Synchrony strategies of six gall inducers that share a superhost, Eugenia copacabanensis (Myrtaceae).

Abstract

The life cycles of galling insects are synchronized with their host plant phenology, allowing them to better explore available resources. Distinct strategies among six galling species that share a superhost, Eugenia copacabanensis, were expected: optimizing growth of galls in times of increased availability of water and other resources. The vegetative and reproductive phenology of E. copacabanensis in Brazilian Restingas, climate patterns, and development cycles of six gall morphotypes were assessed throughout a year. The vegetative phenophases of E. copacabanensis presented peaks associated with the rainy season. Reproductive phenophases occurred at two different times: flower buds and flowers in anthesis occurred only during the rainy season, whereas fruits developed and matured during the dry season. Distinct strategies occur among Cecidomyiidae galls. Spiral globoid and clavate galls induced by Stephomyia spp. (Cecidomyiidae) are univoltine and occur only at the beginning of the rainy season, with emergence of leaves. Precipitation peaks influenced emergence of leaves and distinct periods of emergence of globoid, leaf-rolling, and lenticular galls. Multivoltine life cycles occur for globoid and leaf-rolling galls induced by Dasineura spp., lenticular Cecidomyiidae galls, and fusiform Hymenoptera galls. The different life cycles among the gall inducers allow exploitation of plant nutritional resources at different times and oviposition sites, thereby avoiding potential nutritional competition. Thus, gall inducers of E. copacabanensis exhibit strategic adjustments that enable them to occupy the same host and ensure completion of their life cycles.