The Science & Technology Group

Organising committee:  Tanya Dempster, Paul McKay, Bill Devitt, Kurt and Lynda Kovach - science@ashbyu3a.co.uk -

This group is for both people who have a general interest in science as well as those whose careers have been in this area. We meet monthly with talks given mainly by members on a mixture of science/ engineering topics, some science news, information about famous scientists, good YouTube ideas and even the occasional practical activity.

We normally meet in the main hall at Packington Village Hall, High Street, Packington LE65 1WJ on the 2nd Tuesday of the month at 2pm.
Parking is limited, so please try to car-share if possible.

Tuesday 14th April.

'Forensic Entomology' by Dr Kate Barnes

Tanya introduced today’s speaker by listing her qualifications; she had obtained a PhD at Lincoln University, had researched woodland environment at Nottingham West Hallam University and is currently a Senior Lecturer in Forensic Biology at the University of Derby.

Kate described how environmental studies had been used in a legal framework as far back as 1235 in China but not until 1935 in Britain. She went on to explain how the corpse is gradually broken down by insect infestation. There are three types of invasive insects that are involved, most important are necrophages that feed on the decomposing soft tissue of the body, while predators and parasites also contribute. The green/blue blowfly is often the first to invade the carcass, its sensitive sense of smell being able to detect bodies buried in shallow graves or wrapped in bin liners, suitcases and wheelie bins. Kate has researched how long it takes for blowflies to colonise various dead animals and how the presence of water and coverings like a duvet affects the rate of colonisation. The main objective of these studies is provide a scientific basis for the time of death, a crucial factor in most legal investigations.

Kate described the anatomy of the most common invasive insects noting that they do not have haemoglobin in their blood, so it is green in colour, not red. Also, these insects cannot regulate their body temperature, so need to find a suitable environment to survive. High ambient temperature accelerates the life cycle of blowflies so data loggers are often used to estimate the temperature profile at the scene and then correlate the data against local weather measurements. Blowflies are attracted to natural body orifices, eyes, nose, genitals or an open wound and this is factored into time of death studies. It is important to understand the stages of the blow flies life cycle, from egg, larvae, pupae to adult and how the time-frames are affected by temperature and humidity. Kate explained that the forensic entomologist must search for evidence of blowfly eggs, larvae and pupae under carpets, behind skirting boards or other cracks and crevices to understand the scene of a crime or an accident. Kate also supervises post-graduate students who investigate specific aspects of entomology in outdoor conditions, such as the effects of a wet environment and the collection of flies in bottle traps for study in the laboratory. From Kate’s description of her work to estimate the time of death of a person, even when all the evidence is meticulously collected and recorded, it was still subject to wide variation.

After the talk there were many questions on this fascinating subject. Were maggots of blowflies really used to clean open wounds, as shown in the film ‘Gladiator’ or was that pure fantasy? Turns out, sterile maggots are used under clinical conditions to eat away only the decomposed flesh of a wound, leaving living tissue untouched!

For our next Science & Technology meeting on Tuesday 12th May, Andrew Chandler-Grevatt will take us on a Moss Safari. This will be a virtual talk using Zoom technology and if successful, will allow guest speakers to deliver talks from their homes and avoid the need for long journeys.

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