Plant potentialities determine anatomical and histochemical diversity in Mikania glomerata Spreng. galls

Arthropod gall super-hosts have distinct developmental responses to each gall inducer species. The taxa and feeding habits of the gall inducers determine each gall's histological patterns, but the host plant imposes histological constraints on gall differentiation. Mikania glomerata Spreng. (Asteraceae) is a gall super-host, presenting at least six distinct gall morphotypes. The aim of current study was to evaluate how different species of Cecidomyiidae can manipulate the same host plant tissues, demonstrating the potentialities of M. glomerata under distinct external signaling. We compared M. glomerata anatomy and histochemistry in fusiform galls induced by Liodiplosis cylindrica (Gagne 2001) on petioles, globoid galls induced by L. spherica (Gagne 2001) on leaf laminae, and conic galls of Clinodiplosis sp. on leaf laminae as well as in non-galled leaves and petioles. Even though each gall presents several distinct features, they share anatomical and histochemical patterns, determined by the host plant potentialities. We found that the ground and dermal system tissues were manipulated differently by each inducer, generating distinct gall morphotypes. Alterations on epidermal cell shapes and suppression of the capitate glandular trichomes occured in all studied galls. We report for the first time the occurrence of nutritive cells containing starch in globoid galls. The anatomical diversity of the galls on M. glomerata seems to be more related to distinct differentiation pathways of the host plant than to the taxonomic relationships between the gall-inducing species.