Food web data from 20 farms in the UK This data sets represents information on plant-herbivore-parasitoid interactions collected on 20 farms throughout 2005 and 2006. The farms were paired with each organic farm (A1-A10) being paired with a conventional farm (B1-B10) of similar size nearby (but without adjacent field boundaries). Plants and insects were sampled using transects in a range of habitat-types on each farm. More information about how we collected this data set can be found in Gibson et al. 2007 and Macfadyen et al. 2009. The data has been split into four files: 1. Plant_20farms_0506: contains just the plant information. The plant names and a measure of abundance of the plant on each farm for the two years of the study (Abun). 2. Plant_Herb_Int_20farms_0506: The interactions between plants and insect herbivores (Lepidoptera and Diptera). There is a measure of the frequency with which the interaction (Int) was recorded throughout the study, and a measure of herbivore abundance (tot) per farm (a sum of all interaction records for that species). For example on farm A1the herbivore Acronicta psi was recorded once on the plant Corylus avellana and once on the plant Prunus spinosa, so the abundance score was recorded as 2 for this herbivore species. Species that could not be identified at all have been removed. However some species were given a unique morphospecies identifier because we had some information about these specimens. ukL### corresponds to Lepidopterans and ukD### corresponds to Dipterans. 3. Herb_Para_Int_20farms_0506: The interaction between insect herbivores and parasitoids (Hymenoptera and Diptera). There is a measure of the frequency with which the interaction (Int) was recorded throughout the study, and a measure of parasitoid abundance (tot) per farm (a sum of all interaction records for that species). 4. Location_20farms: Contains the names of each farm (A1-A10 or B1-B10), the UK grid reference, and corresponding latitude and longitude. These correspond to the center of each farm or near the farm buildings. Published articles that used data collected from these 20 farms are: Gibson, R.H., Pearce, S., Morris, R.J., Symondson, W.O.C. & Memmott, J. (2007) Plant diversity and land use under organic and conventional agriculture: a whole-farm approach. Journal of Applied Ecology, 44, 792-803. Macfadyen, S., Gibson, R., Polaszek, A., Morris, R.J., Craze, P.G., Planque, R., Symondson, W.O.C. & Memmott, J. (2009) Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control? Ecology Letters, 12, 229-238. Macfadyen, S., Gibson, R., Raso, L., Sint, D., Traugott, M. & Memmott, J. (2009) Parasitoid control of aphids in organic and conventional farming systems. Agriculture Ecosystems & Environment, 133, 14-18. Macfadyen, S., Craze, P.G., Polaszek, A., van Achterberg, K. & Memmott, J. (2011) Parasitoid diversity reduces the variability in pest control services across time on farms. Proceedings of the Royal Society B Biological Sciences, 278, 3387-3394. Macfadyen, S., Gibson, R., Symondson, W.O.C. & Memmott, J. (2011) Landscape structure influences modularity patterns in farm food webs: consequences for pest control. Ecological Applications, 21, 516-524. For further information about these data sets please contact: Jane Memmott (Jane.Memmott@bristol.ac.uk) or Sarina Macfadyen (sarina.macfadyen@csiro.au)