Meeting Abstract
The relatively low metabolic rates of larger organisms compared to small organisms is among the most pervasive trends in biology. Yet, most studies that examine the relationship between body mass and metabolic rate are conducted across species. Here we examine resting and recovery metabolic rates in a species of brentine weevil that vary more than an order of magnitude in size among adults. These weevils also exhibit extreme positive allometry of their sexually selected rostra, used as weapons during male-male contests; larger male carry proportionally larger weapons for their body size. We find resting metabolic rates scales with a similar slope as those found across species, consistent with low metabolic scaling. Metabolic rates after sustained activity were higher in all individuals yet scaled with the same hypo-allometric relationship with body size as during rest. Further, cuticle tissue of the weapon scales in direct proportion to mass of the weapon, while soft tissue within the weapon scales with low allometry. These results suggest that as these weapons get larger in size they are comprised of a proportionally higher mass of metabolically inactive structural tissue and proportionally less active metabolic tissue. Our findings reveal the low scaling of metabolic rate in a single species is consistent with across species trends, and that larger individuals carry disproportionally larger weapons but likely at a reduced metabolic cost per gram of tissue.
