Laura Chu - Invasions Ecology Lab  

University of Colorado, Boulder, CO

                                           

 

Abiotic Factors Controlling Populations of the Introduced Parasite: Loxothylacus panopei , in the white fingered mudcrab, Rithropanopeus harrisii , effects of temperature and salinity on host survivorship

Project description

Although much attention has been devoted to the problems caused by invasive species and possible use of their parasites as biological control agents, limited work has been done on the effects of introduced marine parasites on native populations of host organisms. The rhizocephalan barnacle Loxothylacus panopaei is a good example of a non-native species that parasites native mudcrabs, Rithropanopeus harrisii and Eurypanopeus depressus , in the Chesapeake Bay. Introduced to the Chesapeake Bay from the Gulf of Mexico coast in the 1960s L. panopaei is a parasitic castrator which takes over the endocrine system of the host and causes the crab to cultivate the parasite instead of its own egg mass.

Little is known about factors which control L. panopaei's population, and studies have shown highly variable spatial prevalence in the population. Though previous literature suggests that R. harrisii larvae may have low tolerance of low salinities, little research has focused on how the parasites affect host survivorship at different salinities and temperatures. This study will compare how varying salinities and temperatures affect the survival of both parasitized and non-parasitized R. harrisii .

The outcome of the temperature and salinity tolerance trials suggest that temperature, salinity and parasitism all have significant effects on host survivorship, with a significant interaction between temperature and parasitism for R. harrisii . These results demonstrate that at high temperatures and low salinities, conditions consistent with summer 2003 bay conditions, that parasitism has a significant effect on host survivorship. Therefore, this may help explain the recent decline in parasite prevalence in the Chesapeake Bay.  

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