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Keywords:

  • detritus;
  • ecological stoichiometry;
  • homoeostasis;
  • phosphorus;
  • temperature

Summary

  1. Regimes of temperature and nutrient availability are undergoing rapid modification at global scales. Both temperature and nutrients can influence consumer physiology and growth via several mechanisms. We examined how temperature and the nutrient content of food interact to affect consumption, growth and body stoichiometry of a detritivorous consumer (the caddisfly Pycnopsyche gentilis).

  2. In a 7-week growth study, P. gentilis larvae were reared at two different temperatures (5 and 10 °C) while fed conditioned red maple (Acer rubrum) litter at one of two stoichiometric qualities (manipulated by raising phosphorus supply in one litter conditioning treatment; Amb: mean litter P = 0.03%, mean litter N = 0.79%; Hi-P: mean litter P = 0.14%, mean litter N = 1.2%).

  3. Temperature and litter quality had differential effects on bulk consumption, element-specific (N and P) consumption, growth and elemental body content of P. gentilis larvae. Temperature was the only factor affecting bulk feeding rates. Larvae in the Warm/Hi-P treatment had by far the highest growth rates; the negligible growth in the Cold/Amb treatment was increased by either higher temperature (Warm/Amb) or higher food quality (Cold/Hi-P).

  4. Higher temperature had no effect on body P content in Hi-P treatments, but decreased body P content in the Amb treatments. Shifts in temperature and resource quality are both important components of global change and our results show that these factors can have interactive effects on detrital food webs, through which most primary production flows.