Date of Award

8-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Committee Chair/Advisor

J. Antonio Baeza

Committee Member

Michael Childress

Committee Member

Matthew Turnbull

Abstract

Anthropogenic stressors and climate change are contributing to the rapid deterioration of marine ecosystems and the important ecological services they provide to coastal communities; concomitantly, this allows infectious agents that cause disease to proliferate in marine environments. At the forefront of marine disease ecology are the impacts of pathogens and parasites on commercially and recreationally exploited decapod crustaceans, including the Caribbean spiny lobster Panulirus argus. While there are few pathogens and parasites known to infect P. argus, emerging threats such as the nemertean micro-egg predator Carcinonemertes conanobrieni pose new, unexposed problems across its Greater Caribbean distribution. Beyond its current distribution in host populations and its sole infestation site of egg-bearing female brood clutches, there is limited knowledge that exists for this host-egg predator system. Therefore, I investigated the effect of C. conanobrieni on egg-bearing female P. argus reproduction and active parental care behaviors. In my second chapter, spiny lobsters were used to formally test if C. conanobrieni has an effect on reproductive performance (fecundity, reproductive output, embryo mortality). In my third chapter, P. argus with C. conanobrieni were used in experimental assays to determine if lobsters use active parental care as behavioral mitigation to limit the negative effects of infestation on host broods. To achieve my objectives, I collected female lobsters across the Florida Keys reef tract for two summer field seasons (2022 and 2023). Across both years and all coral reef sites, my collected females were infested with one or more stages of C. conanobrieni (100% prevalence). Declines in female lobster reproductive performance were attributable to C. conanobrieni based on my findings. I found that the life history of this egg predator aligns closely with the cycle of P. argus embryo development. During my investigation into the effect of C. conanobrieni on P. argus active parental care, there was limited evidence to suggest that this nemertean had a significant effect on these behaviors. Additionally, I found no evidence that P. argus are actively sensing C. conanobrieni when this nemertean is infesting their brood masses. As a whole, I have defined the costs associated with C. conanobrieni and explored putative behavioral adaptations the host may use in the face of brood infestation.

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