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Macronutrient intake and simulated infection threat independently affect life history traits of male decorated crickets
  • +4
  • Kristin Duffield,
  • Kylie Hampton,
  • Tom Houslay,
  • James Rapkin,
  • John Hunt,
  • Ben Sadd,
  • Scott Sakaluk
Kristin Duffield
Illinois State University
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Kylie Hampton
Illinois State University
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Tom Houslay
University of Cambridge
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James Rapkin
University of Exeter Cornwall Campus
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John Hunt
Western Sydney University
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Ben Sadd
Illinois State University
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Scott Sakaluk
Illinois State University
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Abstract

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.

Peer review status:Published

23 Jun 2020Submitted to Ecology and Evolution
24 Jun 2020Submission Checks Completed
24 Jun 2020Assigned to Editor
25 Jun 2020Reviewer(s) Assigned
24 Jul 2020Review(s) Completed, Editorial Evaluation Pending
24 Jul 2020Editorial Decision: Revise Minor
07 Aug 20201st Revision Received
08 Aug 2020Review(s) Completed, Editorial Evaluation Pending
08 Aug 2020Submission Checks Completed
08 Aug 2020Assigned to Editor
10 Aug 2020Reviewer(s) Assigned
28 Aug 2020Editorial Decision: Accept
22 Sep 2020Published in Ecology and Evolution. 10.1002/ece3.6813