Patterns and processes of larval emergence in an estuarine parasite system.
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TLDR
Together, exogenous and endogenous factors control emergence of trematode cercariae, mitigating the vagaries of an intertidal environment.Abstract:
Trematode parasites in intertidal estuaries ex- perience constantly varying conditions, with the presence or absence of water potentially limiting larval transport be- tween hosts. Given the short life spans (24 h) of cercariae, emergence timing should be optimized to enhance the prob- ability of successful transmission. In the present study, field measurements and laboratory experiments identified pro- cesses that regulate the emergence of cercariae from their first intermediate snail hosts in an intertidal marsh. Larvae emerged over species-specific temperature ranges, exclu- sively during daylight hours, and only when snails were submerged. The three factors operate over different tempo- ral scales: temperature monthly, light diurnally (24-h pe- riod), and water depth tidally (12-h period). Each stimulus creates a necessary condition for the next, forming a hier- archy of environmental cues. Emergence as the tide floods would favor transport within the estuary, and light may trigger direct (downward or upward) swimming toward host habitats. Abbreviated dispersal would retain asexually re- produced cercariae within the marsh, and local mixing would diversify the gene pool of larvae encysting on sub- sequent hosts. In contrast to the timing of cercarial release, emergence duration was under endogenous control. Dura- tion of emergence decreased from sunrise to sunset, perhaps in response to the diminishing lighted interval as the day progresses. Circadian rhythms that control cercarial emer- gence of freshwater species (including schistosomes) are often set by the activity patterns of subsequent hosts. In this estuary, however, the synchronizing agent is the tides. To-read more
Citations
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Journal ArticleDOI
Ecosystem energetic implications of parasite and free-living biomass in three estuaries
Armand M. Kuris,Ryan F. Hechinger,Jenny C. Shaw,Kathleen L. Whitney,Leopoldina Aguirre-Macedo,Charles A. Boch,Andrew P. Dobson,Eleca J. Dunham,Brian L. Fredensborg,Todd C. Huspeni,Julio Lorda,Luzviminda Mababa,Frank T. Mancini,Adrienne B. Mora,Maria Pickering,Nadia L. Talhouk,Mark E. Torchin,Kevin D. Lafferty +17 more
TL;DR: It is shown that parasites have substantial biomass in these ecosystems and that the annual production of free-swimming trematode transmission stages was greater than the combined biomass of all quantified parasites and was also greater than bird biomass.
Journal ArticleDOI
Global warming and temperature-mediated increases in cercarial emergence in trematode parasites.
TL;DR: The results suggest that the small increases in air and water temperature forecast by many climate models will not only influence the geographical distribution of some diseases, but may also promote the proliferation of their infective stages in many ecosystems.
Journal ArticleDOI
Effects of temperature, salinity, and water level on the emergence of marine cercariae
Janet Koprivnikar,Robert Poulin +1 more
TL;DR: It is proposed that trematode parasitism in intertidal zones is likely to be impacted by various changes in the marine environment resulting from global warming.
Journal ArticleDOI
Production of marine trematode cercariae: a potentially overlooked path of energy flow in benthic systems
David W. Thieltges,Xavier de Montaudouin,Brian L. Fredensborg,K. Thomas Jensen,Janet Koprivnikar,Robert Poulin +5 more
TL;DR: Results suggest that trematode cercariae represent potentially important paths of energy flow in benthic systems as well as a potentially important food supply to benthics organisms.
Journal ArticleDOI
Thermodynamics of cercarial development and emergence in trematodes.
Neil J. Morley,John W. Lewis +1 more
TL;DR: Temperature appears to have no significant effect on the rate of development of cercariae within molluscan hosts, and some evidence of strain-specific differences and thermostability over a wide temperature range for both cercarial development and emergence was apparent.
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