From microstructures to macroclimates: SEM-based differentiation and MaxEnt habitat suitability of Hypocassida subferruginea and Cassida palaestina in Türki

Abstract

This study integrates scanning electron microscopy (SEM) and MaxEnt ecological niche modeling to investigate morphological differentiation and climate-driven habitat suitability of two Cassidini species in Türkiye, Hypocassida subferruginea (Schrank, 1776) and Cassida palaestina Reiche & Saulcy, 1858. SEM analyses revealed distinct diagnostic differences, including the deep longitudinal antennal grooves beneath the pronotum in Hypocassida , supporting genus-level divergence within Cassidinae. Additional differences were observed in antennal sensilla, sternal structures, and tarsomere morphology. The pupal stage of H. subferruginea is described for the first time, while the fifth instar larva of C. palaestina is documented using SEM. Immature stages provided previously underreported characters, including cauliflower-shaped sensilla, scoli differentiation, and spiracular-associated structures, contributing new diagnostic traits for Cassidini morphology. Habitat suitability was modeled using occurrence records and WorldClim v2.1 bioclimatic variables. Models showed high predictive performance (AUC = 0.942 for H. subferruginea ; 0.997 for C. palaestina ). Temperature variables were the primary drivers of H. subferruginea distribution, whereas both temperature and precipitation influenced C. palaestina . Predicted distributions indicated a clear north–south ecological gradient in Türkiye. The combined use of SEM and ecological modeling provides valuable insights into taxonomy, species differentiation, and ecological divergence within Cassidini.