A pelagic snail can float on the surface of the sea by means of a raft of trapped air bubbles

Éanna Ní Lamhna on mosquitoes, a washed-up whale bone and breeding ospreys in Fermanagh

Whilst having a swim in Cloghane in Liscannor, Co Clare, I came across this unusual violet sea snail. Apparently they float up from the Tropics. James McCusker

There have been several sightings of them this summer. Catherine Ciechanowicz found some on Nairn beach in Donegal, while James Armstrong found some with his grandchildren on Dugort beach in Achill. It is indeed the violet sea snail, a pelagic snail that can float on the surface of the sea by means of a raft of trapped air bubbles, which is evident in your photo, and feeds on small jellyfish-like animals in the Siphonophore group. They are an Atlantic species.

What are these tiny creatures which appeared swimming in a basin of rainwater and non-peat compost – maybe compressed coconut fibre. There were hundreds of them but after a few days there were a lot fewer. Aileen Mulhern

They are, you will be delighted to know, the larval stage of the culicine group of mosquitoes. While the females can bite us in the adult form, these are not the malaria-carrying group. They develop rapidly into pupae and then flying adults, so that is where they have gone. They love to lay eggs in stagnant rain-filled basins and flowerpot saucers, so this summer suited them admirably.

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I saw these colourful growths on the stems of wild roses on a country lane. I haven’t noticed them previously and am intrigued. Ethna Sheehan, Co Waterford

As was Mairéad Blackall in Co Kildare and a reader in Co Offaly, who sent in pictures too. They are the galls of a species of gall wasp (Diplolepis rosae) and they go by the name of Robin’s pincushion. The solitary wasp lays eggs on the wild rose, which cause the plant tissues to form this gall, which provides abundant food for the larvae that develop within.

This beautiful elephant hawkmoth was at the bottom of the laundry basket that I’d left outside. It didn’t look very happy but had gone later in the day. Diana Gilbert, Co Cork

I am not sure how you would know whether a hawkmoth looked happy or unhappy. This beautifully coloured moth is what the snake-mimicking caterpillar that graced this column last week turns into after a period as a chrysalis.

We found this curious tusk-like object on a beach in Inishbofin. It is smooth to the touch despite being rather weathered, and appears to be honeycombed at either end. Could it be part of the rib of a large cetacean? Jack O’Farrell Co Galway

Kevin Flannery of Dingle Aquarium agrees about it being a whale bone, but suggests that it is what remains of the whale’s lower jaw bone rather than the rib. Possibly one of the baleen whales, which have baleen plates instead of teeth that they use to sieve food from the water.

Sinéad Craig of Inishowen Wildlife Club sent in this excellent picture of an osprey, which was seen fishing near the mouth of the river Bann around Coleraine at the end of August. Ospreys were a breeding species in Ireland up to the end of the 1700s. They are a highly migratory species and the majority over-winter in the estuaries and mangrove creeks of west Africa. They fly over Ireland on their way to and from their breeding grounds in Scotland and Scandinavia. They live entirely on fish, which they catch following a headlong plunge from 40m, entering the water feet first. A pair has successfully bred for the first time this year in Fermanagh, and a first group of 10 osprey chicks from Norway were released in the southeast in late August as part of the NPWS release programme.

Please submit your nature query, observation, or photo with a location, via irishtimes.com/eyeonnature

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