vamosi pictures
Bruchid natural history anecdotes

 Bruchid natural history anecdotes

 Callosobruchus chinensis

One interesting aspect of Callosobruchus chinensis is the marked sexual dimorphism in antennal structure. Males have elaborated, comb-like (= pectinate) antennae, whereas females have simple, club-like (= serrate) antennae. Pectinate antennae are thought to be quite rare in bruchids, suggesting that they may play a special role in locating females and (or) subsequent mating success. Interestingly, evidence suggests the presence of an additional stimulatory sex pheromone in females, which is apparently absent in females of other species (e.g., C. maculatus).

See also: Colgoni A & SM Vamosi (2006) Entomol. Sci. 9: 171-179.

 Callosobruchus maculatus

Geographically isolated strains of Callosobruchus maculatus may exhibit variation in the degree to which antagonistic interactions occur between developing larvae within beans. On one end of the spectrum, individual larvae engage in very few direct antagonistic interactions and develop in different parts of the bean. Such strains are said to have a scramble competition strategy. On the other end of the spectrum, individual larvae actively seek each other out, typically by burrowing towards the center of the bean, and attempt to kill each other. The (often sole) surviving larvae then have access to the entire contents of the bean. Such strains are said to have a contest competition strategy.

See also: Midori Tuda's page, where she describes the outcome of a very interesting laboratory experiment examining long term host-parasitoid population and evolutionary dynamics.