MATE LOCATION BEHAVIOR OF THE LARGE SKIPPER BUTTERFLY OCHLODES-VENATA FLEXIBLE STRATEGIES AND SPATIAL COMPONENTS

Male Ochlodes venata were studied in lightly wooded heath land at Lindow, Cheshire, U.K., using a combination of transects and more detailed observations of movements and behavior in a woodland clearing. Males locate mates by perching and patrolling but are also opportunists and approach females when feeding. Behavior is flexible, and varies with time of day, weather, season, and location. On clear, sunny days, males show a significant bias for patrolling during midand late morning, and for perching during early morning and afternoon. Switches then from one activity to another are not entirely related to temperature and energy levels, and may depend on availability of females, males perching when females are relatively scarce. Scent seems to playa prominent part in the location of females during patrolling. Defended territories are located at topographic vantage points (at habitat edges and path junctions), and have a biased distribution to areas where female resources (nectar, oviposition sites) are also available. Territories and even the same perches (specific locations where the insects alight) within them are used by different individuals in the same and different years. Additional key words: Hesperiidae, England, territoriality. In the process of obtaining mates, male butterflies are described by Scott (1974) as adopting one of three strategies: perching or waiting for them, patrolling or actively seeking them in flight, and locating them with the use of long -distance pheromones. The last is regarded as of rare occurrence and understood to be a proximate cue (Scott 1972), vision dominating long-distance communication. But Heliconius erato males locate preemergent females using chemicals emitted by the pupae (Bellinger 1954). Perching males select characteristic sites, distinct in surface, height, and situation where they bask in the sun and launch themselves at passing insects (Baker 1972, Davies 1978, Dennis 1982a, Bitzer & Shaw 1979, 1983). Patrolling males typically cover much larger areas but differ in the extent and nature of the areas covered (Courtney 1980, Dennis 1982b, Peachey 1980). Scott (1974) regards these processes as distinct; when perching occurs the females necessarily find males, but patrolling males actively find females. Perching has been likened to territoriality by Baker (1972), since defense of some "resource" is involved, but this is denied by Scott (1974). Recently, mate location behavior has been shown to be more varied. Perching and patrolling provide alternative strategies in some species depending on demographic trends (distribution of females, male-female 46 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY ratio) and environmental conditions (sunshine and temperatures, time of day, habitat topography, physical resources) (Scott 1975, 1983, Dennis 1982a, Shreeve 1984, Rutowski 1983, Wickman 1985a). Moreover, it seems that many butterflies adopt intermediate strategies, involving intermittent flight, basking, and feeding bound only to loose areas and without territories, where males are constantly vigilant for females (Dennis 1982a, Morton 1985). The various aspects of mate location in butterflies are far from resolved. The present paper on Ochlodes venata (Bremer & Grey) responds to the need for comparative data. In particular, it addresses issues of territoriality, switches in mate location activity, and siting and structure of territories. O. venata is single-brooded in Britain and flies from the latter half of June into late July (Heath et al. 1984).