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Author (up) Anderson, R.S. file  url
  Title Resource partitioning in the carrion beetle (Coleoptera:Silphidae) fauna of southern Ontario: ecological and evolutionary considerations Type Journal Article
  Year 1982 Publication Canadian Journal of Zoology Abbreviated Journal Can. J. Zool.  
  Volume 60 Issue 6 Pages 1314-1325  
  Keywords Beetle; Silphid fauna; Nicrophorinae  
  Abstract Resource partitioning in the silphid fauna of southern Ontario is examined in detail, using baited pitfall traps placed in four different habitats. During 1979 and 1980, a total of 9549 specimens of Silphidae were collected, representing 12 species, of which 5 were in the subfamily Silphinae and 7 in the subfamily Nicrophorinae. The roles of different seasonal patterns, habitat specificity, and food type and size in resource partitioning are discussed for all species. At the subfamilial level, resource partitioning is accomplished through selection of different sizes of carcasses, while at the specific level, seasonal patterns and habitat specificity appear to be the primary means permitting coexistence.In the Silphidae, competition for food resources appears to be the primary factor inducing ecological character displacement. The possible origins of patterns of resource use in this assemblage are discussed in an ecological and geological time framework.  
  Call Number Serial 2137  
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Author (up) Bakker, T.C.M.; Pomiankowski, A. file  url
  Title The genetic basis of female mate preferences Type Journal Article
  Year 1995 Publication Journal of Evolutionary Biology Abbreviated Journal J Evolution Biol  
  Volume 8 Issue 2 Pages 129-171  
  Keywords Callosobruchus maculatus; Genetic variation; Mate preferences; Female; Male; Beetle  
  Abstract We review the evidence for genetic variation in female and male mate preferences. Genetic differences between species and partially isolated races show that preferences can evolve and were genetically variable in the past. Within populations there is good evidence of genetic variation, both of discrete genetic effects (8 cases) and quantitative genetic effects (17 cases), from a diverse range of taxa. We also review evidence for the presence of genetic covariance between mate preferences and sexual traits in the other sex. The 11 studies go a long way to validating the theoretical prediction of positive genetic covariance. The few negative results are best explained by a lack of appropriate experimental design. One unresolved question is whether genetic covariance is due to linkage disequilibrium between unlinked genes or physical linkage. Some evidence points to linkage disequilibrium but this is not yet conclusive.  
  Call Number Serial 1694  
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Author (up) Callaham, M. file  url
  Title Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass Type Journal Article
  Year 2003 Publication Soil Biology and Biochemistry Abbreviated Journal Soil Biology and Biochemistry  
  Volume 35 Issue 8 Pages 1079-1093  
  Abstract The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.

Subject headings: Biomass; Earthworms; Cicadidae; Scarabaeidae; Elateridae; Curculionidae; Insect herbivores; Disturbance; Nitrogen; Phosphorus; Fertilizer; Grassland; Fire; Fertilization
  Call Number Serial 2349  
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Author (up) Cope, J.M.; Fox, C.W. file  url
  Title Oviposition decisions in the seed beetle, Callosobruchus maculatus (Coleoptera: Bruchidae): effects of seed size on superparasitism Type Journal Article
  Year 2003 Publication Journal of Stored Products Research Abbreviated Journal Journal of Stored Products Research  
  Volume 39 Issue 4 Pages 355-365  
  Keywords Beetle; Egg dispersion; Egg load; Seed size; Superparasitism; Callosobruchus maculatus; Cowpeas  
  Abstract The seed parasite Callosobruchus maculatus generally disperses eggs uniformly among seeds. We used cowpeas (Vigna unguiculata) of two class sizes (large and small) to test predictions based on a simple resource threshold model that females will distribute eggs among seeds in a manner that maximizes the amount of resources allocated to each offspring. When females were presented with multiple seeds of the same size, they tended to distribute their eggs relatively uniformly among seeds (0.27 where I is the variance/mean ratio, and I=1 reflects a random Poisson distribution). However, when seeds varied in size females distributed their eggs in a manner that maximized the amount of resources per offspring; females distributed eggs as predicted by seed differences in mass rather than as predicted by seed differences in surface area. Therefore, females must evaluate the relative quantity of resources available inside of a seed more accurately than if they compared the ratio of surface areas between seeds of varying size. Instead, females must either use cues other than surface area when estimating seed mass, or must have the ability to extrapolate non-linearly from surface area to seed mass. Females with higher egg loads (4-d-old females) laid more eggs when presented with seeds, but did not distribute their eggs less uniformly, than females with lower egg loads (1-d-old females), indicating that high egg load does not reduce female sensitivity to seed size and the presence of conspecific eggs.  
  Call Number Serial 2138  
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Author (up) Credland, P.F.; Dick, K.M.; Wright, A.W. file  url
  Title Relationships between larval density, adult size and egg production in the cowpea seed beetle, Callosobruchus maculatus Type Journal Article
  Year 1986 Publication Ecological Entomology Abbreviated Journal Ecol Entomol  
  Volume 11 Issue 1 Pages 41-50  
  Keywords Beetle; Cowpeas; Adult eclosion  
  Abstract 1The eggs of the cowpea seed bettle Callosobruchus maculatus (Fab.) are attached to cowpeas. On hatching, the larvae penetrate the testa and remain in the seed until development is complete and adult eclosion has occurred. The adults do not need to feed and were not allowed to do so.

2Strains from Brazil and Nigeria can produce more than twelve adults from a seed bearing numerous eggs, whereas a strain from the Yemen Republic rarely produced more than three.

3In all three strains the mean weight of the adults produced from a single cowpea declined with increasing initial larval density in the seed.

4Egg production by females is positively correlated with their weight at the time of mating, shortly after emergence.

5Lifetime egg production by females of the Brazilian and Nigerian strains was lower if they came from cowpeas with higher initial larval densities. No such relationship could be demonstrated in the Yemen strain.

6The fecundity of one generation of these beetles, at least in some geographical strains, is significantly affected by the number of larvae entering the hosts in which the adults of that generation have developed.
  Call Number Serial 2134  
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