Evol Ecol Res 20: 69-82 (2019)     Full PDF if your library subscribes.

Investigating the association between armour coverage and parasite infection in an estuarine population of stickleback

Meghan F. Maciejewski¹, Catherine A. Hernandez^2,3 and Daniel I. Bolnick^1,3

¹University of Connecticut, Storrs, Connecticut, USA, ²University of California at Berkeley, Berkeley, California, USA and ³University of Texas at Austin, Austin, Texas, USA

Correspondence: M.F. Maciejewski, Ecology and Evolutionary Biology, 75 N. Eagleville Road, University of Connecticut, Storrs, CT 06269, USA. email: meghan.maciejewski@uconn.edu

ABSTRACT

Background: When Threespine stickleback colonized fresh water, they repeatedly evolved reduced armour plating via changes in Eda allele frequency. This evolution is typically attributed to differential predation pressure between marine and freshwater environments. However, the chromosomal region containing Eda is associated with many other phenotypes, including schooling, antipredator behaviour, and immunity. Consequently, the evolution of armour plating may be driven by multiple selective pressures acting on Eda or linked genes.

Question: Is parasite infection associated with armour phenotype?

Hypothesis: Parasite load differs between stickleback armour plate morphs.

Organisms: An armour-polymorphic population of Threespine stickleback (Gasterosteus aculeatus), and their parasites.

Field site: In June 2009 and 2012, we sampled stickleback from a single human-made saltmarsh pool in the Campbell River Estuary on Vancouver Island.

Methods: We counted macroparasites on approximately 100 fish per year and counted lateral armour plates. We used generalized linear models to test for correlations between armour morph and parasite load.

Results: Most parasite species were not associated with armour. The gill parasite Thersitina was more abundant on more fully armoured fish in both years. The nematode Eustrongylides also exhibited a marginally significant positive trend. If parasitic infections reduce stickleback fitness, this positive covariance between armour and infection would accelerate the loss of armour plating in stickleback colonizing fresh water.

Keywords: Ectodysplasin (Eda), Gasterostereus aculeatus, lateral plates, pleiotropy, Threespine stickleback.

DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.

 

        © 2019 Meghan F. Maciejewski. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.