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Microhabitat selection in an assemblage of crickets (Orthoptera: Ensifera) of a tropical evergreen forest in Southern India

Authors


Rohini Balakrishnan, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India. E-mail: rohini@ces.iisc.ernet.in

Abstract

Abstract.  1. Habitat selection is a universal aspect of animal ecology that has important fitness consequences and may drive patterns of spatial organisation in ecological communities.

2. Measurements of habitat selection have mostly been carried out on single species and at the landscape level. Quantitative studies examining microhabitat selection at the community level are scarce, especially in insects.

3. In this study, microhabitat selection in a natural assemblage of cricket species was examined for the first time using resource selection functions (RSF), an approach more commonly applied in studies of macrohabitat selection.

4. The availability and differential use of six microhabitats by 13 species of crickets inhabiting a tropical evergreen forest in southern India was examined. The six available microhabitats included leaf litter-covered ground, tree trunks, dead logs, brambles, understorey and canopy foliage. The area offered by the six microhabitats was estimated using standard methods of forest structure measurement. Of the six microhabitats, the understorey and canopy accounted for approximately 70% of the total available area.

5. The use of different microhabitats by the 13 species was investigated using acoustic sampling of crickets to locate calling individuals. Using RSF, it was found that of 13 cricket species examined, 10 showed 100% selection for a specific microhabitat. Of these, two species showed fairly high selection for brambles and dead logs, which were rare microhabitats, highlighting the importance of preserving all components of forest structure.

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