Fatal attraction: adaptations to prey on native frogs imperil snakes after invasion of toxic toads

Mattias Hagman*, Benjamin L. Phillips, Richard Shine

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)

Abstract

Adaptations that enhance fitness in one situation can become liabilities if circumstances change. In tropical Australia, native snake species are vulnerable to the invasion of toxic cane toads. Death adders (Acanthophis praelongus) are ambush foragers that (i) attract vertebrate prey by caudal luring and (ii) handle anuran prey by killing the frog then waiting until the frog's chemical defences degrade before ingesting it. These tactics render death adders vulnerable to toxic cane toads (Bufo marinus), because toads elicit caudal luring more effectively than do native frogs, and are more readily attracted to the lure. Moreover, the strategy of delaying ingestion of a toad after the strike does not prevent fatal poisoning, because toad toxins (unlike those of native frogs) do not degrade shortly after the prey dies. In our laboratory and field trials, half of the death adders died after ingesting a toad, showing that the specialized predatory behaviours death adders use to capture and process prey render them vulnerable to this novel prey type. The toads' strong response to caudal luring also renders them less fit than native anurans (which largely ignored the lure): all toads bitten by adders died. Together, these results illustrate the dissonance in behavioural adaptations that can arise following the arrival of invasive species, and reveal the strong selection that occurs when mutually naive species first interact.

Original languageEnglish
Pages (from-to)2813-2818
Number of pages6
JournalProceedings of the Royal Society B: Biological Sciences
Volume276
Issue number1668
DOIs
Publication statusPublished - 8 Aug 2009
Externally publishedYes

Keywords

  • Acanthophis praelongus
  • ambush predator
  • Bufo marinus
  • Elapidae
  • foraging mode
  • invasive species

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