Body Size Relationship between Sphecius speciosus (Hymenoptera: Crabronidae) and Their Prey: Prey Size Determines Wasp Size

Jon M. Hastings, Charles W. Holliday, Joseph R. Coelho

Abstract


Eastern cicada killers, Sphecius speciosus Drury, are large, ground-nesting, mass-provisioning wasps that use cicadas to feed their offspring. Previous studies have reported that female S. speciosus provide each male offspring with 1 or rarely 2 cicadas, and each female offspring with 2 or rarely 3 cicadas, regardless of cicada size. We collected samples of male and female cicada killers and samples of their cicada prey from 12 locations in 10 different states of the USA. We measured right forewing length of the wasps and dry body mass of the cicadas as indicators of size; ANOVA revealed significant differences in mean masses among local populations of cicadas. We predicted that wasp size would also vary among locations, and would be positively correlated with mean size of local cicada prey. ANOVA did reveal significant differences in mean wing length in both male and female wasps among study sites. Regression analysis, with local mean cicada mass as the independent variable and local mean wasp wing length as the dependent variable, suggests that the size of available cicada prey is a good predictor of size for both male and female S. speciosus.

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