Morphological variation of the predatory cladoceran Leptodora kindtii in relation to prey characteristics

Abstract

The responses of invertebrate predators to changes in the morphology of their prey, and especially the responses for induced defences, are largely unexplored, compared with the vast amount of data on predator-induced defences. This study demonstrates that the size of the feeding basket, the anatomical structure used to capture prey by the predaceous freshwater cladoceran Leptodora kindtii, shows significant allometric changes with the average body size of the prey (herbivorous cladocerans) in six lakes of northeastern Poland. Prey density influences the basket size only in adult Leptodora individuals, whereas induced defences such as helmets of Daphniasp. seem to have no effect on Leptodora's morphology. In a feeding experiment it is shown that the increase in the feeding basket enables Leptodora to capture larger prey. The seasonal pattern of morphological change, and its measurable benefit suggest that the observed morphological variability of Leptodora is phenotypic plasticity.

Effects of Bythotrephes longimanus (Crustacea, Cladocera) on the abundance, morphology, and prey community of Leptodora kindtii (Crustacea, Cladocera)

“…Leptodora ingestion rate (Branstrator, 1998) and maximum prey size (Herzig & Auer, 1990) increase with feeding basket size (and body size with which it is strongly correlated), and thus one would expect Leptodora to be as large as possible regardless of the zooplankton size distribution. However, Abrusán (2003) found that feeding basket size (corrected for body size) varied directly with seasonal changes in the size of their zooplankton prey. While this is an interesting possibility, it does not appear to be the mechanism at work in our study lakes: we would expect Leptodora to be comparatively larger (not smaller) in invaded lakes if they were responding to a paucity of small cladoceran prey.…”

“…1) of 10-100 females when Leptodora were abundant. This measurement has been used in previous studies and has been shown to correlate with average prey size (Herzig & Auer, 1990;Abrusán, 2003). We did not measure external dimensions (Branstrator, 1995;Manca & Comoli, 1995) which are unduly affected by feeding appendage orientation during measurement.…”

“…The maximum-sized prey Leptodora can exploit is constrained by the size of its feeding basket and smaller Leptodora have smaller feeding baskets (Herzig & Auer, 1990;Branstrator, 1995;Manca & Comoli, 1995). Leptodora body size and relative feeding basket size can vary seasonally with changes in prey size and density (Abrusán, 2003). Therefore, modifications to zooplankton community composition and size structure after Bythotrephes invasion may result in changes in Leptodora body and feeding basket size.…”

Zooplankton predators and prey: body size and stable isotope to investigate the pelagic food web in a deep lake (Lake Iseo, Northern Italy)

“…L. kindtii body length was measured from top of head to caudal portion of the body, furca excluded, on 251 individuals. Individual feeding basket diameter was estimated from Manca and Comoli (1995), to assess L. kindtii edible prey body length spectra along the seasons (Abrùsan, 2003).…”

A trade-off between prey- and predator-induced polyphenisms in larvae of the salamander Hynobius retardatus

“…Diverse prey taxa construct inducible morphological defenses to escape predators, but they share in common the cost of slower growth (e.g., fish, salamanders, snails, and Daphnia; Bronmark and Pettersson 1994;Agrawal et al 1999;Van Buskirk and Schmidt 2000;Trussell and Nicklin 2002). A representative example, the prey rotifer species Keratella slacki has been well characterized for its ability to develop a larger body and longer anterior spines in the presence of the predatory rotifer Asplanchna, making it less vulnerable to predation but at the cost of a drastically decreased growth rate (Abrusán 2003). Although it is still important to extend traditional research on adaptive phenotypic plasticity in a specific environmental setting, the recognition that plasticity can be adaptive has stimulated a wealth of studies on less understood aspects of the relationships among different adaptive phenotypic plasticities induced in an individual by more complex environmental conditions (Relyea 2002).…”