Abstract
The hormonal control of the inhibition of pupation in Tribolium freemani larvae caused by crowding has been investigated using several types of anti-juvenile hormone agents (AJHAs); precocenes, imidazoles, ETB and FMev. The precocenes were the only chemicals which could induce the pupation by releasing the inhibition, although FMev seemed to have weaker effect, compared to them. An exogenous juvenoid (S31183) administrated along with the precocene antagonized the action of the precocene to the larvae. These results suggest that the corpora allata of the larvae reared under crowded conditions secrete high levels of juvenile hormone. The characteristics observed in the beetle suggest that this insect could be applied as a test animal for either screening or assaying new insect growth regulators.
