Host defense or parasite cue: Skin secretions mediate interactions
between amphibians and their parasites
Abstract
Amphibian skin secretions (substances produced by the amphibian plus
microbiota) plausibly act as a first line of defense against pathogen
attack, but may also provide chemical cues for pathogens. To clarify the
role of skin secretions in host-parasite interactions, we conducted
experiments using cane toads (Rhinella marina) and their lungworms
(Rhabdias pseudosphaerocephala) from the range-core and invasion-front
of the introduced anurans’ range in Australia. Depending on the
geographic area, toad skin secretions can reduce the longevity and
infection success of parasite larvae, or attract lungworm larvae and
enhance their infection success. These striking differences between the
two regions were due both to differential responses of the larvae, and
differential effects of the skin secretions. Our data suggest that skin
secretions play an important role in host-parasite interactions in
anurans, and that the arms race between a host and parasite can rapidly
generate spatial variation in critical features of that interaction.