Diapause phenology and egg bank dynamics of a calanoid copepod in floodplain habitats
Libman, B. S.; Threlkeld, S. T.
Archiv für Hydrobiologie Volume 145 Number 3 (1999), p. 349 - 358
published: Jun 28, 1999
ArtNo. ESP141014503006, Price: 29.00 €
Zooplankton populations in floodplain habitats such as oxbow lakes are adversely affected through wash out or dilution. We hypothesized that zooplankton may produce diapausing eggs to avoid local extinction caused by floods. To test this hypothesis, we determined the type of clutch (diapausing or subitaneous) produced by Diaptomus pallidus (Copepoda: Calanoida) females during a 13-month period in eight ponds on the Little Tallahatchie River, Mississippi, floodplain. At five of eight sites, a maximum of 10-60 % of D. pallidus females switched from production of subitaneous to diapausing clutches between mid-November and early December. The timing of the switch occurred before the historical date of first flood. Females did not produce any diapausing clutches at two of four sites where flooding occurs irregularly due to flood control. The size of the egg bank at sites with flood control was smaller than at sites without flood control. The results suggest that flooding regime is important in shaping some life history characteristics of this species.