Demographic costs of Chaoborus-induced phenotypic plasticity in Daphnia pulex

Abstract

It has been proposed that morphological defenses against predation have demographic costs. We measured the cost of a predator-induced morphological defense, using predaceous phantom midge larvae Chaoborus americanus (Insecta, Diptera) and the prey species Daphnia pulex (Crustacea, Cladocera). The induced defense is a neck tooth (and other pleiotropic structures) developed in juvenile D. pulex in the presence of C. americanus. Laboratory life table experiments, in the absence of predation, indicated the population growth rate of typical D. pulex was 11% to 39% greater than that of D. pulex exposed to C. americanus extract, or C. americanus-conditioned water. The reduction in population growth rate was most frequently associated with an increase in the time between birth and first reproduction. Induced individuals required twenty more hours at 23°C, and twenty five more hours at 20°C, to develop to the age of first reproduction. Under limiting food conditions age-specific survivorship and the number of offspring produced per female by the induced form were reduced relative to the typical form. As a result, the difference in population growth rates among forms was greater at the low food level as indicated by a highly significant food by form interaction effect. In addition to neck teeth and lowered reproductive rates, the offspring of induced form individuals had significantly longer tail-spines (7.2-7.5%), and primiparous adults from the induction treatment were significantly shorter than controls (3-8%).

Predator‐induced phenotypic plasticity in Daphnia pulex: Life history and morphological responses to Notonecta and Chaoborus

“…In practically every reported case of predator-induced morphological shifts, possession of the induced morphology is coupled with shifts in life history traits (for Daphnia, Black and Dodson 1990;Riessen and Sprules 1990;for rotifers, Stemberger 1988;for Bryozoa, Harvell 1986). When life history traits of the induced form result in lower fitness relative to the uninduced form, in the absence of the predator, investigators have interpreted the life history shifts as the cost of the induced morphology (Stemberger 1988;Walls and Matti 1989;Black and Dodson 1990;Riessen and Sprules 1990).…”

“…When life history traits of the induced form result in lower fitness relative to the uninduced form, in the absence of the predator, investigators have interpreted the life history shifts as the cost of the induced morphology (Stemberger 1988;Walls and Matti 1989;Black and Dodson 1990;Riessen and Sprules 1990).…”

“…= 0.05. Randomization models (Sokal and Rohlf 198 1) were used to conduct the one-way analysis and the subsequent multiple comparisons of the intrinsic rates of increase (Black and Dodson 1990). A randomization model designed to conduct the one-way comparison was developed following the general application of randomization models to life tables outlined by Black and Dodson (1990).…”

Comparing and contrasting development and reproductive strategies in the pupal hyperparasitoids Lysibia nana and Gelis agilis (Hymenoptera: Ichneumonidae)

“…The relative importance of trade-offs in life-history traits critically depends on the quality of the habitat in which the organism lives, feeds and reproduces, in terms of resource availability (Pexton and Mayhew 2002;Holomuzki and Biggs 2006). Further, the risk of mortality experienced by the organism early during development may also influence metabolic investment towards maintenance or reproduction (Black and Dodson 1990;Riessen 1992;Vollrath and Parker 1992). Ultimately, life-history trade-offs may play an important role in shaping the structure of ecological communities (Bonsall et al 2004).…”

Effects of salinity tolerances on survival and life history of 2 cladocerans

“…Smaller taxa are generally numerically more abundant than larger species (Cowgill, 1987;Sarma et al, 2005). According to Ranta (1979) and Black and Dodson (1990), Daphnia magna, the largest daphnid, can resist high salinity levels, as it was one of the most resistant among cladocerans to salinity increase. However, for the smaller cladocerans, LC 50 values for NaCl were much lower (Mount et al, 1997).…”