The cellular responses of migratory grasshoppers (Melanoplus sanguinipes F.) and African desert locusts (Schistocerca gregaria L.) to Diplotriaena tricuspis (Nematoda:Diplotriaenoidea)

Abstract

Twelve hours after infection first-stage larvae of Diplotriaena tricuspis (Nematoda:Diplotriaenoidea) had hatched, penetrated the gut wall, and entered lobules of the fat body of grasshoppers (Melanoplus sanguinipes F.) and African locusts (Schistocerca gregaria L.). Capsule development was similar in grasshoppers and locusts. Capsules, which had fibrous walls and contained both normal and degenerating adipocytes, developed at least as early as 4 days after infection. Capsules were well developed when the third stage was reached. The fibrous wall probably resulted from conversion of adipocytes to fibrous tissue. Larvae apparently had a readily available source of food (adipocytes) and were protected from the haemocytic response of the insect by the capsule wall. Larvae were not destroyed by haemocytes or melanization. Few larvae developed free in the haemocoele.