TY - JOUR
T1 - Fitness consequences for copepods feeding on a red tide dinoflagellate
T2 - Deciphering the effects of nutritional value, toxicity, and feeding behavior
AU - Prince, Emily K.
AU - Lettieri, Liliana
AU - McCurdy, Katherine J.
AU - Kubanek, Julia
N1 - Funding Information:
Acknowledgements This research was supported by NSF IGERT fellowships to E.K.P. and L.L., by an NSF-REU fellowship to K.J.M., and by NSF grant OCE-0134843 to J.K. We are grateful to J. Naar for ELISA analysis of brevetoxins, to D. Fields for assistance in the identification of copepods and for information about their life histories, and to T. Riggens for advice about culturing phytoplankton. We also thank M. Hicks and K. Mobley for guidance with statistical analyses, A. Prusak for discussions related to experimental design, and M.E. Hay and M. Weissburg for comments that improved this manuscript. The experiments reported herein comply with the current laws of the United States of America.
PY - 2006/3
Y1 - 2006/3
N2 - Phytoplankton exhibit a diversity of morphologies, nutritional values, and potential chemical defenses that could affect the feeding and fitness of zooplankton consumers. However, how phytoplankton traits shape plant-herbivore interactions in the marine plankton is not as well understood as for terrestrial or marine macrophytes and their grazers. The occurrence of blooms of marine dinoflagellates such as Karenia brevis suggests that, for uncertain reasons, grazers are unable to capitalize on, or control, this phytoplankton growth - making these systems appealing for testing mechanisms of grazing deterrence. Using the sympatric copepod Acartia tonsa, we conducted a mixed diet feeding experiment to test whether K. brevis is beneficial, toxic, nutritionally inadequate, or behaviorally rejected as food relative to the palatable and nutritionally adequate phytoplankter Rhodomonas lens. On diets rich in K. brevis, copepods experienced decreased survivorship and decreased egg production per female, but the percentage of eggs that hatched was unaffected. Although copepods showed a 6-17% preference for R. lens over K. brevis on some mixed diets, overall high ingestion rates eliminated the possibility that reduced copepod fitness was caused by copepods avoiding K. brevis, leaving nutritional inadequacy and toxicity as remaining hypotheses. Because egg production was dependent on the amount of R. lens consumed regardless of the amount of K. brevis eaten, there was no evidence that fitness costs were caused by K. brevis toxicity. Copepods limited to K. brevis ate 480% as much as those fed only R. lens, suggesting that copepods attempted to compensate for low food quality with increased quantity ingested. Our results indicate that K. brevis is a poor food for A. tonsa, probably due to nutritional inadequacy rather than toxicity, which could affect bloom dynamics in the Gulf of Mexico where these species co-occur.
AB - Phytoplankton exhibit a diversity of morphologies, nutritional values, and potential chemical defenses that could affect the feeding and fitness of zooplankton consumers. However, how phytoplankton traits shape plant-herbivore interactions in the marine plankton is not as well understood as for terrestrial or marine macrophytes and their grazers. The occurrence of blooms of marine dinoflagellates such as Karenia brevis suggests that, for uncertain reasons, grazers are unable to capitalize on, or control, this phytoplankton growth - making these systems appealing for testing mechanisms of grazing deterrence. Using the sympatric copepod Acartia tonsa, we conducted a mixed diet feeding experiment to test whether K. brevis is beneficial, toxic, nutritionally inadequate, or behaviorally rejected as food relative to the palatable and nutritionally adequate phytoplankter Rhodomonas lens. On diets rich in K. brevis, copepods experienced decreased survivorship and decreased egg production per female, but the percentage of eggs that hatched was unaffected. Although copepods showed a 6-17% preference for R. lens over K. brevis on some mixed diets, overall high ingestion rates eliminated the possibility that reduced copepod fitness was caused by copepods avoiding K. brevis, leaving nutritional inadequacy and toxicity as remaining hypotheses. Because egg production was dependent on the amount of R. lens consumed regardless of the amount of K. brevis eaten, there was no evidence that fitness costs were caused by K. brevis toxicity. Copepods limited to K. brevis ate 480% as much as those fed only R. lens, suggesting that copepods attempted to compensate for low food quality with increased quantity ingested. Our results indicate that K. brevis is a poor food for A. tonsa, probably due to nutritional inadequacy rather than toxicity, which could affect bloom dynamics in the Gulf of Mexico where these species co-occur.
KW - Acartia tonsa
KW - Compensatory feeding
KW - Copepod
KW - Karenia brevis
KW - Toxin
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U2 - 10.1007/s00442-005-0274-2
DO - 10.1007/s00442-005-0274-2
M3 - Article
C2 - 16261377
AN - SCOPUS:33644584920
SN - 0029-8549
VL - 147
SP - 479
EP - 488
JO - Oecologia
JF - Oecologia
IS - 3
ER -