Parasite species coexistence and limiting similarity: a multiscale look at phylogenetic, functional and reproductive distances
| Authors | |
|---|---|
| Year of publication | 2005 |
| Type | Article in Periodical |
| Magazine / Source | Oecologia |
| MU Faculty or unit | |
| Citation | |
| Field | Ecology |
| Keywords | Assembly rules; niche conservatism; Dactylogyrus species; Morava river basin |
| Description | Factors controlling biodiversity have been the focus of numerous recent investigations; these include species interactions, speciation, environmental gradients and heterogeneity, with all of these operating differently at each observation scale. We used a null model to examine the influence of two forces shaping community structure of Dactylogyrus species parasitic on roach (Rutilus rutilus) gills: interspecific competition that might prevent the coexistence of the most similar species, and environmental filters that might result in the most similar species coexisting together. The study was carried out on two sets of fish from two different localities in the Morava river basin (Czech Republic) to evaluate the consistency of the results across host populations, and at three different scales of observation to test for the scale-dependence of assembly rules. In decreasing order, from largest to smallest, the three spatial scales investigated were the individual fish, the individual gill arch, and individual sections of each gill arch. The similarity between pairs of parasite species was measured using three different criteria: (1) phylogeny, (2) quantitative functional traits consisting of parasite size and morphometric measurements of the attachment organs sclerotized parts, and (3) qualitative attributes of reproductive organs. First, our study reveals a strong conservatism of ecological characters for the nine Dactylogyrus parasite species, in particular regarding the attributes of their copulatory organs. Second, our study did not find any limitation of similarity among coexisting Dactylogyrus species due to interspecific competition whatever the scale and the similarity measure considered. Conversely, our results support the niche filtering hypothesis preventing species too dissimilar from one another to co-occur. This process is particularly apparent at the scale of the fish individual and for functional traits associated with the hard parts of the parasites attachment organs. The Dactylogyrus species that occur on the same fish individuals tend to have similar values for the haptor dimensions, in both localities. Our study supports previous studies on monogenean parasite communities indicating a weak influence of competition as a structuring force, but it goes a step further by identifying environmental filtering as a key process shaping these communities. |
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