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- All Subjects: Forensic Entomology
- All Subjects: Insects
- Creators: Chahal, Aunmolpreet Singh
Medicolegal forensic entomology is the study of insects to aid with legal investigations (Gemmellaro, 2017). Insect evidence can be used to provide information such as the post-mortem interval (PMI). Blow flies are especially useful as these insects are primary colonizers, quickly arriving at a corpse (Malainey & Anderson, 2020). The age of blow flies found at a scene is used to calculate the PMI. Blow fly age can be estimated using weather data as these insects are poikilothermic (Okpara, 2018). Morphological analysis also can be used to estimate age; however, it is more difficult with pupal samples as the pupae exterior does not change significantly as development progresses (Bala & Sharma, 2016). Gene regulation analysis can estimate the age of samples. MicroRNAs are short noncoding RNA that regulate gene expression (Cannell et al., 2008). Here, we aim to catalog miRNAs expressed during the development of three forensically relevant blow fly species preserved in several storage conditions. Results demonstrated that various miRNA sequences were differentially expressed across pupation. Expression of miR92b increased during mid pupation, aga-miR-92b expression increased during early pupation, and bantam, miR957, and dana-bantam-RA expression increased during late pupation. These results suggest that microRNA can be used to estimate the age of pupal samples as miRNA expression changes throughout pupation. Future work could develop a statistical model to accurately determine age using miRNA expression patterns.
All organisms perform best at a balanced point of intake where nutrients are ingested in specific amounts to confer optimal performance. However, when faced with limited nutrient availability, organisms are forced to make decisions which prioritize intake of certain macronutrients. While intake regulation has been more thoroughly studied in omnivores and carnivores, no research exists regarding lipid regulation in generalist herbivores. Traditionally, proteins and carbohydrates were thought to be the most important macronutrient for herbivore intake; however the large differences in lipid nutritional content between different plant species offers lots of potential for regulation of an important macronutrient. We studied whether generalist herbivores can regulate lipid intake, using the migratory locust (Locusta migratoria). Though herbivore protein and carbohydrate intake is well studied, less research studies regulation of lipid intake. We tested this by offering choice diets of varying carbohydrate and lipid content makeup and measuring consumption of each diet choice to determine overall carbohydrate and lipid intake. Four different lipid sources were used in order to control for taste or texture related confounds; canola oil, sunflower oil, grapeseed oil, and a lab designed synthetic oil based on the four most abundant fatty acids in common plant oils. On three out of four diet sources, groups evidences strong regulation of narrow intake target, with little disparity in overall intake of carbohydrate and lipid content between various choice diet treatments. Groups feeding on canola oil and sunflower oil based diets displayed the best regulation based on their having small disparities in intake between treatments, while those feeding on grapeseed oil based diets displayed wide variation in feeding behavior between treatments. Groups feeding on the synthetic oil based diet choice unexpectedly consumed much more carbohydrates than lipids when compared to all other groups. In conclusion, generalist herbivores are capable of regulating lipid intake.