Estimating the intra-puparial period of Hydrotaea spinigera (Stein,1910) (Diptera: Muscidae) with morphological and gene expression changes

Shipeng Shao; Gengwang Hu; Liangliang Li; Yi Sheng; Yinghui Wang; Yanan Zhang; Yi Guo; Chengtao Kang; Wang Xu; Jie Chen; Jiangfeng Wang; Yu Wang

doi:10.1016/j.actatropica.2023.106910

Estimating the intra-puparial period of Hydrotaea spinigera (Stein,1910) (Diptera: Muscidae) with morphological and gene expression changes

Acta Trop. 2023 Jun:242:106910. doi: 10.1016/j.actatropica.2023.106910. Epub 2023 Mar 23.

Authors

Shipeng Shao¹, Gengwang Hu¹, Liangliang Li¹, Yi Sheng¹, Yinghui Wang¹, Yanan Zhang¹, Yi Guo¹, Chengtao Kang¹, Wang Xu¹, Jie Chen², Jiangfeng Wang¹, Yu Wang³

Affiliations

¹ Department of Forensic Medicine, Soochow University, Ganjiang East Road, Suzhou, China.
² Clinical Experimental Center, Xi'an International Medical Center Hospital, Xi'an, Shaanxi 710100, China.
³ Department of Forensic Medicine, Soochow University, Ganjiang East Road, Suzhou, China. Electronic address: yuw@suda.edu.cn.

PMID: 36963598
DOI: 10.1016/j.actatropica.2023.106910

Abstract

Hydrotaea spinigera (Stein, 1910) (Diptera: Muscidae) is a forensically important sarcosaprophagous species widely distributed throughout the Oriental and Australasian regions. At the advanced decomposition stage or the skeletonize stage, the immature stages of H. spinigera, especially the pupae, can still be found in large quantities and could be used as important indicators to estimate the minimum postmortem interval (PMI_min). However, there have been no studies on the intra-puparial period of this species. Herein, we studied morphological and differential gene expression changes during the intra-puparial development of H. spinigera, aiming to accurately estimate the intra-puparial age of H. spinigera. The intra-puparial morphological changes of H. spinigera were observed at seven constant temperatures ranging from 16 °C to 34 °C and divided into 12 sub-stages. Structures that could be used to estimate the intra-puparial age, such as compound eyes, mouthparts, antennae, thorax, legs, wings, and abdomen, were observed in detail, and the developmental process of each structure was divided into 5 to 10 stages. The time range of each sub-stage, or when a structure appeared, was recorded. For the gene expression section, the most suitable reference genes were screened by geNorm, NormFinder, BestKeeper, and ΔCt methods. Based on the selected reference genes, real-time quantitative PCR (RT qPCR) was used to detect the expression changes of the white and hsp90 genes with developmental time at 19 °C, 25 °C, and 31 °C. Results showed that the trend of hsp90 gene expression under different temperatures was not consistent, while white genes exhibited regular changes during development, and could thus be used for age estimation of H. spinigera. This study provides an important basis for forensic entomology to use morphological and differential gene expression for estimating the age of H. spinigera during the intra-puparial period. Moreover, the combination of the two methods can produce a more accurate minimum postmortem interval (PMI_min) estimate compared to when each method is used separately.

Keywords: Differentially expressed genes; Forensic entomology; Hydrotaea spinigera; Morphology; Postmortem interval.

MeSH terms

Animals
Diptera*
Forensic Entomology*
Gene Expression
Larva
Muscidae* / genetics
Postmortem Changes
Pupa / genetics
Temperature