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721.
Mating structure and nestmate relatedness in a communal bee, Andrena jacobi (Hymenoptera, Andrenidae), using microsatellites 总被引:1,自引:0,他引:1
Complex eusocial insect societies are generally matrifilial, suggesting kin selection has been of importance in their development. For simpler social systems, factors favouring their existence, in particular kin selection, have rarely been studied. Communal nesting is one of these simple social organizations, and is found in a diversity of insect species. To examine whether kin selection may play a role in the evolution and maintenance of communality, we estimated genetic relatedness of nestmate females of the facultatively communal bee, Andrena jacobi . Microsatellite loci were developed for this species and used to analyse individuals from two populations. Loci were variable, they were in heterozygote deficit and showed positive inbreeding coefficients. This may arise from nonrandom mating; previous observations (Paxton & Tengö 1996) indicate that a large proportion of females mate intranidally with nestmate males in their natal nests before first emerging. Nestmate relatedness was low, no different from zero for all loci in one population and for three of four loci in the other population. The large number of nestmates sharing a common nest (up to 594) may explain the low relatedness estimates, although relatedness was also independent of the number of females sharing a nest. Lack of inclusive fitness payoffs could constrain social evolution in this communal species. 相似文献
722.
723.
Emma S. Gaudreault Ilona Naujokaititis-Lewis David R. Lapen Risa D. Sargent 《Agricultural and Forest Entomology》2023,25(1):53-65
- Neonicotinoid-coated corn and soybean seeds are a common crop in Canada and the US. A growing body of research is demonstrating that, through various exposure routes, neonicotinoids can impact a suite of nontarget organisms including beneficial insects such as bees. However, to date, only a few studies have examined the effects of neonicotinoids in field settings.
- We assessed the relationship between agricultural crop soil neonicotinoid levels and wild bee abundance and diversity at 16 agricultural sites representing different soil neonicotinoid levels. We detected clothianidin at 11 sites, thiamethoxam at three sites; imidacloprid was not detected.
- Hedgerow and crop soils were consistent in terms of where clothianidin was detected; thiamethoxan was not detected in hedgerow soils. Based on model outcomes, fields with higher levels of soil neonicotinoids exhibited significantly lower wild bee abundance and diversity than those with low or no neonicotinoids detected.
- Crop soil neonicotinoid level, hedgerow floral resource abundance and crop type were consistent predictors of bee abundance across models; only neonicotinoid level and crop type were significant predictors of diversity.
- Our results are consistent with recent findings in the midwestern US, and underscore the potential risk of soil neonicotinoids to wild bee populations across regions and crop systems.
724.
Z. -Y. Huang G. E. Robinson 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,165(1):18-28
Honey bee colonies can respond to changing environmental conditions by showing plasticity in age related division of labor,
and these responses are associated with changes in juvenile hormone. The shift from nest taks to foraging has been especially
well characterized; foraging is associated with high juvenile hormone titers and high rates of juvenile hormone biosynthesis,
and can be induced prematurely in young bees by juvenile hormone treatment or by a shortage of foragers. However, very few
studies have been conducted that study plasticity in division of labor under naturally occurring changes in the environment.
To gain further insight into how the environment and juvenile hormone influence foraging behavior, we measured juvenile hormone
titers and rates of biosynthesis in workers during times of the year when colony activity in temperate climates is reduced:
late fall, winter, and early spring. Juvenile hormone titers and rates of biosynthesis decreased in foragers in the fall as
foraging diminished and bees became less active. This demonstration of a natural drop in juvenile hormone confirms and extends
previous findings when bees were experimentally induced to revert from foraging to within-hive tasks. In addition, endocrine
changes in foragers in the fall are part of a larger seasonally related phenomenon in which juvenile hormone levels in younger,
pre-foraging bees also decline in the fall and then increase the following spring as colony activity increases. The seasonal
decline in juvenile hormone in foragers was mimicked in summer by placing a honey bee colony in a cold room for 8 days. This
suggests that seasonal changes in juvenile hormone are not related to photoperiod changes, but rather to changes in temperature
and/or colony social structure that in turn influence endocrine and behavioral development. We also found that active foragers
in the late winter and early spring had lower juvenile hormone levels than active foragers in late spring. In light of recent
findings of a possible link between juvenile hormone and neuroanatomical plasticity in the bee brain, these results suggest
that bees can forage with low juvenile hormone, after previous exposure to some threshold level of juvenile hormone leads
to changes in brain structure. 相似文献