Distribution modelling of the rare stink bug Ceratozygum horridum (Germar, 1839): isolated in small spots across the Neotropics or a continuous population?

Abstract

ABSTRACT Cyrtocorinae species are morphologically remarkable stink bugs (Heteroptera: Pentatomidae) from the Neotropics. Ceratozygum horridum (Germar, 1839) is a little-known species with scarce occurrence data but presenting a broad and discontinuous distribution in Amazon and Atlantic Forest, lacking records in the dry diagonal. Field trips in Bolivia registered new records of C. horridum in an ecotone between the Southwest Amazon forest, the Chiquitano Dry Forest and the Dry Chaco forest. We used the maximum entropy algorithm aiming to model the occurrence probability of C. horridum on the Amazon Forest and transferred this model to the dry diagonal and the Atlantic Forest looking for continuous areas of probable occurrence for this species. We used ten records for a constrained portion of the Amazon forests and four environmental layers to train models with different numbers of background points. The average model performances returned AUC values higher than 0.7 and maximum sensitivity was reached. The models could not predict species occurrence with reliability when transferred to the whole Amazon area, dry diagonal, and the Atlantic Forests. Our findings suggest a low probability of occurrence of C. horridum in the dry diagonal, supporting the hypothesis that the Amazon and Atlantic Forests populations are isolated by the dry diagonal. The populations of C. horridum seem to be isolated in small spots with dissimilar ecological features across the complex ecoregions of the Neotropics. Building species distribution models for species with poorly known distribution is challenging and may raise more questions than light answers. Even the small pieces of evidence are pertinent to the knowledge of rare species like C. horridum. http://www.zoobank.org/urn:lsid:zoobank.org:author:E11F3EE3-C93F-40EB-AC68-AD1B7C954E5E