# Temperature Effects on Development and Population Growth of Two Parasitoids (Hymenoptera) of the Coffee Berry Borer (Hypothenemus hampei)

## TL;DR

This study examines how temperature affects two parasitoid wasps used to control coffee berry borer, identifying optimal temperature ranges for their survival and population growth.

## Contribution

The study provides new temperature-dependent life table data and degree-day models for two parasitoids used in biological control of coffee pests.

## Key findings

- Optimal survival and fecundity of both parasitoids occur at 22–25°C.
- Development fails at extreme temperatures (32 and 35°C), indicating upper thermal limits.
- Predicted annual generations vary by region, with 22–28°C areas supporting the highest efficacy.

## Abstract

Coffee berry borer, Hypothenemus hampei Ferrari (Coleoptera: Curculionidae), is the most damaging pest of coffee worldwide, reducing both yields and quality. African parasitoid wasps have been widely released in Colombia as biological control agents for H. hampei, yet their establishment has been inconsistent, partly due to limited information on how temperature affects their performance. We evaluated the thermal biology of two key parasitoids of H. hampei: the larval-pupal ectoparasitoid Prorops nasuta Waterston (Hymenoptera: Bethylidae) and the adult endoparasitoid Phymastichus coffea LaSalle (Hymenoptera: Eulophidae). Using age-stage, two-sex life tables across eight constant temperatures, we quantified temperature effects on development, survival, fecundity, and population growth. We identified 22–25 °C as the optimal range for survival, and fecundity peaked at 25 °C. Life-table parameters indicate maximal population growth at 25 °C for both parasitoids. Development failed at extreme temperatures (32 and 35 °C), highlighting upper thermal limits relevant to mass-rearing and field releases for both parasitoids. Degree-day models were developed to estimate the potential number of generations across Colombian coffee-growing regions. We predict 5.5–11.6 annual generations of P. nasuta and 2.2–8.6 of P. coffea, depending on local temperature regimes. These results identify optimal temperature ranges for rearing and deploying P. nasuta and P. coffea and provide spatially relevant predications for their establishment potential in Colombian coffee-growing regions. Regions with mean temperatures between 22 and 28 °C are expected to support the greatest efficacy of augmentative biological control programs targeting the coffee berry borer.