@article {1819,
	title = {Confidence of paternity and paternal care: covariation revealed through the experimental manipulation of the mating system in the beetle Onthophagus taurus},
	journal = {Journal of Evolutionary Biology},
	volume = {15},
	year = {2002},
	pages = {784-795},
	abstract = {Theoretical models of paternal care predict that facultative reductions in male care may occur under certain conditions. One important parameter that has been shown to influence the outcome of these models is a male{\textquoteright}s confidence of paternity. In this study, we tested whether the amount of care provided by horned males in the dimorphic beetle, Onthophagus taurus, varied with his confidence of paternity. Male care results in an increased weight of dung provided in the brood masses produced by the pair. Using the sterile male technique we showed that a horned male{\textquoteright}s paternity declined with the number of sneak males in the population. The relationship was nonlinear, with paternity declining most rapidly between a frequency of one and three sneaks, and stabilizing thereafter at about 50\%. A horned male{\textquoteright}s paternity was directly related to the number of copulations with the female, relative to the number of copulations achieved by sneaks. Horned males were shown to reduce their care in relation to their declining paternity. Video analysis demonstrated that reductions in male care occurred through a combination of male desertion and a trade-off between caring and paternity assurance behaviours. The number of fights with sneak males was negatively related to the amount of care provided by a horned male. These results suggest that by gauging his expected paternity through the number of fights with sneaks, a horned male is able to assess his paternity and reduce his investment accordingly. Our data thus provide strong empirical support for the proposed link between paternity and paternal care. },
	keywords = {alternative mating tactics, confidence of paternity, Onthophagus taurus, paternal care},
	author = {Hunt, John and Simmons, Leigh W.}
}
@article {1822,
	title = {A cost of maternal care in the dung beetle Onthophagus taurus?},
	journal = {Journal of Evolutionary Biology},
	volume = {15},
	number = {1},
	year = {2002},
	note = {EnglishArticleJANJ EVOLUTION BIOL},
	pages = {57-64},
	abstract = {Parental care theory assumes that investment in current offspring will trade against future investment. A number of field studies on birds have used clutch size manipulations to demonstrate a survival cost to chick rearing. However, such studies do not account for costs accrued during earlier stages of reproduction because not all aspects of reproductive effort are manipulated by varying the number of nestlings. in this study, we investigate the effect of reproductive effort on female survival in the dung beetle, Onthophagus taurus. By experimentally manipulating mating status and dung availability, we demonstrate that virgin females survive longer than mated females and that the survival of mated females was negatively associated with the number of brood masses produced. Using a novel manipulation of the mating system, we separated the effects of egg production and maternal care on female survival. Previously, we have shown that females provisioning with the assistance of a major male provide relatively less care than unassisted females. However, paternal assistance did not alter the number of brood masses produced and hence the amount of reproductive effort that was allocated to egg production. Therefore, our finding, that female survival was increased when receiving paternal assistance provides, to our knowledge, the first definitive evidence that maternal care reduces female lifespan. These results are of major importance to theoretical models on the evolution of parental care.},
	keywords = {BREEDING BLUE TITS, BROOD-SIZE, CLUTCH-SIZE, drosophila-melanogaster, fluctuating asymmetry, LIFE-HISTORY EVOLUTION, life-history trade-off, Onthophagus taurus, PARENTAL, Parental care, reproductive cost, reproductive effort, SURVIVAL},
	author = {Hunt, J. and Simmons, L. W. and Kotiaho, J. S.}
}
