6 research outputs found
Reproduction in eusocial bees (Apidae: Apini, Meliponini)
This thesis presents some key aspects of the regulation and the mechanisms of colony reproduction in honeybees and stingless bees. Special attention is paid to key questions about how the production of males, gynes and swarms takes place, and what intranidal and extranidal factors are related to these processes.
Firstly, the nest architecture and colonial characteristics were described and studied in three sympatric stingless bee species: Lisotrigona carpenteri, Trigona laeviceps and Trigona ventralis in Cucphuong forest, north Vietnam, with the first description of the nest of L. carpenteri (chapter 3).
Secondly, the natural pattern of male production in Melipona favosa was investigated in Trinidad and Tobago (W.I.) and subsequently the relationship between emerging males and haploid eggs laid by laying workers was studied in the laboratory at Utrecht University. The laying workers of this species play an important role in the production of males that appears periodic (chapter 4).
Thirdly, the regulation of reproductive processes such as the production of males and gynes were studies in Trigona ventralis in North Vietnam. This species produces sexuals and workers over the year although the number of sexuals was variable, depending on the availability of flowering to forage on. At the colony level, male production was periodic and occurred in distinct periods over the season. Different from the production of males, gynes were produced in low numbers. The behavioural repertoire of newly emerged gynes was described, with emphasis on the behavioural interactions between gynes and workers (chapter 5).
Fourthly, in 20 colonies of Apis cerana, in northern Vietnam, observations on colony growth, on production of drones and queens, and on swarming and supersedure were related to available flowers to forage on and climatic data. In Apis cerana, the production of drones and virgin queens was restricted to two periods from March to July and from September to December. Positive correlations between available forage, colony growth and production of sexuals suggest that the synchronized production of drones and queens is defined by the forage flow into the colony. Production of reproductives is
synchronized because foraging conditions are only part of the year sufficient to allow growth. Patterns in male and gyne rearing by A. cerana are similar to patterns found in Apis mellifera.
Fifthly, similarities and differences in reproductive strategies between the honey bee and stingless bee species in the same habitat are compared and discussed to generalize collective evolutionary and adaptive significance in highly eusocial bees
(chapter 7). Apis cerana is well adapted to exploit seasonal or temporal resources, because it responds quickly to changing environmental conditions while the stingless bees will in general flourish most in stable environments. However, some differences can be observed among sympatric stingless bee species. Species with large colonies like Trigona ventralis focus more on colony defence and growth of the colony itself. Species with small colonies like Lisotrigona carpenteri probably focus more on colonizing many new nest sites
Behavioural data on the production of males by workers in the stingless bee Melipona favosa (Apidae, Meliponinae)
Male production was studied in four queenright
M. favosa colonies by permanent and long duration observation
of egg-laying and subsequent bee emergence. Workers
produced males in all colonies; they produced 94.5% of all
males
Production of reproductives in the honey bee species Apis cerana in northern Vietnam
In 20 colonies of Apis cerana in northern Vietnam, colony growth, production of drones and queens (sexuals), and swarming and supersedure were related to available flower forage and climate. Despite the tropical setting of the study with year-round forage, production of sexuals was restricted to two periods from March to July and from September to December. Most swarming occurred in May when forage was most abundant. Positive correlations between available forage, colony growth, and production of sexuals suggest that the synchronized production of drones and queens is defined by nutrient flow into the colony. If flow is high, the colony starts growing; when the colony is large enough drones and queens are produced, and eventually the colony swarms. Production of sexuals is synchronized because foraging conditions are sufficient to allow growth for only part of the year. Patterns in drone and queen rearing by A. cerana are similar to patterns found in Apis mellifera. Variation may reflect differences in environment and between specie
Nest and colony characteristics of three stingless bee species in Vietnam with the first description of the nest of Lisotrigona carpenteri (Hymenoptera: Apidae: Meliponini)
In tropical primary forest and its buffer zones in North Vietnam, nests of three stingless bee species were studied: Lisotrigona carpenteri Engel, Trigona (Tetragonula) laeviceps Smith and Trigona (Lepidotrigona) ventralis Smith. We record nest architecture, adult population, the number of brood cells, the presence of adult reproductives, the proportion of males in the brood, the number of queen cells and storage pots, and other features, on the basis of 35 field collected nests. Lisotrigona carpenteri and T. laeviceps arrange brood cells in clusters, T. ventralis, in horizontal combs surrounded by an involucrum of multiple lamellae. Lisotrigona carpenteri constructs its small nests (up to 400 adult bees) mainly in crevices in man-made structures while colonies of T. laeviceps (up to 1200 adults) and T. ventralis (up to 10,000 adults) are generally in cavities in living trees. The flexibility for using nest substrates other than living trees appears in these species related to colony siz
Caste fate conflict in swarm-founding social Hymenoptera: an inclusive fitness analysis
A caste system in which females develop into morphologically distinct queens or workers has evolved independently in ants, wasps and bees. Although such reproductive division of labour may benefit the colony it is also a source of conflict because individual immature females can benefit from developing into a queen in order to gain greater direct reproduction. Here we present a formal inclusive fitness analysis of caste fate conflict appropriate for swarm-founding social Hymenoptera. Three major conclusions are reached: (1) when caste is self-determined, many females should selfishly choose to become queens and the resulting depletion of the workforce can substantially reduce colony productivity; (2) greater relatedness among colony members reduces this excess queen production; (3) if workers can prevent excess queen production at low cost by controlled feeding, a transition to nutritional caste determination should occur. These predictions generalize results derived earlier using an allele-frequency model [Behav. Ecol. Sociobiol. (2001) 50: 467] and are supported by observed levels of queen production in various taxa, especially stingless bees, where caste can be either individually or nutritionally controlled