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

Abstract

Abstract. 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.

Treeline proximity alters an alpine plant–herbivore interaction

“…Research took place over 3 years (2006)(2007)(2008) in the alpine meadows of Jumpingpound Ridge, in Kananaskis Country, Alberta, Canada (50°57 0 N, 114°55 0 W), a series of meadows used for the long-term study of P. smintheus dynamics (e.g., Roland et al 2000;Fownes and Roland 2002;Roland and Matter 2007). Data were collected in two separate but ecologically similar meadows, one near the northern (G) and one near the southern (L) end of Jumpingpound Ridge (Fig.…”

“…Parnassius smintheus is common in alpine meadows throughout the Rockies, but is limited to areas with a sufficient supply of its host plant, S. lanceolatum (Fownes and Roland 2002), and nectar flowers like Arnica spp., Senecio spp., Aster spp., and other large yellow or yellowcentered composites. The life-cycle of P. smintheus varies along the species' north-south range, and many of its details remain unknown.…”

“…The life-cycle of P. smintheus varies along the species' north-south range, and many of its details remain unknown. On Jumpingpound Ridge, adults fly from mid-July until late August and occasionally into September (Guppy and Shepard 2001), during which time eggs are laid near, but not directly on, S. lanceolatum (Fownes and Roland 2002). Eggs hatch after snowmelt, usually in April, with larvae feeding continuously before pupating in mid-to late June.…”

From Individual Behavior to Metapopulation Dynamics: Unifying the Patchy Population and Classic Metapopulation Models

“…We assume that migrating females move according to the rules of correlated random walk both within habitat patches as well as in the surrounding matrix, though possibly with different parameter values in the habitat and the matrix. Correlated random walk models have been frequently used in butterfly studies (Odendaal et al 1989;Turchin 1991;Schultz and Crone 2001;Fownes and Roland 2002). In addition to the correlated random walk, we assume that individuals show edge-mediated behavior and bias their movements toward the habitat patch when close to patch boundary.…”

Encroaching forests decouple alpine butterfly population dynamics

“…1), has demonstrated that movement (7)(8)(9) and gene flow (10,11) are severely limited by encroaching forests. These butterflies are restricted to open alpine meadows in the Rocky Mountains where their larval host plant, lance-leaved stonecrop, Sedum lanceolatum, and adult nectar resources are present (12). By monitoring the population size of P. smintheus over an 11-year interval in a series of alpine meadows, we determine whether population growth is most similar between meadows close to each other, suggesting that local dispersal synchronizes nearby populations, and identify the components of landscape that determine the degree of synchrony, in particular the effect of encroaching forest.…”