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.
This content will become publicly available on July 1, 2025
Macronutrients play a vital role in host immunity and can influence host–pathogen dynamics, potentially through dietary effects on gut microbiota. To increase our understanding of how dietary macronutrients affect physiology and gut microbiota and investigate whether feeding behaviour is influenced by an immune threat, we conducted two experiments. First, we determined whether zebra finches (
- Award ID(s):
- 2016423
- NSF-PAR ID:
- 10539414
- Editor(s):
- Bonneaud, Camille
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Molecular Ecology
- Volume:
- 33
- Issue:
- 14
- ISSN:
- 0962-1083
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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