Species-and sex-specific adjustments of movement behavior to landscape heterogeneity in butterflies

Abstract

Landscapes are often considered as islands of suitable habitat patches located in a hostile and homogeneous matrix. Variation in matrix quality, however, can be differently perceived by individuals, generating variation in movements related to external conditions (i.e., contrasted boundaries, corridors, or barriers) and/or individual phenotypes (i.e., sex or age). Accordingly, movements may differ both among species and among conspecific individuals of various age and/or sex. Here, we quantified sex-dependent and condition-dependent variations in orientation capacity, exploration behavior, and adjustment of flight speed to landscape heterogeneity in 2 related butterfly species (Boloria aquilonaris and B. eunomia). Using experimental cages, we assessed 1) individual butterfly's ability to discriminate between habitat and matrices of different types and hence to orientate themselves towards their habitat, 2) individual butterfly's ability to adapt their flight behavior to their local environment, and 3) their propensity to cross habitat-matrix boundaries. We showed the existence of species-specific orientation capacity, changes in exploration behavior according to local environment, and differences in behavior at habitat boundaries that are consistent between sexes. The adjustment of flight speed was also species-specific and varied in an opposite way between sexes. We explore how these differences might have arisen from adaptive responses to differences in the spatial configuration of habitats and in life-history traits, and we discuss how they can lead to differences in functional connectivity measurements. © 2011 The Author.