Aganacris insectivora, Aganacris pseudosphex

Belwood (1990) reported effects of predation on the singing behavior of A. insectivora on Barro Colorado Island, Panama. Leaf- gleaning bats often use echolocation for general orientation but tend to locate their katydid prey passively by listening for the sounds they make. Four of the six katydid species taken by Micronycteris hirsuta on Barro Colorado Island in Panama call in the 23-27 kHz range, suggesting which prey are taken depends on whether the bat can hear their call or not (Belwood 1990).

The selection pressure from bats has resulted in a number of adaptations in calling behavior. Some species avoid predation by calling when bats are least active. For example, Aganacris insectivora has two active periods, one during the day and one during the night. Their mimicry of wasps protects them from daytime predators such as birds, monkeys, and lizards, but not during the night. At night, they sing in a very narrow time band between 3 and 5 AM, coinciding with a lull in feeding behavior of leaf-gleaning bats. The strategy appears to be effective because gleaning bats do not appear to take these species (Robinson and Hall 2002). It has not been demonstrated whether this singing cycle also occurs in South American species, but in northern Peru leaf-gleaning bats are pres- ent in rainforests inhabited by A. pseudosphex and are most active in the early evening (9 PM-12 AM) (Belwood, pers. observ.). [1]

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