Shelter use during exploratory and escape behaviour of the crab Chasmagnathus granulatus: a field study
- 140 Downloads
The use of shelters has had a predominant adaptive value in many species throughout evolution. Shelters provide protection and reduce the risk of predation during the search for food and mates. However, they imply the additional danger of having the refuge appropriated by an intruder because of intraspecific competition, especially in densely populated communities. In this work we studied the burrow-centred strategies of exploration and the burrow-oriented escape responses of the crab Chasmagnathus granulatus during surface activity outside their burrows. Exploratory excursions were described through diverse characteristics that enabled their functional analysis and categorization. Results showed that surface exploration is mainly accomplished by slow and near-the-burrow excursions that could be composed of two or three stages. Exploratory behaviour is drastically replaced by a conspicuous burrow-oriented escape response when crabs are faced with an aerial stimulus or the approach of a conspecific neighbour. We describe and compare this escape run with regard to whether individual survival or burrow resource is at risk. This study provides evidence of the effect of the crabs’ shelter on surface activity and social interactions in the natural habitat of C. granulatus and supplies valuable tools for field and laboratory studies using this crab as an animal model.
KeywordsShelter use Field study Neohelice granulata (=Chasmagnathus granulatus) Exploratory excursions Conspecific interactions Escape response
We thank Iribarren L., Kunert M.C., Piriz G., Tedesco M. and Vidal A. for technical assistance in the field. This work was supported by FONCYT (Grant PICTR 00349, PICT-2006-02261), UBACYT (Grant X326) and CONICET (PIP 112-200801-02457 and PIP 2004-5466.
- Botto JL, Irigoyen HR (1979) Bioecologia de la comunidad del cangrejal I—Contribución al conocimiento biológico del cangrejo de estuario, Chasmagnathus granulata Dana (Crustacea, Decapoda, Grapsidae) en la desembocadura del Rio Salado, Provincia de Buenos Aires. Seminario de Biología Bentónica y Sedimentación de la Plataforma Continental del Atlántico Sur. UNESCO, Montevideo, pp 161–169Google Scholar
- D’Incao F, Ruffino ML, Silva KG, Braga AC (1990) Habito alimentar do caranguejo Chasmagnathus granulata Dana, 1851 na barra de Rio Grande, RS (Decapoda, Grapsidae), vol 1. Atlantica, Rio Grande, pp 85–93Google Scholar
- Maldonado H (2002) Crustacean as model to investigate memory illustrated by extensive behavioral and physiological studies in Chasmagnathus. In: Wiese K (ed) The crustacean nervous system. Springer, BerlinGoogle Scholar
- Sakai K, Türkay M, Yang SL (2006) Revision of the Helice/Chasmagnathus complex (Crustacea: Decapoda: Brachyura). Abh Senckenberg Naturforsch Ges 565:1–76Google Scholar
- Spivak E (2010) The crab Neohelice (=Chasmagnathus) granulata: an emergent animal model from emergent countries. Helgol Mar Res 198. doi: 10.1007/s10152-010-0198-z
- Zar JH (1999) Biostatistical analysis. Prentice-Hall, Upper Saddle RiverGoogle Scholar