Cane toads a threat to West Indian wildlife: mortality of Jamaican boas attributable to toad ingestion

Abstract

The notorious “cane toad” (Bufo marinus) is considered to be one of the 100 worst invasive species in the world. A native of South and Central America, Mexico, and the Rio Grande Valley of the United States, this large toad was intentionally introduced to islands in the Caribbean, and subsequently throughout the southern Pacific, as a biological control agent to combat sugar cane pests. Unfortunately, the primary result of those introductions has been deleterious impacts on native biotas, primarily through competition and predation. More recently, the cane toad has devastated populations of amphibian-eating predators in Australia, through the ingestion of this highly toxic anuran. Elsewhere, however, the impact of the toad on native predators has not been documented. Here we report the first evidence that the cane toad is impacting native predators in other geographic regions. Specifically, we document death due to cane toad poisoning in the endemic and threatened Jamaican boa (Epicrates subflavus). To our knowledge, this is the first report of cane toads causing mortality in naturally occurring predators outside of Australia. Like all members of the genus, B. marinus secretes a powerful bufogenin toxin, which is often fatal if ingested by naive species that have not co-evolved with Bufo species. Our results should therefore serve as a warning that other endemic predator species in the West Indies and elsewhere may be at risk. Thus, efforts to control the population growth and spread of cane toads may be of even greater conservation concern than previously recognized.