Dung beetles use their dung ball as a mobile thermal refuge

Summary, in English

At midday, surface temperatures in the desert often exceed 60°C. To be active at this time, animals need extraordinary behavioural or physiological adaptations. Desert ants, for instance, spend up to 75% of their foraging time cooling down on elevated thermal refuges such as grass stalks [1]. Ball-rolling dung beetles work under similar thermal conditions in South African savannahs. After landing at a fresh dung pile, a beetle quickly forms a dung ball and rolls it away in a straight line, head down, walking backwards [2]. Earlier studies have shown that some dung beetles maintain an elevated body temperature to gain a competitive advantage [3], [4] and [5], and that heat shunting may prevent overheating during flight [6] and [7]. However, we know little about the behavioural strategies beetles might employ to mitigate heat stress while rolling their dung balls. Using infrared thermography and behavioural experiments, we show here that dung beetles use their dung ball as a mobile thermal refuge onto which they climb to cool down while rolling across hot soil. We further demonstrate that the moist ball functions not only as a portable platform, but also as a heat sink, which effectively cools the beetle as it rolls or climbs onto it.

• Author: Jochen Smolka; Emily Baird; Marcus Byrne; Basil el Jundi; Eric Warrant; Marie Dacke
• Department/s: Department of Biology; Functional zoology; Lund Vision Group
• Publishing year: 2012
• Language: English
• Pages: 863-864
• Publication/Series: Current Biology
• Volume: 22
• Issue: 20
• Full text: - 728 kB; Download statistics
• Links: http://dx.doi.org/10.1016/j.cub.2012.08.057
• Document type: Journal article
• Publisher: Elsevier
• Topic: Biological Sciences
• Keywords: Dung beetles; thermoregulation; thermal refuge; Scarabeidae; Scarabaeinae
• Status: Published
• Research group: Lund Vision Group
• ISBN/ISSN/Other: ISSN: 1879-0445