Image of the Day: That Toad Is Poison

The introduction of the poisonous Duttaphrynus melanostictus into Madagascar could be fatally risky for the island’s native predators.

Jun 5, 2018
Sukanya Charuchandra

Asian toad (Duttaphrynus melanostictus)DUTTAPHRYNUS_MELANOSTICTUS_ASIAN_TOAD_PHOTO_WOLFGANG_WUSTERA genetic study published yesterday (June 4) in Current Biology reaffirms earlier fears of conservation biologists that the entry of the Asian toad (Duttaphrynus melanostictus) into Madagascar could be disastrous for the island’s native wildlife. The toad’s poison obstructs the function of a sodium-potassium pump needed for proper functioning of the cell membrane. Resistance to this toxin by animals that eat the toad is reflected in the form of a mutated genetic sequence for this pump. When researchers sequenced this region of the genome for 77 island species, they found only one rodent exhibited a possible resistance to the Asian toad.

Wolfgang Wüster, a coauthor on the paper, cautions in a statement, “predators that frequently feed on toads and do not rapidly learn or evolve to avoid them are likely to become much rarer or possibly extinct.” His results reinforce the need for urgent implementation of a plan to control the spread of this species.

B.M. Marshall et al., “Widespread vulnerability of Malagasy predators to the toxins of an introduced toad,” Curr Biol, doi:10.1016/j.cub.2018.04.024, 2018.