The role of voucher specimens in validating faunistic and ecological research

Deposition of vouchers permits correction of published errors

Sperling et al. (1994) published a molecular analysis of three forensically important species of Calliphoridae (Diptera) used in determining postmortem intervals. The authors noted the deposition of voucher specimens of adult flies, in addition to vouchered sequence data. Subsequently, Wells and Sperling (2000) re-examined the original voucher specimens and determined that specimens identified as Phormia regina in Sperling et al. (1994) were, in fact, Protophormia terraenovae. Based on the available vouchers, Wells and Sperling (2000) published a correction to the original publication.

Ruedas et al. (2000) cited a number of molecular studies in which the results were suspect, despite the deposition of DNA sequence data in electronic databases. Subsequent examination of documented voucher specimens from which DNA was extracted revealed misidentification of some species and incomplete identification of other species now known to constitute complexes of sibling species.

Baumann (1974) examined old museum specimens of Alloperla imbecilla (Say), a putatively widespread eastern North American species of Plecoptera, and found that the species regarded by most authors as A. imbecilla was in fact two species: A. imbecilla, largely restricted to the Ohio River drainage; and A. atlantica Baumann, widespread in eastern North America. Most voucher specimens of “A. imbecilla” deposited by previous authors were actually specimens of A. atlantica.

Ellison (1991) published an ecological study of case-bearing moths (Lepidoptera: Coleophoridae) in New England. Apparent inconsistencies in the reported phenology and host plant of one of the species prompted J.-F. Landry, a specialist in coleophorid systematics, to re-examine the vouchers deposited by Ellison. Because the specimens were available, Landry was able to correct the identification of the coleophorid and resolve the apparent ecological and behavioural differences in the larvae (J.-F. Landry, pers. comm.)

The above is only a small subset of the available examples. In the field of biological control alone, there is a large body of literature (Sabrosky 1955, Danks 1988, Huber 1998, and many papers cited in those publications) listing case studies of failed attempts, primarily resulting from misidentified pest species or misidentified natural enemies. Some such errors have been traced, confirmed and corrected in cases where vouchers were deposited.

Page updated on Feb 23, 2014