Weekly Wildlife

This week we will be focusing on a group of species that have a truly fascinating life cycle…

The leafminers! Species that literally live inside a leaf. They are absolutely crazy.

They are a tiny little larvae (basically like a caterpillar) that spend their days eating the tissue inside a leaf. All in a bid to one day break out and turn into something a bit more impressive.

A leafminer in bramble, possibly Stigmella aurella. By Indy Kiemel Greene

Some species start off eating at the central vein on the leaf and slowly work their way zigzaging across the leaf getting nearer and nearer to the end (like Stigmella titryella, which likes beech). But as you can see in the picture above (showing Sitgmella aurealla, which likes bramble) they don’t always begin at the central vein so it does vary a little.

However, what always stays the same is the growth rate. They start off absolutely tiny but get bigger and bigger while munching on all that greeny goodness. 🌿

Leaf mines showing green islands of colour. Possibly Stigmella titryella. By Indy Kiemel Greene.

This only gets better people, because this is living proof of how truly crazy nature is. As you can see from the picture above, a part of this usually autumn orange-coloured beach leaf is still green. That’s because of a special bacterium that lives inside the leaf miner, which keeps a small strip of the leaf alive so the miner can continue to chomp on it during the autumn. This incredible relationship between the leaf miner and the bacteria is called a symbiotic relationship, which basically means both species can live side by side and even benefit from each other!

Once they have eaten right the way through their little green world around them, and they are almost twice the size from when they started, they are ready to leave the leaf! Because there are so many different species of leaf miner it can be really difficult to tell what they might pupate into. It could be a moth, a sawfly, a fly or even a beetle!

This is a very successful relationship between the leaf and the leaf miner as the leaf offers constant protection. All that is left is some very creative autumn squiggles (which are filled with leaf miner poo by the way! 😂🍁) to remember the fantastic season by.

Another mine of S. titryella, including a green island and exit hole at the end. By Lucy Hodson

Let us know what you see!

Remember to fill in the recent sightings book in the Visitor Centre. Leave your comments on our Facebook page and tag us in your Tweets on Twitter if you have any wildlife sightings or identification queries.