Energetics of Brooding in the Freshwater Amphipod Gammarus minus

• Heather S. Galbraith

  Juniata College

  Author

• Johnathan G. White

  Juniata College

  Author

Reproductive strategies among organisms vary greatly, as do the energetic investments associated with producing young. Amphipod crustaceans carry their eggs in a brood pouch and release them as juveniles. However, very little is known about the reproductive energy investments of amphipod females during the period when they are carrying their young. The goal of this research was to determine the energetic costs associated with carrying a brood in the freshwater amphipod, Gammarus minus. We hypothesized that there would be no difference in metabolic rate between G. minus females carrying a brood and females from which the brood was removed. To test this hypothesis we measured oxygen consumption of female amphipods carrying broods, debrooded females, and their removed eggs. We found no difference in metabolic rate between females carrying broods and debrooded females (t = 0.38, df = 44, P = 0.705). However, we found that the combined metabolic rate of debrooded females and their removed young was higher than that of females carrying broods (t = 5.28, df = 44, P < 0.001). These results indicate that there is no additional metabolic cost to carrying a brood, suggesting that conditions within the brood pouch lower the metabolic rate of the embryos.

• PDF