Investigating the effects of floral nectar composition on the thermal tolerance and life-history traits of a beneficial insect parasitoid

Abstract

Rising global temperatures and climatic extremes are threatening the viability of parasitoids in biological pest control systems. As agricultural demand rises to meet the needs of a growing population, developing methods to enhance parasitoid resilience are critical for sustaining effective pest management. Floral nectar, rich in sugar, may offer supplementary nutrition to boost parasitoid survival and performance. This study investigates the effects of nectar sugars on life-history traits and thermotolerance of the parasitoid wasp Aphidius ervi under simulated heatwave and low-temperature conditions. Using controlled dietary treatments of sucrose, glucose, fructose, and water (negative control), we assessed the impact of diet on parasitoid thermotolerance and life-history traits central to biological control (longevity, egg load, egg volume). Results suggest that diet exerts a significant effect on the life-history traits and thermal tolerance of A. ervi. These findings indicate that supplementary feeding through nectar-rich plantings, such as flower strips, could enhance parasitoid survival and efficacy under climatic extremes. This ongoing research highlights the potential for tailored ecological strategies to mitigate the effects of climate change on agricultural pest control systems and emphasises the importance of nectar composition in promoting parasitoid fitness. Further work will demonstrate the full extent of dietary effects on overall pest control outcomes.

Date of Award	9 Dec 2025
Original language	English
Awarding Institution	University of Bristol
Supervisor	Lucy Alford (Supervisor) & Bex Pike (Supervisor)