Abstract Age-specific rates of survival and reproduc-tion in iteroparous organisms remain a key issue in pop-ulation ecology. How patterns of survival vary with age in large herbivores is well known; much less is known regarding age-specific patterns of reproduction. The se-nescence hypothesis predi...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.456.7634 http://folk.uio.no/atlemy/pdf/art26.pdf |
| Summary: | Abstract Age-specific rates of survival and reproduc-tion in iteroparous organisms remain a key issue in pop-ulation ecology. How patterns of survival vary with age in large herbivores is well known; much less is known regarding age-specific patterns of reproduction. The se-nescence hypothesis predicts a progressive loss of func-tion accompanied by decreased performance with age. The terminal investment hypothesis predicts that the pro-portion of resources a mother invests (i.e. effort relative to costs) is expected to increase toward the end of her life-span, when the number of offspring she can expect to rear in the future is low. Assuming that the costs re-main stable, the terminal investment hypothesis predicts increased reproductive effort with age. We used data on body weight of 1,956 semi-domestic reindeer (Rangifer tarandus) calves from females with known age and weight to test these two (not mutually exclusive) hypoth-eses. Body weight of calves clearly decreased after 7 years of age was reached (also after controlling for female body weight), which was in support of the senes-cence hypothesis. We can conclude that either the termi-nal investment hypothesis is wrong, and/or the reproduc-tive costs increase with age in female reindeer. |
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