Jf. Tuckerman et al., RELIABLE ACOUSTIC CUES FOR FEMALE MATE PREFERENCE IN A KATYDID (SCUDDERIA-CURVICAUDA, ORTHOPTERA, TETTIGONIIDAE), Behavioral ecology, 4(2), 1993, pp. 106-113
The call of male Scudderia curvicauda (Orthoptera: Tettigoniidae) cons
ists of a series of phrases, and each phrase contains syllables. Femal
es respond to the male signal with ticks that follow male phrases afte
r a specific period of time. Pair formation takes place after males lo
cate the female using her response sounds. Repeated recordings of male
s revealed that the average number of syllables produced per phrase wa
s a stable, within-male parameter and that this parameter was a reliab
le predictor of male size (pronotum length). Thus, phrase length could
be a reliable cue by which females evaluate males. We presented virgi
n females with a sequential choice of two tape-recorded male calls tha
t differed only in the mean number of syllables produced per phrase. T
wo different playback tapes were used, and each female was tested on e
ach of 5 consecutive days with the same playback tape. Females respond
ed more often and with a greater number of ticks to calls containing m
ore syllables per phrase, and this preference was maintained throughou
t the testing period. Male size was a poor predictor of the size of th
e spermatophore food-gift produced by the male; therefore, females are
probably not selecting males for this attribute. For one of the playb
ack tapes, there was a significant increase in female responsiveness o
ver several playback trials, suggesting that females may employ a fall
ing-threshold tactic with respect to mate preference.