Effect of Olea europea and Cestrum parquii Leaveson the Cuticle and Brain of the Desert Locust, Schistocerca gregaria Forsk. (Orthoptera: Acrididae)

摘要

Olea europea (Oleaceae) leaf powder added at 2% in an artificial diet resulted in a partial inhibition of cuticle genesis of the desert locust, Schistocerca gregaria. This inhibition was expressed by cuticuline and wax layers narrowing the epicuticlewhich may explain the soft aspect of integument and the persistence of juvenile colour until mature stage. Whereas, brain structure at this stage, does not show visible modifications. In the case of Cestrum parquii (Solanaceae) leaf powder at 2%, the cuticle structure of 5th instars larvae was highly modified. In the absence of exuvial space, the layers of new procuticle were partially developed and the old cuticle partially reduced. Regarding the brain cells of treated locust, we notice the occurrenceof well developed vacuoles and its pycnotic nucleus. Between these cells, gigantic vacuoles flood the brain. These observations show the toxic effects of Cestrum leaf powder.