrepancy between sperm count and microsatellite estimates of the number of matings in A. florea suggests that despite direct injection of semen into the spermatheacal duct, either A. florea drones inject only a small proportion of their semen, or queens are able to rapidly expel excess semen after mating. A model of sexual selection (first proposed by Koeniger and Koeniger) is discussed in which males attempt to gain reproductive dominance by increasing ejaculate volume and direct injection of spermatozoa into the spermatheca, while queens attempt to maintain polyandry by retaining only a small fraction of each males ejaculate. It is shown, at least in this limited sample, that the effective number of matings is lower in A. florea than in A. mellifera.

Task specialization in a wild bee, Apis florea (Hymenoptera: Apidae), revealed by RFLP banding

Workers in a wild in situ colony of the dwarf honey bee, Apis florea, were observed undertaking the following behavior: liquid foraging, pollen foraging, guarding, stinging, fanning and wagging abdomen. Bees of each behavioral class were separately collected and frozen. Collections were made over a period of 10 days. Random samples of brood and workers were also collected. DNA was extracted from each bee and “fingerprinted” using a probe of unknown sequence obtained from an A. mellifera genomic library. Patterns of fingerprints (Fig. 1) were dissimilar among behavioral classes (Tables 1 and 2), strongly suggesting a genetic component to division of labor in this species. This result supports similar findings in A. mellifera in a species that is not troubled by many of the experimental difficulties inherent in A. mellifera.

Time of drone flight in four honey bee species in south-eastern Thailand

SUMMARYAt Chanthaburi, Thailand, four species of Apis, A. andreniformis, A. florea, A. cerana and A. dorsata, are sympatric. Observations were carried out on three wild colonies of each species on various days in February 1992. The daily drone flight periods were only partially specific: A. andreniformis from 12.15 h to 13.45 h; A. florea from 14.00 h to 16.45 h; A. cerana from 15.15 h to 17.30 h; and A dorsata from 18.15 h to 18.45 h. The significance of these partially separate drone flight periods is discussed in terms of both reproductive isolation and evolution.

Comparative nest architecture of the dwarf honey bees

SUMMARYComplete descriptions using a variety of measurements are provided for nests of Apis andreniformis from south-eastern Thailand, Sichuan and Hunan Provinces of China, and Palawan, Philippines and Apis florea from southeastern Thailand and Hunan Province of China. Overall, the single-comb nest of A. andreniformis has a very different structure from that of A. florea. The comb built by A. andreniformis has a midrib both above and below the supporting branch. However, the comb built by A. florea has a mid-rib only in the brood area below the supporting branch. The honey storage mid-rib of A. andreniformis nests gives them a characteristic crown appearance. Other differences include the overall size of the nest, the width and depth of worker cells and the width of drone cells.

Purification and Characterization of α-Glucosidase I from Japanese Honeybee (Apis cerana japonica) and Molecular Cloning of Its cDNA

α-Glucosidase (JHGase I) was purified from a Japanese subspecies of eastern honeybee (Apis cerana japonica) as an electrophoretically homogeneous protein. Enzyme activity of the crude extract was mainly separated into two fractions (component I and II) by salting-out chromatography. JHGase I was isolated from component I by further purification procedure using CM-Toyopearl 650M and Sephacryl S-100. JHGase I was a monomeric glycoprotein (containing 15% carbohydrate), of which the molecular weight was 82,000. Enzyme displayed the highest activity at pH 5.0, and was stable up to 40 °C and in a pH-range of 4.5–10.5. JHGase I showed unusual kinetic features: the negative cooperative behavior on the intrinsic reaction on cleavage of sucrose, maltose, and p-nitrophenyl α-glucoside, and the positive cooperative behavior on turanose. We isolated cDNA (1,930 bp) of JHGase I, of which the deduced amino-acid sequence (577 residues) confirmed that JHGase I was a member of α-amylase family enzymes. Western honeybees (Apis mellifera) had three α-glucosidase isoenzymes (WHGase I, II, and III), in which JHGase I was considered to correspond to WHGase I.

Pollen resource partitioning by Apis dorsata, A. cerana, A. andreniformis and A. florea in Thailand

SUMMARYThe sympatric congeners Apis dorsata, A. cerana, A. andreniformis and A. florea were observed foraging for pollen on the nocturnally-dehiscent king palm (Archontophoenix alexandrea). The larger A. dorsata and A. cerana foraged earliest but in low numbers, presumably exploiting the resource at its most productive time. The smaller A. andreniformis and A. florea followed in large numbers. Although there was minimal separation of A. andreniformis and A. florea foragers in either space or time, no aggressive interactions between the species were observed.

Genetic differentiation of the honey bee (Apis cerana) in Thailand: evidence from microsatellite polymorphism

SUMMARY Differentiation of the honey bee (Apis cerana) populations, collected from north, north-east, the central region and peninsular Thailand, and Samui island was examined using a polymorphism of three microsatellite loci (A28, A107 and A113). The results indicated high genetic diversity in the mainland (north, central, northeast and peninsular Thailand) populations (H0 = 0.40–0.46) but limited diversity in the Samui population (H0 = 0.18) implying that genetic drift or founder effects may have occurred in this population. Intraspecific population subdivision was observed in Thai A. cerana (P < 0.0001 for both geographic heterogeneity and FST statistics). Five conspecific populations of A. cerana in Thailand were allocated to four different groups; north and central region (A), peninsular Thailand (B), Samui island (C) and north-east (D).