Paternal care has been neglected in behavioral studies because it is rare among most animals. Birds express wide variation in male care across a broad life-history gradient, but such variation among species remains poorly explored. At the same time, contributions of male assistance with incubation have been largely overlooked with the assumption that incubation is a time of low parental energy expenditure. We compared male versus female biparental incubation effort between two tropical antbird species in the northern Andes of Venezuela. We found that males and females apportion reproductive effort differently between these two species, but that male contributions of time and incubation effort were generally greater than for north temperate species which exhibit different life-history strategies. Males spent an equal or greater amount of time incubating, yet maintained lower egg temperatures than females during different age-specific stages of the incubation period. Despite sex differences in incubation temperatures, males rewarmed cold clutches at similar rates to females suggesting similar sex-specific physiological incubation abilities. For the first time in a nidicolous species, we found that temperatures experienced by developing embryos increased with age of eggs independent of male and female time spent on the nest. Our results suggest that males may benefit embryo development by minimizing time eggs experience cold temperatures during female absences, and concurrently benefit female physiological condition for future nesting efforts. Lastly, we report standardized measures of reproductive traits in these two endemic tropical species in hope of improving data collection efforts outside of North America. Standardized measures of reproductive traits are essential for improving our understanding of reproductive biology and avian life-history evolution among different regions of the world. The Tropical Andes are among one of the most species-rich areas in the world and represent an area of critical conservation concern. Yet, for many endemic taxa inhabiting this region even basic descriptions of reproductive traits are entirely absent. This study extends the range of variation in reproductive strategies among a broader range of species among geographical regions.
| Identifer | oai:union.ndltd.org:MONTANA/oai:etd.lib.umt.edu:etd-05072008-151032 |
| Date | 15 January 2009 |
| Creators | Schwartz, Brian A |
| Contributors | Thomas E Martin |
| Publisher | The University of Montana |
| Source Sets | University of Montana Missoula |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/octet-stream |
| Source | http://etd.lib.umt.edu/theses/available/etd-05072008-151032/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Montana or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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