Thermal sensitivity of metabolic rate in a hemimetabolous insect: variation across life stages

Abstract

Environmental temperature strongly influences insect metabolic rate (MR), yet the thermal sensitivity of MR across developmental stages remains understudied in hemimetabolous species. Here we quantified resting metabolic rate (RMR) thermal sensitivity in Rhodnius prolixus, a hemimetabolous insect and an important Chagas disease vector. For that, we measured real-time CO2 production by open flow-respirometry as a proxy for MR at six temperatures (10, 15, 20, 25, 30, and 35 ◦C) across all life stages. We found a stage-specific thermal sensitivity of the RMR. Instantaneous Q10 estimates revealed ontogenetic variation: early nymphs exhibited higher thermal sensitivity at cooler temperatures and lower sensitivity at warmer temperatures, while adults maintained constant Q10 values across the thermal range. These findings provide novel insights into thermal biology of hemimetabolous insects and show that developmental stage influences metabolic responses to temperature. Understanding these patterns is crucial for predicting how climate warming may affect the physiology, population dynamics and disease transmission potential of this vector species.