A. A. Guerra

Effect of Irradiation with 60Co on Transfer and Motility of Sperm and on Mating of the Tobacco Budworm

Adult tobacco budworms, Heliothis virescens (F.), irradiated as pupae within 24 hr of adult eclosion with 20 or 40 krad gamma irradiation were paired singly in all possible combinations. The effects of treatment on the quantity and motility of sperm were generally related to dose. However, the quantity and motility of sperm and mating frequency of irradiated males were affected by 20 or 40 krad at 5 days after adult eclosion but not after 10 days. The mating frequency of irradiated females was not affected by either dose at either time, but fecundity was affected. A dose of 40 krad completely sterilized both sexes; a dose of 20 krad caused 64 and 98% sterility in males and females, respectively. Both doses of irradiation increased longevity of males, but female longevity was increased with 20 krad.

Attractiveness of tobacco budworm females altered by oral chemosterilants and dietary additives

FemaleHeliothis virescens (F.) moths reared from larvae on diet treated (0.1%) with experimental chemosterilants or the dietary additive, DL-leucine, were used as bait in sex lure traps in field cages when they were 2–4 nights old. Catches of untreated released males were used to determine relative attractiveness of the chemically treated females. The catch (indicating quantity or production frequency of pheromone) was significantly increased whendl-leucine had been fed in the larval diet, and sulfanilamide caused a slight increase in female attractiveness. The catch of males was significantly reduced when either reserpine or quercitin had been added to the diet. The other chemicals, bisdicumarol, 2,4-dichlorophenoxyacetic acid, β-sitosterol, and dihydrocholesterol, did not significantly affect the catch.