The quick and the dead: might differences in escape rates explain the changes in the zooplankton community composition of Lake Michigan after invasion by Bythotrephes?

Abstract

We demonstrate that zooplankton escape abilities are consistent with the composition of the zooplankton community in the Great Lakes following the invasion of the visually preying invertebrate predator Bythotrephes longimanus. Escape abilities were analyzed by videotaping responses of freeswimming zooplankton to encounters with tethered Bythotrephes. Both maximum speed and maximum acceleration of the escape response were appreciably greater in Daphnia mendotae and diaptomids, whose populations remained relatively unchanged, than those of Daphnia retrocurva and Daphnia pulicaria, whose populations greatly decreased after the Bythotrephes invasion. Maximum speed of all species was higher in the light than in complete darkness, likely due to a different level of activity of Bythotrephes. Contrary to treatments with Bythotrephes, mean and maximum swimming speeds of all species were similar to each other and the same in light and dark in treatments without Bythotrephes. This implies that the prey were responding to infochemicals produced by Bythotrephes.

Seasonal zooplankton dynamics in Lake Michigan: Disentangling impacts of resource limitation, ecosystem engineering, and predation during a critical ecosystem transition

“…The large immediate changes in zooplankton community structure seen in Lake Michigan and other lakes following the Bythotrephes invasion (e.g., Lehman, 1987Lehman, , 1991Yan and Pawson, 1997) may be related to escape abilities of prey (Pichlová-Ptáčníková and Vanderploeg, 2011). In Lake Michigan, Daphnia pulicaria and D. retrocurva, which had slow escape speeds relative to D. mendotae and calanoid copepods, disappeared immediately after the Bythotrephes invasion.…”

“…Order of size of zooplankton is taken primarily from Liebig and Vanderploeg (2008) and secondarily from Hawkins and Evans (1979 Muirhead and Sprules (2003). l Escape reactions from Drenner an McComas (1980), Vanderploeg et al (1993), Link (1996), Vanderploeg (1994), Liebig and Vanderploeg (1995) and Vanderploeg et al (2002), Pichlová-Ptáčníková and Vanderploeg (2011). histories of temperatures over the annual cycle for each year, we plotted up the 30-day moving average of daily mean temperatures (Fig.…”

“…Bythotrephes has the following order of prey preference: cladocerans > nauplii > copepodites and adult copepods (Schulz and Yurista, 1998;Vanderploeg et al, 1993). Capture probability is strongly affected by escape speeds of the prey (Pichlová-Ptáčníková and Vanderploeg, 2011). It is likely the nauplii and copepodite stages of Diacyclops, a small species relative to most calanoids, would be vulnerable to predation since escape speeds are a function of prey size (Link, 1996) within copepods.…”

Influence of habitat heterogeneity on the foraging ecology of first feeding yellow perch larvae, Perca flavescens, in western Lake Erie

“…), even though they were the most abundant zooplankton prey group. This result suggests that cladocerans in general may exhibit higher predator avoidance capabilities relative to other zooplankton groups (Graeb et al, 2004;Pichlová-Ptáčníková and Vanderploeg, 2011). This is not the case for larger YP larvae and juveniles that do prey heavily on cladocerans in general, especially in the summer, when these prey reach their highest abundances (Makarewicz, 1993;Leclerc et al, 2011).…”

The invasive predator Bythotrephes induces changes in the vertical distribution of native copepods in Lake Michigan

“…Thus copepods could be responding to Bythotrephes due to selection imposed by prior contact with this predator. To our knowledge, Leptodiaptomus are found only in the New World and therefore are unlikely to have had any previous exposure to Bythotrephes in the Great Lakes, however, Diacyclops is a cosmopolitan genus (Pennak 1978) and may have had an ancestor that existed with Bythotrephes in the past, or may have hybridized with a European Diacyclops species that may have been recently introduced to Lake Michigan. Differences in the evolutionary histories of Diacyclops and Leptodiaptomus could indicate different ultimate causes underlying the behavioral responses of these two genera to Bythotrephes.…”