Friday, 30 March 2012

Grass ID guide needed

John Langmaid joined me for some fieldwork on Wednesday so, inevitably, having a grown-up present, I saw a couple of species I've not seen in the larval stage before. Spring is the best time to look for most Elachista species as larvae and as most of them rarely seem to come to light, this is the best way to record them.

The down side is that most Elachistas mine grasses, sedges or rushes! So, get your grasses book out or hire a tame botanist and have a look for:

This is Elachista humilis and the larval foodplant is Tufted Hair-grass Deschampsia cespitosa.

The Nationally Scarce Elachista obliquella produces a simlar mine on False Brome Brachypodium sylvaticum although the leaf is somewhat more twisted by the mine.

Wednesday, 28 March 2012

Nemapogon clematella

The larvae of Nemapogon clematella feed in fungus on a variety of trees and shrubs and can be detected by frass exuded from the fungus. This seems to be particularly easy to find on the small black fungus that occurs commonly on dead Hazel stems in overstood coppice. The moth can be bred easily.

Thursday, 15 March 2012

Norway Spruce

So why have I got a bag of Norway Spruce cones in my house? Well it isn't to spray them for christmas decorations!

The larvae of two species can be bred from Norway Spruce cones collected at this time of year; Assara terebrella and Cydia strobilella. Cones containing A. terebrella larvae are reported to be stunted and sometimes deformed but those with C. strobilella rarely show any external signs of being occupied so you just need to collect a random selection. Whilst A. terebrella comes to light, people don't often trap conifer plantations so it is under recorded. C. strobilella flies around the top of spruces in afternoon sunshine and is therefore rarely recorded as an adult.

Cones that are collected now should be kept in a container that allows circulation of air (to prevent mould) but you will obviously need to have some sort of netting over the container to prevent any emerging adults from disappearing before you notice them! I give the cones a light spray with water occasionally.