Environment

What is this colourful insect I spotted in my tree? Readers’ nature queries

Ethna Viney answers questions on a sawfly, raft spider, fungus and caterpillar

A sawfly spotted in the trees in Cork

Ethna Viney
Sat Oct 19 2019 - 06:00

I was trimming trees last month when I saw this insect. It was 4-5cm long.

– C Lowney, Castletownbere, Co Cork  

It’s a sawfly, the female wood wasp also called the horntail, which uses her ovipositor to bore into pine trees to lay her eggs. They hatch and remain in the tree for 2-3 years, from which they emerge as fully grown sawflies.

I watched a snail trying to get down a gap in the decking but it was not going to fit with its shell. Why would it not leave the shell behind?

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– Eithne Mackell, Blackrock, Co Dublin 

The shell is attached to the snail and grows with it.

Raft spider in Portumna Forest Park

We came across these beautiful spiders in the grass in Portumna Forest Park.

– Ava Gleeson, Oranmore, Co Galway 

It’s the raft spider, Dolomedes fimbriatus, a hunting spider which waits at the water’s edge with two feet in the water to catch ripples from prey. It then runs across the water to attack sticklebacks, water insects or snails.

Small stagshorn fungus in Connemara

Hiking on Leenane Hill in Connemara recently we came across these colourful plants but don’t know what they are.

– Anne Marie Keoghan, Shanowen Crescent, Dublin, 9 

It’s a fungus called the small stagshorn, Calocera cornea.

Caterpillar in Co Mayo

Will this caterpillar survive the winter?

– Barbara Browne, Knockmore, Co Mayo 

It looks like the caterpillar of the large yellow underwing moth, which will feed until mid-winter when it goes into hibernation. It will complete its growth in spring, when it pupates and the moth emerges in June.

Remains of what might have been a locust or grasshopper

I saw this big fella on the beach at Castlefreke in west Cork after the Lorenzo storm. It was larger than anything I’ve seen airborne around here. I also counted 58 Portuguese men-o’-war along the length of the beach.

– Mary Callaghan, Clonakilty, Co Cork 

Experts think it might be the remains of a very large insect like a locust or grasshopper.

Ethna Viney welcomes observations and photographs at Thallabawn, Louisburgh, Co Mayo, F28 F978, or by email at viney@anu.ie. Please include a postal address.