Hatching Asynchrony in Birds: The Hypothesis of Sexual Conflict Over Parental Investment

1989 ◽  
Vol 134 (2) ◽  
pp. 239-253 ◽  
Author(s):  
Tore Slagsvold ◽  
Jan T. Lifjeld
Keyword(s):  
Sexual Conflict ◽  
Parental Investment ◽  
Hatching Asynchrony

scholarly journals Sexual conflict in humans: evolutionary consequences of asymmetric parental investment and paternity uncertainty

2009 ◽  
Vol 59 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Todd Shackelford ◽  
Aaron Goetz
Keyword(s):  
Sex Differences ◽  
Sperm Competition ◽  
Sexual Conflict ◽  
Parental Investment ◽  
Sexual Coercion ◽  
Evolutionary History ◽  
Internal Fertilization ◽  
Men And Women ◽  
Paternity Uncertainty ◽  
Evolutionary Consequences

AbstractWe argue that sexual conflict was a recurrent feature of human evolutionary history, just as it has been in every sexually reproducing species that does not practice life-long genetic monogamy. We suggest that the source of much of the conflict between men and women can be reduced to an asymmetry in reproductive biology. This asymmetry—fertilization and gestation occurring within women—produces (a) sex differences in minimum obligatory parental investment and (b) paternity uncertainty. We argue that these consequences of internal fertilization and gestation are responsible for many phenomena in humans, such as sexual coercion, commitment skepticism, sexual overperception, and a host of adaptations associated with sperm competition.

scholarly journals Yolk hormones and sexual conflict over parental investment in the pied flycatcher

2010 ◽  
Vol 65 (2) ◽  
pp. 257-264 ◽  
Author(s):  
Toni Laaksonen ◽  
Freya Adamczyk ◽  
Markus Ahola ◽  
Erich Möstl ◽  
C(Kate). M. Lessells
Keyword(s):  
Sexual Conflict ◽  
Parental Investment ◽  
Pied Flycatcher ◽  
Yolk Hormones

scholarly journals The evolutionary outcome of sexual conflict

2006 ◽  
Vol 361 (1466) ◽  
pp. 301-317 ◽  
Author(s):  
C(Kate). M Lessells
Keyword(s):  
Sexual Conflict ◽  
Parental Investment ◽  
The Other ◽  
Research Traditions ◽  
Antagonistic Coevolution ◽  
Evolutionary Changes ◽  
Sexually Antagonistic Selection ◽  
Collateral Harm ◽  
Sexually Antagonistic Coevolution

Inter-locus sexual conflict occurs by definition when there is sexually antagonistic selection on a trait so that the optimal trait value differs between the sexes. As a result, there is selection on each sex to manipulate the trait towards its own optimum and resist such manipulation by the other sex. Sexual conflict often leads additionally to the evolution of harmful behaviour and to self-reinforcing and even perpetual sexually antagonistic coevolution. In an attempt to understand the determinants of these different outcomes, I compare two groups of traits—those related to parental investment (PI) and to mating—over which there is sexual conflict, but which have to date been explored by largely separate research traditions. A brief review suggests that sexual conflict over PI, particularly over PI per offspring, leads less frequently to the evolution of manipulative behaviour, and rarely to the evolution of harmful behaviour or to the rapid evolutionary changes which may be symptomatic of sexually antagonistic coevolution. The chief determinants of the evolutionary outcome of sexual conflict are the benefits of manipulation and resistance, the costs of manipulation and resistance, and the feasibility of manipulation. All three of these appear to contribute to the differences in the evolutionary outcome of conflicts over PI and mating. A detailed dissection of the evolutionary changes following from sexual conflict exposes greater complexity than a simple adaptation–counter-adaptation cycle and clarifies the role of harm. Not all of the evolutionary changes that follow from sexual conflict are sexually antagonistic, and harm is not necessary for sexually antagonistic coevolution to occur. In particular, whereas selection on the trait over which there is conflict is by definition sexually antagonistic, collateral harm is usually in the interest of neither sex. This creates the opportunity for palliative adaptations which reduce collateral harm. Failure to recognize that such adaptations are in the interest of both sexes can hinder our understanding of the evolutionary outcome of sexual conflict.

Parental care and brood division in a songbird, the black redstart

Behaviour ◽  
2005 ◽  
Vol 142 (11-12) ◽  
pp. 1495-1514 ◽  
Author(s):  
Tudor I. Draganoiu ◽  
Laurent Nagle ◽  
Raphael Musseau ◽  
Michel Kreutzer
Keyword(s):  
Parental Care ◽  
Sexual Conflict ◽  
Parental Investment ◽  
Negative Relationship ◽  
Feeding Rates ◽  
Close Link ◽  
Brood Division ◽  
Black Redstart ◽  
Phoenicurus Ochruros ◽  
Brood Desertion

AbstractSexual conflict over parental care can be mediated through differences in male and female overall feeding rates, brood division or both. At present, it is not clear whether post-fledging brood division occurs due to sexual conflict over parental investment or is due to bi-parental cooperation, e.g. increase offspring fitness. We provide evidence suggesting that brood division in the black redstart, Phoenicurus ochruros is due to sexual conflict. Males and females had similar feeding contributions during the nestling stage, which is common for most passerine species. After fledging, each parent showed long-term feeding preferences for particular chicks within the brood. In most cases (74%; 17/23) both parents provided care but males tended to feed less fledglings than females did and in about a quarter of cases (26%; 6/23) females fed the whole brood by themselves. The relative amount of male to female post-fledging feedings showed a significant negative relationship with the proportion of fledglings cared for exclusively by the male. These results suggest (1) a close link between the amount of parental care and brood division; (2) sexual conflict can be mediated through brood division; (3) female redstarts appear to loose this conflict more often than male redstarts, with in the extreme cases males showing post-fledging brood desertion. A literature review shows brood division to occur in at least a dozen of songbird species but male black redstarts have the lowest relative post-fledging parental investment, expressed either as feeding rates or number of chicks in care.

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