Heat resistance of ectotherms can be increased both by plasticity and evolution, but these effects may have trade-offs resulting from biotic interactions. Here we test for predation costs in Drosophila melanogaster populations with altered heat resistance produced by adult hardening and directional selection for increased heat resistance. In addition, we also tested for genetic trade-offs by testing heat resistance in lines that have evolved under increased predation risk. We show that while 35/37°C hardening increases heat resistance as expected, it does not increase predation risk from jumping spiders or mantids; in fact there was an indication that survival may have increased under predation following a triple 37°C compared to a single 35°C hardening treatment. Flies that survived a 39°C selection cycle showed lower survival under predation, suggesting a predation cost of exposure to a more severe heat stress. There was however no correlated response to selection because survival did not differ between control and selected lines after selection was relaxed for one or two generations. In addition, lines selected for increased predation risk did not differ in heat resistance. Our findings suggest independent evolutionary responses to predation and heat as measured in laboratory assays, and no costs of heat hardening on susceptibility to predation.
Heat experiment with hardening treatments
This data set contains heat knockdown time (min) of female and male D. melanogaster after a control treatment (Cont), a single 35°C (35-1) and 37°C (37-1) hardening treatment and a triple 35°C (35-3) and 37°C (37-3) hardening treatment, scored in two experimental blocks (A and B).
Predation experiment with hardending treatment
This data set contains survival (yes or no) of female and male D. melanogaster after different heat hardening treatments when exposed to two predators (jumping spiders and juvenile mantids). Hardening treatments included a control treatment (Cont), a single 35°C (35-1) and 37°C (37-1) hardening treatment and a triple 35°C (35-3) and 37°C (37-3) hardening treatment. Five different colors were used to mark the treatments (blue, orange, yellow, pink and violet) and 40/20 replicate vials containing 1/2 flies per treatment were used for the spider/mantids predation respectively.
Predation experiment with spiders
This data set contains survival (yes or no) of female and male D. melanogaster under predation by jumping spiders. Survival of control lines (Control1-5) and lines selected for increased heat resistance (Heat1-5) was scored after 0, 1 and 2 generations of relaxation. Six different colors were used to mark the selection lines (blue, green, orange, yellow, pink and violet) and 50 replicate vials containing 6 flies from 3 control and 3 selected lines were used.
Predation experiment with mantids
This data set contains survival (yes or no) of female and male D. melanogaster under predation by juvenile mantids). Survival of control lines (Control1-5) and lines selected for increased heat resistance (Heat1-5) was scored after 0, 1 and 2 generations of relaxation. Six different colors were used to mark the selection lines (blue, green, orange, yellow, pink and violet) and 30 replicate vials containing 12 flies from 3 control and 3 selected lines were used.
Heat experiment with predation lines
This data set contains heat knockdown time (min) of female and male D. melanogaster originating from two experiments: episodic and continuous predation. The episodic experiment contained two replicate lines of predation by juvenile mantids (Pred1 and Pred2) and controls (Cont1 and Cont2). The continuous experiment contained four replicate lines of predation by juvenile mantids (PR1-4), predation by jumping spiders (SR1-4) and controls (CR1-4). Heat knockdown time was scored in two experimental blocks (A and B).