Monday, December 10, 2007 - 8:41 AM

Survival of giant water bug embryos in water and in air (Hemiptera: Belostomatidae)

Christine L Goforth, and Robert L. Smith, University of Arizona, Department of Entomology, P.O. Box 2100:36, Tucson, AZ

While the paternal care behaviors of belostomatids are well characterized, there is almost nothing known about belostomatid embryos and how brooding contributes to their survival. Belostomatid embryos left unattended do not survive, so brooding is clearly necessary for their development. For this experiment, we simulated two potential dangers belostomatid eggs may be exposed to, submersion and desiccation. Fresh eggs were collected from the back brooding species Abedus herberti and the emergent brooding species Lethocerus medius. Eggs from both species were submerged in water or left in air, then removed at several intervals throughout the course of development and allowed to continue developing under simulated normal conditions. Lethocerus embryos are much more resistant to desiccation than those of Abedus, but are much more susceptible to drowning. However, neither species could remain in water or in air throughout development. Both species require both water and oxygen for survival and brooding provides the proper balance between these two necessities. Additionally, the oxygen and/or water requirements of embryos at the beginning of development are apparently low enough that brooding is not necessary until late in development. This suggests that embryos receive some yet unknown benefit from brooding, males may waste energy brooding throughout embryonic development, or brooding behaviors may help contribute to the survival of the father as well as the embryos.

Species 1: Hemiptera Belostomatidae Abedus herberti (giant water bug)
Species 2: Hemiptera Belostomatidae Lethocerus medius (giant water bug)