Energetics of singing in crickets: Effect of temperature in three trilling species (Orthoptera: Gryllidae)

Abstract

1. Oxygen consumptions of resting and trilling crickets were measured at various temperatures. Oscillograms taken at comparable temperatures were used to identify the major factors determining the cost of stridulation. 2. Species used wereAnurogryllus arboreus (mass ≃0.4 g), wing stroke rate at 23°C of 71 strokes per s; andOecanthus celerinictus andO. quadripunctatus, two sibling species, (masses ≃0.06 g), wing stroke rates at 23°C of 57 and 38 strokes per s respectively. 3. At 23°C the three species have similar total mass-specific metabolism during singing (\(\dot V_{O_2 }\) μl·(g·h)−1; Table 3) even though their wing stroke rates are different. 4. A. arboreus has no change in net singing metabolism with increasingTa; however, cost per wing stroke decreases slightly. TheOecanthus both increase their net singing costs with increasedTa and the cost per wing stroke remains roughly constant.O. quadripunctatus has a cost per wing stroke about 1.6 timesO. celerinictus (Tables 1, 3; Fig. 10).A. arboreus does not elevate its thoracic temperature significantly while stridulating and it is doubtful that tree crickets thermoregulate due to their small size. 5. The cost of singing inA. arboreus varies from 10 to 16 times resting; inOecanthus, from 6 to 12 times resting (Table 3). 6. Although the two tree cricket species have different wing stroke rates at any common temperature, the number of file teeth struck per s is almost the same;A. arboreus strikes nearly twice as many teeth per s as do either of the tree crickets (Fig. 9). 7. The two factors that explain most of the variation in net cost of trilling are the wing stroke rate (Fig. 10) and the number of teeth struck·(wing stroke)−1. Related factors that merit study are interspecific differences in file tooth depth and angle, wing mass, and wing velocity. 8. For three species of crickets and two species of katydids the average net cost of trilling is about 1.5×10−5 ml O2·(g·wing stroke)−1 (Fig. 10). 9. Chirping should be energetically less expensive than trilling, with costs equivalent to the average cost per wing stroke times the total number of wing strokes per time. The latter factor is 10–95% lower in chirping species than in trillers. 10. An estimated daily respiratory energy budget shows calling taking about 56% of the daily respiratory budget ofO. celerinictus and 26% forA. arboreus (Table 4).