It might be helpful for me to add, cereals were made up of 52% wheat, 37% barley and the rest were oats and maize. Mainly dominated by winter cereals.

Spiders and ground-beetles have usually a long life cycle, and they are negatively affected by tillage and/or by the absence of (winter or summer) refuges and/or long periods without available preys. Parasitoids are usually limitated by the absence of flowers producing nectar (adult diet) and secondly by the absence of (winter or summer) refuges. You should consider also the possibility of movement between adjoining fields. The risk is that your results are valid just for the local situation you are studying.

Some interesting papers on parasitoids of pests of wheat and other cereals:

http://www.agriculturejournals.cz/publicFiles/02539.pdf

Aelia acuminata parasitoid:

http://www.efflatounia.com/files/10%2007-14.pdf

http://www.landesmuseum.at/pdf_frei_remote/LBB_0042_2_1421-1435.pdf

It could also be  useful:

Encyclopedia of pests and natural enemies of field crops

http://www.hgca.com/media/524972/g62-encyclopaedia-of-pests-and-natural-enemies-in-field-crops.pdf

Dear Victoria,

To my point, you should not only consider management differences for elucidating such result. Climatic differences, living habits of different insects, intercrops, as well as soil features should be included into your accounts. For example, the intensity, height, surface roughness of winter wheat, and the arid cold waether are suitable for spiders, especially the red spiders. Good luck!

Ping

You mention maize among cereals and you add there were mostly winter cereals around your fields. Was the maize of the previous year (maize for grain kept dry inn fields during autumn) or maize of the next spring? In other words what was the differencesin phenology within the crop mosaic? Maize from the previous year may be a source and maize from springg a sink. This is conceptually discussed in Vasseur, C., A. Joannon, S. Aviron, F. Burel, J.-M. Meynard & J. Baudry (2013). "The cropping systems mosaic: How does the hidden heterogeneity of agricultural landscapes drive arthropod populations?" Agriculture, Ecosystems, Environment 166(0): 3-14.

Anyhow, this question of the importance of the composition and spatial patterns of the crop mosaic need further investigations

best

jacques

Thank you for your insight Jacques. The maize was of the previous year. I like your thinking with the differences in phenology. The paper you mention is one of my favourites as it happens, very interesting research. 

Many thanks,

Victoria