Publication Date:
2016-08-20
Description:
The tolerance traits of zooplankton co-occurring with toxic cyanobacteria are poorly understood. To evaluate the tolerance mechanisms of Notodiaptomus iheringi , an abundant tropical copepod coexisting with toxic cyanobacteria blooms across South America, grazing and egg production rates were measured in the laboratory using single- and mixed-food diets containing either a microcystin producing (MC+) or lacking (MC–) strain of Microcystis with Cryptomonas as control food. Pure Microcystis diets resulted in no egg production. In mixed-food diets, the MC+ strain had no effect, while the MC– strain increased egg production relative to the controls. Clearance rates were highest on Cryptomonas , intermediate on the MC– strain and lowest on the MC+ Microcystis . Notodiaptomus iheringi selectively avoided Microcystis in mixed diets. Total grazing was not inhibited by Microcystis abundance as long as Cryptomonas was available. Egg production was unaffected by the ingestion of Microcystis but depended on the abundance and ingestion of Cryptomonas . Consequently, both selective grazing on nutritious food and the detoxification of ingested cyanobacteria may be critical traits for N. iheringi to tolerate blooms of toxic cyanobacteria. The results contrast with reports showing strong negative effects of Microcystis on zooplankton fitness and highlight the diversity in zooplankton tolerance traits.
Print ISSN:
0142-7873
Electronic ISSN:
1464-3774
Topics:
Biology
