Which specimens from a museum collection will yield DNA barcodes? A time series study of spiders in alcohol

We report initial results from an ongoing effort to build a library of DNA barcode sequences for Dutch spiders and investigate the utility of museum collections as a source of specimens for barcoding spiders. Source material for the library comes from a combination of specimens freshly collected in the field specifically for this project and museum specimens collected in the past. For the museum specimens, we focus on 31 species that have been frequently collected over the past several decades. A series of progressively older specimens representing these 31 species were selected for DNA barcoding. Based on the pattern of sequencing successes and failures, we find that smaller-bodied species expire before larger-bodied species as tissue sources for single-PCR standard DNA barcoding. Body size and age of oldest successful DNA barcode are significantly correlated after factoring out phylogenetic effects using independent contrasts analysis. We found some evidence that extracted DNA concentration is correlated with body size and inversely correlated with time since collection, but these relationships are neither strong nor consistent. DNA was extracted from all specimens using standard destructive techniques involving the removal and grinding of tissue. A subset of specimens was selected to evaluate nondestructive extraction. Nondestructive extractions significantly extended the DNA barcoding shelf life of museum specimens, especially small-bodied species, and yielded higher DNA concentrations compared to destructive extractions. All primary data are publically available through a Dryad archive and the Barcode of Life database.

Spider hosts (Arachnida, Araneae) and wasp parasitoids (Insecta, Hymenoptera, Ichneumonidae, Ephialtini) matched using DNA barcodes

The study of parasitoids and their hosts suffers from a lack of reliable taxonomic data. We use a combination of morphological characters and DNA sequences to produce taxonomic determinations that can be verified with reference to specimens in an accessible collection and DNA barcode sequences posted to the Barcode of Life database (BOLD). We demonstrate that DNA can be successfully extracted from consumed host spiders and the shed pupal case of a wasp using non-destructive methods. We found Acrodactylaquadrisculpta to be a parasitoid of Tetragnathamontana; Zatypotapercontatoria and Zatypotabohemani both are parasitoids of Neottiurabimaculata. Zatypotaanomala is a parasitoid of an as yet unidentified host in the family Dictynidae, but the host species may be possible to identify in the future as the library of reference sequences on BOLD continues to grow. The study of parasitoids and their hosts traditionally requires specialized knowledge and techniques, and accumulating data is a slow process. DNA barcoding could allow more professional and amateur naturalists to contribute data to this field of study. A publication venue dedicated to aggregating datasets of all sizes online is well suited to this model of distributed science.

New species in the Old World: Europe as a frontier in biodiversity exploration, a test bed for 21st century taxonomy

The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late.