A look at lepidoptera | Day 22 of 30 Days Wild

TWT 30 Days Wild_countdown_22

After a rather moist and misty start, the receding clouds and emerging sunshine revealed a sparkling vista of water droplets carpeting the island; everything from spider’s webs to the delicate seed heads of grasses were laden with water, refracting the sun in a cliche but stunning scene! The fragrance of wildflowers and rich vegetation was brilliant.

My main focus for today’s 30 Days Wild blog is on the more nocturnal members of the order lepidoptera: moths! Monitoring the moth populations of the island is a key part of Bardsey Bird Observatory’s work here, and the primary form this takes is running a number of moth traps throughout the year.

It was staff at the observatory that first encouraged me to venture into this awesome and exciting area of natural history back in my first summer on the island (in 2008), and my interest in moths has grown ever since. Every summer I try and keep two or three heath moth traps out every night to record the diversity of species as the seasons change.

one of my battery-powered heath traps stationed in the most vegetated area of the island: Nant. A mix of conifer plantation and broadleaved woodland results in a good mix of geometrid and noctuid moth species

The last week has been a little quiet in the traps, despite daily posts by friends on the mainland reporting catches of many hundred moths and triple-figure counts of species…whilst here we have barely been scraping double figure species lists!

Nevertheless, the overcast, warm and calm conditions over recent nights has made for some good turn-outs. Common species such as Large Yellow Underwings, White and Buff Ermines, Flame Shoulders and Brown Rustics have been accompanied by a supporting cast of Peach Blossom, Pinion-streaked Snout, Double Line, Map-winged Swifts, Garden Tigers and the odd Small Angle Shades. The first Lackeys of the year have also been making an appearance, after all those hundreds of caterpillars and tents we were seeing back in May!

Peach Blossom: this stunning species wasn’t recorded on Bardsey until 2009, and yet since then has become an annual occurrence. One of many colonisation events we’ve noted recently

A selection of recent moths…

The Double Line (top left) in this collage is by far the scarcest moth we’ve had, being a National Scarce species that occurs as an immigrant. This is our third record following two in 2014. Yesterday I also plucked another of our Nationally Scarce residents from the trap: a smart little micro called Eana penziana, which occurs in its subspecies form E. p. colquhounana, feeding on Sea Plantain and Thrift.

Eana penziana

There have also been a few migrant Silver Ys turning up in the traps, in addition to nectaring on some of the wildflowers during the day too. The scientific name of this species, Autographa gamma, also describes the distinctive mark emblazoning each wing: the word autographa suggests the moth has signed the mark on itself, whilst gamma refers to the Greek symbol that looks like a ‘Y’…

The silver Y of a Silver Y

Moth rearing update

As you may remember, at the beginning of the month I constructed a small rearing box in which to house a number of different moth caterpillars. Their insatiable appetite has kept me busy collecting damson, bramble, sallows and nettles on a daily basis, whilst a number of additions has seen me branch out into acquiring Bird’s Foot Trefoil (for Six-spot Burnets) and Bedstraws (for Small Elephant Hawkmoths.

A contrasting scale: Northern Eggar final instar caterpillar vs. a Yellowtail moth final instar!

I’ve currently got a number of Lackey pupae that should be hatching imminently; Yellowtail caterpillars are munching their last few leaves before also pupating in the coming days; two giant Northern Eggar caterpillars have a week or so before I think they too will pupate! Most of the Six-spot Burnets have already constructed their yellowy pupal cases, and will be transforming into gleaming adult Burnets in the coming days…

Six-spot Burnet pupal case
An adult Six-spot Burnet on wild thyme

The most exciting inhabitants of the box at the moment are some Small Elephant Hawkmoth caterpillars. They hatched out from a small cluster of bright green eggs laid by an adult female a week ago. Just a centimetre or so in length, it’s hard to believe these tiny larvae will grow into such stunning adult moths by next summer!

I also notice this pupa on one of the willow leaves within my rearing box, but am not totally sure which species it belongs to!


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