Time allocation during breeding was studied in unmated male common frogs Rana temporaria Linnaeus in three populations along a gradient of altitude, climate and length of feeding season. The length of the breeding period decreased with increased altitude. All three populations had low activity levels (0-33% of the time during peak chorusing). Peak chorusing in the lowland population was due to more males participating in the chorus, and not to increased individual calling activity. An increase in mating effort at this time was nevertheless indicated by the males 'using more time for moving in the pond. At both montane localities, males called more sparsely, and not at all at night. During peak chorusing, calling and moving males became significantly rarer with increased altitude. Aggressive males were significantly rarer in the alpine population. Between-locality variation was evident in fat reserves after hibernation and during breeding; the relative fat body mass was significantly higher in lowland males than in mid-altitude and alpine males. We discuss male mating activity (here: calling, mate searching and aggression) in ultimate terms as a trade-off between mate acquisition and survival.
|Tidskrift||Annales Zoologici Fennici|
|Status||Publicerad - 1991|
- Biologi (106)