Bat poo reveals the winged world of the night – The Irish Times

We live and think in parallel worlds. In one, we watch the advance of climate change with awe and apprehension. In the other, we follow workaday science as if there’s all the time there ever was.

Biologists still seek discoveries with significance and promise, even excitement. Helped by new technologies, their research could assist in the human condition, along with their own careers.

Take bats, for example. What, exactly, do they catch and eat as they flicker through the night sky? And what’s the point of knowing, except to know more?

The clues lie in their dark droppings, a bit bigger than those of mice, but longer, like seeds, and easily crumbled to dust. Before we changed the roof I used to find them scattered on the sill outside the kitchen window.

In 1989, when Prof James Fairley was pioneering bat research at NUI Galway, he and star student Kate McAney teased apart no fewer than 630 droppings from lesser horseshoe bats to examine their hard, chitinous insect remains under the microscope. This traditional analysis helped them detect eight orders of arthropods (the broadest groupings), with the insects identified only at family level.

Dr McAney went on to make conservation of the west of Ireland’s protected horseshoe bats her special mission, securing their roosts in old buildings and tunnels.

With the smallest, the pipistrelle, credited with eating some 3,000 insects a night, the benefits to human food supply are substantial

Then came advances in genetics and DNA analysis, and new university scientists with PhD students. Dr Denise O’Meara is lecturer in molecular ecology at the Waterford campus of the new South East Technological University.

Her PhD student is Thomas Curran, whose paper published in Biology and Conservation is headed: One bat’s waste is another man’s treasure: a DNA metabarcoding approach for the assessment of biodiversity and ecosystem services in Ireland using bat faeces.”

His study is the first of its kind in Ireland or Britain to use metabarcoding, based on rapid DNA sequencing and the fast-growing genetic database of insects. It analyzed just 24 “faecal pellets” of horseshoe bats, gathered from plastic sheets laid at the entrance of six summer roofs.

It detected no fewer than 161 arthropod species from 11 orders, including 38 potential pests of vegetables, tree fruit and cereals. More than half of the insects were moths and some 18 per cent were flies (arthropods also include spiders, mites, aphids and beetles). The moths included the large tortrix, whose larvae bore into apples and pears, and the diamondback, whose caterpillars perforate brassicas. Among the many species of cranefly were five not previously recorded in Ireland. All their grubs eat the roots of grasses and cereals. And the carrot root fly is the familiar bane of vegetable gardeners.

The multitude of prey identities are ringed in a big “doughnut” of species in Curran’s paper. The bats’ diet varied from one habitat to another. Most were in farming areas near to woodland, with moths most abundant around the Kerry roost, in dense and protected native woods.

Such analysis is clearly a project whose time has come. Curran’s research deals with one kind of bat, the lesser horseshoe, but Ireland so far has nine (11 adding in the odd and rare). With the smallest, the pipistrelle, credited with eating some 3,000 insects a night, the benefits to human food supply are substantial.

Thus, in July last year, UCD’s BatLab and Bat Conservation Ireland launched a new “citizen science” website supported by the National Parks and Wildlife Service. At batsandbugs.ie it encouraged people with bat roots in their properties to send in samples of bat droppings for metabarcoding analysis.

Of the 19 mammals that live longer than humans, all but one are bats. Their extreme longevity seems to counter the rule that bigger animals live longer

The UCD BatLab was cofounded by zoologist Prof Emma Teeling and is now a global consortium of scientists dedicated to sequencing the genomes of 1,421 living, global bat species. While promoting their conservation, a leading drive for Dr Teeling’s team is to relate the genomes and evolution of bats to those of humans.

This has allowed them to uncover the bat’s unique and peculiar adaptations, not only in flight and echolocation but in tolerating virus infections and living to remarkable old age.

Even the tiny pipistrelle, inhabiting so many of Ireland’s roof spaces, may live as long as 15 years. And of the 19 mammals that live longer than humans, all but one are bats. Their extreme longevity seems to counter the rule that bigger animals live longer.

It has also led Dr Teeling to conjecture that deep in their DNA “may lie the secret of everlasting youth” — a proposition, offered in public lectures, that startles and intrigues the biological community.

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