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排序方式: 共有121条查询结果,搜索用时 31 毫秒
111.
Vincent Dietemann Jochen Pflugfelder Stephan Härtel Peter Neumann Robin M. Crewe 《Behavioral ecology and sociobiology》2006,60(6):785-793
Social parasites exploit their host’s communication system to usurp resources and reproduce. In the honeybee, Apis mellifera, worker reproduction is regulated by pheromones produced by the queen and the brood. Workers usually reproduce when the queen is removed and young brood is absent. However, Cape honeybee workers, Apis mellifera capensis, are facultative intraspecific social parasites and can take over reproduction from the host queen. Investigating the manner in which parasitic workers compete with host queens pheromonally can help us to understand how such parasitism can evolve and how reproductive division of labour is regulated. In A. m. capensis, worker reproduction is associated with the production of queen-like pheromones. Using pheromonal contest experiments, we show that Apis mellifera scutellata queens do not prevent the production of queen-like mandibular gland compounds by the parasites. Given the importance of these pheromones in acquiring reproductive status, our data suggest that the single invasive lineage of parasitic workers occurring in the range of A. m. scutellata was selected for its superior ability to produce these signals despite the presence of a queen. Such resistance was indeed less frequent amongst other potentially parasitic lineages. Resistance to reproductive regulation by host queens is probably the key factor that facilitates the evolution of social parasitism by A. m. capensis workers. It constitutes a mechanism that allows workers to evade reproductive division of labour and to follow an alternative reproductive option by acquiring direct fitness in foreign colonies instead of inclusive fitness in their natal nests. 相似文献
112.
113.
A. Brückner Erich Becher R. O. Neumann V. Jollos U. Friedemann 《Die Naturwissenschaften》1923,11(10):180-183
114.
115.
Early detection and identification of dangerous states in chemical plants using neural networks 总被引:1,自引:0,他引:1
Joachim Neumann Grge Deerberg Stefan Schlüter 《Journal of Loss Prevention in the Process Industries》1999,12(6):297-453
The suitability of pattern recognition for safety diagnosis of chemical plants will be discussed. Therefore, experiments in a miniplant and with a process simulator are carried out. The process characteristics are treated with different recognition methods and classified with the aid of expert know how. Afterwards, the trained system can be used for process diagnosis. The capability of neural networks for this problem could be shown. 相似文献
116.
Benthic epifauna in three areas of the northern North Sea was studied from 1999 to 2007 to investigate the effect of temperature
changes on community structure and species abundance and biomass. Abundance and/or biomass of 16 epifauna species was significantly
correlated with temperature anomalies of the mean sea surface temperature (SST) from 1971 to 2000. The response of species
to SST changes was different in the study areas depending on species life history and, most likely on food supply, which in
turn is strongly influenced by the timing and duration of primary production and regional hydrographical conditions (e.g.
stratification). Also, changes in community structure were obvious in the three areas between 2002 and 2003 coinciding with
high temperature anomalies and SST. On the other hand, these changes were mainly caused by the variability in abundance of
dominant species and altogether no clear trends in community structure were found. In contrast to epifauna communities in
the shallow southern North Sea temperature changes in the northern North Sea affected only single epifauna species until now. 相似文献
117.
The development of animals depends on both genetic and environmental effects to a varying extent. Their relative influences can be evaluated in the social insects by raising the intracolonial diversity to an extreme in nests consisting of workers from more than one species. In this study, we studied the effects of mixed honeybee colonies of Apis mellifera and Apis cerana on the rearing of grafted queen larvae of A. cerana. A. mellifera sealed worker brood was introduced into A. cerana colonies and on emergence, the adults were accepted. Then, A. cerana larvae were grafted for queen rearing into two of these mixed-species colonies. Similarly, A. cerana larvae and A. mellifera larvae were also grafted conspecifically as controls. The success rate of A. cerana queen rearing in the test colonies was 64.5%, surpassing all previous attempts at interspecific queen rearing. After emergence, all virgin queens obtained from the three groups (N=90) were measured morphometrically. The A. cerana queens from the mixed-species colonies differed significantly in size and pigmentation from the A. cerana control queens and closely approximated the A. mellifera queens. It is inferred that these changes in the A. cerana queens reared in the mixed-species colonies can be attributed to feeding by heterospecific nurse bees and/or chemical differences in royal jelly. Our data show a strong impact of environment on the development of queens. The results further suggest that in honeybees the cues for brood recognition can be learned by heterospecific workers after eclosion, thereby providing a novel analogy to slave making in ants. 相似文献
118.
M. F. Neumann 《Behavioral ecology and sociobiology》1988,23(6):389-393
Summary While honeybees use magnetic fields as references to orient in space, there is no unequivocal evidence that honeybees use magnetic cues to orient in time. In this report, it is demonstrated that magnetic fields usually have no influence on the time sense of honeybees, and the bees' rhythmicity is not driven exclusively by exogenous factors. All the variations of the forager bees' behavior are explicable by an endogenous control of rhythmicity; differences are due to individually different periods of the forager bees and dependent on the season. The coincidence of curves calculated from the constellation of sun and moon and the behavior of bees is shown to be an artifact and not a causal relationship. 相似文献
119.
120.
Mark K. Greco Dorothee Hoffmann Anne Dollin Michael Duncan Robert Spooner-Hart Peter Neumann 《Die Naturwissenschaften》2010,97(3):319-323
Workers from social insect colonies use different defence strategies to combat invaders. Nevertheless, some parasitic species
are able to bypass colony defences. In particular, some beetle nest invaders cannot be killed or removed by workers of social
bees, thus creating the need for alternative social defence strategies to ensure colony survival. Here we show, using diagnostic
radioentomology, that stingless bee workers (Trigona carbonaria) immediately mummify invading adult small hive beetles (Aethina tumida) alive by coating them with a mixture of resin, wax and mud, thereby preventing severe damage to the colony. In sharp contrast
to the responses of honeybee and bumblebee colonies, the rapid live mummification strategy of T. carbonaria effectively prevents beetle advancements and removes their ability to reproduce. The convergent evolution of mummification
in stingless bees and encapsulation in honeybees is another striking example of co-evolution between insect societies and
their parasites. 相似文献