DOI: 10.5061/dryad.pr76b
title: Data from: Does variation in the intensity and duration of predation drive evolutionary changes in senescence?

description: 1. The evolutionary theory of senescence predicts that increased rates of
 extrinsic mortality select for faster declines in fertility and survival
 with age. One predicted mechanism is that increased mortality favors
 alleles that enhance fitness early in life at the expense of survival or
 reproduction later in life (antagonistic pleiotropy). 2. We tested these
 predictions in natural populations of Daphnia ambigua from lakes that vary
 in the severity and duration of fish predation. Daphnia are found in lakes
 with: (1) anadromous alewife (Alosa pseudoharengus) that migrate between
 marine and freshwater, (2) permanent landlocked alewife, and (3) no
 alewife. Daphnia are rare year-round in ‘landlocked lakes’ and are
 seasonally eliminated from the water column in ‘anadromous lakes’ due to
 the very strong predatory impact of anadromous alewife on populations of
 zooplankton. Previous work has also shown that intense seasonal bouts of
 predation by anadromous alewife has selected for increased allocation
 towards growth and reproduction in Daphnia found in lakes with anadromous
 alewife. Such variation in the risk of mortality and the expression of
 life history traits early in life provides the raw materials to test the
 evolutionary theory of ageing. 3. We reared replicate populations of
 Daphnia from all three lake types and quantified lifetime rates of
 offspring production and intrinsic survival. We found no differences in
 age-related declines in fertility or survival. Daphnia from anadromous
 lakes produced significantly more offspring throughout their lifetime
 despite no differences in lifespan or in the number of reproductive bouts
 compared with Daphnia from lakes with landlocked and no alewife. 4. The
 lack of divergence in ageing contradicts the prediction that elevated
 mortality rates drive evolutionary shifts in ageing. We reconcile these
 results by considering the predictions of theoretical frameworks that
 incorporate feedbacks associated with increased mortality such as density-
 and condition-dependent processes. Our results, which are better explained
 by a consideration of these processes, thus call for a greater
 consideration of models that more explicitly consider the ecology of focal
 organisms.
description: lifetime_fecundity_survivalFile name: lifetime_fecundity_survival.xls. Contents: Contains total number of offspring produced per replicate, no. of eggs produced per replicate, and number of reproductive bouts. Tab 2: lifespan per replicate. Columns: lake type = anadromous, landlocked, or no alewife, replicate lake, clone per lake, experimental temperature, and individual trait value. Offspring = total number of offspring produced, eggs_per_clutch = no. of offspring produced per clutch, no_clutches = total number of clutches.SurvivalFile name: survival.xls. Contents: proportion alive per lake and temperature; Tab1 = high temperature, Tab2 = low temperature. Columns: Day and proportion alive for each lake.lifetimefecundity_rawdataFile name: lifetime_fecundity_rawdata.xls. Contents: no. of offspring produced per clutch per clone per lake.