VARIATION IN OVIPOSITION PREFERENCE OF HELIOTHIS VIRESCENS IN RELATION TO MACROEVOLUTIONARY PATTERNS OF HELIOTHINE HOST RANGE.

When cotton, geranium, petunia, tobacco, tomato, and velvetleaf were presented simultaneously to strains of the Heliothine moth, Heliothis virescens (F.), from Arizona (AZ), Mississippi (MS), and North Carolina (NC), oviposition choices were similar, while a strain from the Virgin Islands (VI) was significantly different from both the AZ and MS strains. In the MS-VI six-host test, the VI strain laid a higher proportion of its eggs on tomato and a lower proportion of its eggs on petunia than did the MS strain. Since petunia and tomato are in the same plant family (Solanaceae), differences between the strains in host preference do not appear to involve traits common to all members of a plant family. In the AZ-VI six-host test, the AZ strain laid a higher percentage of its eggs on tobacco and lower percentages on geranium and velvetleaf (Malvaceae) than did the VI strain. The percentages of eggs laid on cotton (Malvaceae) by the two strains were not significantly different. When moths were placed in cages with only tobacco and geranium, the AZ strain again laid a higher percentage of its eggs on tobacco than did the VI strain. However, when host choice was restricted to tobacco and cotton or velvetleaf and cotton, no significant difference between strains was found. Reciprocal hybrids of the AZ and VI strains were intermediate to the parental stocks in their preference for tobacco over geranium, indicating that a genetic mechanism was responsible for oviposition preference. The relevance of these findings to seemingly rapid fluxes in host range among members of the Heliothinae is discussed.