Meeting Abstract

77.2  Monday, Jan. 6 08:30  Nutrient availability influences resting metabolism in wing-dimorphic Gryllus firmus crickets CLARK, R.M.*; ZERA, AJ; BEHMER, S; Texas A&M University; University of Nebraska-Lincoln; Texas A&M University r11clark@gmail.com

Nutrient availability shapes physiological function, yet connections between feeding, metabolic physiology and life-history trade-offs have rarely been explored. We examined how variation in the availability of dietary protein and carbohydrate affects feeding and resting metabolic rates of female Gryllus firmus crickets from a population selected to produce either flightless (short-winged; SW) or flight-capable [long-winged; LW(f)] adults. In this species, flight ability trades-off with early fecundity; SW females reproduce sooner than their LW counterparts. We gave newly molted adult females (n=130) one of 13 diets with different relative and absolute amounts of protein and carbohydrate and allowed them to feed for five days, before measuring resting metabolism via indirect calorimetry (carbon dioxide production). Feeding patterns were similar for both morphs, and highest on dilute diets with balanced ratios of protein to carbohydrate. The crickets could not fully compensate for nutrient dilution, however; individuals on high-nutrient diets obtained twice as much total protein and carbohydrate, and SW crickets gained more mass than LW crickets, especially on high-protein foods. Despite these differences, nutrient availability influenced mass-independent resting metabolic rates equivalently for both morphs; crickets that acquired more nutrients had higher resting metabolism. The latter finding demonstrates a direct connection between food quality and resting metabolism, while the morph-specific mass gain patterns indicate further complexity at play in the expression of the dispersal-reproduction life-history trade-off.