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The bumblebee Bombus terrestris is not only an effective pollinator, but also a potential invasive alien species outside its native range. Recently, nearly
30% of queens of the Japanese native species Bombus hypocrita sapporoensis and B. hypocrita hypocrita were estimated to copulate with B. terrestris males in the field, suggesting that indigenous bumblebees could be genetically deteriorated through hybrid production with
the introduced species. In this study, we evaluated hybrid production between the introduced B. terrestris and the indigenous B. hypocrita sapporoensis under laboratory conditions. The hatching rate of eggs derived from interspecific matings was 0% and 8.6% depending on the
direction of the cross, which was significantly lower than that from intraspecific matings of B. terrestris (76.9%) and B. hypocrita sapporoensis (78.9%). Genetic studies using microsatellite markers revealed that both haploid and diploid individuals were present in
the egg stage, whereas all hatched larvae were haploid. In addition, histological studies revealed that eggs derived from
interspecific matings terminated development 2 days after oviposition. These results strongly suggested that eggs derived
from interspecific matings are inviable due to post-mating isolation mechanisms. Mass release of exotic pollinators could
cause serious population declines of native bumblebee species. 相似文献
2.
J. Cnaani G. E. Robinson G. Bloch D. Borst A. Hefetz 《Behavioral ecology and sociobiology》2000,47(5):346-352
Endocrine analyses were used to investigate the well-known association between queen production and the onset of worker reproduction
(termed the competition phase, CPh) in Bombus terrestris. Larvae that reached the age of 5 days before the CPh had a worker-like profile: low juvenile hormone (JH) biosynthesis rates
and low JH hemolymph titers. In contrast, larvae that reached the age of 5 days during the CPh had a queen-like profile: high
JH biosynthesis rates and high hemolymph JH levels. Larval fate could be manipulated by transplanting egg cells into host
colonies with different social structures. There was a steep rise in JH production in larvae transplanted into colonies near
or during the CPh. This indicates that during colony development, larvae switch from the ”worker developmental pathway” to
the ”queen developmental pathway,” and that the switch is socially regulated. In small rearing groups, larvae reared with
queens before the CPh developed into workers, whereas those reared with queens after the CPh developed into queens. Variation
in worker type (naive or experienced) did not affect caste determination. Therefore, we hypothesize that queens produce a
pheromone that directly inhibits queen differentiation by larvae. We also present two alternative scenarios that explain the
timing of gyne production in B. terrestris, one based on ecological constraints and the other based on queen-worker competition.
Received: 20 October 1999 / Received in revised form: 18 December 1999 / Accepted: 23 January 2000 相似文献
3.
Diane Lefebvre Jacqueline Pierre Yannick Outreman Jean-Sébastien Pierre 《Behavioral ecology and sociobiology》2007,61(11):1707-1715
The patch living rules of a pollinator, the bumblebee Bombus terrestris L., are studied here in the framework of motivational models widely used for parasitoids: The rewarding events found during
the foraging process are supposed to increase or decrease suddenly the tendency of the insect to stay in the current patch
and therefore to adjust the patch residence time to the patch profitability. The foraging behaviour of these pollinators was
observed in two environment types to determine their patch-leaving decisions. The rich environment was composed of male-fertile
flowers, offering pollen and nectar, and the poor one of male-sterile flowers, offering little nectar and no pollen. The experimental
design consisted of a patch system in which inflorescences were evenly arranged in two rows (1 m distance). Residence times
of foragers inside inflorescences and rows were analysed by a Cox proportional hazards model, taking into account recent and
past experience acquired during the foraging bout. Most of the results showed a decremental motivational mechanism, that is,
a reduction in the residence time on the inflorescence or in the row related to exploitation of flowers within inflorescences
and inflorescences within rows These results indicate that bumblebees tend to leave the patch using departure rules similar
to those found in parasitoids. The results also provide information on the memory, learning and evaluating capabilities of
bumblebees especially when rich and poor environments were compared. The patch-leaving mechanism suggested by this study is
consistent with the central place foraging theory. 相似文献
4.
In eusocial Hymenoptera, queen control over workers is probably inseparable from the mechanism of queen recognition. In primitively eusocial bumblebees (Bombus), worker reproduction is controlled not only by the presence or absence of a dominant queen but also by other dominant workers. Furthermore, it was shown that the queen dominance is maintained by pheromonal cues. We investigated whether there is a similar odor signal released by egg-laying queens and workers that may have a function as a fertility signal. We collected cuticular surface extracts from nest-searching and breeding Bombus terrestris queens and workers that were characterized by their ovarian stages. In chemical analyses, we identified 61 compounds consisting of aldehydes, alkanes, alkenes, and fatty acid esters. Nest-searching queens and all groups of breeding females differed significantly in their odor bouquets. Furthermore, workers before the competition point (time point of colony development where workers start to develop ovaries and lay eggs) differed largely from queens and all other groups of workers. Breeding queens showed a unique bouquet of chemical compounds and certain queen-specific compounds, and the differences toward workers decrease with an increasing development of the workers' ovaries, hinting the presence of a reliable fertility signal. Among the worker groups, the smallest differences were found after the competition point. Egg-laying females contained higher total amounts of chemical compounds and of relative proportions of wax-type esters and aldehydes than nest-searching queens and workers before the competition point. Therefore, these compounds may have a function as a fertility signal present in queens and workers. 相似文献
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The mechanisms of regulating worker reproduction in bumblebees were studied by direct behavioral observations and by measuring
ovarian development and juvenile hormone (JH) biosynthesis rates in workers under different social conditions. Workers in
the last stage of Bombus terrestris colony development (the competition phase) had the lowest ovarian development and JH biosynthesis rates. Callows introduced
into colonies immediately after queen removal (dequeened colonies) demonstrated a significant increase in ovarian development
before, but not during, the competition phase. These findings differ from the higher ovarian development in colonies during
the competition phase predicted by the prevailing hypothesis that worker reproduction starts in response to a decrease in
queen inhibition. Reproduction of callows housed with dominant workers in small queenless groups was inhibited as in queenright
colonies. This suggests that the reduced ovarian development and JH biosynthesis rates observed in dequeened and normally
developing colonies during the competition phase also reflect inhibition by dominant workers. Thus, two distinct stages of
inhibition of reproduction seem to exist: (1) before the competition phase, when the queen slows down worker ovarian development
and prevents oviposition; (2) during the competition phase, when dominant workers inhibit ovarian development of other workers.
Between these stages there seems to be a temporal “window” of enhanced worker reproductive development. The queen's typical
switch to haploid egg production was not associated with changes in worker ovarian development or JH biosynthesis rates. These
findings suggest that regulation of worker reproduction in B. terrestris is not determined by simple changes in the queen's inhibition capacity or by the sex of offspring and that the worker's role
is more important than previously believed.
Received: 18 March 1998 / Accepted after revision: 18 July 1998 相似文献
7.
Queen and worker Bombus terrestris have different optima for the timing of gyne production. Workers, being more related to their gyne-sisters than to their sons, should ascertain that gyne production has started before attempting to reproduce. Their optimal timing for gyne production will be as early as possible, while allowing sufficient ergonomic colony growth to support gyne rearing. Queen optimum, on the other hand, should be to postpone gyne production toward the end of colony life cycle, in order to minimize the time-window available for worker reproduction. Thus, the timing of gyne production may profoundly affect the outcome of queen–worker competition over male production. In this study we investigated some of the social correlates possibly affecting this timing. It was found that neither keeping colony size constant and as low as 20 workers, nor decreasing worker average age, influenced the onset of gyne production. To test the effect of queen age we created young colonies with old queens and vice versa. When colony social composition remained unchanged, in young colonies headed by old queens gynes were produced earlier than predicted, but in the inverse situation gyne production was not delayed. When colony social composition was completely standardized queen age had a decisive effect, indicating that the timing of gyne production is both under queen influence and affected by queen age. Furthermore, queens assess colony age from the time of first worker emergence rather than from their own first oviposition. In these experiments the factors affecting gyne production also affected the onset of queen–worker conflict for male production, suggesting that both are regulated by the same causal effect. Postponing gyne production as much as possible provides another mechanism, in addition to extensive oophagy, for the queen to outcompete her workers in male production. 相似文献
8.
The non-random movement patterns of foraging bees are believed to increase their search efficiency. These patterns may be
innate, or they may be learned through the bees’ early foraging experience. To identify the innate components of foraging
rules, we characterized the flight of naive bumblebees, foraging on a non-patchy “field” of randomly scattered artificial
flowers with three color displays. The flowers were randomly mixed and all three flower types offered equal nectar volumes.
Visited flowers were refilled with probability 0.5. Flight distances, flight durations and nectar probing durations were determined
and related to the bees’ recent experiences. The naive bees exhibited area-restricted search behavior, i.e., flew shorter
distances following visits to rewarding flowers than after visits to empty flowers. Additionally, flight distances during
flower-type transitions were longer than flight distances between flowers of the same type. The two movement rules operated
together: flight distances were longest for flights between flower types following non-rewarding visits, shortest for within-type
flights following rewarding visits. An increase in flight displacement during flower-type shifts was also observed in a second
experiment, in which all three types were always rewarding. In this experiment, flower-type shifts were also accompanied by
an increase in flight duration. Possible relationships between flight distances, flight durations and flower-type choice are
discussed.
Received: 20 November 1995/Accepted after revision: 10 May 1996 相似文献
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