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The role of biotic and abiotic cues in stimulating aggregation by larval cane toads ( Rhinella marina )
Author(s) -
Raven Camilla,
Shine Richard,
Greenlees Matthew,
Schaerf Timothy M.,
Ward Ashley J. W.
Publication year - 2017
Publication title -
ethology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.739
H-Index - 74
eISSN - 1439-0310
pISSN - 0179-1613
DOI - 10.1111/eth.12645
Subject(s) - abiotic component , tadpole (physics) , attraction , biology , ecology , larva , predation , biotic component , toad , linguistics , philosophy , physics , particle physics
Tadpoles of the cane toad ( Rhinella marina ) form dense aggregations in the field, but the proximate cues eliciting this behavior are not well understood. We sampled water‐bodies in the Northern Territory of Australia, finding that the density of cane toad tadpoles increased with increasing temperature. Furthermore, we conducted laboratory experiments to explore the roles of biotic factors (attraction to conspecifics; chemical cues from an injured conspecific; food) and spatially heterogeneous abiotic factors (light levels, water depth, physical structure) to identify the cues that induce tadpole aggregation. Annulus and binary choice trials demonstrated weak but significant attraction between conspecifics. Tadpoles decreased swimming speeds, but did not increase grouping in response to cues from an injured conspecific. Larvae aggregated in response to abiotic cues (high levels of illumination and proximity to physical structures) and were strongly attracted to feeding conspecifics. Overall, aggregation by cane toad tadpoles is likely driven by weak social attraction coupled with a shared preference for specific abiotic features, creating loose aggregations that are then reinforced by movement toward feeding conspecifics.