Population structure and habitat occupation in two sympatric Aegla species (Decapoda, Anomura, Aeglidae) in Atlantic Forest, Brazil

Abstract

This study deals with population structure and habitat sharing of two sympatric aeglid species, Aegla jarai Bond-Buckup and Buckup, 1994 and Aegla muelleri Bond-Buckup and Buckup, 2010 at Espingarda Creek, Serra do Itajaí National Park, Rio Itajaí-Açú basin, Santa Catarina, Brazil. Individuals of A. jarai (n = 190) and A. muelleri (n = 131) were captured from June/2001 to May/2002 in monthly collection. A total of 89 males and 101 females (2 ovigerous) of A. jarai were collected with a sex ratio of 1:1, and 56 males and 75 females (2 ovigerous) of A. muelleri, with a predominance of females. Aegla jarai was larger than A. muelleri and the reproductive period of A. jarai was in the winter and spring, while that of A. muelleri was in the spring. Three cohorts were observed throughout the year, and both species have a recruiting period in the spring and summer. Both species perform their entire life cycle in the Espingarda Creek and their coexistence is attributed to space partitioning: the larger A. jarai lives in the large spaces formed between boulders, while the smaller A. muelleri shelters in the small spaces between pebbles.

Keywords
Aegla jarai; Aegla muelleri; distribution; freshwater crustacean; Neotropical region; sex ratio