Temperature and nutrient availability interact to mediate growth and body stoichiometry in a detritivorous stream insect

Abstract

Summary 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). 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%). 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). 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.

A stream insect detritivore violates common assumptions of threshold elemental ratio bioenergetics models

“…Previous studies indicated potential intraspecific variation in body C ∶ P among some aquatic insects (Cross et al 2003, Small and Pringle 2010, Kendrick and Benstead 2013. In our study, oak-fed P. lepida exhibited nonstrict homeostasis (H = 4.74), whereas maple-fed P. lepida appeared to be strictly homeostatic.…”

“…Maximum rates of P. lepida growth in our study (0.046/d) approached or were greater than maximum growth for Pycnopsyche spp. in previous studies (0.041, 0.061, and 0.030/d; Eggert and Wallace 2003, Chung and Suberkropp 2009, Kendrick and Benstead 2013, suggesting that conditions closely approximated those of optimal growth. Moreover, despite the limitations of growth-based methods, our study shows that, compared to many bioenergetics models, growth data across varying resource C ∶ P provide a less error-prone means of estimating TER C ∶ P that more accurately represents organism stoichiometry and should be more applicable to diverse taxa.…”

Changes in rainfall level and litter stoichiometry affect aquatic community and ecosystem processes in bromeliad phytotelmata

“…This pattern is probably due to the decrease in the relative concentration of growth-limiting nutrients (N) in the system (Kendrick & Benstead, 2013;Sardans et al, 2012). This pattern is probably due to the decrease in the relative concentration of growth-limiting nutrients (N) in the system (Kendrick & Benstead, 2013;Sardans et al, 2012).…”

Development of Dichelops melacanthus and its egg parasitoid Telenomus podisi reared on Bt-soybean MON 87701 x MON 89788 and its near conventional isoline under different temperatures

“…The importance of the infl uence of temperature on the biology and biodynamics of pests has been increasingly studied (Nondillo et al 2008, Silva et al 2011, Kendrick and Benstead 2013. In Brazil, some insects have recently gained greater importance, and it is believed that the occurrence of higher temperatures has favored some insect pests.…”