Caterpillars

If you should go down to the woods today and discover a caterpillar or two in your hair or on your clothing don’t worry, it’s perfectly normal for this time of year.

With the rising temperatures of late spring providing a catalyst for growth, the deciduous woodlands of the British Isles increasingly act as a larder for thousands of hidden creatures.

For many of us who enjoy the commons, this situation was recently highlighted by the large numbers of caterpillars that could be seen suspended from their silky life-lines above the commons many woodland tracks.

Among others, one of the most prolific caterpillars to be seen throughout the commons predominantly Oak woodlands has been the green oak tortrix (Tortrix viridana).

Easily identified, the green oak tortrix caterpillar is entirely green in colour and rarely exceeds 12mm in length. Reaching maturity the moth also remains completely green with a wingspan of approximately 20mm.

Coinciding with the initial burst of leaf development, the caterpillars are active as soon as the leaves unfold and steadily feed until the maturing leaves fill with tannin and become unpalatable for the caterpillars consumption. While the damage to leaves is sometimes striking, the trees will survive and no permanent injury is sustained.

For those of you who prefer a little less intimate contact with our woodland inhabitants, it may come as good news that there is only one brood of these caterpillars each year and they are extremely high on the food list for many of our favourite woodland birds.