Generalist dung attraction response in a New Zealand dung beetle that evolved with an absence of mammalian herbivores

1. Dung beetles (Scarabaeidae: Scarabaeinae) are integral parts of manyecosystems because of their role in decomposition of dung; particularly mammal dung,which forms the diet of both larvae and adults.2. New Zealand dung beetles are unusual as they are flightless and evolved onislands with a highly depauperate mammal fauna and thus without the usual dungresource used by dung beetles elsewhere. The diet of New Zealand dung beetles isunknown.3. We hypothesised (1) that the endemic dung beetleSaphobius edwardsiwould beattracted to a broad range of food types, and (2) thatS. edwardsiwould be able tosurvive and reproduce on a range of dung types and puriri (Vitex lucens) humus.4. Laboratory choice tests identified thatS. edwardsiwas attracted to a range ofmammal, bird, invertebrate, and reptile dung types, but not to non-dung food sources.Five-month no-choice tests found that beetle survival rates were lower for beetles fedwith humus compared with those fed on mammal, bird, or invertebrate dung. Noneof the beetles reproduced.5. This study suggestsS. edwardsihave a strong preference for dung, and are likelyto be broad dung generalists in their feeding behaviour.