Exposure to predator kairomones influences egg number and size in Littorina littorea

Abstract

Predator kairomones play an important role in intertidal ecosystems, but knowledge on their potential role in influencing maternal effects is lacking. The aim of this study was to test whether egg production by female Littorina littorea was influenced by short-term exposure to predator kairomones before egg laying. Laboratory populations were exposed to predator cues from the intertidal crab Carcinus maenas for nine days, and egg number, egg size, and survivorship of the offspring were measured and compared with those from reference populations. Snails exposed to predator cues produced significantly more eggs, which were also significantly smaller than those produced from mothers in control seawater, suggesting a trade-off between egg size and number. This effect was consistent over time, but egg production decreased in each treatment over the course of the study. Furthermore, eggs from the predator cue treatment had lower survivorship. These results suggest that the presence of predator kairomones in marine environments could significantly alter the reproductive investment strategies in prey species.