Toxins and stomach contents of Humbolt squids

Heather presented the results from the barcoding of squid stomach contents at the CSEE conference in Quebec city today.

A Tale of Two Caterpillars

These two caterpillars are representatives of groups which turned out to be species complexes. The Ailanthus webworm moth discovery has been written about in a paper which has been accepted by the journal ZooKeys. The Andromeda satyr discovery has been covered by Janzen et al. 2009 (MOL ECOL RES) and in a new paper in review at ZooTaxa. Both groups are the subject of a talk I presented recently at the College of Biological Sciences (University of Guelph) Graduate Student Symposium and I will be presenting again at the Canadian Society of Zoologists Meeting in Vancouver, BC in a week.

Assigning unknowns to higher taxa using DNA barcodes: A case study in Sphingidae

When a specimen belongs to a species not yet represented in a DNA barcode reference library, there is considerable disagreement in the literature over the effectiveness of using sequence comparisons to accurately assign the query to a higher-taxon. Library species richness has been proposed as a critical factor affecting the accuracy of such assignments, but was never thoroughly investigated.

We explored the accuracy of assignments to genus, tribe and subfamily of 118 query species with five different assignment criteria, one distance-based and four tree-based. These Costa Rican species belong to Sphingidae; a family for which there is an almost complete DNA barcode reference library. An automated procedure was used to simulate different levels of species richness (10 to 100% of the available species) in reference libraries, and to record assignments (positive or ambiguous) and their accuracy (true or false based on current classification) under the five criteria.

Using a liberal tree-based criterion, an average of 80% of queries were accurately assigned a genus name with libraries containing 20% of available species, while 87% were accurately assigned a genus name with a library containing all available species. The liberal tree-based criterion assigned an average of 74% of queries accurately to tribes and an average of 90% accurately to subfamilies, across all libraries. The results suggest that the species richness of the reference library had only a weak effect on assignment accuracy, whereas which assignment criterion was used had a strong effect. Additional parameters in the tree-based criteria, such as exclusivity of taxa, decreased the number of false positive assignments, but also increased the number of false ambiguous assignments. Our findings suggest that barcode reference libraries can be useful for higher-taxon assignments long before the libraries achieve complete species richness.

Rapidly improving Linnaean taxonomy through DNA barcoding combined with online biodiversity tools (scratchpads): two case studies using caterpillars

Taxonomy is undergoing a revolution. New techniques like “DNA barcoding” are providing better understanding of species boundaries while online tools such as “Scratchpads” are helping connect this information with classical Linnaean taxonomy and rapidly disseminate findings to users. I present two case studies to demonstrate this revolution, one a butterfly, one a moth, both common species, both hiding under incorrect Linnaean names.
Extensive inventory of Area de Conservacion Guanacaste (ACG), Costa Rica, revealed evidence that butterflies inventoried as Taygetis andromeda for 25 years, belonged to a species complex. Further investigations revealed two species diagnosable by DNA barcodes and wing patterns, however, the name T. andromeda, could not be correctly applied to either species (http://taygetis.myspecies.info).
The ailanthus webworm moth, a conspicuous member of eastern North American micromoth assemblages, is commonly recorded as Atteva punctella. We discovered that webworm moths were assigned different names in our inventories – A. ergatica in ACG and A. punctella in North America -- but had identical DNA barcodes. Further investigations revealed two sympatric species diagnosable by DNA barcodes and wing patterns, however, neither name could be correctly applied to either species (http://atteva.myspecies.info).