Prey productivity and predictability drive different axes of life-history variation in carnivorous marsupials

Variation in life-history strategies has usually been characterized as a single fast-slow continuum of life-history variation, in which mean lifespan increases with age at maturity as reproductive output at each breeding event declines. Analyses of plants and animals suggest that strategies of repro...

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Bibliographic Details
Published in:Proceedings of the Royal Society. B, Biological sciences Biological sciences, 2018-10, Vol.285 (1890), p.20181291
Main Authors: Collett, Rachael A, Baker, Andrew M, Fisher, Diana O
Format: Article
Language:English
Subjects:
Animals
Carnivory
Evolution
Female
Insecta
Life History Traits
Litter Size
Longevity - physiology
Marsupialia - physiology
Rain
Reproduction - physiology
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Summary:Variation in life-history strategies has usually been characterized as a single fast-slow continuum of life-history variation, in which mean lifespan increases with age at maturity as reproductive output at each breeding event declines. Analyses of plants and animals suggest that strategies of reproductive timing can vary on an independent axis, with iteroparous species at one extreme and semelparous species at the other. Insectivorous marsupials in the Family Dasyuridae have an unusually wide range of life-history strategies on both purported axes. We test and confirm that reproductive output and degree of iteroparity are independent in females across species. Variation in reproductive output per episode is associated with mean annual rainfall, which predicts food availability. Position on the iteroparity-semelparity axis is not associated with annual rainfall, but species in regions of unpredictable rainfall have longer maximum lifespans, more potential reproductive events per year, and longer breeding seasons. We suggest that these two axes of life-history variation arise because reproductive output is limited by overall food availability, and selection for high offspring survival favours concentrated breeding in seasonal environments. Longer lifespans are favoured when reproductive opportunities are dispersed over longer periods in environments with less predictable food schedules.
ISSN:0962-8452
1471-2954
DOI:10.1098/rspb.2018.1291