The prevalence of diapause response to risk of size-selective predation in small- and large-bodied prey species

Abstract

The prevalence of diapause response to the simulated threat of fish predation was compared in three species of planktonic crustaceans of the genus Daphnia (D. magna, D. pulicaria and D. longispina), which due to their different body size vary in vulnerability to fish predation pressure in natural conditions. Higher incidence of diapause response was presumed in the larger-bodied species, which due to their higher conspicuousness and higher energetic content experience the greatest size-selective pressure from visually foraging fish. Small-bodied species were expected to utilize less costly yet less effective active defences, e.g. lower conspicuousness achieved due to slower body growth when facing risk of size-selective predation. Proportions of females forming diapausing structures as well as females body size at the maturation period were compared in experimental beakers containing or not containing fish kairomones (chemical cues of fish predation) in a few clonal lineages of 3 species of Daphnia derived from a single lake inhabited by fish. The highest incidence of diapause response to fish kairomones was observed in D. magna (when measured both as proportion of sensitive individuals and as proportion of inductive clones), the largest of the tested Daphnia species. The lowest proportion of individuals and clones that employed diapause was reported in the smallest tested species, D. longispina. In addition, the large-bodied Daphnia (D. magna) showed a greater reduction in body size in response to fish kairomones than the small-bodied species (D. longispina). The results of the present study support the assumption of higher prevalence of diapause response to the threat of selective predation in larger and more vulnerable prey species.

Prevalence of kairomone-induced diapause in Daphnia magna from habitats with and without fish

“…Due to its large body size, D. magna seems to be at high risk of fish predation, and thus is likely to utilise this costly response to ensure survival in habitats containing fish. The findings of our previous study, which documented the occurrence of the diapause response in three species of Daphnia (D. magna, D. pulicaria and D. longispina) (Slusarczyk et al, 2012), together with the results of the present study, suggest that similar reaction may occur in many sites and species.…”

“…So far, the few described examples of diapause induction by fish kairomones in Daphnia are limited to specimens originating from a single site: the shallow coastal lake Grosser Binnensee located in northern Germany, which is inhabited by fish. A positive diapause response to fish kairomones was observed in three species of Daphnia (D. magna, D. pulicaria and D. longispina) isolated from this lake (Slusarczyk et al, 2012). The most intense diapause response to fish kairomones was found in D. magna, the largest of the three tested species.…”

“…The method used for the reactivation of diapausing eggs and the experimental protocol were similar to those described in detail in our previous study (Slusarczyk et al, 2012). The ancestors of the experimental animals were kept under standardized favourable conditions for at least two generations to minimize potential effects of earlier environmental variability on the experimental results.…”

Probing of mortality rate by staying alive: The growth‐reproduction trade‐off in a spatially heterogeneous environment

“…Growth that accompanies reproduction in short‐lived water invertebrates has been suggested to evolve when both the assimilation of resources and mortality risk increase along with body size (Perrin, Sibly, & Nichols, ; Taylor & Gabriel, ). The death rates of many planktonic crustaceans are strongly affected by the activity of visual predators, with large species or individuals being exposed to a higher risk of death than small ones (Ebert, ; Gliwicz, Slusarczyk, & Slusarczyk, ; Slusarczyk, Ochocka, & Cichocka, ). However, intraspecific reactions of mortality risk to body size in planktonic crustaceans can be more complex.…”

Review: Diapause in Crustaceans and its Ecological and Biogeographical Implications: An Example from Patagonian Ephemeral Pools

“…Although there are no reported studies of diapause in southern freshwater amphipods, the presence of species in ephemeral pools and wetlands with drying and flooding periods such as Tres Puentes wetlands close to Punta Arenas, and some ephemeral pools close to Puerto Natales, would indicate the presence of diapause mechanism to explain the presence of these amphipods (De los Ríos-Escalante, personal observations, February 2012). Diapause has been observed for Hyalella azteca (Bayley et al, 2005;Doobay 2011;Alekseev, 2007a It was reported in the literature that diapause egg production can be induced by direct or indirect predator exposure, specifically the presence of fish kairomones (semiochemicals emitted by the fish which benefit the recipient organism) that induced diapause process reproduction in large bodied cladocerans (Santangelo et al, 2010;Slusarczyk, 2010;Slusarczyk et al, 2012). None of the sites studied in the Magallanes and Aysen region had zooplanktivorous fishes, and in these pools the main predator would have been the large-bodied copepod Parabroteas sarsi (De los Ríos-Escalante, 2010), an active zooplankton predator in Patagonian inland waters (Vega, 1996(Vega, , 1997(Vega, , 1998(Vega, , 1999.…”