RESEARCHERS and students at the Scottish Centre for Ecology and the Natural Environment (SCENE) are at the forefront of studies looking into the effects of urbanisation on the food chain.
Working from SCENE near Sallochy on the east side of Loch Lomond, lead field co-ordinator Jess Clark and her fellow researchers are using a variety of methods to trap mosquitos, blackfly, midges and other vectors – carriers of diseases that aren’t affected by the diseases themselves – to find out their feeding habits.
The effects of these vectors on birds combined with other research into what, and how often, the birds are eating will give valuable insights into the impact of urbanisation on the environment.
“We have 500 bird boxes set up between Glasgow city centre and here (Sallochy),” explains Jess. “So it’s like a gradient going from dense uranbisation in the city to the undisturbed habitats around SCENE.
“The bird boxes have sticky traps which catch the insects looking for somewhere to rest after they feed on the birds…by examining the insects we can work out what they’ve been eating.”
Some of the bird boxes have miniature cameras installed that let Jess and her colleagues see what kind of food the birds are bringing back to the nest and how often.
Jess explains: “We take measurements from the beginning of the birds nesting season – so when the birds first start laying down material to make nests – all the way through the nest making, egg laying, egg incubation, hatching and chick fledging periods.
The measurements include offspring survival success – how many eggs are laid, how many hatch, how many chicks fledge; their rate of feeding the offspring; and adult and offspring immunology.
The data is collected through a range of experiments run by Jess’s fellow researchers Pablo Capilla Lasheras and Christopher Pollock who are working on their masters theses. They are looking at differences between immunology and food provided by the parents between the city and the country.
“The studies aren’t complete,” says Jess. “But so far we’re seeing a huge difference in the birds’ health, wellbeing and quality of available food sources between the city and the country.
“In the city the parents must work much harder to provide for their offspring in order to ensure any of them survive. In addition the health and immunology of the chicks is much lower in the city in comparison to the countryside.”
A link between the insect and bird work, is Jess, Giovanni and their colleagues’ interest in the fact that the vectors carry avian malaria.
“It’s a fantastic way to study a non-lethal infection that will never affect humans but has similarities in its qualities to those that can,” explains Jess.
“Our further interest in midges is the financial aspect. Billions are invested every year to protect livestock from diseases spread by midges such as Schmallenberg and Blue Tongue Virus. But in comparison to how much is spent protecting our economic industries from these diseases, we really don’t know very much about the midges’ lifestyle, habits, abundance, locations and niches.
“So even small scale studies such as undergraduate honours projects, provide a great amount of information to help us build a bigger picture.”
This wider study of insects and vectors involves different types of traps which eagle-eyed visitors to East Loch Lomond might come across.
CDC (Centre for Disease Control) traps in the trees emit light to attract insects which are then sucked by small fans into a collecting cups. Other traps include Gravid traps which use a liquid ‘mosquito soup’ to attract insects and resting boxes designed to appeal to vectors looking to ‘rest’ after a blood meal…on birds, cattle…or even humans!
A simple DNA test identifies the insects’ stomach contents and reveals what animal it’s latest blood meal is from. This enables the researchers to work out the vector’s ecology such as where it feeds, where it rests after feeding and if they feed on more than one animal.
These insect studies are important as Jess explains: “As climates change, disease is spreading and encroaching into new areas. To mitigate this we have to understand the basic ecology of the insects that spread these diseases. Avian malaria is a good system to begin with and provides a platform to move into other diseases.”