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Measurement for Solitariness and Gregarism: Analysing Spacing, Attraction and Interactions in Four Species of Zetoborinae (Blattaria)


Corresponding author: Joan van Baaren, UMR 6552, Ethologie Evolution Ecologie, Université de Rennes I, Campus de Beaulieu, Avenue du Général Leclerc, 35042 Rennes Cedex, France. E-mail:


Abstract Distinguishing gregarism based on attraction between conspecifics from aggregation based on environmental factors is not a trivial task. In this paper, we propose a laboratory experimental design for characterizing gregarism, using Zetoborine cockroaches as a model. Three complementary tests were used: the classical spacing and attraction tests, complemented by analyses of social interactions with flow charts on factorial maps. Convergent results from the three tests allowed a tentative characterization of solitariness and different degrees of gregarism. These elements were used to improve the interpretation of spacing patterns of four species of cockroaches observed in the field.