A host-endoparasite network of Neotropical marine fish: are there organizational patterns?

Abstract

Properties of ecological networks facilitate the understanding of interaction patterns in host-parasite systems as well as the importance of each species in the interaction structure of a community. The present study evaluates the network structure, functional role of all species and patterns of parasite co-occurrence in a host-parasite network to determine the organization level of a host-parasite system consisting of 170 taxa of gastrointestinal metazoans of 39 marine fish species on the coast of Brazil. The network proved to be nested and modular, with a low degree of connectance. Host-parasite interactions were influenced by host phylogeny. Randomness in parasite co-occurrence was observed in most modules and component communities, although species segregation patterns were also observed. The low degree of connectance in the network may be the cause of properties such as nestedness and modularity, which indicate the presence of a high number of peripheral species. Segregation patterns among parasite species in modules underscore the role of host specificity. Knowledge of ecological networks allows detection of keystone species for the maintenance of biodiversity and the conduction of further studies on the stability of networks in relation to frequent environmental changes.

Developmental Stage of Parasites Influences the Structure of Fish-Parasite Networks

“…Specialized host-parasite networks tend to be characterized by a low connectance (i.e., the number of interactions observed relative to the potential number of interactions in the network [18]); thus, these networks are expected to present a more modular structure than networks dominated by generalists [5], [6], [8]. A modular structure is characterized by groups of species that interact more with one another than with other species in the same network, thereby forming modules or compartments.…”

“…A modular structure is characterized by groups of species that interact more with one another than with other species in the same network, thereby forming modules or compartments. There is evidence that the processes that create interaction patterns in ecological networks (e.g., phylogeny, coevolution, functional diversity and habitat structure) tend to be stronger within modules [6]–[8], [19], [20], and each species in a network has its own interaction pattern. In modular networks, these patterns characterize the functional role of species, i.e., how its interactions are distributed within the module to which it belongs and with respect to other modules [20]–[22].…”

Is the community of fish gill parasites structured in a Neotropical floodplain?

“…The main factors structuring the parasite communities of the Upper Paraná River Floodplain are acting more intensely among subsystems, at regional level, than inside each subsystem. In a study on metazoan ectoparasites of marine fish little evidence of non-randomized interactions of their component communities was found (Gotelli and Rohde 2002); this pattern was also observed in endoparasites of marine fish by Bellay et al (2011). The segregation between parasite infracommunities of the Unauthenticated Download Date | 5/10/18 6:17 AM Paraná and Baia Subsystems, of both host sexes, was directly affected by the local habitat of the host and its development stage, which reflects also possible ecological differences between young and adult S. marginatus.…”

“…Co-occurrence, nestedness and intra/interspecific spatial aggregation of parasites have pointed out to great variability in community structure, showing a gradient from non-random to random communities (Guégan and Hugueny 1994;Poulin 1996;Morand et al 1999;Poulin and Guégan 2000;Gotelli and Rohde 2002;González and Poulin 2005;Krasnov et al 2006Krasnov et al , 2010Bellay et al 2011). Besides, positive interactions (e.g.…”

Parasite abundance and its determinants in fishes from Brazil: an eco-epidemiological approach

“…As part of the characteristic of aggregation inherent to parasitism, abundance can be considered a highly variable species attribute, which is dependent on various characteristics intrinsic to the biology of the parasite and host and to the environment (ARNEBERG et al, 1998;PAMPOULIE et al, 2004;POULIN, 2006;HUTSON et al, 2011). The variability in parasite abundance is important from an ecological point of view, as a potential regulator of parasite populations and as a creator of interactive spatial structures (PEDERSEN & FENTON, 2007;BELLAY et al, 2011BELLAY et al, , 2015, as well as from an epidemiological point of view, where the importance of parasite abundance in the spread of parasitic diseases is stressed (GALVANI, 2003). The best way to study patterns related to parasite abundance is by considering this quantitative parameter in the context of several host biological characteristics; therefore, databases that include hosts from the same locality to minimize geographical variations TIMI et al, 2010;HUTSON et al, 2011;CANTATORE & TIMI, 2015) are used to allow selection of a set of biotic characters common to the various species.…”