INTERSPECIFIC AND INTRASPECIFIC VARIATION IN NIGHTLY CALLING DURATION IN FIELD CRICKETS, GRYLLUS-INTEGER AND G RUBENS (ORTHOPTERA, GRYLLIDAE)

The time that male field crickets spend calling was measured electronically in the laboratory to examine nightly calling duration from different species and populations. Male Gryllus integer from Davis, CA, and Las Cruces, NM, called approximately 7 h per 24 h, whereas male G. integer from San Antonio and Austin, TX, and Norman, OK, and male G. rubens from McAlester, OK, and Arkadelphia, AR, called approximately 3 h per 24 h. Variation in duration of calling is discussed in terms of the energetic costs of producing song and selection against calling by acoustically orienting parasites and predators. Duration of calling was also studied in field-collected male G. integer. Males were first observed in field populations and then collected. Those males observed calling in the field later called significantly more in the laboratory than males observed showing non-calling, satellite behavior. Flying G. integer collected under lights were intermediate in their calling duration to calling and satellite males. These data are discussed in terms of the heritability of nightly calling song duration in field crickets.