Diapause in Populations of Tetranychus urticae (Acari: Tetranychidae) from the Tropical Climate Zone: Morphological, Behavioral, and Metabolomic Characterization

Diapause is a pre-programmed adaptive strategy that enables many arthropods to survive unfavorable conditions and is well documented in Tetranychus urticae from temperate regions. However, phenotypes resembling diapause have recently been reported in tropical regions of Brazil, where the classical environmental cues associated with diapause induction, particularly short days and low temperatures, were not consistently observed across the sampled regions. This study investigated whether these phenotypes represent true diapause by evaluating morphological and reproductive traits in T. urticae populations from five Brazilian states. In addition, comparative GC-MS metabolomics was performed on diapausing and non-diapausing phenotypes. Reddish-orange body coloration, loss of the dorsal striae lobes, and reproductive arrest confirmed the diapause phenotype in four of the five populations sampled. Metabolomics analysis identified 73 metabolites, including 53 shared between phenotypes, three detected exclusively in diapausing females, and 17 detected exclusively in non-diapausing females. Twelve shared metabolites differed significantly in abundance between phenotypes. Key biomarkers (VIP score > 1.5) included 1-deoxypentitol and glucaric acid, both detected exclusively in diapausing females. These findings provide the first evidence of diapause in T. urticae populations from tropical regions and reveal metabolic adjustments associated with this physiological state.