EFFECTS OF JUVENILE HORMONE ANALOGUES ON THE METAMORPHOSIS OF BEETLES TROGODERMA GRANARIUM (DERMESTIDAE) AND CARYEDON GONAGRA (BRUCHIDAE)

MONIR M. METWALLY ¹ and FRANTIEK SEHNAL ¹

¹ Institute of Entomology, Czechoslovak Academy of Sciences, Prague

1. The metamorphosis of Trogoderma granarium and Caryedon gonagra may be deranged with as little as 0.000005 µg and, respectively, 0.05 µg of certain juvenile hormone analogues.

2. Under the prolonged influence of analogues the larvae of Trogoderma undergo several "stationary" extra larval molts with no increase in the body size. The larvae of Caryedon do not molt but their pupation is considerably delayed. In extreme cases the larvae die.

3. Exposure of Trogoderma and Caryedon to the analogues during the last third of the last larval instar often induces development of larval-pupal intermediates. The species differ in the distribution of larval and pupal features in these intermediates.

4. The larval-pupal intermediates develop into creatures composed of larval, pupal, and adult tissues.

5. Treating the insects shortly before or after the pupal ecdysis results in formation of pupal-adult intermediates with a similar distribution of pupal and adult tissues in both species.

6. Pupal assays revealed that the investigated species differ from one another as well as from other beetles in their responsiveness to certain analogues and also in their responsiveness to the analogues in general.

7. Trogoderma is affected by the vapors of analogues.