Method:
Using a slant board system, larvae of Tipulids will be presented to roots of Lolium and Trifolium in combination and in isolation.  Two extra larvae will be added (4 now in total) to each board at the start of the experimental measurement period.  Faeces will be collected every two days over the 3-day exposure and halved into a fresh and a freeze-dried sample.  The fresh sample will be sampled daily and stored in the cold room then passed to S.Grayston/E.Reid for microbial assessment (bacterial and PLFA).  The freeze-dried sample will go to J.Ross for analysis on the GC for alkane/alkene analysis. 

At the end of the 3-day exposure the plants will be harvested and measured for biomass characteristics. The root material will be separated into a) species, b) main axes and laterals c) nodules where appropriate, and then analysed for C/H/N and alkane/alkene assessments. Fresh and dried weights will be taken. (Shoots also). Numbers and weights of larvae will be measured.
The positions of the larvae each day will be located and an image recorded using a digital camcorder (Sony DSR-PDIP) to assess grazing behaviour and location in relation to root types.

Treatments:
On each board

2 clover plants (with nodules) 
2 grass plants 
1 clover plant plus 1 grass plant 

Replicated 8 times to provide sufficient faecal material. (Based on previous exp. data)

5*8 grass plants
5*8 clover plants 

Giving 24 slant boards 
Requiring 24 clover plants and 24 grass plants form P.Murray
Requiring 96 larvae i.e. 4 per board positioned equidistant from both plants (from field sampling in June at Sourhope)

The experiment will be performed in a growth room at MLURI under similar condition to the last exp. (currently clonal material are in the room but can be moved to cabinets for the duration of this experiment)
It is envisaged that it will run throughout June, to be harvested in the last week of June.
 

L.Dawson and S.Pratt