Intraspecific scaling and early life history determine the cost of free ‐flight in a large beetle (Batocera rufomaculata)

Methodological restrictions limit our understanding of the scaling of flight energetics with body mass in free-flying insects particularly at the intraspecific level where variation in body mass is low. The tree-boring beetle,Batocera rufomaculata (i), exhibits a large intraspecific variation in adult size resulting from the condition of the host tree during larval growth (ii). We applied the13C stable isotope method to investigate the scaling of energetics with body mass during free-flight in an open environment of adults ranging in body mass from 1 to 7 g (iii). We show that flight metabolic rate scales with body mass to the power of 0.57, with smaller conspecifics having up to 2.3 fold higher mass-specific flight metabolic rate than larger ones (iv). While the scaling exponent for free-flight metabolic rate was found to be similar to that measured in tethered-flight, the cost was 2.7 fold higher even after attempting to accurately correct for the effects of the tether. Hence, now enabled by the13C technique, the metabolic cost of flight and its scaling with body mass can and should be studied under free-flight conditions to obtain accurate estimates. AbstractThe scaling of the energetic cost of locomotion with body mass is well documented at the interspecific level. However, methodological restrictions limit our understanding of the scaling of flight metabolic rate (MR) in free-flying insects. This is particularly true at the intraspecific level, where variation in body ma...
Source: Insect Science - Category: Biology Authors: Tags: ORIGINAL ARTICLE Source Type: research