Species of the Month - August 2013

Vapourer Moth

Orgyia antiqua

In August the Vapourer Moth can be seen in the form of caterpillar, cocoon, adult and egg.  The caterpillars are very distinctive and can't be mistaken for anything else.  Where you find one you will generally find many more in the same area.  They feed on a wide variety of deciduous trees, shrubs and woody plants including Bilberry and Bog Myrtle, so can be found almost anywhere including treeless areas.  All the same they are not frequently encountered and we only have records of them from 3 places.  The NBN map shows very few records from our area.

Orgyia antiqua, larva

When the caterpillar is ready to pupate, usually between July and September, it spins a cocoon around itself and turns into a pupa inside the cocoon.

Orgyia antiqua, cocoon   Orgyia antiqua, cocoon

Vapourer Moth cocoon, and its underside, incorporating hairs from the caterpillar.  Within a population the caterpillars stagger their pupation times and so the emergence of adults from the cocoons is also staggered.  Some adults may emerge and lay eggs on their cocoon while other caterpillars have not yet pupated, so it is possible to see all four stages at once.

Orgyia antiqua, adult male

This is a male adult which has emerged from its cocoon and will fly off to look for a female.  The females do not have wings and remain on their cocoons, where they mate with a visiting male and then lay eggs on or near the cocoon.  These eggs remain there over the winter and hatch into caterpillars the following spring.  I haven't yet seen females or eggs but will make sure I look for them next time I find cocoons.  Photos of female and eggs at http://en.wikipedia.org/wiki/Orgyia_antiqua

The adult male normally flies by day, but can sometimes come to house lights or moth traps.  I had one at my window in Taynuilt in August last year.

Orgyia antiqua caterpillar   Orgyia antiqua caterpillar

More views of the caterpillar.  The one on the left was found by Cynthia on our field trip to Loch na Sreinge on 30 July 2013.  It was the first of many that we saw that day, on an amazing variety of plants.

The pic above shows a very young caterpillar.



Please send in your Vapourer sightings using the form below, or email sightings@lnhg.org.uk with the details if you prefer.  If you are not sure of the identity of your find, please send a photo to sightings@lnhg.org.uk, or put one on the LORN forum and let me know it is there.

Date of sighting 
Grid reference 
Number seen 
Stage (adult male/female, larva, cocoon, eggs) 
Name of finder 
Your name (if different) 
Email (not needed if I already know it!) 
Any other details, e.g habitat, behaviour   


By filling in this form you agree that the information contained in this form may be collated and disseminated manually or electronically for environmental decision-making, education, research and other public benefit uses in accordance with the LNHG data access policy.  Your email address will not form part of the record and will not be passed on to anyone.

Carl Farmer
G Biological Records Manager


Note you can still send in records for past species of the month.  Here is the list of species we've had so far:

Jul 2013 - Emerald Damselfly
Jun 2013 - Globe Flower
May 2013 - Early Purple Orchid
Apr 2013 - Peacock Butterfly
Mar 2013 - Oak Beauty
Feb 2013 - Coral Lungwort

Jan 2013 - Willow Jelly Button & Birch Jelly Button
Dec 2012 - Dice Lichen
Nov 2012 - Feathered Thorn
Oct 2012 - Dryad's Saddle
Sep 2012 - Tawny Grisette
Aug 2012 - Forest Bug
Jul 2012 - Grayling
Jun 2012 - Greater and Lesser Butterfly Orchids
May 2012 - Small Copper
Apr 2012 - Green Tiger Beetle
Mar 2012 - March Moth
Feb 2012 - Barren Strawberry
Jan 2012 - Brambling
Dec 2011 - Red Squirrel
Nov 2011 - Hazel Gloves
Oct 2011 - Small Tortoiseshell
Sep 2011 - Fly Agaric
Aug 2011 - Grass of Parnassus
Jul 2011 - Golden-ringed Dragonfly
Jun 2011 - 7-spot Ladybird
May 2011 - Green Hairstreak
Apr 2011 - Townhall Clock

Mar 2011 - Frogspawn

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All photos and other content copyright Carl Farmer except where stated