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Journal of the Lepidopterists' Society
on the leaf of another forb was seen. Though no determination of the relative frequencies of utilization of various substrates was possible, oviposition on the coneflowers appears to be a major behavioral characteristic and not the result of "mistakes" or random choice. About 600 inflorescences with eggs were tagged during desultory inspection in 16 ha of habitat in 1978, and a sampling program in 32 ha in 1979 revealed several times that number with ova on them. Ova were found on coneflowers at two other sites in southwestern Minnesota in 1978 and in several pastures near the study site in 1979. No evidence of oviposition by females on other flowers was found.
This use of a non-host oviposition substrate is reminiscent of the behavior of some populations of Hesperia lindseyi Holland reported by MacNeill (1964, Univ. Calif. Publ. Entomol. 35: 1-130) which oviposit on an arboreal lichen. The selective pressures responsible for the behavior in H. ottoe are unknown. Domestic livestock avoid grazing the evidently unpalatable coneflower as presumably bison did, and it may be that larvae in the immediate vicinity of these plants are thus less likely to be trampled or eaten by large ungulates. H. ottoe is known to occur in the absence of Echinacea pallida (e.g., a colony in southeastern Minnesota in a relict sand dune habitat, and Michigan populations), and it may be that the distribution of the behavior will provide a clue to its significance. It is hoped that this note will alert observers elsewhere to look for the behavior.
I thank Dr. William E. Miller for his helpful review of the manuscript and gratefully acknowledge a generous private gift and grants from The Nature Conservancy, World Wildlife Fund (U.S.), and the Xerces Society.
Robert P. Dana, 2618 16th Avenue South, Minneapolis, Minnesota 55407.
Journal of the Lepidopterists' Society 35(1), 1981, 78-79
POLYMORPHISM IN LARVAE OF CATOCALA BLANDULA (NOCTUIDAE)
On 25 April 1979 six larvae of Catocala blandula Hulst hatched from eggs laid by one female from Lebanon, New Jersey. They were fed on Crataegus. When in the
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ultimate larval stage, 13 May, I found three larvae of the regular grayish-brown form, and three larvae of the same color and markings, but with a broad brown, dorsal, longitudinal band reaching from the prothorax to the last abdominal segment. Only in the last larval instar was this difference in the larvae detected. The 1:1 ratio of the two larval morphs suggests that the presence or absence of dorsal banding is under simple genetic control, i.e., a single autosomal locus having two alleles may control the presence or absence of the brown banding. One larva of each form has been inflated (Figs. 1 & 2). The two larvae of each form pupated and emerged as adults. From 13 to 18 June both sexes of adults emerged from both larval forms. When these moths were compared with each other, no phenotypic differences were detected. More rearings of this species will be done in the future.
Joseph Muller, Route 1, Lebanon, New Jersey 08833.
Figs. 1 & 2. 1, usual grayish larva of C. blandula; 2, brown striped larva of C. blandula. Both are last instar larvae.