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VOL. 10, ISSUE 12 (2025)
Influence of temperature variation on the fitness and parasitism efficiency of Trichogramma evanescens Westwood, 1833 (Hymenoptera: Trichogrammatidae)
Authors
Ahmed H EL Kenawy, Doaa S Abdel Motaal, Hassan A Hassan
Abstract
Temperature is a critical abiotic factor
influencing the biology and efficacy of egg parasitoids used in biological
control programs. This study evaluated the effects of eight constant
temperatures (22.5, 25, 27.5, 30, 32.5, 35, 37.5, and 40°C) on the fitness and
parasitism efficiency of Trichogramma evanescens Westwood (Hymenoptera:
Trichogrammatidae) reared on Ephestia kuehniella Zeller
eggs under controlled laboratory conditions. Results demonstrated significant
temperature-dependent variation in all measured life history parameters.
Parasitism capacity, emergence rate, and female-biased sex ratios peaked at
32.5°C (45.10 eggs/female, 92.88% emergence, 83.74% females), while preadult
developmental time decreased inversely with temperature. Life table analysis
revealed maximum net reproductive rate (R₀ = 97.26) and intrinsic rate of
increase (r = 0.541 day⁻¹) at 32.5°C, with sharp declines at thermal extremes
(≥35°C). Lower developmental thresholds were estimated at 7.91°C (females) and
10.74°C (males). These findings indicate that T. evanescens exhibits optimal performance between 30–32.5°C, suggesting that
augmentative releases should be timed to coincide with ambient conditions
within this thermal window to maximize establishment and pest suppression in
agricultural ecosystems.
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Pages:199-206
How to cite this article:
Ahmed H EL Kenawy, Doaa S Abdel Motaal, Hassan A Hassan "Influence of temperature variation on the fitness and parasitism efficiency of <i>Trichogramma evanescens</i> Westwood, 1833 (<i>Hymenoptera</i>: <i>Trichogrammatidae</i>) ". International Journal of Entomology Research, Vol 10, Issue 12, 2025, Pages 199-206
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