Biological Sciences

Forensic Entomology

Dr Michelle Harvey's Research Interests:

Forensic entomology is a field with wide-ranging applications involving any interaction of insects and other arthropods with the law, from food-related insect infestations to infestation of dwellings, neglect of animals and humans to the estimation of postmortem interval.

The estimation of postmortem interval is one of the critical roles of the forensic entomologist.

Blowflies are generally the first insects to locate a corpse, laying eggs that hatch to be larvae that play a vital role in the decomposition process. They arrive fairly predictably, and therefore, they are frequently used in estimation of postmortem interval. The majority of my research focuses on these flies.

Decomposition studies:

• Succession: how can the predictable behaviour of insects be used to estimate time since death?
• How does the arrival and behaviour of insects on carrion change with factors such as geographical location, clothing of a body, vegetation as a concealing factor, season and other variables?

Invertebrate soil corpse fauna:

• Beneath the body is an established community of soil arthropods and invertebrates: how does the decay process affect these organisms? Fluids are released into the soil and disrupt their lifestyles... are these disruptions and subsequent recovery able to be used to estimate time since death?

Palaeoentomology:

• Insects may be associated with burials or concealed bodies of an historical nature. Insect remains such as fly pupal casings may persist in the environment for hundreds of years... what information can be taken from these insect remnants?
• Insects may exhibit seasonal variation in distribution... can the presence of remnants from particular species cast light on ancient burials, particular seasonality of burial, and possible movement and re-burial?

Molecular studies of the Calliphoridae (blowflies)

• Identification of insects: the estimation of PMI relies on accurate identification of insects, and knowledge of their rate of growth. Larvae (maggots) may look very similar from different species, so my research uses DNA to discriminate species
• Following collection of larvae, the insect's DNA can be sequenced, and computer-based analysis with insects of known species used to provide information about the species identity of the insect. This diagram illustrates the outcome of such an analysis- in this case, we would conclude that our unknown insect is most likely Ch. rufifacies and use this to estimate time since death

Current Undergraduate Research projects :

• Insects attracted to carrion in the Portsmouth area: surveys of carrion-related fauna and importance in the application of succession data to the estimation of post-mortem interval
• Study of forensically important flies of the Portsmouth area using combined light microscopy and scanning electron microscopy techniques
• Utility of pupal development for the estimation of postmortem interval
• The use of non-human DNA in forensic investigation: applications, limitations and implications
• Forensic Entomology: the variables that affect the field and the status of current research
• Wildlife and animal crime: the capture, trade and exploitation of protected species and animal products