Global drivers of parasitism in freshwater plankton communities

Abstract

Zooplankton and phytoplankton communities play host to a wide diversity of parasites, which have been found to play a significant role in a number of ecosystem processes, such as facilitating energy transfer and promoting species succession through altering interspecific competition. Yet we know little about the mechanisms that drive parasite dynamics in aquatic ecosystems. Recent mathematical models have shown how habitat can shape parasite dynamics through influencing the efficacy of parasite transmission; however, these predictions have yet to be tested at larger ecological scales. Here, we present a comparative analysis of parasitism in planktonic communities, assembling data from a range of host and parasite taxa, habitat types, and geographic regions. Our results suggest that the prominent depth-prevalence relationship observed in studies on Daphnia in temperate lakes of North America is applicable to a wide range of aquatic habitats, hosts, and parasites; however, differences in transmission strategies between parasites can lead to considerable variation in parasite dynamics. Observational studies which incorporate a diversity of habitat types will be important in uncovering the mechanisms which underlie this relationship. In particular, more experimental work on transmission stage survivability and infectivity in aquatic environments will be necessary before we can make accurate predictive models of parasite spread in these ecosystems. Additional Supporting Information may be found in the online version of this article *Correspondence: amanda.valois@otago.ac.nz 1707 LIMNOLOGY and OCEANOGRAPHY

Diversity and host specificity of monogenean gill parasites (Platyhelminthes) of cichlid fishes in the Bangweulu-Mweru ecoregion

“…Cichlidogyrus zambezensis was not found on the local O. mweruensis in Mweru-Luapula, of which a sufficient number of hosts were investigated. We propose that there is a geographic pattern to host specificity (Krasnov et al, 2004;Korallo-Vinarskaya et al, 2009) and host-parasite dynamics (Valois & Poulin, 2015) in species of Cichlidogyrus/ Scutogyrus, which implies that distribution and host specificity are not only taxon-bound but also determined by ecology and geography. However, a formal statistical analysis is in order to investigate this further.…”

Molecular evidence of host-parasite interactions between zooplankton and Syndiniales

“…Including parasites in ecological networks increases species richness and the number of food web links (Lafferty et al 2006). Parasites can further facilitate energy transfer and promote species succession through altering interspecific competition (Valois and Poulin 2015). Marine surveys targeting the protist diversity often observe novel uncultured marine alveolate groups, which include the parasitic dinoflagellates Syndiniales, as the most abundant sequences (Guillou et al 2008;Massana 2011;.…”

Hot and sick? Impacts of warming and a parasite on the dominant zooplankter of Lake Baikal

“…Host–parasite relationships in the plankton provide examples of such complex species interactions. Parasites of phytoplankton and zooplankton are common in lakes and oceans and can strongly affect the populations of parasitized species as well as ecosystem processes (Burns 1989; Ebert 2005; Duffy 2007; Ibelings et al 2011; Valois and Poulin 2015; Valois and Burns 2016). Most of the work on freshwater parasites of zooplankton has involved Daphnia species and their bacterial and fungal parasites in small lakes and ponds (e.g., Ebert 2005; Duffy 2007; Wolinska et al 2008; Hall et al 2010; Duffy and Hunsberger 2018).…”

“…While Daphnia often dominate zooplankton communities in small, warm, and productive lakes, copepods are more important members of the pelagic plankton in large and cold lakes as well as in the world's oceans (Gallienne and Robins 2001; Barbiero et al 2019; Moore et al 2019). Various parasites, including dinoflagellates, microsporidians, and oomycetes, affect copepods (Burns 1989; Miao and Nauwerck 1999; Valois and Poulin 2015), but much less is known about these host–parasite interactions. In particular, few studies have examined the potential effects of warming temperatures and other environmental stressors on parasitism in copepods.…”