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Life‐history changes in the cold tolerance of the two‐spot spider mite Tetranychus urticae : applications in pest control and establishment risk assessment
Author(s) -
White Nicola,
Bale Jeffrey S.,
Hayward Scott A. L.
Publication year - 2018
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/phen.12262
Subject(s) - biology , tetranychus urticae , spider mite , diapause , pest analysis , wolf spider , zoology , overwintering , spider , ecology , horticulture , larva
Lethal time 50 (LTime 50 ) and lethal temp (LTemp 50 ) are commonly used laboratory indices of arthropod cold tolerance, with the former often being employed to predict winter survival in the field. In the present study, we compare the cold tolerance of different life‐history stages (nondiapausing and diapausing females, as well as males and juveniles) of a major agricultural pest: the two‐spot spider mite Tetranychus urticae Koch (Acarina: Tetranychidae). Diapausing females from European populations of this species are shown to be freeze avoiding, supercooling to −23.6 ± 0.37 °C and with an LTemp 50 of −23.2 °C. However, nondiapausing females [supercooling point (SCP) –19.1 ± 0.49 °C, LTemp 50 –14.32 °C], males (SCP –21.27 ± 0.52 °C, LTemp 50 –16 °C) and juveniles (SCP –25.34 ± 0.29 °C, LTemp 50 –18.3 °C) are subclassified as strongly chill tolerant juveniles. LTime 50 is 148.3 days for non‐acclimated diapausing females, whereas nondiapausing females, males and juveniles reach 50% mortality by 21.7 days. When individuals are acclimated at 10 °C for a period of 7 days, no effect is found. Cold tolerance is suggested to be a major contributor to the successful spread of T. urticae across temperate countries, although it is dependent on a diapause trait, suggesting a potential target for control. Winter field trial data from diapausing females indicate that LTime 50 is a reliable indicator of winter survival even within diapause, supporting the use of these indices as a valuable component within environmental niche models for the prediction of future pest invasions.