The early developmental stages of gall-inducing insects define final gall structural and histochemical profiles: the case of <i>Bystracoccus mataybae</i> galls on <i>Matayba guianensis</i>

Abstract

Gall morphotypes depend on continuous chemical and feeding stimuli of the gall inducer, which promotes specific structural and metabolic changes in plant tissues. The galling insect manipulates host-plant tissues and may stimulate the production of primary and secondary metabolites. The type of chemical arsenal and the storage site varies according to the developmental potentials of the host plant and the insect’s feeding habit. Here, we investigated whether the structural and histochemical profiles of the gall system Matayba guianensis Aubl. (Sapindaceae) – Bystracoccus mataybae (Eriococcidae) are dependent on the instars of the galling insect. Standard anatomical analyses were carried out, as well as histochemical evaluation of reactive oxygen species and primary and secondary metabolites. Structural changes induced by the first instar nymphs were detected on the stem, while deep changes induced by the second instar nymphs and adult females were detected in leaflet galls, indicating that the host-plant tissue can impose more limits on gall development and complexity than the stages of galling insect development. The compartmentalization of primary and secondary compounds is established during the early stages of development of the leaflet gall by the second instar nymphs. Despite deep structural differences between stem and leaflet galls, there were no significant changes in the establishment of the histochemical profiles.