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Hay, Mark E.

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Start date: 2000 × End date: 2010 × Author: Kicklighter, Cynthia Ellen ×

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Now showing 1 - 3 of 3
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    Integrating prey defensive traits: contrasts of marine worms from temperate and tropical habitats
    (Georgia Institute of Technology, 2006-05) Kicklighter, Cynthia Ellen ; Hay, Mark E.
    Marine worms are speciose and numerically prominent members of marine communities where they play critical roles in trophic interactions and in affecting biogeochemical cycles. Despite the ecological importance of this group, little is known about their palatability to, and defenses against, consumers. In addition, most studies of prey defenses in marine organisms have focused on overt, sessile species: few studies have investigated more mobile and behaviorally complex species that could potentially be integrating predator deterrents with refuge use and other escape behaviors. To increase our understanding of consequences of defensive traits among mobile marine prey, we surveyed the palatability of 81 species of worms from the Caribbean and warm-temperate western Atlantic. Thirty-seven percent of the species were unpalatable. Worms with differentially exposed body portions commonly defended exposed feeding appendages with chemical or structural deterrents, while palatable and undefended bodies remained sheltered within structural refuges. Unpalatable worms tended to be brightly colored and sedentary, exposed to epibenthic predators, and to occupy hard substrates. Palatable worms tended to be drab, to live in structural refuges from consumers, to be mobile, and to inhabit unconsolidated sediments. Overall, taxonomy (Sabellidae and Terebellidae) and color were the traits most strongly associated with unpalatability. Unpalatable species appeared less constrained by predation and freer to forage for long periods on higher quality surface sediments or on other invertebrates at the sediment surface (thus, potentially influencing the distribution and abundance of other species). In contrast, palatable species appeared more constrained by predation risk. They fed on lower quality subsurface sediments and foraged at times or locations where consumers were less active. These ecological patterns may be generalized to other soft-bodied prey, such as caterpillars, which show similar trends regarding palatability and lifestyle.
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    Chemical defense of hydrothermal vent and hydrocarbon seep organisms: a preliminary assessment using shallow-water consumers
    (Georgia Institute of Technology, 2004-07-14) Kicklighter, Cynthia Ellen ; Fisher, C. R. ; Hay, Mark E.
    Organisms at deep-sea hydrothermal vent or cold-seep communities represent oases of prey in an otherwise prey-poor desert. Why deep-sea consumers that remove other dense food patches do not rapidly remove the high biomass of prey from these communities is unclear. One potential explanation is that hydrogen sulfide, or other metabolites, in these chemoautotrophic prey could be serving as chemical defenses against generalist consumers; however, neither the palatability of these prey nor their potential defenses have been assessed. We fed tissues from 10 species of deep-sea polychaetes and 2 species of bivalves to shallow-water fishes Fundulus heteroclitus and Leiostomus xanthurus or crabs Callinectes similis and Pachygrapsus crassipes to assess their palatability to generalist consumers. Tissues from 4 polychaetes (Archinome rosacea, Lamellibrachia luymesi, Riftia pachyptila, and Seepiophila jonesi) and 1 bivalve (Calyptogena magnifica) were rejected by some consumers. Blood, which can be sulfide-rich, from R. pachyptila did not deter feeding. Sharp setae deterred feeding on the polychaete A. rosacea, while the other unpalatable species produced chemical extracts that deterred feeding. All of the chemically deterrent species contained chemoautotrophic endosymbiotic bacteria, suggesting that these microbial symbionts may produce metabolites that defend their host species. In several instances, consumers encountering novel, deep-sea prey consumed more on the first day of feeding than on later dates, or initially rejected the foods, but then consumed them after repeated encounters. Investigations with predators from the deep-sea are required to more fully understand the ecological role of prey defenses for deep-sea species.
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    Palatability and defense of some tropical infaunal worms: alkylpyrrole sulfamates as deterrents to fish feeding
    (Georgia Institute of Technology, 2003-11-28) Kicklighter, Cynthia Ellen ; Kubanek, Julia ; Barsby, Todd ; Hay, Mark E.
    Numerous studies have investigated chemical defenses among sessile species growing on hard substrates, but few have addressed this for mobile species in soft-sediment communities. We investigated the palatability and potential chemical defenses of 11 worm species from soft-sediment systems in southern Florida, USA. Three species were unpalatable to the bluehead wrasse Thalassoma bifasciatum. The polychaete Cirriformia tentaculata and the hemichordate Ptychodera bahamensis were uniformly unpalatable. For the polychaete Eupolymnia crassicornis, the exposed tentacles were unpalatable, but the body, which remains protected in a deeply buried tube, was palatable. These unpalatable worms were chemically defended; extracts of C. tentaculata, P. bahamensis, and the tentacles of E. crassicornis deterred fish feeding. For C. tentaculata, bioassay-guided fractionation demonstrated that a mixture of 3 closely related alkylpyrrole sulfamates deterred fish at naturally occurring concentrations (2-n-hexylpyrrole sulfamate [1.6% of worm dry mass], 2-n-heptylpyrrole sulfamate [3.1% dry mass], and 2-n-octylpyrrole sulfamate [0.8% dry mass]). This appears to be the first documentation of characterized natural products defending a marine worm from consumers. For P. bahamensis and the tentacles of E. crassicornis, deterrent effects of crude extracts decomposed before specific compounds could be identified