Boletín de la Sociedad Geológica Mexicana Volumen 70, núm. 2, 2018, p. 369 ‒ 377 http://dx.doi.org/10.18268/BSGM2018v70n2a7

Análisis de rastros en el desplazamiento de cangrejos ermitaño terrestres: una ventaja al usar conchas ligeras

Oscar Larrañaga^1,*, Karla Kruesi

¹ Laboratorio de Ecofisiología, Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Ciudad Universitaria, Coyoacán, 04510, Ciudad de México, México.

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Abstract

For the hermit crabs, one of the most import ant resources is the shell of gastropod they carry along their life. This shell gives them different benefits like protection, refuge and prevents desiccation. The semi-terrestrial hermit crabs (Family Coenobitidae) perform a behavioral remodeling process from the inside of the gastropod shell, increasing its internal volume and making them lighter. In this study the advantages provided by remodeling a shell were evaluated with a locomotion approach. For this, terrestrial hermit crabs from Coenobitacompressus species were collected in Playa Troncones, Guerrero. Locomotion experiments were performed where the crabs walked on wet sand occupying remodeled and non-remodeled shells with the purpose of measure their performance. Depth measurements and type of imprint were taken; also the walking velocity of each crab was measured.

As a result we obtained that the hermit crabs occupying remodeled shells had a lower drag, shallower shell traces and they reached a greater speed. Therefore, the benefits of using a remodeled shell were demonstrated from a locomotive point of view. Besides, this study showed an application of the neo-ichnology as an implement in ecological and biological studies

Keywords: Remodeled shells, non-remodeled shells, locomotion, imprints, depth, walking velocity.