Food or safety? The determinants of aggressive behavior in the house cricket, Acheta domesticus

Presenter: Rebecca Fehn
Advisor: Zeynep Benderlioglu

Abstract

Aggressive displays among males are used to establish dominance and ensure access to valuable resources in a variety of species. Much attention has been paid to the determinants of aggressive behavior regarding the availability of mates, food and water sources, and extreme temperatures. On the other hand, the effect of predator presence on intra-specific aggression has not received much attention. This remains an important gap in our knowledge, considering animals have to compete for valuable resources and face predation risk at the same time. The current study examines aggression under predation risk in male domestic crickets, Acheta domesticus. Mature male crickets were isolated and food starved for seven consecutive days. They had ad libitum access to water.  Previous observations indicated that lack of food for a week-long period had no discernable adverse effects on the crickets. After the isolation procedure, the crickets were randomly allocated to two groups; control and experimental. Behavioral trials were then conducted immediately after isolation. Each trial consisted of placing two crickets from the same group on two opposing ends of an arena. A filter paper covering one third of the total arena was present in the middle with a food item. The control group had a cue-free, blank filter paper. The experimental group, on the other hand, had filter paper with chemical cues deposited by a generalist wolf spider predator, Hogna helluo. Aggressive behaviors as indicated by the frequency of biting, chasing, chirping, and antennae jousting were recorded. The experiments are currently being performed. It is predicted that aggressive displays will be reduced under predation risk even when animals face starvation. This has important implications for conservation biology, especially when food resources are limited where generalist predators have an advantage over specialists.

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