Effects of meadow suitability on female behaviour in the alpine butterfly Parnassius smintheus

1. Many butterfly populations persist in networks of naturally fragmented habitat patches. Movement and reproductive decisions made by adult females are critical to the persistence of these populations because colonisation of extinct habitat patches in the network requires emigration of fecund adult females from their natal meadow and their subsequent establishment in the extinct patch. 2. Movement and oviposition behaviours of mated Parnassius smintheus females released in suitable meadows (a good- and a poor-quality meadow) and an unsuitable meadow were compared, to determine whether adult females consider meadow suitability for their offspring despite frequent oviposition events off the larval host plant. 3. Bootstrap and correlated random walk analyses of female step lengths and turn angles demonstrated that females flew more randomly in the unsuitable meadow than in the suitable meadows. Although females tended to turn the sharpest angle between landing sites in the good-quality meadow, and fly the smallest distance between landing sites and displace the smallest distance from the release site in the suitable meadows, no significant differences were detected in turn angle, step length, and dispersal rates between suitable and unsuitable meadows. 4. Results from female flight observations and a caged oviposition study suggest that females lay significantly more eggs in suitable habitat than in unsuitable habitat despite not ovipositing on the host plant, and support the above findings. 5. Movement and oviposition behaviours of adult female P. smintheus promote their retention within meadows that can support their offspring.