BUILDING TWO HOUSES ON A SINGLE HOST PLANT: GALLING INSECT SYNCHRONIZES ITS LIFE CYCLE WITH PLANT PHENOLOGY

Galls are specific interactions between specialist herbivores and their host plants. They are considered neoformed plant organs developed from cellular hypertrophy, tissue hyperplasia and cellular redifferentiation of the host tissues. Among several organisms capable of inducing galls, insects induce them with high morphological complexity. The induction and development of galls depend on the availability of responsive sites in the host plant that react to the chemical and/or mechanical stimuli of galling insects. The synchronization between the timing of availability of these responsive sites and the galling insect life cycle is essential for the establishment of the interaction. Galling insects are subject to several chemical, physiological and phenological changes in their host plant. Thus, changes in the host cycle may alter the insectu0027s life cycle, distribution and abundance. This study focused on the morphological aspects and phenological relationship of the Matayba guianensis Aubl. (Sapindaceae) – Bystracoccus mataybae Hodgson, Isaias u0026 Oliveira (Eriococcidae) system, carried out in a semi-deciduous forest located at the Estacao Ecologica do Panga (EEP), Uberlândia, MG, Brazil. We monitored the host plant phenology monthly from April 2015 to April 2016, and galls were sampled throughout the year to determine the stage of development of the galling insect. During leaf flushing, galling insects were collected every two days. The second-instar nymph induced leaf galls during leaf sprouting (peaks in September and October). The growth, development and maturation of the gall and of the galling insect occur concomitant to leaf maturation (peaks from February to May). Before the first leaves fall (August), the first-instar nymph moves from the senescent leaflet gall to branches and induces a stem gall, where it remains during part of the dry season until the next leaf flush. The synchrony between the life cycle of the galling insect and the host plant phenology maintains the univoltine cycle.