Cryptic Species in a Food Web Figure 5. Neighbour-Joining tree of specimens from the parasitoid Scambus. (Ichneumonidae; Pimplinae) [i.e. a secondary parasitoid whose host records include both primary parasitoids and consumers] (determined morphologically). Tip labels morphological species|Sample ID|Host species|Barcode MOTU. Upon barcoding, the species split into 6 provisional species. Of these, 5 are trophic specialists, one appears to be a trophic specialist, while 4 are species specialists and two are species generalists. One of the provisional species appears to remain a trophic and species generalist. doi:10.1371/journal.pone.0014424.g005 appreciation for magnitude of importance for the Type II error (of accepting the same when they are separate). Consider the example of Glypta fumiferanae in Figure 6. Here, morphology suggests that all specimens belong to one species; the sequence data from three genes suggests that there are four species. Ecological differences of host species suggest there are three species. Finally, if we use the presence of complementary base pair changes (CBCs) to infer reproductive isolation (and the biological species concept) then the specimens currently named G. fumiferanae, are correctly considered to be two species. Prior to DNA evidence, there was no evidence to suggest different species (except for multiple hosts). Thus, Ho is that all individuals arise from one species, while H1 is that individuals from different hosts represent different species. In this scenario, the emphasis is on Type 1 error (incorrectly rejecting when it’s true). However, this discussion to date has not identified the importance of sampling (how many specimens are sufficient to detect the pattern) and what to do if the sampling is fixed (i.e. in the scenario of an after-the-fact analysis using museum specimens – sample size is fixed by the number of specimens deposited and there are no more). How many individuals does it take to ensure that the species is well sampled? Whatever number this is (ideally more PLoS ONE | www.plosone.org 8 July 2011 | Volume 6 | Issue 7 | e14424