Predicting Geographic Distribution of Forensically Significant Blow Flies of Subfamily Chrysomyinae (Diptera: Calliphoridae) in Northern Thailand

Abstract

Blow flies (Diptera: Calliphoridae) are carrion-breeding flies that are commonly used as evidence in forensic investigation. An adequate knowledge of ecological and geographical data of blow fly has a direct application in forensic science, as far as estimating time of colonization or corpse relocation. The aim of this study was to evaluate the occurrence of four species of Chrysomyinae (Chrysomya pinguis, Chrysomya chani, Chrysomya villeneuvi, and Ceylonomyia nigripes) across six land use types in central Chiang Mai, northern Thailand. Eighteen study sites were selected for sampling across three districts of Chiang Mai province (Mueang Chiang Mai, Mae Rim, and Hang Dong). Adult flies were collected every two weeks using a funnel trap baited with 1-day tainted beef offal. The predicted geographic distributions of forensically important blow fly species were modeled using the computer program ArcGIS, based on selected climatic variables (temperature, relative humidity, and light intensity) recorded at study sites. During the study period, 1298 adult flies were collected, with peak fly occurrence during summer (April–May). Seasonal fluctuation patterns varied depending on fly species. Climatic factors displayed diverse impact on associated fly populations. Identified species were restricted mainly to mixed deciduous forests (MDF) especially in the mountainous area. None of these flies were trapped in an urban area.

Spatial Distribution of Forensically Significant Blow Flies in Subfamily Luciliinae (Diptera: Calliphoridae), Chiang Mai Province, Northern Thailand: Observations and Modeling Using GIS

“…Previous investigations have shown the spatial models of C. megacephala , C. rufifacies , C. pinguis , C. chani , C. villeneuvi and Cey. nigripes [33,34,35]. According to this study, H. ligurriens was predicted to occur across a variety of land uses in Mueang Chiang Mai district especially nearby residential areas (e.g., city/town and lowland village), which is similar to C. megacephala and C. rufifacies [33,34].…”

“…On the other hand, L. porphyrina and L. papuensis showed preference in the mixed deciduous forest, which is consistent with C. pinguis , C. chani , C. villeneuvi and Cey. nigripes [35]. The greatest number of H. pulchra was predicted mainly in mixed orchard and lowland village, with low altitudes ranging between 300 and 400 m a.s.l., which is in contrast with a previous study that found this species only at 901–1050 m a.s.l.…”

“…Although surveys of forensically important flies have been conducted on a local scale in Thailand, a comprehensive landscape assessment of the distribution of Luciliinae that are forensically important is limited [30,31,32]. Previous work on spatial analysis of forensically important blow flies has focused on Chrysomya megacephala (Fabricius) [33], Chrysomya rufifacies (Macquart) [34], Chrysomya pinguis (Walker) , Chrysomya chani Kurahashi, Chrysomya villeneuvi Patton and Ceylonomyia nigripes (Aubertin) [35]. However, studies on Luciliinae flies are lacking.…”

Applications of forensic entomology: overview and update

“…Informacje zgromadzone na podstawie modeli zwierzęcych mogą mieć przełożenie na przypadki kryminalne i służyć jako baza danych dotyczących entomofauny w określonym siedlisku [14]. W niektórych krajach nie ma jednak literatury na ten temat lub jest ona skąpa [15].…”

“…The experimental data on animal models seem to be applicable to actual forensic cases and can act as a valid database of entomofauna in the same habitat [14]. There is no or little literature about geographical distribution of forensically important species in some countries [15].…”