Abstract
In many bird populations, variation in the
timing of reproduction exists but it is not obvious how this
variation is maintained as timing has substantial fitness
consequences. Daily energy expenditure (DEE) during the
egg laying period increases with decreasing temperatures
and thus perhaps only females that can produce eggs at low
energetic cost will lay early in the season, at low temperatures.
We tested whether late laying females have a higher
daily energy expenditure during egg laying than early
laying females in 43 great tits (Parus major), by comparing
on the same day the DEE of early females late in their
laying sequence with DEE of late females early in their egg
laying sequence. We also validated the assumption that
there are no within female differences in DEE within the
egg laying sequence. We found a negative effect of temperature
and a positive effect of female body mass on DEE
but no evidence for differences in DEE between early and
late laying females. However, costs incurred during egg
laying may have carry-over effects later in the breeding
cycle and if such carry-over effects differ for early and late
laying females this could contribute to the maintenance of
phenotypic variation in laying dates.
Original language | English |
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Pages (from-to) | 631-638 |
Journal | Oecologia |
Volume | 168 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2012 |
Keywords
- international