A biological employment model of reproductive inequality

Continuing the centuries-long exchange between economics and biology, our model of reproductive skew is an adaptation of the principal-agent relationship between an employer and an employee. Inspired by the case of purple martins (Progne subis) and lazuli buntings (Passerina amoena), we model a dominant male whose fitness can be advanced not only by coercing a subordinate male but, where coercion is impossible or not cost-effective, also by providing positive fitness incentives for the subordinate that induce him to behave in ways that contribute to the dominant's fitness. We model a situation in which a dominant and subordinate contest over a variable amount of joint total fitness, both the level and division of which result from the strategies adopted by both. Thus there is not some given amount of potential fitness (or 'pie') that is to be divided between the two (or wasted in costly contests). The fitness incentives that in evolutionary equilibrium are conceded to the subordinate by the dominant maximize the dominant's own fitness. The reason is that the larger pie resulting from the subordinate's increased helping more than compensates for the dominant's reduced fitness share. But the conflict over fitness shares nonetheless limits the size of the pie. This article is part of the theme issue 'Evolutionary ecology of inequality'.

Unveiling the Necrocapitalist Dimensions of the Shadow Carceral State: On Pay-to-Stay to Recoup the Cost of Incarceration

The expansion of monetary sanctions constitutes what Beckett and Murakawa describe as the "shadow carceral state," where covert penal power is expanded through institutional annexation by blending civil, administrative, and criminal legal authority. A growing body of work on monetary sanctions has begun to dissect covert penal power by tracing increased civil and administrative pipelines to incarceration, civil financial alternatives to criminal sanctions, and innovations to generate criminal justice revenue. However, institutional annexation and innovation in the form of contemporary pay-to-stay practices remain understudied and undertheorized. In this article, I first examine statutes and practices to theorize pay-to-stay as exemplary of the shadow carceral state-an outcome of legal hybridity and institutional annexation legitimated using the legal construction of "not punishment," which frames monetary sanctions as non-punitive. Second, I expand Beckett and Murakawa's framework to argue pay-to-stay practices reveal how the shadow carceral state compounds or initiates the civil death of those charged. I broaden our notion of civil death to include financial indebtedness to the shadow carceral state. I suggest covert penal power expands through the accumulation of resources extracted from people marked for civil death through criminal justice contact. Finally, I conclude that monetary sanctions such as pay-to-stay reveal how the shadow carceral state expands covert penal power through necrocapitalism, meaning institutional accumulation occurs through dispossession and the subjugation of life to the power of death.

Commodity-specific punishment for experimentally induced defection in cooperatively breeding fish

Coercion is an important but underrated component in the evolution of cooperative behaviour. According to the pay-to-stay hypothesis of cooperative breeding, subordinates trade alloparental care for the concession to stay in the group. Punishment of idle subordinates is a key prediction of this hypothesis, which has received some experimental scrutiny. However, previous studies neither allowed separating between punishment and effects of disruption of social dynamics, nor did they differentiate between different helping behaviours that may reflect either mutualistic or reciprocal interaction dynamics. In the cooperative breeder Neolamprologus pulcher, we experimentally engineered the ability of subordinates to contribute to alloparental care by manipulating two different helping behaviours independently from one another in a full factorial design. We recorded the treatment effects on breeder aggression, subordinate helping efforts and submissive displays. We found two divergent regulatory mechanisms of cooperation, dependent on behavioural function. Experimental impediment of territory maintenance of subordinates triggered punishment by dominants, whereas prevented defence against egg predators released a compensatory response of subordinates without any enforcement, suggesting pre-emptive appeasement. These effects occurred independently of one another. Apparently, in the complex negotiation process among members of cooperative groups, behaviours fulfilling different functions may be regulated by divergent interaction mechanisms.

Negotiation and appeasement can be more effective drivers of sociality than kin selection

Two alternative frameworks explain the evolution of cooperation in the face of conflicting interests. Conflicts can be alleviated by kinship, the alignment of interests by virtue of shared genes, or by negotiation strategies, allowing mutually beneficial trading of services or commodities. Although negotiation often occurs in kin-structured populations, the interplay of kin- and negotiation-based mechanisms in the evolution of cooperation remains an unresolved issue. Inspired by the biology of a cooperatively breeding fish, we developed an individual-based simulation model to study the evolution of negotiation-based cooperation in relation to different levels of genetic relatedness. We show that the evolution of negotiation strategies leads to an equilibrium where subordinates appease dominants by conditional cooperation, resulting in high levels of help and low levels of aggression. This negotiation-based equilibrium can be reached both in the absence of relatedness and in a kin-structured population. However, when relatedness is high, evolution often ends up in an alternative equilibrium where subordinates help their kin unconditionally. The level of help at this kin-selected equilibrium is considerably lower than at the negotiation-based equilibrium, and it corresponds to a level reached when responsiveness is prevented from evolving in the simulations. A mathematical invasion analysis reveals that, quite generally, the alignment of payoffs due to the relatedness of interaction partners tends to impede selection for harsh but effective punishment of defectors. Hence kin structure will often hamper rather than facilitate the evolution of productive cooperation.