Eye on Nature: ‘An alderfly is usually found resting in large numbers on waterside vegetation’

Éanna Ní Lamhna on dreolíns, alderfly and Hebrew character moth

After mating, the female alderfly will lay eggs on the foliage of plants growing in water. Photograph: Paul Aiken
After mating, the female alderfly will lay eggs on the foliage of plants growing in water. Photograph: Paul Aiken

Have you any idea what this insect might be? I found it basking on a metal fence by the banks of the Lagan. – Paul Aiken, Belfast

This is an alderfly, which is usually found resting in large numbers on waterside vegetation or flying, rather weakly, on sunny days at the end of spring. This is Sialis lutaria, the larger of our two alderfly species. After mating, females will lay eggs on the foliage of plants growing in the water. Upon hatching, the larvae fall into the water, where they feed voraciously on other small creatures in the mud. They leave the water after a year and pupate in cells in the nearby soil, from whence the adults come.

I found this on the seawall at Booterstown. It was only 2in from tip of bill to tip of tail. I initially thought it was only resting but, on closer inspection, it was very much demised. What is it? – Michael Keegan, Dublin

Dreoilín (wren), supplied by Michael Keegan
Dreoilín (wren), supplied by Michael Keegan

This is a poor dead dreoilín – a wren – our second smallest bird. It is exceedingly common: there are an estimated six million-plus of them in the country. They are rarely seen as they don’t come to bird tables, but their loud song with the 200 notes per second thrill at the end – is one of the highlights of the dawn chorus. Males build several dome-shaped nests; when the female is installed in the one of her choice, laying and incubating eggs, he is not above taking a second partner to one of the other unoccupied portions of real estate.

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Nature fights back! Spotted recently on my car, a seedling sprouting from behind a plastic panel to the rear of the front wheel. – Nigel Burgess, Dublin

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Sycamore tree seedling, supplied by Nigel Burgess
Sycamore tree seedling, supplied by Nigel Burgess

This is a seedling of a sycamore tree. The “helicopter” seedlings are carried everywhere by the wind and will germinate if they land on the smallest bit of soil. They are not native and can become quite invasive, as any inspection of an untended back garden will reveal after a few years. This one is on a hiding to nothing, however, so you needn’t worry that your car will come to resemble “Birnam’s Woods removing to Dunsinane”.

This guy was hiding on my windowsill. What type of moth is it? – Katrina Collins, Cork

Hebrew character moth, supplied by Katrina  Collins
Hebrew character moth, supplied by Katrina Collins

This moth is called a Hebrew character because of the distinctive black mark on each forewing, which is said to resemble a Hebrew letter. It holds its wings tent-wise while at rest. It flies in late spring and the females lay their eggs on the leaves of various trees and shrubs, as the caterpillars are not too specific in their food requirements. These then pupate in the soil and pass the winter as pupae before emerging as adults the following year.

Having lifted a mooring from the seabed, we discovered some sea creatures. We think the little fish is a lumpsucker and would love to know more. The creatures were all safely returned to the sea after the photo shoot. – Laurence Bree, Dublin

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Lumpsucker, supplied by Laurence Bree
Lumpsucker, supplied by Laurence Bree

It is indeed a lumpsucker, also known as a sea hen. It is so-called because its body is covered with lumps and fleshy knobs. It has no scales and its skin feels leathery. It has a modified pelvic fin that acts as a suction disc and allows it to attach itself to objects such as rocks, pieces of kelp or, as in this case, a mooring. Females will deposit a spongy mass of eggs into a nest made by the male on the sea floor. She then departs, leaving himself to defend the nest and mind the eggs having fertilised them.

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Éanna Ní Lamhna

Éanna Ní Lamhna

Éanna Ní Lamhna, a biologist, environmentalist, broadcaster, author and Irish Times contributor, answers readers' queries in Eye on Nature each week