Circatidal rhythmic behaviour in the coastal tiger beetle Callytron inspecularis in Japan

Abstract

Larvae of the coastal tiger beetle Callytron inspecularis (W. Horn) (Coleoptera: Cicindelidae) plug their burrow opening before submergence at high tide. Field observations showed that burrow plugging was a rhythmic behaviour that coincided with the tidal cycle (ca. 12.4 h). On average, larvae plugged their burrows 41.8 min before the tide covered the habitat. The mean interval between consecutive burrow-plugging events in the field was 12.40 h. In the laboratory, in the absence of tidal inundation, the mean interval between consecutive burrow-plugging events was 12.45 h. This suggests that the burrow-plugging rhythm of the coastal tiger beetle is governed by an endogenous circatidal rhythm.

Keywords:

• Burrow plugging
• circadian
• coastal tiger beetle
• tidal rhythm

Acknowledgements

We thank Dr Hideharu Numata (Osaka City University) and Dr Eiji Yoshioka (Kobe Yamate College) for many helpful comments on this study. This work was supported by a Grant for Biodiversity Research of the 21st Century COE (A14).