Effects of an Ostracod ( Cypris pubera ) on the Rotifer Keratella tropica : Predation and Reduced Spine Development

• Published in: International Review of Hydrobiology
• Main Author: Gilbert, John J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2012
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Copepods; Rotifer
• Online Access: http://dx.doi.org/10.1002/iroh.201201455; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Firoh.201201455; https://onlinelibrary.wiley.com/doi/pdf/10.1002/iroh.201201455

Abstract This study investigates two different effects of an ostracod on a rotifer. The rotifer Keratella tropica and the ostracod Cypris pubera were cultured on the alga Cryptomonas erosa . Adult ostracods (2.2 mm body length) significantly reduced the population growth rate (r day –1 ) of K. tropica from 0.42 to 0.13. Individuals of this size ingested live rotifers and produced fecal pellets with rotifer loricas. Smaller ostracods (both 0.59 and 1.61 mm body lengths) did not affect K. tropica 's population growth rate. Surprisingly, C. pubera significantly inhibited spine development in K. tropica . Rotifers cultured with juvenile, non‐predatory ostracods had similar lorica lengths but right and left posterior spines that were 10 and 30% shorter, respectively. The spine reduction induced by the ostracod kairomone is in striking contrast to the spine elongation induced in this rotifer by kairomones from copepods, cladocerans and Asplanchna . In shallow ecosystems, large ostracods that swim in the plankton may be important predators of rotifers. In addition, the presence of ostracods in plankton communities may be one of many factors affecting rotifer spine development. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)