Fig. 3.

Diel and seasonal variation in fictive calls. (A) A night versus day comparison of mean baseline grunt duration in reproductive and non-reproductive males. Asterisk, reproductive males at night have a significantly higher fictive grunt duration than all other groups (see text). (B) Call duration change over 120 min with 40 stimulus trains at each recording. Reproductive males were housed on a 14 h L:10 h D cycle, and non-reproductive in 10 h L:14 h D cycle (all N=3). There was a significant, overall effect of reproductive state (see text). (C) 100 stimulus trains (1 s^–1) at baseline in reproductive males at night versus 100 stimulus trains at 120 min in all groups (N=5 for reproductive night; 3 each for reproductive day, non-reproductive night and non-reproductive day; 6 each for 24 h D and baseline reproductive night). Letters (a, b, c) denote significant differences (see text). (D) The call threshold stimulus current significantly decreases in reproductive (14 h L:10 h D) males at night, but rises during the day (asterisks indicate significant differences, see text).