Thermal variation associated stress response regulates the growth and reproductive potential of soybean looper.

Authors: DEBNATH, RAHUL - University Of Arkansas; George, Justin; KARIYAT, RUPESH - University Of Arkansas; Reddy, Gadi

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/19/2026
Publication Date: 2/20/2026
Citation: Debnath, R., George, J., Kariyat, R. and Reddy, G.V.P. Thermal variation associated stress response regulates the growth and reproductive potential of soybean looper. Sci Rep 16, 9976 (2026). https://doi.org/10.1038/s41598-026-36978-1
DOI: https://doi.org/10.1038/s41598-026-36978-1

Interpretive Summary: The soybean looper (SBL) causes significant crop damage to soybeans and other economically important crops worldwide. Although temperature can influence pest growth and development, not much is known about how extreme temperature variations influence SBL population trends, which may aid in predicting SBL population outbreaks and dispersal. To examine this, we measured the life table parameters of SBL based on their age and life stage, under varying temperature conditions. We also performed comparative analysis of different antioxidant enzymes and total protein concentration from soybean leaves and SBL to examine the enzymatic stress levels. Analyzing their life tables under varying temperature conditions revealed a significant extension in the developmental and pre-reproductive periods of SBL. The key demographic and reproductive parameters such as the net reproduction rate (R0), intrinsic growth rate (r), and finite rate of increase ('), were significantly higher in ambient field temperature conditions (27°C and 31°C) compared to both temperature extremes (low temperature, ELT: 19°C and high temperature, EHT: 35°C). Overall, this study showed that stress associated with temperature changes can elevate the antioxidant level in SBL and soybean leaves. Additionally, temperature stress conditions negatively affected the growth and development of SBL, resulting in reduced plant damage. Population prediction models based on an 80-day timescale showed that extreme temperatures can significantly reduce the number of SBL generations, compared to optimal temperatures. These research findings will help researchers and pest managers towards developing a more efficient and sustainable SBL pest management program. This work supports USDA mission areas and aligns with the Secretary of Agriculture’s priorities by improving farm profitability, protecting crops from invasive pests, and advancing sustainable pest-management practices, ultimately helping farmers make informed decisions that contribute to more resilient and sustainable agricultural systems.

Technical Abstract: The soybean looper (SBL) is one of the most damaging insect pests of soybeans and other economically important crops worldwide. Although temperature has been reported to be a critical predictor of pest growth and development, very little is known about how temperature variations influence SBL population dynamics, which may aid in predicting SBL population outbreaks and dispersal. To examine this, we analysed the life table parameters of SBL by the age-stage, two-sex method under different temperature conditions. We also performed comparative analysis of antioxidant enzymes [catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APOX)] and total protein concentration from soybean leaves and SBL to unfold the enzymatic stress levels. Life table analysis revealed a significant extension in the developmental and pre-reproductive periods of SBL under extreme (extended) temperature conditions. The key demographic and reproductive parameters such as the net reproduction rate (R0), intrinsic growth rate (r), and finite rate of increase ('), were significantly higher in ambient field temperature conditions (27°C and 31°C) compared to both temperature extremes (low temperature, ELT: 19°C and high temperature, EHT: 35°C). Overall, this study showed that temperature stress elevated the antioxidant level in SBL and soybean leaves. Additionally, temperature stress conditions negatively affected the growth and development of SBL, resulting in reduced plant damage. Population projections over an 80-day timescale indicated that total SBL numbers would be significantly reduced during extreme temperature events compared to optimal temperatures. These findings will facilitate the development of a more efficient and sustainable SBL management strategy.