Morphological study of the hindgut in larvae of Anticarsia gemmatalis Hübner(Lepidoptera: Noctuidae)

The velvetbean caterpillar (Anticarsia gemmatalis Hübner) has great economical interest as it affects the soybean crop worldwide. This work describes the morphology of the hindgut in A. gemmatalis larvae emphasizing their histological aspects. Distinct morphological regions, identified as pylorus, ileum, colon and rectum, constitute the hindgut of A. gemmatalis. A thin cuticular intima, a simple epithelium and muscular layer compose the hindgut wall, independent of the region. Microspines project from the cuticular intima in the posterior interstitial ring, between the midgut and the hindgut, and the posterior pyloric region. A single circular layer of large fibers, differing from the other hindgut regions that present two layers of muscular fibers, forms the rectal musculature. The distal ends of Malpighian tubules cross the rectum wall and constitute the cryptonephric excretory system typical in Lepidoptera larvae.