Wandee Wattanachaiyingcharoen

Nest site selection in the open-nesting honeybee Apis florea

We studied nest site selection by swarms of the red dwarf honeybee, Apis florea. By video recording and decoding all dances of four swarms, we were able to determine the direction and distances indicated by 1,239 dances performed by the bees. The bees also performed a total of 715 nondirectional dances; dances that were so brief that no directional information could be extracted. Even though dances converged over time to a smaller number of areas, in none of the swarms did dances converge to one site. As a result, even prior to lift off, bees performed dances indicating nest sites in several different directions. Two of four swarms traveled directly in what seemed to be the general direction indicated by the majority of dances in the half hour prior to swarm lift off. The other two traveled along circuitous routes in the general direction indicated by the dances. We suggest that nest site selection in A. florea has similar elements to nest site selection in the better-studied Apis mellifera. However, the observation that many more locations are indicated by dances prior to lift off also shows that there are fundamental differences between the two species.

Moving home: nest-site selection in the Red Dwarf honeybee (Apis florea)

The Red Dwarf honeybee (Apis florea) is one of two basal species in the genus Apis. A. florea differs from the well-studied Western Hive bee (Apis mellifera) in that it nests in the open rather than in cavities. This fundamental difference in nesting biology is likely to have implications for nest-site selection, the process by which a reproductive swarm selects a new site to live in. In A. mellifera, workers show a series of characteristic behaviors that allow the swarm to select the best nest site possible. Here, we describe the behavior of individual A. florea workers during the process of nest-site selection and show that it differs from that seen in A. mellifera. We analyzed a total of 1,459 waggle dances performed by 197 scouts in five separate swarms. Our results suggest that two fundamental aspects of the behavior of A. mellifera scouts—the process of dance decay and the process of repeated nest site evaluation—do not occur in A. florea. We also found that the piping signal used by A. mellifera scouts to signal that a quorum has been reached at the chosen site, is performed by both dancing and non-dancing bees in A. florea. Thus, the piping signal appears to serve a different purpose in A. florea. Our results illustrate how differences in nesting biology affect the behavior of individual bees during the nest-site selection process.

Lack of worker reproduction in the giant honey bee Apis dorsata Fabricius.

Summary: Worker policing (any behavior performed by workers that reduces reproduction by other workers) via egg eating has been observed in three species of honey bee (Apis mellifera, A. cerana, and A. florea). The maternity of drones of the giant honey bee A. dorsata (n = 660) was determined using DNA microsatellite analysis. None carried markers from the queens mates indicating that none was a workers son. In addition, dissection of 1,902 workers from 8 colonies showed that none had activated ovaries indicating that worker sterility is usual. Worker policing behavior involves costs when police workers make errors: removing eggs laid by a queen or failing to remove worker-laid eggs. We develop a model that examines the effect of these costs on the acceptance threshold of eggs. The model shows that costs may be reduced by any cues that help police workers distinguish worker-laid and queen-laid eggs. Once such cue may be the use of unique cells for rearing drones and workers. Unlike other Apis, A. dorsata rear both workers and drones in the same-size cells with the drone brood scattered among worker brood. Thus, the ability of A. dorsata workers to detect and eliminate (police) worker-laid eggs may be associated with higher costs than in other species. Our model suggests that these higher costs may select for a more permissive egg-acceptance threshold, because of the costs of erroneously removing queen-laid eggs, leading to greater worker reproduction. However our empirical results suggest that worker reproduction is very low in the species, suggesting that worker policing is efficient and that police workers have no difficulty in distinguishing queen-laid and worker-laid eggs.

Aggregations of unrelated Apis florea colonies

Intensive surveys of an area of woodland in Phitsanulok province, Thailand, revealed 15 colonies of Apis florea. The colonies had a highly aggregated spatial distribution (Standardized Morisita’s Index of Dispersion = 0.59). Microsatellite analysis based on 5 loci showed that no colonies were related as mother-daughter, suggesting that unrelated colonies tend to nest near existing colonies.ZusammenfassungBei vier der Honigbienenarten werden Nester oft in gehäuften räumlicher Verteilungen vorgefunden. So können zum Beispiel bei den Riesenhonigbienen Apis dorsata und A. laboriosa mehr als 100 Kolonien an einem einzelnen Baum oder Felsüberhang nisten. Auch die rote Zwerghonigbiene, A. florea, weist eine gehäufte räumliche Verteilung der Nester auf. Eine offensichtliche Erklärung von Nestansammlungen ist eine ungleichmäßige Verteilung geeigneter Nistplätze. Dies ist allerdings bei A. florea, die ihre Nester an kleinen Baumästen anlegt, eine wenig wahrscheinliche Erklärung. Es ist daher schwer zu sehen, dass hier ein Mangel an geeigneten Nistplätzen zu einer gehäuften räumlichen Verteilung führen sollte.Für die Entstehung von Nestansammlungen bei Honigbienen gibt es mindestens vier plausible Hypothesen: (i) Schwärme könnten sich wegen der Möglichkeit kooperativer Nestverteidigung Ansammlungen anschließen; (ii) Schwärme könnten sich zur Verbesserung des Paarungserfolges von Königinnen und Drohnen Ansammlungen anschließen; (iii) Schwärme könnten von der Anwesenheit anderer erfolgreicher Kolonien als Anzeiger einer ressourcenreichen Umgebung angelockt werden; (iv) Ansammlungen könnten durch sehr kurze Wegstrecken der reproduktiven Schwärme hervorgerufen werden, oder dadurch, dass wandernde Schwärme während ihrer Wanderung den gleichen Verhaltensregeln folgen.Wir untersuchten die natürliche Verteilung und die Verwandtschaftsbeziehungen von Nestern der roten Zwerghonigbiene A. florea in der Phitsanulok Provinz im tieferen nördlichen Thailand. Die Verteilung der von uns gefundenen 15 Völker war stark gehäuft (Abb. 1: Morisita’s Verteilungsindex > 0,5). Die Untersuchung von Arbeiterinnen dieser Nester anhand vom Mikrosatelliten zeigte, dass keine der Nester eine Mutter-Tochter Verwandtschaft aufwiesen. Daher konnten diese Ansammlungen nicht auf Grund von geringer Ausbreitung der Nachkommenskolonien vom Ursprungsnest entstanden sein. Eher legen unsere Ergebnisse nahe, dass Schwärme von Gebieten angezogen werden, die Nester enthalten.

Worker reproductive parasitism in naturally orphaned colonies of the Asian red dwarf honey bee, Apis florea

The truce between honey bee (Apis spp.) workers over reproduction is broken in the absence of their queen. Queenright workers generally abstain from personal reproduction, raising only the queen’s offspring. Queenless workers activate their ovaries, produce eggs, and reduce the rate at which they destroy worker-laid eggs, so that some eggs are reared to maturity. Reduced policing of worker-laid eggs renders queenless nests vulnerable to worker reproductive parasitism (WRP), and may result in the colony raising eggs of unrelated (non-natal) workers that parasitize it. Queenless colonies of A. florea are heavily parasitized with the eggs of non-natal workers. However, queenless colonies often abscond upon disturbance and build a small comb in which to rear their own male offspring. We investigated three naturally occurring orphaned colonies to determine if they are also parasitized. We show that WRP is present in orphaned colonies, and non-natal workers have significantly higher rates of ovary activation than natal workers. In contrast to experimentally manipulated colonies, in our samples, natal and non-natal workers had statistically equal reproductive success, but this may have been due to the small number of non-natals present.

A scientific note on a genetically-determined color morph of the dwarf honey bee, Apis andreniformis

in Southeast Asia (reviewedin Oldroyd and Wongsiri, 2006). Although the twospecies can be reliably separated by the architectureof the comb, the morphology of the endophallusand hind leg of the male, and worker wing venation(reviewed in Oldroyd and Wongsiri, 2006), varia-tion of worker colour within the two species canlead to confusion (Hepburn et al., 2005). Typicallythe first two abdominal segments of an

Lack of interspecific parasitism between the dwarf honeybees Apis andreniformis and Apis florea

The dwarf honeybees Apis florea and Apis andreniformis are sympatric in Southeast Asia. We examined undisturbed nests of both species finding that heterospecific workers are present in some nests at low frequency. This suggested that workers may enter heterospecific nests as a prelude to reproductive parasitism. To test this hypothesis, we created mixed-species colonies and determined the reproductive response of workers within them based on molecular markers. In queenless colonies, workers of both species activated their ovaries at equal frequency. However, the majority species, A. florea, had complete reproductive dominance over A. andreniformis, most likely because the A. florea workers recognised and removed heterospecific larvae. In queenright mixed-species colonies, workers responded to heterospecific signals of the presence of the queen and did not activate their ovaries. Thus, despite predictions from kin selection theory that workers would benefit from parasitising heterospecific nests, we find no evidence that selection has established a parasitic strategy in these sibling species.