Mines on Hybrid Black Poplar

More of these Ectoedemia mines have been found - this time in Norfolk by Andy Musgrove.

Tips on rearing miners such as this are given by John Langmaid who says:

'Maitland Emmet's recommended way of breeding Ectoedemia species is to put some earth into a flower pot, cover it with some sphagnum and then lay the leaves on top. Cover the whole thing with cling-film till the larvae have left the mines and then remove the leaves. Semi-sink the flower pot in the garden for the winter, cover with muslin or nylon and cover half the pot with polythene to reduce the amount of rain getting into the pot. Remember to put some sort of label or colour-coded daub onto the pot and have a notebook saying what the leaves are and where and when collected. It is very easy to forget which pot contains what!'
 

 Image:© Andy Musgrove

Paul Sokoloff has his theory for Green Islands:

'You can artificially induce green islands by applying synthetic plant hormones, fungal and yeast extracts to a leaf surface before the abscision layer forms, but I am not convinced that the presence of the larva mimics these effects (whether mediated by cytokinins or other  substances). One strange observation is that green islands develop even when the larva dies in an early instar.

My theory is that the plant is responding to "invasion" by a foreign organism - the larva- by "isolating" the part of the leaf containing the offending organism. Similar reactions can be seen in response to some bacterial and fungal pathogens, and some rust and mildew infections show green islands around the site of initial infection, and these persist against a background of chlorotic and senescent tissue.

The easy explanation is that this reaction blocks the leaf veins serving the area containing the larva (brilliantly illustrated if you look at the green islands of Ectoedemia argyropeza, but maybe less convincingly with others!!). The "blockage" in effect prevents the leaf from dying in the prescribed manner at a time when natural senescence beginning.'

Image:© Ian Thirlwell