The effect of temperature on the developmental rate of Lucilia sericata (Diptera: Calliphoridae) found within the Western Cape of South Africa

Naiker, Darshni

The effect of temperature on the developmental rate of Lucilia sericata (Diptera: Calliphoridae) found within the Western Cape of South Africa

Thesis / Dissertation

2026

Publisher

University of Cape Town

Department

Department of Pathology

Faculty

Faculty of Health Sciences

Abstract

In the context of medico-legal forensic entomology, a vital component of the investigative process is determining minimum post-mortem intervals (minPMI). Insect succession patterns and developmental data can vary due to temperature, humidity and geographical location. Therefore, despite the availability of developmental data, region-specific data cannot be applied to the same species from different geographical regions as it may result in inaccurate minPMI estimations. This study aimed to establish developmental data for Lucilia sericata (Meigen, 1826) (Diptera: Calliphoridae) for the Western Cape Province of South Africa. L. sericata is a widely distributed blowfly and their tendency to be the first insect to colonise a carrion after death makes them pivotal in estimating minPMI. Developmental curves were established at six different constant temperatures (15°C, 18°C, 22°C, 25°C, 30°C, 34°C) using developmental landmarks and body length as measures of age. Measurements were collected every four hours for the higher temperatures (30°C and 34°C) and every eight hours for the lower temperatures (15°C, 18°C, 22°C, and 25°C). The experimental process was replicated three times for each temperature interval. Isomegalen, isomorphen and thermal summation models were constructed to aid in PMI estimation. The developmental data indicated that temperature had a significant effect on development, with the developmental rate of L. sericata generally increasing with temperature. However, at 34°C, the developmental rate slowed down, indicating that extreme temperatures can hinder growth. A comparison of this study's data with existing literature indicated great variation among the developmental times for L. sericata, reflected by the isomegalen and isomorphen diagrams generated. The thermal constant for the complete development of L. sericata from egg to adult was 7058.8 ± 0.01°C hours, however, the lower developmental threshold for overall development was 9.6°C, which was in line with the literature. The accumulated degree days (ADD) calculated fluctuated across the developmental stages and temperatures, however, no distinct pattern was noted. The fluctuations in ADD seen may be influenced by more than temperature, such as stage-specific base temperatures (which differ for different geographical locations). The notable discrepancies in the data highlights the impact of temperature on the development of insects and the importance of understanding this factor for the improvement of minPMI estimations. As well as generating region-specific data for L. sericata and other species to ensure more reliable minPMI estimations.

Keywords

Lucilia sericata

temperature

Reference:

Collections

Masters

Full item page