The Influence of Corpus Allatum Activity on the Susceptibility of Oncopeltus fasciatus to Precocene2,3

Abstract

Treatment of newly molted 4th instars of Oncopeltus fasciatus (Dallas) with precocene 2 (6,7-dimethoxy-2, 2-drmethyl chromene) led to precocious metamorphosis at the subsequent molt, without the involvement of an intercalary or 5th instars. Metamorphosis was not affected if precocene was applied to 1- or 2-day-old 4th instars, but the resulting female adults were sterile. Corpus allatum (CA) of these adults had atrophied. The normal looking sterile females laid eggs in response to topical application of juvenile hormone III. Precocene did not have any effect on the CA, or on the metamorphosis and fecundity when applied to 5th instars. Apparently precocene is effective only when the insect's CA is active or it is free from any inhibitory control.