Tailored Defense Warnings in Tiger Moths
September 04, 2008
The warning signals used by tiger moths to deter would-be predators vary depending on the time of year, and therefore the type of predator they are most likely to meet, according to a study of 26 moth species in south-eastern Ontario, Canada.
Moth species that emerge in the spring, when birds are the biggest threat, tend to use visual signals such as bright colouration to warn of their unpalatability to predators. In contrast, species that emerge in the summer rely more on ultrasonic clicks, which act as a warding-off message to echolocating bats, which pose the main threat during these later months.
Similarly, species active during the day tend to rely more on visual warning signals, whereas ultrasonic clicks are more useful at night, report John Ratcliffe and Marie Nydam in the September 04, 2008 Nature. The research demonstrates how evolutionary pressures from two distinct predators can guide the evolution of separate components of the insects' warning systems, resulting in a diverse arsenal of anti-predator defences within the same species.
Abstract © 2008, Nature
John M. Ratcliffe, University of Southern Denmark, Odense, Denmark
Marie Nydam, Cornell University, Ithaca, NY