Lake water chemistry and population of origin interact to shape fecundity and growth in Daphnia ambigua

Freshwater environments vary widely in ion availability, owing to both natural and anthropogenic drivers. Field and laboratory work point to the importance of overall salinity as well as cation depletion, in shaping the physiology, behavior, and ecology of freshwater taxa. Yet, we currently have a poor understanding of the degree to which populations may vary in response to ion availability. Using Daphnia collected from three lakes that differ greatly in salinity and calcium availability, we conducted a laboratory reciprocal transplant experiment to assess how animals representing these populations vary in fecundity, body size, and survival when reared in lake water from each environment. The lake water environment and population of origin strongly interacted to shape Daphnia growth and reproduction. Surprisingly, we found only modest evidence that lake water with abundant calcium (5.5 mg/L vs. 1.2-2.3 mg/L) increased Daphnia growth or reproduction. In contrast, water from a relatively ..., We reared Daphnia from three lakes in lake water from each of these lakes. We included 4 clonal lineages per lake and 4-13 replicates per clonal lineage/ lake/ treatment. We measured body size at 7 days and noted whether Daphnia reproduced by that time. We noted survival to maturity. We counted offspring over 21 days and measured Daphnia again at 21 days.
If Daphnia did not survive to 7 or 21 Days, 7-day and/or 21-day length is NA. 
If Daphnia did not survive to reproduce, totaloffspring = NA and rep_by_day7 = NA
Column headers are:

Lake: Lake of origin (from Egypt, Hall, or Sewell Pond)
Trt: Lake water rearing conditions (E: Egypt, S: Sewell, H: Hall)
Clone: clonal lineage (one of four from each lake)
Replicate: experimental replicate for a given lake x treatment x clone
Died_before_mature: did the animal die before reproducing? 0: no, 1: yes
rep_by_day7: reproduced by day 7 (0: no, 1: yes)
totaloffspring: total offspring produced over the 21 day trial
Day7_length_mm: body length meas...,