Bioacoustics of Conocephalus (Anisoptera) ictus

Diagnostic description.— General characteristics as described above, body quite robust as for the genus; most individuals in Costa Rican population brachy- to mesopterous, less frequently fully macropterous. Stridulatory file of male 1.63 mm long, with 61 teeth, maximum width of file 68.5 μm ( Fig. 40 B); teeth of file thick, peg-like, nearly uniformly spaced along entire file. Left (upper) mirror of stridulatory apparatus as in Fig. 1 D, as long as or slightly longer than eye diameter. Fastigium of vertex as wide as 3/4 of scapus, its sides slightly divergent towards apex. Outer ventral edge of hind femur unarmed or armed with 1-3 minute, black spines. Male cercus as in Fig. 39 C; ovipositor only slightly shorter than hind femur (ratio ovipositor/hind femur 0.79-0.89), straight ( Fig. 2 D). Coloration .— General coloration pale green, dorsal band on head and pronotum very dark, often nearly black, bordered by two thin, lighter stripes; posterior half of abdomen in male yellow to reddish-brown, cerci yellow to light brown; abdomen in females usually green or faintly yellowish. Measurements .— Table 2 . Bioacoustics.— The call of C. ictus is similar to that of C. cinereus , and consists of two parts: a train of continuous buzz followed by a series of short, individual chirps (in C. cinereus the sequence is reversed and the buzz always follows the individual chirps) ( Fig. 51 A-B). At 32°C the continuous buzzes last 1.68- 13.86 s (avrg. 6.15±4.05, n=17) and consist of pulses (chirps) produced at the rate of 18- 19/s, with each pulse lasting 50-54 ms (avrg. 51.2±0.7, n=30). The slow series last 0.57- 2.79 s (avrg. 1.64±0.68, n=13) and consist of 3-6 individual pulses produced at the rate of 2.8-3/s. Within the audible part of the call most energy is allocated between 10 and 17 kHz.