Climatic niche comparison between closely related trans-Palearctic species of the genus Orthocephalus (Insecta: Heteroptera: Miridae: Orthotylinae)

Abstract

Previously climatic niche modelling had been studied for only a few trans-Palearctic species. It is unclear whether and to what extent those niches are different, and which climatic variables influence such a wide distribution. Here, environmental niche modelling is performed based on the Worldclim variables using Maxent for eight species of the genus Orthocephalus (Insecta: Heteroptera: Miridae: Orthotylinae). This group belongs to one of the largest insect families and it is distributed across Palearctic. Orthocephalus bivittatus, O. brevis, O. saltator and O. vittipennis are distributed across Europe and Asia; O. coriaceus, O. fulvipes, O. funestus, O. proserpinae have more limited distribution. Niche comparison using ENMTools was also undertaken to compare the niches of these species, and to test whether the niches of closely related species with trans-Palearctic distributions are more similar to each other, than to other congeners. It has been found that climatic niche models of all trans-Palearctic species under study are similar but are not identical to each other. This has been supported by niche geographic projections, climatic variables contributing to the models and variable ranges. Climatic niche models of all the trans-Palearctic Orthocephalus species are also very similar to two species having more restricted distribution (O. coriaceus, O. funestus). Results of this study suggest that trans-Palearctic distributions can have different geographic ranges and be shaped by different climatic factors.