Equal rights for parasites: Windsor 1995, revisited after ecological parasitology has come of age

Abstract

Lack of data to properly model key biological characteristics like abundance or distribution, seriously hinder comprehension of biodiversity patterns and their drivers — even for historically well-studied and charismatic organisms. Knowledge shortfalls are more extreme in the case of parasites, which are mostly part of the “hidden biodiversity” and generally have a bad reputation. However, being an extremely large portion of biodiversity and a fundamental part of ecosystems, failure to consider parasites is itself an information shortfall for conservation, and can result in important consequences not only for planning strategies to conserve biological diversity, but also to understand fully the patterns and processes that shape ecosystems. Parasites exhibit a marked duality: while some species are pathogenic and do compromise their host's survival (and human interests), the majority exert apparently negligible negative effects on their hosts and could be considered non-pathogenic; indeed, parasites are beneficial as they provide important ecosystemic functions and services. Using a comprehensive dataset of fish host-helminth parasites in Mexico as a case study, we review knowledge shortfalls relating to parasites, exemplifying their impacts — both positive and negative. A holistic appreciation of parasites should consider both their (many) beneficial and (a few, proven) detrimental impacts, something which could be operationally incorporated into conservation assessments and strategies (e.g., IUCN Green and Red Lists, respectively). Outreach and education are key to modify negative perceptions towards parasites, and to induce recognition of their importance for ecosystemic function and structure.