Eichler's rule
{{Short description|Coevolutionary principle regerding parasites and hosts}}
Eichler's rule is one of several coevolutionary rules which states that parasites tend to be highly specific to their hosts, and thus it seems reasonable to expect a positive co-variation between the taxonomic richness of hosts and that of their parasites.
History
A rule to describe the taxonomic relationship between parasites and their hosts was developed in 1942 by Wolfdietrich Eichler (1912–1994), a German authority in zoology and parasitology who served as a professor of parasitology at Leipzig University.{{Cite journal |last=Eichler |first=Wolfdietrich |date=1966 |title=Two New Evolutionary Terms for Speciation in Parasitic Animals |url=https://www.jstor.org/stable/2411393 |journal=Systematic Zoology |volume=15 |issue=3 |pages=216–218 |doi=10.2307/2411393 |jstor=2411393 |pmid=5924358 |issn=0039-7989}}{{cite journal |last=Eichler |first=W. |year=1942 |title=Die Entfaltungsregel und andere Gesetzmäßigkeiten in den parasitogenetischen Beziehungen der Mallophagen und anderer ständiger Parasiten zu ihren Wirten |url=http://phthiraptera.info/sites/phthiraptera.info/files/39548.pdf |journal=Zoologischer Anzeiger |volume=136 |pages=77–83 |access-date=2012-12-28 |archive-date=2017-03-04 |archive-url=https://web.archive.org/web/20170304041639/http://phthiraptera.info/sites/phthiraptera.info/files/39548.pdf |url-status=dead}} The principle was later dubbed 'Eichler's rule'. It is one of the first three coevolutionary rules, created in opposition to Heinrich Fahrenholz's research into coevolution.{{Cite journal |last=Klassen |first=G. J. |title=Coevolution: a history of the macroevolutionary approach to studying host-parasite associations |url=https://pubmed.ncbi.nlm.nih.gov/1635016/ |journal=The Journal of Parasitology |year=1992 |volume=78 |issue=4 |pages=573–587 |doi=10.2307/3283532 |jstor=3283532 |pmid=1635016}}
Research
As a part of their 2012 study, Vas and his co-authors tested Eichler's rule, and concluded that exceptionally strong correlational evidence supports the positive co-variation between the species richness of avian and mammalian families and the generic richness of their parasitic lice.{{cite journal|last=Vas|first=Z.|author2=Csorba, G.|author3=Rozsa, L.|year=2012|title=Evolutionary co-variation of host and parasite diversity – the first test of Eichler's rule using parasitic lice (Insecta: Phthiraptera)|url=http://www.zoologia.hu/list/Vas_Csorba_Rozsa_2012.pdf|journal=Parasitology Research|volume=111|issue=1|pages=393–401|doi=10.1007/s00436-012-2850-9|pmid=22350674|s2cid=14923342}}
In volume nine of Advances in Parasitology, parasitologist W. Grant Inglis posited that, when studying the co-variation between the taxonomic richness of hosts and parasites, it is easier to study parasites than free-living host organisms.{{Cite book|url=https://books.google.com/books?id=yovuRdSJmWwC&q=eichler%27s+rule&pg=PA201|title=Advances in Parasitology|date=1971-03-31|publisher=Academic Press|isbn=978-0-08-058055-5|language=en}}
References
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{{Biological rules}}