Non-consumptive effects of predator presence on copepod reproduction: insights from a mesocosm experiment

Jan Heuschele, Sara Ceballos, Marc Andersen Borg, Oda Bjærke, Stamatina Isari, Rachel Lasley-Rasher, Elin Lindehoff, Anissa Souissi, Sami Souissi, Josefin Titelman

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Reproduction in planktonic animals depends on numerous biotic and abiotic factors. One of them is predation pressure, which can have both direct consumptive effects on population density and sex ratio, and non-consumptive effects, for example on mating and migration behaviour. In copepods, predator vulnerability depends on their sex, motility pattern and mating behaviour. Therefore, copepods can be affected at multiple stages during the mating process. We investigated the reproductive dynamics of the estuarine copepod Eurytemora affinis in the presence and absence of its predator the mysid Neomysis integer in a mesocosm experiment. We found that the proportion of ovigerous females decreased in the presence of predators. This shift was not caused by differential predation as the absolute number of females was unaffected by mysid presence. Presence of predators reduced the ratio of males to non-ovigerous females, but not by predation of males. Our combined results suggest that the shift from ovigerous to non-ovigerous females under the presence of predators was caused by either actively delayed egg production or by shedding of egg sacs. Nauplii production was initially suppressed in the predation treatment, but increased towards the end of the experiment. The proportion of fertilized females was similar in both treatments, but constantly fell behind model predictions using a random mating model. Our results highlight the importance of non-consumptive effects of predators on copepod reproduction and hence on population dynamics.
Original languageEnglish
JournalMarine Biology
Volume161
Issue number7
Pages (from-to)1653-1666
ISSN0025-3162
DOIs
Publication statusPublished - 2014

Keywords

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