Cryptic Species in a Food Web Figure 6. Species concepts and criteria as applied to one member of the SBW food web, Glypta fumiferanae. Evidence that this primary parasitoid (Ichneumonidae) is between 1 and 4 species is presented depending on which set of operational criteria one uses. doi:10.1371/journal.pone.0014424.g006 than 5 [60], 20 or more [61], or as high as several hundred [62]) in a retrospective analysis as described above we are unlikely to reach this number. Furthermore, one must also consider the ‘‘effect size’’ of the relationship being compared (nominally categorised as ‘small’ or ‘large’) – and what this may be in the context of confusing intraspecific morphological variation. If sample sizes are small, statistical power is low – especially if the confidence level is maintained at 0.05 – we maintain that researchers should consider optimizing statistical thresholds (e.g., compromise analysis). We must explicitly consider the selection of hypotheses as regards species testing. Specifically, within parasitoid communities, it may be beneficial to consider altering the default selection of the statistical hypothesis. If sample sizes are low, but specimens are known to arise from different hosts, the hypothesis ought to be that they are different species (if and until evidence is collected that unites them). A DNA barcode is an epistemological tool, an evaluation criterion for identification and can act as a catalyst for discovery. It is not an ontological truth that defines a species. Is DNA barcoding a ‘‘solution’’ to the ‘‘species problem’’; unequivocally no. Will it make future hypotheses regarding ‘‘who is who’’ (species membership) and then ‘‘who eats whom’’ more transparent and reproducible – unequivocally yes. Future These analyses are a further contribution to a new approach to food web ecology. Food web ecology has always had to deal with the demons of resolution and how these affect the search for universal properties. When taxa are resolved at a very coarse scale or in a fashion that is not transparent and testable – the data underlying this search becomes extremely questionable [19]. Our approach to food web ecology is resolvable in a pragmatic and repeatable fashion and makes strides towards a very practical application of moving towards easily identified food web units. In addition to extending the analyses presented here – we look forward to tightening now invisible connectences through the amplification of gene fragments from those parts of the collection that were not reared successfully (host fragments) – particularly in cases of hyperparasitoids where the intermediate host is unknown. Other approaches we will investigate in the future include the integration of molecular tools into new field collections where we will amplify the host species’ DNA from the gut-contents of the parasitoid – thereby both enabling the avoidance of the long times sometimes necessary for rearing completely to emergence – and potentially permitting one to map parasitoids to hosts even for those specimens arising from passive collections [63]. Further- more, it will be interesting in the future to consider food web PLoS ONE | www.plosone.org 9 July 2011 | Volume 6 | Issue 7 | e14424