Gnathoclita sodalis

(2 males recorded) We recorded two males from El Ensueno. To a human ear the song is a succession of zips delivered with engine-like regularity (Fig. 40A), each with a particulate, beady quality at any temperature. Singing is interrupted irregularly after several seconds. For one male recorded in the lab with high frequency equipment (96-2, 18°C) zip (train) period was 244 ms (c.v.4.1%); each zip had 22-24 short sinusoidal pulses (Fig. 40 A,B). The number of pulses for the other male (96-1, 24°C) was only 13-16. It is these short pulses that give the zip its particulate quality. The insect's spectrum contains but one peak (Fig. 40 C,E) at 15-16 kHz (96-1, 15.3 kHz, C.v. 1.0%; 96-2, 16.2 kHz, c.v1.7%). In spite of the brevity of the pulses this is still a rather narrow peak and this insect produces a moderately musical song (Fig. 40 C,E).

Male 96-1 was recorded at two temperatures with audiolimited equipment in the field at 12°C and later in a hotel room in Cali at 24°C using the S25 bat detector. In the field this male sang head down on an understory shrub about
waist height at the spot where a pair of this species had been observed mating the night previous. The pulse train period in the field was 484 ms at 12°C, but at 24Cit shortened to 178 ms. Trains in the field had a duration of 53.8 ms with about 16 pulses per train. At the higher temperature trains were much shorter, 30.5 ms, but with about the same number of pulses (15). Wide changes in pulse and train rates occur with temperature.

Pulse durations are typically less than 1 ms, becoming slightly longer toward the end of the train. The mean duration of the penultimate pulse (96-2) was 1.2 ms (c.v 9.3%). This male's last pulse (2.9 ms, C.v. 4.8%) ended consistently with a uniformly slow-falling amplitude envelope (Fig. 40D). [1]

Références