The metabolic costs of sexual signalling in the chirping katydid Plangia graminea (Serville) (Orthoptera: Tettigoniidae) are context dependent: cumulative costs add up fast [RESEARCH ARTICLE]

Marce Doubell, Paul B. C. Grant, Nanike Esterhuizen, Corinna S. Bazelet, Pia Addison, and John S. Terblanche Katydids produce acoustic signals via stridulation, which they use to attract conspecific females for mating. However, direct estimates of the metabolic costs of calling to date have produced diverse cost estimates and are limited to only a handful of insect species. Therefore, in this study, we investigated the metabolic cost of calling in an unstudied sub-Saharan katydid, Plangia graminea. Using wild-caught animals, we measured katydid metabolic rate using standard flow-through respirometry while simultaneously recording the number of calls produced. Overall, the metabolic rate during calling in P. graminea males was 60% higher than the resting metabolic rate (0.443±0.056 versus 0.279±0.028 ml CO2 h–1 g–1), although this was highly variable among individuals. Although individual call costs were relatively inexpensive (ranging from 0.02 to 5.4% increase in metabolic rate per call), the individuals with cheaper calls called more often and for longer than those with expensive calls, resulting in the former group having significantly greater cumulative costs over a standard amount of time (9.5 h). However, the metabolic costs of calling are context dependent because the amount of time spent calling greatly influenced these costs in our trials. A power law function described this relationship between cumulative cost (y) and p...
Source: Journal of Experimental Biology - Category: Biology Authors: Tags: RESEARCH ARTICLE Source Type: research