Influence of two juvenoids, fenoxycarb and hydroprene, on the development, reproduction, and mating behavior of the German cockroach, Blattella germanica (L.)
Abstract
Life stages of the German cockroach, Blattella germanica (L.), were topically treated with the juvenoids fenoxycarb $\{$ethyl (2-(p-phenoxyphenoxy)ethyl) carbamate$\}$ and hydroprene $\{$ethyl (E,E) -3,7,11-trimethyl-2,4-dodecadienoate$\}$ and observed for developmental and reproductive capabilities. Fenoxycarb exhibited much greater lethal activity than hydroprene when applied to the nymphal stages. Nymphal mortality caused by fenoxycarb appeared to be the result of ecdysial failure. Cockroaches treated during the last stadium were mated with untreated mating partners and observed for reproductive capabilities. Fenoxycarb sterilized females and males at significantly lower dosages than hydroprene. Males were sensitive to lower dosages of hydroprene than were females. A strong relationship between wing-twisting (a morphogenetic effect caused by the juvenoids) and sterility was observed in adult cockroaches which had been treated with high juvenoid dosages (100 & 10 $\mu$g) as nymphs. However, a large number of twisted-wing females were fertile when treated with 1 $\mu$g of hydroprene. The sensitive developmental period for juvenoid-induced effects in last instars was found to be limited to the first half of the stadium. Fenoxycarb inhibited reproduction when applied at 10 $\mu$g to virgin and fertilized adult females. Production of offspring was also reduced when fenoxycarb-treated adult males were mated with untreated females. Fenoxycarb also exhibited ovicidal activity, particularly when applied to 4-d old oothecae. No effects were caused by 1 or 10 $\mu$g of hydroprene when applied to adults or oothecae. The mating behavior of juvenoid-treated cockroaches was observed in studies involving three separate pairings (juvenoid-treated females x untreated males, untreated females x juvenoid-treated males and juvenoid-treated females x juvenoid-treated males). Fifth instars were treated topically with fenoxycarb or hydroprene (1 & 10 $\mu$g) and examined after adult emergence. Females treated with 10 $\mu$g of hydroprene were attracted to wing-raising by untreated males but were less able to stimulate the male's spiculum copulatus (SC). Wing-raising activity and copulation attempts were reduced among males treated with 10 $\mu$g of fenoxycarb. Females treated with 1 $\mu$g of hydroprene were able to copulate with untreated males; however, successful copulation was either reduced or precluded among all other juvenoid-treated mating combinations.
Degree
Ph.D.
Advisors
Bennett, Purdue University.
Subject Area
Entomology
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