Data from: The hidden cost of sexually selected traits: the metabolic expense of maintaining a sexually selected weapon

Sexually selected weapons are among the most exaggerated traits in nature.
Theory frequently assumes a high cost of this exaggeration; yet, those
costs are rarely measured. We know very little about the energetic
resources required to maintain these traits at rest and the difference in
energetic costs for the largest relative to the smallest individuals.
Knowledge in this area is crucial; resting metabolic rate can account for
30-40% of daily energy expenditure in wild animals. Here, we capitalized
on the phenomenon of autotomy to take a unique look at weapon maintenance
costs. Using Leptoscelis tricolor (Hemiptera: Coreidae) we measured CO2
production rates before and after a weapon was shed. Males in this insect
species use enlarged hind femora as weapons in male-male combat, and yet
can shed them readily, without regeneration, upon entrapment. We found
that metabolic rate decreased by an average of 23.5% in males after leg
loss and by 7.9% in females. Notably, larger males had less of a drop in
metabolic rate per gram of weapon lost. Our findings suggest sexually
selected weapons contribute to a large portion of resting metabolic rate
in males, but these costs do not scale in direct proportion to size;
larger males can have larger weapons for a reduced metabolic cost. These
energetic maintenance costs may be integral to the evolution of the
allometries of sexually selected weapons, and yet they remain largely
unexplored.