MORTALITY AND PREY BEHAVIOR & LIFE HISTORIES

Risk of predation and prey life histories - Dr. Laura Hechtel (a Ph.D. student) and I showed that Aedes triseriatus that can perceive the presence of predatory Toxorhynchites rutilus larvae undergo metamorphosis at smaller size and later than similar individuals raised without this predator. In contrast to studies of amphibians and other insects, we showed that direct contact with the predator yields stronger effects on life history of A. triseriatus. Thus, the mere presence of T. rutilus reduces A. triseriatus’s growth, perhaps by inducing reduced prey foraging and feeding.

For more details on this research topic, please see:

Hechtel, L. J. & Juliano, S. A. 1997. Effects of a predator on prey size at and time to metamorphosis: plastic response by prey or selective mortality? Ecology 78:838-851. 

Other mortality sources and life history
Troy Stoffregen (an undergraduate) and I showed that another mortality source -- drying of the aquatic habitat -- also induced A. triseriatus to pupate at a smaller size. This result shows that A. triseriatus’s life history responds to different sources of mortality as predicted by evolutionary models. However, different mechanisms seem to produce the responses to predation, which appears to result from behavioral changes that reduce both risk of predation and growth rate, and habitat drying, which does not appear to involve reduced growth rate and may be a product of a developmental change.

For more details on this research topic, please see:

Juliano, S. A. & Stoffregen, T. L. 1994. Effect of habitat drying on size at and time to metamorphosis in the tree hole mosquito Aedes triseriatus. Oecologia 97:369-376.