Meeting Abstract

5.5  Jan. 4  Reproductive character displacement in a wood cricket Gryllus fultoni (Gryllidae: Orthoptera) JANG, Yikweon*; CHOE, Jae C; Ewha Womans University, Seoul, Republic of Korea; Ewha Womans University, Seoul, Republic of Korea jangy@ewha.ac.kr

Two wood cricket species, Gryllus fultoni (Orthoptera: Gryllidae) and G. vernalis, occur together in the eastern US and have a similar calling song structure. A previous study revealed that chirp and pulse rates in G. fultoni was highest (greatest difference vis-�-vis chirp rate in G. vernalis) in sympatric populations, intermediate in near allopatric populations that were located close to the sympatric zone, and lowest in allopatric populations. Here we investigated the song discrimination of females from sympatric and allopatric populations of G. fultoni. Stimuli presented were representative of calling songs in three classes of G. fultoni populations (sympatric, near allopatric, and far allopatric), a calling song of G. vernalis, and three calling songs with parameter values that were intermediate between the songs of far allopatric G. fultoni and G. vernalis. In the single-stimulus playbacks, females of all G. fultoni populations responded poorly if at all to the heterospecific stimulus. Females of sympatric and near allopatric populations responded poorly to all intermediate stimuli, but females of far allopatric populations frequently responded to these sounds. In the two-stimulus playbacks, females of sympatric and near allopatric populations generally discriminated against intermediate and heterospecific stimuli. However, females of far allopatric populations often did not discriminate against intermediate stimuli whose characteristics resembled the calling songs of G. vernalis. The divergent pattern of song discrimination between sympatric and far allopatric populations was thus generally congruent with the pattern of divergence in chirp and pulse rates and was consistent with a pattern predicted by reproductive character displacement.