From leaves to inflorescences: Gall induction of Iatrophobia brasiliensis Rübsaamen, 1915 on inflorescences of Manihot caerulescens Pohl (Euphorbiaceae) during the dry season

Abstract

ABSTRACT Gall-inducing insects are highly specialized herbivores as they have the ability to control and redirect the development of host plants to obtain food and shelter. The distribution of galls on plants can be influenced by seasonality and phenological events, which determines the reproductive success of these insects. The species Manihot caerulescens Pohl (Euphorbiaceae) has a great diversity of gall-inducing insects in the Cerrado of Western Bahia. Our study aimed to (1) study the fauna associated with M. caerulescens Pohl (Euphorbiaceae) and (2) evaluate the phenological events of this host plant species. We performed gall collections between July 2018 and June 2020 and monitored 30 individuals of the host species to study the phenology in the Serra da Bandeira, Bahia, Brazil. The emerged insects in the laboratory were mounted on permanent slides and identified. We found galls on the stems, leaves and inflorescences. Stem galls were induced by lepidopterans (Alucitidae), and leaf and inflorescence galls by Iatrophobia brasiliensis Rübsaamen, 1915 (Cecidomyiidae). Further, we showed that I. brasiliensis preferentially induced galls on the leaves, however during the dry season, galls were induced on the inflorescences. Although the induction of galls on the leaves by I. brasiliensis has already been reported in the literature, here for the first time we record the presence of galls on the inflorescences induced by the same gall-inducing species. Our study constitutes an important contribution towards the knowledge of the insect-plant interaction between M. caerulescens and I. brasiliensis in the Cerrado of Bahia.

Keywords

• Cerrado
• Cecidomyiidae
• Insect-plant interaction
• Iatrophobia