Non-random dispersal in the butterfly Maniola jurtina : implications for metapopulation models

Abstract

The dispersal patterns of animals are important in metapopulation ecology because they a¡ect the dynamics and survival of populations. Theoretical models assume random dispersal but little is known in practice about the dispersal behaviour of individual animals or the strategy by which dispersers locate distant habitat patches. In the present study, we released individual meadow brown butter£ies (Maniola jurtina) in a non-habitat and investigated their ability to return to a suitable habitat. The results provided three reasons for supposing that meadow brown butter£ies do not seek habitat by means of random £ight. First, when released within the range of their normal dispersal distances, the butter£ies orientated towards suitable habitat at a higher rate than expected at random. Second, when released at larger distances from their habitat, they used a non-random, systematic, search strategy in which they £ew in loops around the release point and returned periodically to it. Third, butter£ies returned to a familiar habitat patch rather than a non-familiar one when given a choice. If dispersers actively orientate towards or search systematically for distant habitat, this may be problematic for existing metapopulation models, including models of the evolution of dispersal rates in metapopulations.

Effect of local weather on butterfly flight behaviour, movement, and colonization: significance for dispersal under climate change

“…Released individuals of M. jurtina showed flight patterns resembling those found by Conradt et al (2000): the butterflies either followed a more or less linear route or flew in large petal-like loops around the release site. Both types of flight pattern are significantly less tortuous than the patterns shown by individuals of M. jurtina flying within their habitat.…”

Integrodifference equations in patchy landscapes

“…In recent years, there have been a number of empirical studies that have examined a species perceptual range in fragmented landscapes (Gillis and Nams, 1998;Zollner, 2000;Conradt et al, 2001;Schooley and Wiens, 2003). In particular, Conradt et al (2000) showed that the perceptual range of the meadow brown butterfly, Maniola jurtina, was approximately twice that of its average dispersal distance.…”

Foray Search: An Effective Systematic Dispersal Strategy in Fragmented Landscapes

“…Foray search dispersal was closely modeled on empirical observations (Conradt et al 2000. The first foray loop had an opening angle a and a length l ( fig.…”

“…Such models ignore the possibility that, by using nonrandom, systematic dispersal strategies, animals could achieve higher dispersal efficiency and success (Zollner and Lima 1999;Armsworth et al 2001). This, in turn, could result in population dynamics and gene flow patterns different from those generated by random movements (Zollner and Lima 1999;Conradt et al 2000). Models based on the assumption of random dispersal also often predict unrealistically high dispersal losses (Lande 1988;Hanski and Zhang 1993).…”

“…However, Conradt et al (2000 reported that dispersers of two butterfly species search for suitable habitat systematically by flying in a succession of progressively larger ellipsoidal loops ("forays") away from and back to their starting point ( fig. 1).…”