Columbus Surpassed: Biophysical Aspects of How Stingless Bees Place an Egg Upright on Their Liquid Food

The highly eusocial stingless bees (reviewed in [1, 2]) constitute a phylogenetically old group [3] within the Apidae. Probably related to this ancient origin is their mass provisioning of brood cells: they deposit all the food on which the larva will develop into the brood cell, prior to oviposition and subsequent closure of the cell. The other social members of the Apidae, the honeybees and the bumblebees, regularly visit the larvae in their cells to administer small amounts of liquid food at a time. This system is called progressive provisioning. Mass provisioning is practiced by almost all the other bees. However, while most of them have a solid type of larval food, the stingless bees produce a liquid food. In relation to this, their cylindrical brood cells are constructed vertically and are often arranged in horizontal combs. The food, regurgitated from the stomach, consists of a mixture of pollen, nectar, and glandular secretions [1, 2, 4]. After the workers have put this liquid food into the cell, the queen oviposits. Her egg, with its elongated shape, stands upright on the fluid

Task allocation and reproductive skew in social mass provisioning carpenter bees in relation to age and size

The mass provisioning carpenter bees comprise two tribes, the Xylocopini and the Ceratinini. Although social nesting occurs in both tribes, no morphological castes have evolved and females are totipotent, which makes the tribe as a whole highly suitable to test predictions of reproductive skew models. We review current information for the two tribes with respect to reproductive competition and reproductive skew and then investigate whether the observed skew fits with predictions from optimal skew theory. Social nests of Xylocopa species include a non-foraging guard and a foraging egg layer who completely dominates reproduction. Reproductive dominance is settled by aggression, and the probability of winning this fight is influenced by both age and size. In Ceratina species, task allocation is also very clear: one female guards the nest, while the other female(s) forage(s). Although the guard is usually the first to produce an egg, her eggs are frequently replaced by those of the forager, and skew is incomplete. Using comparisons between species and genera the impact of ecological constraints on solitary nesting, relative group productivity and relatedness on reproductive partitioning between dominants and subordinates are investigated in a qualitative way. In support of the optimal skew model, strong constraints on solitary nesting coincided with strong skew. However, the predicted effects of relatedness and group productivity on skew were not found. Furthermore, no support was found for the predictions of the optimal skew model that high skew coincides with frequent aggressive testing and risky task performance by subordinates

High Humidity in the Honey Bee (Apis mellifera L.) Brood Nest Limits Reproduction of the Parasitic Mite Varroa jacobsoni Oud.

Factors influencing reproduction of the parasitic mite Varroa jacobsoni have become a central theme of honey bee pathology. In large parts of the world the mite has made it impossible for colonies of the honey bee Apis mellifera to survive if no measures of treatment are applied [1]. Originally a parasite of the Eastern honey bee A. cerana, the mite was detected in colonies of A. mellifera only less than 4 decades ago [2]. A. cerana colonies are not damaged by V. jacobsoni because several factors prevent the build-up of a large mite population [3]. The most important factor is that in colonies of A. cerana the parasite, which can reproduce only in capped brood cells, reproduces exclusively in drone brood cells while in colonies of A. mellifera it reproduces in worker brood cells as well [4]. In cold, temperate, and Mediterranean climates the mite population grows exponentially until the colony collapses, due mainly to a high percentage of bees damaged by V. jacobsoni during their pupal development [5]

De Apisticus-Dag en sojameel

5 februari jl. vond voor de 14de keer de Apisticus-Tag in het slot van Munster plaats. In het artikel een weergave van de voordrachten over het kweken van vitale bijen, sojameel als stuifmeel vervanger en de bijenweid

A case of multiple mating in stingless bees (Meliponinae)

In several stingless bee species many males aggregate in the vicinity of a nest when a virgin queen is present in the colony and is preparing for the nuptial flight. We report such male assemblage for Tetragonisca angustula. The departure of a virgin queen from the colony and the subsequent mating could be video-recorded, because the queen and the males that had mounted her fell to the ground. Since at least two males had lost their genitalia, multiple mating seems to have occurred. This is in contrast with the prevailing view found in literature concerning the mating biology of stingless bees

Feeding frequency and caste differentiation in Bombus terrestris larvae

The frequency with which bumble bee larvae are fed during their development was studied using video-recordings. The behaviour of the workers while feeding worker, male and queen larvae of Bombus terrestris was recorded. At the beginning of development, female larvae of both castes were fed at a similar frequency. However, during their last phase queen larvae were fed much more often than worker larvae. Despite the differences in frequency, both queen and worker larval feeding followed a similar pattern. Male larvae were fed more often than worker larvae, but less often than queen larvae. They also differed from the female larvae in the way their feeding frequency increased during development. This suggests that the process of feeding male larvae occurs in a different way. The time intervals between feedings were very variable for all larvae: from a few seconds up to 3 h. Although there was a general tendency for the intervals to decrease in duration with larval development, the irregularity was always present. The differences in feeding frequency found at the individual level for larvae of the same age and the irregularity of the feeding process can be explained by the variation in the amount of food per feeding. Finally, our data suggest that larvae play an active role in the regulation of the feeding process. This subject is discussed and compared to the situation in honey bees

Simultaneous queen raising and egg laying by workers in Africanized honeybee colonies (Apis mellifera L) in Costa Rica.

Twenty small queenless colonies of mixed European-Africanized origin were set up to study the development of emergency queen cells, ovarian activation and egg laying by workers. In 2 of the colonies, laying workers were present in large numbers before the queens matured from the emergency queen cells. A low number of worker-laid eggs was found in 7 colonies. In the other colonies, the level of ovarian activation of the workers at the end of the queenless period was very variable. We conclude that the occurrence of egg-laying workers in colonies that still contain young brood is not a rare phenomenon in Africanized bees. No worker-laid eggs were found in any of the colonies once a queen had emerged. There was no correlation between the level of ovarian activation (ie the size of the eggs inside the ovaries) and either the number of queen cells raised or the number of empty queen cups constructed. The average number of ovarioles per worker per colony varied between 3.79 and 8.33 per ovary. Since there was no correlation between the number of ovarioles and the level of ovarian activation (either within or between colonies), we conclude that these are independent traits in a mixed population