The jump of the click beetle (Coleoptera: Elateridae)—energetics and mechanics
Some aspects of the energetics and mechanics of two jumps made by a single specimen of Athous haemorrhoidalis (Fab.) are considered. In the first jump, the 40 mg beetle had a take-off velocity of 2–4 m/s and the jumping action occurred in about 064 ms; in the second jump, the take/off velocity was 2–26 m/s and the jumping action took about 0–53 ms. Energy budgets have been constructed in two different ways for each jump, and the total energy involved in each case was estimated to lie between 1–6 × 10−4 J and 3–8 × 10−4 J. Power output during the jumping action (a “catapult”) lay between 80 × 103 W/kg muscle and 180 × 103 W/kg muscle, whilst power output during the energy storing pre-jump period (of about 0–4 s) was at least 130 W/kg muscle (at over 25°C). Forces and tensile stresses in the jumping muscles and their apodemes have also been calculated. The method of jumping appears to be fairly inefficient in that only about 50–60% of the energy expended in the jumping action is energy of translation, which actually raises the beetle.