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 se...

A trait's response to natural selection will reflect the nature of the inheritance mechanisms that mediate the transmission of variation across generations. The relative importance of genetic and nongenetic mechanisms of inheritance is predicted to be related to the degree of trait plasticity, with nongenetic inheritance playing a greater role in the cross-generational transmission of more plas...

In order to search for alternative control methods to synthetic pesticides, the potential of essential oils from Allium sativum (L.) (Alliaceae); was evaluated as fumigants against Callosobruchus maculatus (fab.) (Coleoptera: Bruchidae), a pest that attacks pulses during storage. Chickpea seeds were infested with 10 pairs of newly emerged weevils and, fumigated with 0, 1, 2, 3, or 4μl of essent...

Environmental and genetic stress have well-known detrimental effects on ejaculate quality, but their concomitant effect on male fitness remains poorly understood. We used competitive fertilization assays to expose the effects of stress on offensive sperm competitive ability in the beetle Callosobruchus maculatus, a species where ejaculates make up more than 5% of male body mass. To examine the ...

The functional response of the parasitoid Dinarmus basalis (Rond.) (Hymenoptera: Pteromalidae) is determined to evaluate its potential as a biological control agent. Four female wasps in the presence of males parasitoids, were allowed to oviposit during their life span or hosts at different densities. The data were fit by Rogers′ (1972) parasitoid model. The rate of parasitoid search was a′= 0....

1. Offspring from older parents often have shorter adult lifespans than offspring of younger mothers. We examine the effects of offspring genotype, maternal age and paternal age on offspring survival, development and adult lifespan in the seed beetle, Callosobruchus maculatus . 2. Females took about a quarter of a day longer to develop from an egg to an adult and lived ≈ 7 days longer than male...

Sperm competition risk and intensity can select for adaptations that increase male fertilisation success. Evolutionary responses are examined typically by generating increased strength of sexual selection via direct manipulation of female mating rates (by enforcing monandry or polyandry) or by alteration of adult sex ratios. Despite being a model species for sexual selection research, the effec...

Knowledge of heritability and genetic correlations are of central importance in the study of adaptive trait evolution and genetic constraints. We use a paternal half-sib-full-sib breeding design to investigate the genetic architecture of three life-history and morphological traits in the seed beetle, Callosobruchus maculatus. Heritability was significant for all traits under observation and gen...

The population consequences of sexual selection remain empirically unexplored. Comparative studies, involving extinction risk, have yielded different results as to the effect of sexual selection on population densities make contrasting predictions. Here, we investigate the relationship between sexual dimorphism (SD) and population productivity in the seed beetle Callosobruchus maculatus, using ...

Pulses constitute an important part of the daily diet of vegetarian population as a major source of protein. It is estimated that insects cause the most damage to the pulse grains during storage and pulse bruchids are the major storage pests. The stored pulses are usually fumigated to wade away the insect infestation. The residual effect of these chemicals on public health and growing resistanc...