The effects of phototaxis and thigmotaxis on microhabitat selection by a caecilian amphibian (genus Ichthyophis)

摘要

In the field, ichthyophiid caecilians are found in soil and epigeic microhabitats - conditions that provide both the phototactic cue of darkness and the thigmotactic cue of tactile contact. In laboratory experiments, we investigated the use of phototaxis and thigmotaxis on refuge selection in acaecilian of the genus Ichthyophis. Refuges that provided light with tactile cues, darkness with tactile cues, or darkness without tactile cues were sufficient in satisfying refuge-seeking behaviour in this species. Tactile stimuli, however, proved to be more preferred than darkness in refuge-seeking behaviour. Our results are consistent with field observations of Ichthyophis species. Thigmotactic cues may be preferred because they are more biologically significant for a burrowing vertebrate that has reduced vision.