Formosan Entomologist (2004) 24, 53-63

Jiunn-Yaw Lin and Shwn-Bin Horng (2004)
Effects of intraspecific and interspecific male interference and density on reproduction and longevity of the bean weevils Callosobruchus chinensis (L.) and C. maculatus (F.) (Coleoptera: Bruchidae)
Formosan Entomologist 24 (1), 53-63
Abstract: The bean weevils of Callosobruchus chinensis and C. maculatus frequently infest seeds in the same storage house simultaneously. We observed a high frequency of interspecific courtship and mating attempts by these two bean weevils in the lab. Male interference may cause the loss of valuable oviposition time and energy of females, which in turn may affect the fecundity and longevity of females. In this study, the effects of intraspecific and interspecific male interference on the fecundity and longevity of female bean weevils were explored. The results showed that the fecundity and longevity of the females of these two species decreased with increasing conspecific or interspecific male density. However, effects of intraspecific and interspecific male interferences on fecundity or egg hatchability of these two bean weevils significant differed. The interspecific interference of males on the fecundity and longevity of females of both species was significantly higher than that of intraspecific interference. The fecundity and number of eggs hatched by C. chinensis were significantly reduced with increasing interspecific male density than with conspecific male density. In contrast, the effect of interspecific male interference with the fecundity and egg hatching of C. maculatus was higher than that of the intraspecific effect when male density was low. The number of eggs hatched by females of these two species decreased with increasing male density; however, male C. maculatus caused higher egg mortality for both species. Consequently, interspecific male interference is a crucial factor in interspecific competition of these two bean weevils. On the contrary, the reduction in longevity of females by interspecific and conspecific male interferences was similar.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Shwu-Bin Horng

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Callosobruchus chinensis	Stored legumes	Taiwan
	Callosobruchus maculatus	Stored legumes	Taiwan