Movement behavior at habitat boundaries: Mechanism vs pattern

          Many insect species, particularly butterflies, respond to habitat patch edges.  These responses can substantially change expected emigration and inter-patch movement rates, relative to random, undirected dispersal behavior.  However, the ways in which edge behavior scales up to larger-scale processes depends on the mechanisms of these responses.  We show that biased, correlated, random movement at patch edges can create looping movement at patch edges.  These patterns are similar to observations of butterfly movement attributed to a systematic non-random search termed "foray loops" in the literature.  Systematic non-random search has different implications for long-term emigration and dispersal than biased, correlated random movement.  We encourage researchers to both continue to observe animal movement at habitat boundaries, and to consider the consequences of multiple mechanisms that could lead to patterns of edge behavior.