Spatial Dynamics of Two Host-Parasite Relationships on Intertidal Oyster Reefs

Troy D Alphin,Martin H Posey,Marc H Hanke

doi:10.3390/d13060260

Troy D Alphin, Martin H Posey + Show 1 more

Open Access

https://doi.org/10.3390/d13060260

Copy DOI

Abstract

Intertidal reefs comprised of the eastern oyster (Crassostrea virginica) have long experienced habitat loss, altering habitat patch characteristics of size and distance from edge to interior, potentially influencing spatial dynamics of host-parasite relationships. Using two parasitic relationships, one between eastern oyster host and parasitic oyster pea crab (Zaops ostreum) and the other between a xanthid crab (Eurypanopeus depressus) and a parasitic rhizocephalan barnacle (Loxothylacus panopaei), we examined how host-parasite population characteristics varied on intertidal reefs by season, reef size, and distance from edge to interior. Pea crab prevalence was more related to habitat characteristics rather than host density, as pea crab prevalence was the highest on large reefs and along edges, areas of comparatively lower oyster densities. Reef size did not influence densities of parasitized or non-parasitized xanthid crabs, but densities varied from edge to interior. Non-parasitized xanthids had significantly lower densities along the reef edge compared to more interior reef locations, while parasitized xanthid crabs had no significant edge to interior pattern. Organismal size had a varied relationship based upon habitat characteristics, as pea crab carapace width (CW) varied interactively with season and reef size, whereas CW of parasitized/non-parasitized xanthid crabs varied significantly between edge and interior locations. These results demonstrated that influential habitat characteristics, such as patch size and edge versus interior, are both highly species and host-parasite specific. Therefore, continued habitat alteration and fragmentation of critical marine habitats may further impact spatial dynamics of host-parasite relationships.

Highlights

The heterogeneity and spatial configuration of habitat patches within a landscape can strongly influence biodiversity at multiple scales [1,2,3,4]
Alterations to habitat patch size can have limited impacts on host-parasite dynamics within terrestrial habitats due to dilution effects, host sharing, and dynamic host population thresholds for parasites [23,24]
Variations in habitat patch size can structure the relative amount of edge to interior habitat and edge effects can be highly influential in host-parasite interactions

Summary

Introduction

The heterogeneity and spatial configuration of habitat patches within a landscape can strongly influence biodiversity at multiple scales [1,2,3,4]. Habitat patches within a landscape can become fragmented either through natural or anthropogenic forces, reducing patch size and altering edge to interior ratios [5,6]. The alteration of these habitat characteristics can impact species interactions, often due to altered intra-patch densities and distributions [1,7,8,9,10] and may be important for host–parasite relationships [11,12,13]. In a recent review, Peterson and Andres [30] highlighted how most parasites within coastal aquatic habitats are only given attention when they are problematic and the ecological implications, at varied hierarchal levels, are often ignored

Objectives

Methods

Results

Conclusion