Response of adult Colorado potato beetles (Coleoptera: Chrysomelidae) to water in the landscape

Abstract

This laboratory study confirmed that the strategy of adult terrestrial Colorado potato beetle (Leptinotarsa decemlineata (Say); Coleoptera Chrysomelidae) to survive the threat of drowning in water is based on avoidance of water crossings. It also showed that beetles at the surface of a body of water after failing to avoid it, long considered limited to passive floating and phoretic transport were in fact likely to rely on a complex fight or flee response. Beetles showed capacity to swim in a pattern similar to land foraging beetles. Beetles also tolerated submergence and walked underwater. These active behaviours should improve their probability of finding shore or refuge for longer survival. Results confirmed that Colorado potato beetles are likely to accumulate near water features in the potato agro-ecosystem landscape but suggest that successful crossings and colonisation of crops on the other side are more likely than previously expected. On a larger scale, new information provided by this study combined with our knowledge of dominant winds and currents should make it possible for future research to better predict the probability of surviving encounters with water and the orientation of invasive Colorado potato beetle colonisers dispersing at the surface of bodies of water.

Sex-specific effects of a parasite on stress-induced freezing behavior in a natural beetle-nematode system

“…The vibration treatment involved placing a cell phone under the metal tray, and using a cell phone app to vibrate the phone and tray. The beetles in the tray thus experienced vibration stimulus, which is known to trigger immobility or startle responses in other beetle species [40][41][42]. The last treatment was the vibration stimulus, plus where the observer sharply rapped 5 times on the side of the metal tray with a metal rod, which we reasoned would serve as an additional vibration and noise stimulus; in preliminary trials we noted that freezing can be induced with just the metal rod (see S1 Video).…”