Fecundity of First-Generation Captively Reared Heterelmis comalensis (Coleoptera: Elmidae)

The Comal Springs riffle beetle Heterelmis comalensis Bosse, Tuff, and Brown is listed as endangered by the U.S. Fish and Wildlife Service. Rearing this species in captivity is important to maintaining a refuge which is a goal of the Edwards Aquifer Habitat Conservation Plan. Although captive larval production has been observed for years, the production of larvae per female has been relatively unknown. Production chambers were constructed from PVC to house one female and male and the production of larvae was monitored ca. monthly until the female died. Females were found to be iteroparous and produced 29.3 ± 37.1 larvae. The number of larvae produced was found to be a function of female longevity rather than size. Other aspects of captive production and observations from the study are discussed.