Millipedes, weevils and ants: Understanding a cane toad’s diet

September 15, 2023

Conservancy biologists Melinda Schuman and Dr. Jeff Schmid, along with Conservancy volunteers Susan Snyder and Copley Smoak, have published their findings on the diet of cane toads in Southwest Florida golf course communities in the online scientific journal “Animals”. Their article was part of a special issue highlighting the effects of urbanization on herpetofauna (amphibians and reptiles).

Understanding what these invasive toads eat is key to interpreting their relationships with other species and how they function in landscapes altered by humans. Most diet studies, including three earlier studies in Florida, have identified beetles and ants as the primary food items for cane toads but this level of identification does not offer much insight into their role in urban ecosystems. Using more detailed prey identification, the current study found that cane toads mainly fed upon yellow-banded millipedes, hunting billbug weevils, and bigheaded ants – which are all considered pests in areas of human habitation such as golf course communities. 

Yellow-banded millipedes are a nuisance when large numbers invade houses and other structures but they also provide important ecosystem functions such as feeding on dead and decomposing plant matter. Similarly, bigheaded ants may become an annoyance when nesting in buildings but they also help to control other insect pests. Extensive use of mulch in residential landscaping provides habitat for millipedes and ants. Hunting billbug weevils are damaging pests in the expanse of lawns and fairways found in golf course communities and bigheaded ants are known to feed on weevil larvae but it is not known if there is a predator-prey relationship between them. Cane toads also consumed mulch and grass, providing evidence they were feeding in these urban habitats.

Thus, a complex food web with multiple ecologic functions becomes apparent with a more detailed identification of cane toad food items. Just as ants may be providing pest control services, so may cane toads by consuming these perceived urban pests. However, further studies are needed to determine if cane toads actually suppress pest populations in altered ecosystems.

This publication is one of two journal articles and four natural history notes that have stemmed from the Conservancy’s extensive research on cane toads.