Mating behaviour and light conditions cause seasonal changes in the dispersal pattern of the satyrine butterfly Lethe diana

Abstract

Summary1. The spatial arrangement of resources and climatically favourable sites affects the dispersal pattern of butterflies.2. The microdistribution of the satyrine butterfly Lethe diana changes seasonally, meaning that the relative spatial arrangement of resources also changes seasonally. The seasonal change in the dispersal pattern of this butterfly was studied.3. Males of the May–June generation tended to stay in a restricted habitat patch while females of the same generation did not. A number of the May–June generation males became resident at prime forest edge sites, where a territorial behaviour that was rarely seen in other generations was prevalent. Females of the May–June generation moved to these territorial sites for mating but left after copulation to avoid male harassment; their residency was therefore weak.4. In both sexes, the July–August generation tended to be more mobile than the September–October generation. This was because the July–August generation butterflies utilised dark environments for thermoregulation and, because these conditions were widespread throughout the forest, the butterflies were able to move widely. The September–October generation, however, preferred intermediate light conditions, which tended to be restricted to the forest edge; as this was a relatively small area, butterfly movement was restricted.

Seasonal changes in the territorial behaviour of the satyrine butterfly Lethe diana are mediated by temperature

“…Ide, unpublished data). To separate the two generations, census data were divided into two groups, that is, from July to August and from September to October (Ide 2000a(Ide , 2002. In this way, three generations can be distinguished: the May-June, July-August, and September-October generations.…”

“…Males of the satyrine butterfly Lethe diana (Butler) hold territories around sunlit branch tips that face an open space in the afternoon (Fukuda et al 1984;Ide 2002). L. diana has three generations a year, and territorial behaviour is observed in the generations in May-June and in September-October, but not in July-August (Ide 2002).…”

“…L. diana has three generations a year, and territorial behaviour is observed in the generations in May-June and in September-October, but not in July-August (Ide 2002). Since the only time when L. diana males do not hold territories is during the summer, it is conceivable that high temperatures prevent the butterflies from doing so; however, mate-locating behaviour has been regarded as an optimal strategy affected by population density, operational sex ratio, or the distribution of each sex (e.g.…”

Selection of age classes of Sasa leaves by caterpillars of the skipper butterfly Thoressa varia using albo-margination of overwintered leaves

“…The bamboo grass S. veitchii var. hirsuta, the main food plant of T. varia in this area, occurs in scattered clumps on the forest floor (Ide 2002). For this study, the blades of this plant were classified into two age classes: current year or overwintered.…”

Butterfly edge effects are predicted by a simple model in a complex landscape

“…A speciWc example of this can be found in the limited literature on butterXy edge responses. Studies have shown that certain butterXy species either avoid (Schultz 1998;Haddad and Baum 1999) or are attracted (Ravenscroft 1994;Bergman 1999;Wahlberg 2001;Ide 2002) to certain edges. Although some of these studies include data showing how changes in microclimate or host plant distribution were associated with these patterns, there is no overarching framework to explain when speciWc butterXy species should be expected to avoid, be attracted to, or ignore speciWc edge types.…”