Please use this identifier to cite or link to this item: https://cris.library.msu.ac.zw//handle/11408/4949
Title: Life-stage related responses to combined effects of acclimation temperature and humidity on the thermal tolerance of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae)
Authors: Mutamiswa, Reyard
Machekano, Honest
Chidawanyika, Frank
Nyamukondiwa, Casper
Keywords: Climate change
Ontogeny
Phenotypic plasticity
Stress resistance
Issue Date: 2019
Publisher: Elsevier
Series/Report no.: Journal of Thermal Biology;Volume 79, Pages 85-94
Abstract: Adaptive thermal plasticity plays a key role in mitigating the effects of seasonal and diurnal thermal fluctuations among ectotherms at various life-stages. While the role of thermal history in conferring such plasticity is widely documented, its interaction with relative humidity (RH), another important driver of ectotherm survival and activity, is relatively underexplored. Yet the potential responses to these combinational stressors across ontogeny remain largely neglected. Against this background, we used a full-factorial design to test the combined acclimation effects of RH (45%, 65% and 85%) and temperature (23, 28 and 33 °C) on various indices of thermal sensitivity of laboratory reared spotted stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) following acclimation beginning at larval, pupal and adult life-stages. Traits measured included critical thermal limits (CTLs), supercooling points (SCPs), chill coma recovery time (CCRT) and heat knockdown time (HKDT). Larval acclimation at 23 °C; 85% RH recorded the lowest critical thermal minima (CTmin) whereas adult acclimation at 28 °C; 45% RH recorded the highest critical thermal maxima (CTmax). There were no significant differences (P > 0.05) in SCPs across all temperature × RH acclimations. Larval and pupal acclimations at 23 °C; 85% RH and adult acclimation at 23 °C; 45% RH significantly improved CCRT. Similarly, commencing acclimation at larval, pupal and adult stages at 28 °C; 85% RH improved HKDT whereas larval and pupal acclimations at 33 °C; 45% RH impaired it. Our results indicate that combinational interactions of temperature and RH have significant thermal fitness costs and benefits and are dependent on the life-stage acclimation timing. Results also imply that both the vulnerability and adaptive potential of C. partellus populations under rapid climate variability varies with ontogeny. This therefore calls for the consideration of the role of ontogeny and multi-factors in better understanding the impact of environmental stress on ectotherms.
URI: https://doi.org/10.1016/j.jtherbio.2018.12.002
http://hdl.handle.net/11408/4949
ISSN: 0306-4565
Appears in Collections:Research Papers

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