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Author (up) Cope, J.M.; Fox, C.W. file  url
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  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
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  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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