Millipede consumption and interaction between food preferences and sex in dung beetle Chalconotus convexus (Coleoptera: Scarabaeinae)

Abstract

AbstractDung beetles feed mainly on scarce and ephemeral mammalian faeces making them vulnerable to declines of mammal populations. Therefore, studying how diverse groups like the Scarabaeinae subfamily utilize alternative food sources, such as decomposing invertebrates, enhances our understanding of their distribution and resilience in defaunated areas. One poorly studied aspect of the feeding habits of dung beetles is the potential differences between the sexes and their predatory behaviour. We evaluated how the sex (male and female) of individuals of Chalconotus convexus affected individual resource attraction to different bait types. Since C. convexus is known to feed on faeces, carrion and dead millipedes, we also test whether it can predate live individuals of millipedes. We used a combination of two field samplings and one laboratory experiment, using pitfall traps baited with faeces, carrion, millipedes and millipede's defensive compounds. While the preference for millipede was not associated with sex, we found a significant relationship between faeces and carrion, where females of C. convexus are significantly less attracted to faeces when compared to males and also males are significantly less attracted to carrion when compared to females. Furthermore, we also show that while actively consuming dead millipedes, C. convexus is unable to predate on live individuals. Our study illustrates that the versatility of food sources may help to explain the high abundance and wide distribution of C. convexus in Africa.