The role of voucher specimens in validating faunistic and ecological research


The Scientific Method is based on the principle that results of studies should be repeatable and verifiable. Research methods are made repeatable through description of the procedures used; results and interpretation are verifiable through peer review; cited references identify sources of previous data, interpretation or comparison. However, all these components of a paper may be rendered useless if there is no way to verify the identity of the study organisms themselves. The value of too many publications is reduced by the subsequent realization that the species actually studied may not have been the species named in the paper.

Errors in specimen identification can enter a study in several ways:

  • Subsequent recognition of multiple species in a complex of closely related species, or changes in species limits.
  • Subsequent recognition of variation in traits of populations that affect morphology, ecology, behaviour or physiology.
  • Subsequent recognition of errors or omissions in keys or guides used for identification.
  • Misidentification of an organism by a trained researcher inexperienced in the systematics of that taxon (an occasional problem).
  • Misidentification of an organism by untrained or poorly trained "consultants" offering contract identifications (a frequent problem).

The above errors can be mitigated (or, at least, their impact reduced) by the deposition of properly prepared voucher specimens in recognized research collections, where they are maintained under long-term care and available for subsequent examination and verification.

Many previous authors (e.g., Sabrosky 1955, Francoeur 1976, Yoshimoto 1978, Lee et al. 1982, Knutson 1984, Danks et al. 1987, Kelleher 1988, Danks 1991, Wiggins et al. 1991, Huber 1998 and numerous other papers cited by those authors) have emphasized the importance of voucher specimens and provided examples of studies with results that were either negated or called into question due to a failure to deposit and document voucher specimens. Unfortunately, the existence of this voluminous literature and of the lessons contained therein have not led to adequate deposition of vouchers, as a quick perusal of the entomological literature will attest.

On the assumption that repeated warnings may eventually prove effective, this document reviews the nature, preparation and deposition of voucher specimens, as well as the benefits of observing recommended practices with regard to vouchers and the potential costs of not doing so.

Page updated on Feb 23, 2014