Can parasites be indicators of free-living diversity? Relationships between species richness and the abundance of larval trematodes and of local benthos and fishes

Abstract

Measuring biodiversity is difficult. This has led to efforts to seek taxa whose species richness correlates with the species richness of other taxa. Such indicator taxa could then reduce the time and cost of assessing the biodiversity of the more extensive community. The search for species richness correlations has yielded mixed results, however. This may be primarily because of the lack of functional relationships between the taxa studied. Trematode parasites are highly promising bioindicators. Diverse assemblages of larval trematode parasites are easily sampled in intermediate host snails. Through their life cycles these parasites are functionally coupled with the surrounding free-living diversity of vertebrate and invertebrate animals. It has been shown that larval trematodes in snails correlate positively with bird diversity and abundance. Here, we explore whether trematodes also correlate with standard measures of fishes, and large and small benthos, for 32 sites in three wetlands. We found associations between trematodes and benthic communities that were not consistent across wetlands. The associations were, however, consistently positive for large benthic species richness and density. Some of the contrasting associations between trematode and benthos may be explained by negative associations between large and small benthos. We found no associations with fish communities (probably because of the inadequacy of standard "snapshot" sampling methods for highly mobile fishes). The results support further exploration of trematodes as bioindicators of diversity and abundance of animal communities.

Parasite manipulation of brain monoamines in California killifish ( Fundulus parvipinnis ) by the trematode Euhaplorchis californiensis

“…Infected populations occur where the California horn snail, Cerithidea californica, is also present in the estuary. The trematode E. californiensis, one of the most abundant trematode parasites in these habitats (Martin 1955;Hechinger et al 2007), uses three hosts in its life cycle: horn snails (C. californica); killifish; and several species of piscivorous birds (Martin 1950). Larval E. californiensis cercariae swim out of their first intermediate snail host, penetrate the skin of F. parvipinnis and migrate to the brain, presumably following blood vessels or nerve tracts (McNeff 1978;Hendrickson 1979;Haas et al 2007).…”

Parasite species richness and intensity of interspecific interactions increase with latitude in two wide‐ranging hosts

“…Because the diversity and abundance of these additional hosts correlates with species richness and prevalence of trematodes infecting horn snails at small spatial scales (Smith 2001, Hechinger and Lafferty 2005, Hechinger et al 2007), these final and second intermediate hosts might drive some of the observed diversity patterns. However, both bird and second intermediate host richness are likely greater in the tropics, considering general diversity patterns in the ocean (Hillebrand 2004, Roy andWitman 2009).…”

“…2; Appendix A). We treated sites as independent samples for our analyses, because these snails have very low mobility, and trematode diversity varies over small spatial scales (Hechinger and Lafferty 2005, Torchin et al 2005, Hechinger et al 2007). We targeted the largest snails from each site for dissections, as these are generally older and have a higher probability of being infected with parasites (e.g., Kuris 1990, Sousa 1993, Torchin et al 2005.…”

“…Diverse communities of trematode parasites infect and castrate the Pacific horn snail, Cerithideopsis californica (¼Cerithidea californica, see Reid and Claremont 2014) and the Atlantic horn snail, Cerithideopsis pliculosa (¼Cerithidea pliculosa) (Martin 1972, Wardle 1974, McNeff 1978, Hechinger et al 2007). These snails are sister species that diverged from one another following the formation of the Isthmus of Panama (Miura et al 2010).…”

Two ‘new’ renicolid trematodes (Trematoda: Digenea: Renicolidae) from the California horn snail, Cerithidea californica (Haldeman, 1840) (Gastropoda: Potamididae)

“…For instance, in an unpublished thesis, Hunter (1942), also working in southern California, included what appear to be two renicolid xiphidiocercariae. More recently, ecological and evolutionary research involving this trematode guild has included what was considered to be a single, undescribed renicolid xiphidiocercaria (for example, "REN2" in Sousa (1993), and "Large Xiphidiocercaria" in Hechinger et al (2007)). A few years ago, while carefully examining the morphology of this "Large Xiphidiocercaria," it became clear that it represented not one, but two species.…”