Abstract: Male chorusing and female choice in a bush katydid, Scudderia pistillata (Orthoptera: Tettigoniidae: Phaneropterinae)
Male katydids call in choruses to attract females. Some produce complex calls that potentially encode signaler quality through variability in call parameters. Male Scudderia pistillata have a unique call compared to other katydids in that they produce a counting series. In field measurements and laboratory experiments I have investigated the spatial structure of the chorus, call variation among males, and acoustic interactions among males and females. In the field, marked males often call from the same perch for several weeks with nearest neighbor distances around 8m ± 4m. Average males count by increasing the number of pulses in successive calling bursts from 3 to 9, then repeat 9 for several bursts per bout, but there is variation in the ascending sequence and number of repeats. Call parameters investigated thus far are not correlated with physical traits indicative of male quality. In response to laboratory playback of male calls that have been altered to produce perfect counting series or just repeat portions, focal males called in response and produced an ascending sequence, but not a repeated series. Further experiments will probe this aspect of male-male interaction more fully. Female phaneropterine katydids produce an auditory response with a species-specific delay after a male stops calling. I will use playbacks of altered male calls to investigate whether females will indicate their preference of male calls, which will then be compared with actual male quality. These findings will then be related back to male calling characteristics in the field, including determining active chorusing space.
