Laboratory Studies of the Searching Capacity of Larvae of Chrysopa carnea for Eggs of Heliothis spp.123

Abstract

Chrysopa carnea Stephens searched equally well for eggs of Heliothis spp. on both the top and bottom surfaces of glass plates (simple searching arena), but on artificial cotton plants (complex arena) the most effective searching occurred in the top ½ of the plants. In the simple arena, 1st-stage larvae consumed 6.7 eggs/day, 2nd- and 3rd- stage larvae consumed ca. 7 times this number, and the rate of successful search by 2nd- and 3rd-stage larvae was 5 times that of 1st-stage larvae in the complex topography, older larvae consumed 3-6 eggs/day. The time spent handling each prey did not affect the rate of successful search, which was 0.033 and 0.037 hr/cm2 in the simple arena and 0.075 and 0.133 hr/cm2in the complex arena for 2nd- and 3rd-stage larvae, respectively.