testwedgwood: 2013

Wednesday 5 June 2013

a brush with death today... possibly

We met this today.

The Cinnibar Moth Caterpillar

Cinnibar moth young have a taste for bitter tasting chemicals that render them inedible to predators and also use extremely colorful markings as a way of warding off the hunters. They are all covered in short hairs that cause irritation

on contact with skin, and chemicals within the hairs can also lead to serious health problems in humans, though skin rashes are far more common. Nonetheless, problems such as atopic asthma, osteochondritis, renal failure, dermatitis and haemorrage have all been caused by these caterpillars in the past, so one needs to be very careful around them.

from http://www.environmentalgraffiti.com

Cinnabar moth

Tyria jacobaea

The Cinnabar moth always strikes me as looking rather sinister with its stark black satin wings and red markings. The hind wings are the same vivid red and show up well in flight. All of which seemingly alerts birds and other would be predators that these moths are toxic. There is only one annual generation, and they fly for three months from mid-May through to mid-August.

The only other black and red moths with which it might be confused are the Burnet moths but, that long red streak on the leading edge of the forewing is a sure identifying feature.

The equally easily recogniseable yellow and black banded caterpillars also flaunt their colours to warn birds that they are inedible.

The main foodplants of the caterpillars are ragwort and groundsel, both rich in alkaloid poisons. The larvae are immune to these toxins which are stored in their bodies and passed on through the pupa stage to the moth, making them the most poisonous moth species in Britain.

Since both adult and larvae have few predators, this should lead to huge larval populations but the caterpillars are so voracious that they tend to eat themselves out of a sustainable food supply. It is not uncommon to see patches of ragwort stripped bare (lower image) and caterpillars wandering around aimlessly looking for alternative sources. Therefore a large caterpillar population one year can lead to many not surviving to pupation due to a lack of sufficient food supply.

The larvae are feeding through the months of July to September and then pupate in a loose cocoon in leaf litter on the ground from September through the winter.

Since the poisons in ragwort are considered to be a danger to grazing animals, cinnabar caterpillars have been considered as a means of ragwort biological control.

from bugsandweeds.co.uk