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Seed Beetle (seed + beetle)
Selected AbstractsSexual selection did not contribute to the evolution of male lifespan under curtailed age at reproduction in a seed beetleECOLOGICAL ENTOMOLOGY, Issue 5 2009ALEXEI A. MAKLAKOV Abstract. 1. Sexual selection is a powerful evolutionary force that is hypothesised to play an important role in the evolution of lifespan. Here we test for the potential contribution of sexual selection to the rapid evolution of male lifespan in replicated laboratory populations of the seed beetle, Callosobruchus maculatus. 2. For 35 generations, newly hatched virgin male beetles from eight different populations were allowed to mate for 24 h and then discarded. Sexual selection was removed in half of these populations by enforcing random monogamy. 3. Classic theory predicts that because of sexual competition, males from sexually selected lines would have higher age-specific mortality rates and shorter lifespan than males from monogamous lines. 4. Alternatively, condition-dependent sexual selection may also favour genes that have positive pleiotropic effects on lifespan and ageing. 5. Males from all eight populations evolved shorter lifespans compared with the source population. However, there was no difference in lifespan between males from populations with or without sexual selection. Thus, sexual selection did not contribute to the evolution of male lifespan despite the fact that such evolution did occur in our study populations. [source] Effects of search experience in a resource-heterogeneous environment on the oviposition decisions of the seed beetle, Callosobruchus maculatus (F.)ECOLOGICAL ENTOMOLOGY, Issue 4 2006ROU-LING YANG Abstract 1.,This study investigates how female seed beetles, Callosobruchus maculatus, distribute their eggs on various-sized seeds when the size of seed was varied during the egg-laying period. 2.,Beetles were allowed to lay eggs on one of three arrays of 64 adzuki beans (Vigna angularis). Each array contained four size classes of seed, ranging from small (5.0,5.5 mm diameter) to large (6.5,7.0 mm), but differed in how they were distributed within the environment. In the most heterogeneous condition (the 64-patch design), the four sizes were interspersed, while in the least heterogeneous condition (the four-patch design) they were grouped into four separate blocks. Thus, a beetle exploring the 64-patch design would frequently encounter all four seed sizes, whereas a beetle exploring the four-patch design would only rarely encounter a change in bean size. 3.,Beetles experiencing greater seed size heterogeneity were more likely to lay eggs on larger seeds, whereas those in the blocked condition were more likely to oviposit on small seeds. Beetle responses to seed size heterogeneity suggest that the degree of preference for large seeds depends on a female's recent experience. 4.,Female beetles exhibited size discrimination throughout their egg-laying process; however, there was a trade-off between seed size and egg discrimination (i.e. avoiding those seeds already containing developing eggs) in response to the change in fitness gained from either laying on larger seeds or lower egg-load seeds during the egg-laying process. 5.,Our model provides the first evidence that evolving seed size discrimination ability is adaptive for the seed beetle with egg-discrimination ability. [source] Genetic architecture of population differences in oviposition behaviour of the seed beetle Callosobruchus maculatusJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2004C. W. Fox Abstract Few studies have examined the genetic architecture of population differences in behaviour and its implications for population differentiation and adaptation. Even fewer have examined whether differences in genetic architecture depend on the environment in which organisms are reared or tested. We examined the genetic basis of differences in oviposition preference and egg dispersion between Asian (SI) and African (BF) populations of the seed beetle, Callosobruchus maculatus. We reared and tested females on each of two host legumes (cowpea and mung bean). The two populations differed in mean oviposition preference (BF females preferred cowpea seeds more strongly than did SI females) and egg dispersion (SI females distributed eggs more uniformly among seeds than did BF females). Observations of hybrid and backcross individuals indicated that only the population difference in oviposition preference could be explained by complete additivity, whereas substantial dominance and epistasis contributed to the differences in egg dispersion. Both rearing host and test host affected the relative magnitude of population differences in egg dispersion and the composite genetic effects. Our results thus demonstrate that the relative influence of epistasis and dominance on the behaviour of hybrids depends on the behaviour measured and that different aspects of insect oviposition are under different genetic control. In addition, the observed effect of rearing host and oviposition host on the relative importance of dominance and epistasis indicates that the genetic basis of population differences depends on the environment in which genes are expressed. [source] Effects of search experience in a resource-heterogeneous environment on the oviposition decisions of the seed beetle, Callosobruchus maculatus (F.)ECOLOGICAL ENTOMOLOGY, Issue 4 2006ROU-LING YANG Abstract 1.,This study investigates how female seed beetles, Callosobruchus maculatus, distribute their eggs on various-sized seeds when the size of seed was varied during the egg-laying period. 2.,Beetles were allowed to lay eggs on one of three arrays of 64 adzuki beans (Vigna angularis). Each array contained four size classes of seed, ranging from small (5.0,5.5 mm diameter) to large (6.5,7.0 mm), but differed in how they were distributed within the environment. In the most heterogeneous condition (the 64-patch design), the four sizes were interspersed, while in the least heterogeneous condition (the four-patch design) they were grouped into four separate blocks. Thus, a beetle exploring the 64-patch design would frequently encounter all four seed sizes, whereas a beetle exploring the four-patch design would only rarely encounter a change in bean size. 3.,Beetles experiencing greater seed size heterogeneity were more likely to lay eggs on larger seeds, whereas those in the blocked condition were more likely to oviposit on small seeds. Beetle responses to seed size heterogeneity suggest that the degree of preference for large seeds depends on a female's recent experience. 4.,Female beetles exhibited size discrimination throughout their egg-laying process; however, there was a trade-off between seed size and egg discrimination (i.e. avoiding those seeds already containing developing eggs) in response to the change in fitness gained from either laying on larger seeds or lower egg-load seeds during the egg-laying process. 5.,Our model provides the first evidence that evolving seed size discrimination ability is adaptive for the seed beetle with egg-discrimination ability. [source] | ||||||||||