Oviposition Response of the Imago of the Corn Earworm, Heliothis Zea (Boddie), To Various Wave Lengths of Light12

Abstract

Continued work on the response of Heliothis zea to various wave lengths of light was suggested by preliminary work on the effects of various preferred host plants and non-preferred plants as a stimulus to oviposition. It was thought that the presence of host plants in oviposition cages of Heliothis zea might stimulate the females to a higher percentage of copulation and egg deposition. Originally two cages approximately 2 feet square were set up with no host plant in one cage and fresh ears of corn, in silk, in the other cage. The cage with corn contained 12 pairs of imagoes and the cage without corn contained 16 pairs. Later, as more imagoes were obtained, the following experiments were set up: A cage with a blooming cotton plant and a cage with a blooming bean plant, both of which are hosts; a cage with a tobacco plant and a cage with a blooming petunia plant, neither of which is normally a host; and a cage with only cloth strips hanging in it. All seven of these cages faced westward toward decreasing crepuscular light intensities, and all were enclosed and had a cloth oviposition surface over the front. Egg counts for the plant and cloth oviposition surfaces in each cage are given in Table I.