Data from: Macronutrient intake and simulated infection threat independently affect life history traits of male decorated crickets

Nutritional geometry has advanced our understanding of how macronutrients
(e.g., proteins and carbohydrates) influence the expression of life
history traits and their corresponding trade-offs. For example, recent
work has revealed that reproduction and immune function in male decorated
crickets are optimized at very different protein:carbohydrate (P:C)
dietary ratios. However, it is unclear how an individual’s macronutrient
intake interacts with its perceived infection status to determine
investment in reproduction or other key life history traits. Here, we
employed a fully factorial design in which calling effort and immune
function were quantified for male crickets fed either diets previously
demonstrated to maximize calling effort (P:C = 1:8) or immune function
(P:C = 5:1), and then administered a treatment from a spectrum of
increasing infection cue intensity using heat-killed bacteria. Both diet
and a simulated infection threat independently influenced the survival,
immunity, and reproductive effort of males. If they called, males
increased calling effort at the low infection cue dose, consistent with
the terminal investment hypothesis, but interpretation of responses at the
higher threat levels was hampered by the differential mortality of males
across infection cue and diet treatments. A high protein, low carbohydrate
diet severely reduced the health, survival, and overall fitness of male
crickets. There was, however, no evidence of an interaction between diet
and infection cue dose on calling effort, suggesting that the threshold
for terminal investment was not contingent on diet as investigated
here.