The population phenology of the cassidines, Coptocycla arcuata and Omaspides trichroa, and the chrysomeline, Platyphora axillaris, was studied at Serra dos Órgãos National Park, State of Rio de Janeiro, southeast Brazil. Monthly surveys of larvae and adults were conducted between 2008 and 2011 at approximately 1000 m altitude on their respective host plants, Cordia polycephala (Boraginaceae), Ipomoea philomega (Convolvulaceae) and Solanum scuticum (Solanaceae). This is the first observation of larviparity and host record for Platyphora axillaris. Although having different life history traits, all species showed similar phenologies. They were abundant from October to March, months of high temperatures and intense rainfall, with two distinct reproductive peaks in the same season. Abundance dropped abruptly during the coldest and driest months, from May to August. Frequently none of these species were recorded during June and July. This phenological pattern is similar to other Chrysomelidae living in subtropical areas of Brazil. Temperature and rainfall appear to be the major factors influencing the fluctuation of these three species.

The mountaintops of the Atlantic Rainforest in Southeastern Brazil are dominated by high altitude grasslands, named Campos de Altitude (CA). Considering the location and the smaller habitat areas of communities on the mountaintops and the high frequency of endemic species, the assemblages in these habitats are particularly threatened by climate change, and the vulnerability of a species should then be higher if its elevational range is narrow. In this study we aim to describe the elevational range of beetle species occurring in the CA and discuss their vulnerability to local extinction in the context of climate change, also considering their trophic group. We selected beetles in five taxa from three trophic groups in the CA of Serra dos Órgãos National Park (SONP) and Itatiaia National Park (INP): detritivores (Scarabaeidae-INP), herbivores (Chrysomelidae-SONP and INP, and Curculionidae-SONP) and predators (Coccinellidae-SONP, and Lampyridae-SONP). We found different elevational ranges among the studied taxa and among species within each taxon. Herbivores tended to have narrower ranges than the detritivores, and predators were the trophic group with the broadest species range. The relatively high frequency of species with narrow elevational range, particularly within the herbivores, suggests that this entomofauna is particularly endangered due to predicted climate warming and an expected range shift upwards. Considering that many endemic species are expected in the CA and that many undescribed species of insects have been found in this habitat, we may lose many yet unknown species.