SATURNIID MOTHS AS MIMICS: AN ALTERNATIVE INTERPRETATION OF ATTEMPTS TO DEMONSTRATE MIMETIC ADVANTAGE IN NATURE.

Abstract

We propose two arguments in this paper: first, that the day-flying males of three species of attacine saturniid moths are Batesian mimics of Battus phizlenor (L.) and/or B. polydamas (L.), the two aristolochia swallowtails which occur in America north of Mexico; second, we suggest an alternative interpretation of the results of experiments designed by L. P. Brower and his associates (Brower et al., 1964; Brower et al., 1967; Cook et al., 1969) to measure the selective advantage of Batesian mimicry in the field. Brower et al. (1964) conceived the brilliant experimental strategy of using the day-flying males of Callosamia promethea (Drury), a North American saturniid palatable to birds, to test the efficacy of Batesian mimicry on Trinidad. Some males were painted to resemble unpalatable' butterflies which occur on Trinidad, while others, the controls, were marked with black paint which did not greatly alter their appearance. All were released, and many were recaptured in traps baited with pheromone-releasing, female C. promethea. It was justifiably assumed that differential recapture would be the result of differential predation. The Brower group concluded that they had not made a convincing demonstration of mimetic advantage. Cook et al. (1969) stated, Taking all the evidence over the four years there is no significant advantage to either mimic or control moths . . . and no heterogeneity between years or between new and old sites, and perhaps it should be concluded that under wild conditions no