Predation risk affects growth and reproduction of an invasive snail and its lethal effect depends on prey size

Abstract

The behavior of invasive species under predation risk has been studied extensively, but their growth and reproductive responses have rarely been investigated. We conducted experiments with juveniles and adults of the invasive freshwater snail Pomacea canaliculata, and we observed changes in growth and reproduction in response to predation risk from a caged predator (Trachemys scripta elegans). P. canaliculata produced eggs earlier in the presence of predators and injured conspecifics compared with the control group (no risk), although the total number of egg masses laid by per female was exceeded by that of the controls after 15 days. Egg hatching success noticeably decreased under predation risk, and the incubation period was significantly prolonged; however, the oviposition height of the snails was not affected. A lethal effect of predation risk was detected in juvenile snails but not in adults. The growth of juvenile P. canaliculata was inhibited under predation risk, probably due to a reduction in food intake. Adult females exhibited a greater reduction in growth under predation risk than males, which likely resulted in part from the high reproductive investment of females in egg laying. These results indicate that P. canaliculata snails under predation risk face a trade-off between predator avoidance and growth and reproduction, where the lethal effect of predation risk is linked to the size of the prey.

Predation risk affects egg mortality and carry over effects in the larval stages in damselflies

“…The presence of predation risk has been shown to affect the timing of hatching in eggs, and the response appears to go in both directions, (i.e. an earlier or delayed hatching; Sih & Moore, 1993;Warkentin, 2000;Jones et al, 2003;Ireland, Wirsing, & Murray, 2007;Guo et al, 2017). Such differences in systems are believed to depend on whether the predation risk is higher in the egg or the subsequent larval stage (Warkentin, 1995).…”

“…While numerous studies have examined how predation risk affects the timing of egg hatching (e.g. Guo, Martin, Zhang, & Zhang, ; Sih & Moore, ), we have limited knowledge on how non‐consumptive predator effects affect physiological stress and mortality in the egg stage. However, Jones, Laurila, Peuhkuri, Piironen, and Seppa () and Fontana‐Bria, Selfa, Tur, and Frago () found no difference in egg hatching success in fish, damselflies and mosquitoes between eggs exposed to predation cues and no predator cues without predation, but Guo et al.…”

“…A theory predicts that high predation on eggs and relatively lower predation on hatchlings should select for early hatching and low predation in the egg stage, and higher predation on hatchlings should select for delayed hatching in the presence of predator cues (Warkentin, 1995). Support for this theory has been found in several studies (Guo et al, 2017;Jones et al, 2003;Sih & Moore, 1993;Warkentin, 1995). In addition, synchronized hatching in the presence of predation risk should be favoured because the search image of predators may be reduced by a large number of prey and because of a swamping effect (Hamilton, 1971; Ims, 1990).…”

“…Guo, Martin, Zhang, & Zhang, 2017;Sih & Moore, 1993), we have limited knowledge on how nonconsumptive predator effects affect physiological stress and mortality in the egg stage. However, Jones, Laurila, Peuhkuri, Piironen, and Seppa (2003) and Fontana-Bria, Selfa, Tur, and Frago (2017) found no difference in egg hatching success in fish, damselflies and mosquitoes between eggs exposed to predation cues and no predator cues without predation, but Guo et al (2017) found a lower hatching success in the presence of a non-lethal predator in a freshwater snail. Hence, more studies are needed before a consensus can be drawn about how the non-consumptive predator effect affects egg mortality.…”

Effects of Fish Predators on the Mass-Related Energetics of a Keystone Freshwater Crustacean

“…Many studies have shown that growth and locomotor activity have major effects on metabolic scaling (reviewed by [27,28,100,132,133]). Furthermore, predators can affect both of these resource-demanding processes, as commonly observed (e.g., [1][2][3]23,36,[42][43][44]48,[116][117][118]134,135]), including in amphipods (e.g., [8,91,121,122,130,[136][137][138][139][140]).…”