Selectivity is manifested when certain resource types are utilized more often than their relative abundance would dictate. In this field study, the oviposition behavior of Colias philodice eriphyle butterflies was analyzed for evidence of selectivity during their search for legume foodplants. Three opportunities for female choice were examined: (1) the probability of laying an egg after landing upon different legumes, (2) the tendency to land upon different foodplants growing within their fightpaths, and (3) the manifestation of flight behaviors that effectively changed the rate at which females encountered different foodplants. Females showed preferences for certain legumes in each of these contexts. (1) They wer most liklely to oviposit after landing upon three legume species in the study area: Vicia americana, Trifolium hybridum, and T. longipes. (2) These same species were chosen as landing sites disproportionately often, but landing selectivity did not correspond exactly to postalightin oviposition probability. Two legumes (Lathyrus leucanthus and Astragalus decumbens) were evidently confused with the preferred V. americana from short distances. (3) Preferred foodplants were more abundant among flightpaths than along randomly place transects, indicating that females aggregated in areas where legumes were abundant. Patch structure of six foodplant species was calculated using a reencounter probability/distance function. Five of the species are contagiously distributed, and females remained in patches of preferred species because they (1) made shorter flights when sought—after legumes were locally abundant, and (2) appeared to search more thoroughly after discovering preferred species.
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Maureen L. Stanton (1982) studied this question.