Species of the Month - August 2017

Broom Moth caterpillar

Ceramica pisi (formerly Melanchra pisi)

Ceramica pisi   Ceramica pisi

Broom Moth caterpillars appear from mid July, when they are very small, to mid September, when they reach a size of 40-45 mm before pupating.  They are frequently seen in the daytime and feed on an extraordinary variety of plants.

Ceramica pisi on Erica tetralix   Ceramica pisi caterpillar - brown form

The caterpillar comes in two colour forms, green banded with a bluish-green head, and brown-banded with a pinkish-brown head.  This does not seem age-related, and I imagine that each caterpillar keeps the same colouring through all its moults.  It would be interesting to know if there is any correlation between colouring and food-plant.  The yellow stripes are common to both colour forms.

Ceramica pisi   Ceramica pisi

Cross-leaved Heath (Erica tetralix) is a popular food-plant.  Other plants we have recorded it on include Heather, Purple Moor Grass, Sitka Spruce, Bracken, Deergrass, Dwarf Birch, Yellow Saxifrage, Devilsbit Scabious, Bog Myrtle, Soft Downy Rose, Jointed Rush, Bramble and Grass of Parnassus.  It was not seen actually feeding on the plant on each occasion, but on several of them it was, and the books list many other plants that it feeds on.  So they're never likely to go hungry.  Unless of course different genetic strains are restricted to different plants.

Ceramica pisi

This one was found on gravel by the shore of Loch Tralaig, perhaps looking for a pupation site, as it was quite large and late in the year.  They form a cocoon within the soil and spend the winter inside it as a pupa, emerging as an adult moth from late May onwards.

Ceramica pisi

Broom Moth caterpillars are most often seen in open country such as heathland and moorland.  They are not likely to be confused with any other species occuring at the same time of year.  They have just 4 fairly broad bright yellow stripes, and 3 even broader green or brown stripes.  Most other species with longitudinal stripes have some of the stripes very narrow.


Please send in your Broom Moth caterpillar 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 caterpillar, please send a photo to sightings@lnhg.org.uk, or put one on the LNHG Facebook page.

Date of sighting 
Grid reference 
Green or Brown form?  
On what plant?  
Seen eating plant?  
Name of finder 
Your name (if different) 
Email (not needed if I already know it!) 
Any other details, e.g numbers, habitat,


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
LNHG Biological Records Manager


Note you can still send in records for past species of the month.  Here are the previous August species:

Aug 2016 - Black Darter
Aug 2014 - Pale Butterwort
Aug 2013 - Vapourer Moth
Aug 2012 - Forest Bug
Aug 2011 - Grass of Parnassus

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This project is supported by Scottish Natural Heritage

All photos and other content copyright Carl Farmer except where stated.  1st, 2nd, 6th and 8th photos are Jan Hamilton.  Mouse over photos to see credits.