Analysis of the Influence of Changing and Fixed Temperatures on the Growth and Pteridine Content in the Head of Adults Sarcophaga crassipalpis (Diptera: Sarcophagidae)

SIMPLE SUMMARY: Sarcophaga crassipalpis Macquart, 1839 (Diptera: Sarcophagidae) is a flesh fly species of medical, veterinary, and forensic importance. It is often used in the laboratory for several biological studies. In the current research, we investigate its life history under changing temperatures ranging from 15.7 to 31.1 °C, with an average of 24.55 °C, and the relative humidity ranges from 31.4 to 82.8% and at six fixed temperatures of 15, 20, 25, 30, 32, and then 35 °C. Also, pteridine from the head was used to assess adult age grading. Our results revealed that the life history and development rate of S. crassipalpis under changing temperatures were very close to those observed at a fixed temperature of 25 °C. The longest and shortest growing times were found at a low rearing temperature of 15 °C and higher temperature of 32 °C, respectively. The pattern of pteridine increase differed depending on the temperature. By employing a changing temperature model in the current study, we aim to provide information on the life history of S. crassipalpis that will be useful in future research. ABSTRACT: Flesh flies (Diptera: Sarcophagidae) are regarded as significant in medical and veterinary entomology, and their development models can be utilized as considerable markers to ascertain the minimum postmortem interval (PMImin). In this research, we explored the growth cycle and larval body length of Sarcophaga crassipalpis Macquart 1839 (Diptera: Sarcophagidae) reared under variable temperatures ranging from 15.7 to 31.1 °C, with an average of 24.55 °C and relative humidity ranges from 31.4 to 82.8% and at six fixed temperatures of 15, 20, 25, 30, 32, and then 35 °C. Moreover, pteridine from the head was used to assess adult age grading. Our results allowed us to provide three development models: the isomorphen chart, the isomegalen chart, and the thermal summation models. The time taken for S. crassipalpis to complete its development from larviposition to adult emergence at constant temperatures of 15, 20, 25, 30, 32, and 35 °C was 1256.3 ± 124.2, 698.6 ± 15.1, 481.8 ± 35.7, 366.0 ± 13.5, and 295.8 ± 20.5 h, respectively, except 35 °C, where all pupae were unable to attain adulthood. They lasted 485.8 ± 5.4 h under variable temperatures. The minimum developmental limit (D(0)) temperature and the thermal summation constant (K) of S. crassipalpis were 9.31 ± 0.55 °C and 7290.0 ± 388.4 degree hours, respectively. The increase in pteridine content exhibited variations across different temperatures. There was quite a considerable distinction in the pteridine contents of male and female S. crassipalpis at 15 °C (p = 0.0075) and 25 °C (p = 0.0213). At 32 °C and variable temperatures, the pteridine content between female and male S. crassipalpis was not statistically divergent. However, temperature and gender remain the main factors influencing the pteridine content in the head of S. crassipalpis. We aim to provide detailed developmental data on S. crassipalpis that can be used as a valuable resource for future research and PMI estimation.