Sexual selection modulates genetic conflicts and patterns of genomic imprinting

Recent years have seen a surge of interest in linking the theories of kin selection and sexual selection. In particular, there is a growing appreciation that kin selection, arising through demographic factors such as sex‐biased dispersal, may modulate sexual conflicts, including in the context of male–female arms races characterized by coevolutionary cycles. However, evolutionary conflicts of interest need not only occur between individuals, but may also occur within individuals, and sex‐specific demography is known to foment such intragenomic conflict in relation to social behavior. Whether and how this logic holds in the context of sexual conflict—and, in particular, in relation to coevolutionary cycles—remains obscure. We develop a kin‐selection model to investigate the interests of different genes involved in sexual and intragenomic conflict, and we show that consideration of these conflicting interests yields novel predictions concerning parent‐of‐origin specific patterns of gene expression and the detrimental effects of different classes of mutation and epimutation at loci underpinning sexually selected phenotypes.     

Disclosure is Inadequate as a Solution to Managing Conflicts of Interest in Human Research

Disclosure is a common response to conflicts of interest; it is intended to expose the conflict to scrutiny and enable it to be appropriately managed. For disclosure to be effective the receiver of the disclosure needs to be able to use the information to assess how the conflict may impact on their interests and then implement a suitable response. The act of disclosure also creates an expectation of self-regulation, as the person with the conflicting interests will be mindful of their own potential biases and aware that their decisions may be monitored. This article discusses some of the problems of relying on disclosure as a solution to address conflicts of interest in research, including the added complexities around institutional conflicts of interest. The case of Dan Markingson illustrates these issues and highlights the vulnerable position relying on disclosure as a solution leaves research participants in.     

The evolution of hermaphroditism by an infectious male-derived cell lineage: an inclusive-fitness analysis

There has been much recent interest in the role for genetic conflicts to drive the evolution of genetic systems. Here we consider the evolution of hermaphroditism in the scale insect tribe Iceryini and the suggestion that this has been driven by conflict between a female and an infectious male tissue derived from her father. We perform an inclusive-fitness analysis to show that, owing to genetic relatedness between father and daughter, there is scope for collaboration as well as conflict over the establishment of the infectious tissue. We also consider the evolutionary interests of a maternally inherited bacterial symbiont that has been implicated in mediating the tissue's establishment. More generally, our analysis reveals that genetic conflicts can drive the evolution of hermaphroditism.     

Cheap talk when interests conflict

Most evolutionary analyses of animal communication suggest that low-cost signals can evolve only when both the signaller and the recipient rank outcomes in the same order. When there is a conflict of interest between sender and receiver, honest signals must be costly. However, recent work suggests that low-cost signals can be evolutionarily stable, even when the sender and the receiver rank outcomes in different orders, as long as the interest in achieving coordination is sufficiently great. In this paper, we extend this body of work by analysing a game theory model that shows that low-cost signals can evolve when there are conflicts of interest and no interest in coordination, as long as individuals interact repeatedly. We also present an empirical example indicating that female rhesus macaques, Macaca mulatta, use honest, low-cost, vocal signals to facilitate interactions when conflicts of interest exist. Copyright 2000 The Association for the Study of Animal Behaviour.     

Integrating biodiversity priorities with conflicting socio-economic values in the Guinean–Congolian forest region

Identifying important areas for conserving biodiversity has attracted much discussion, but relatively few studies have dealt with conflicting socio-economic interests in a manner that is fully accountable. For the Guinean–Congolian forest region, we applied quantitative methods to select a network of coarse-scale areas sufficient to represent all forest mammal and bird species at least once. In a separate exercise, we prioritised 50% of the region to represent the same species as many times as possible. In both cases, we sought to minimise potential conflicts between conservation and other socio-economic imperatives by considering benefit-to-cost ratios. We found that by choosing areas to reduce conflicts, we were able to increase markedly the proportion of selected areas with low or medium conflict and decrease the proportion with high conflict. Nonetheless, we cannot expect that conservation goals will always be met unless some of these conflicts are faced and resolved. By working together with specialists from both the biological and socio-economic fields, we show that easily implemented quantitative tools could be useful for supporting the process of finding important areas for biodiversity conservation, while avoiding much of the conflict with other interests.     

Conservationists,hunters and farmers: the European rabbit Oryctolagus cuniculus management conflict in the Iberian Peninsula

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Gendering ethnic conflicts: minority women in divided societies – the case of Muslim women in India

ABSTRACT

This article explores the practical and theoretical significance and long-term consequences of the failure to incorporate women’s interests in post-conflict negotiations by examining the case of Muslim women in India. Analyses of deeply divided societies must recognize that political competition and political violence do not affect all citizens equally. Also, the “larger picture” depicted by inter-community conflicts should not overshadow the effects of intra-community conflicts, which are no less important. Evident within each community conflict are the winners and the losers of the political accommodation process, in which the marginalized and weaker sections of each “side” of the conflict may be the real “losers”. Gendered analysis of ethnic conflicts and ethnic conflict resolution demands a reorientation of the concepts of conflict and security – Whose conflict is being solved and who is being secured?     

Financial Conflicts of Interest and Reporting Bias Regarding the Association between Sugar-Sweetened Beverages and Weight Gain: A Systematic Review of Systematic Reviews

Background

Industry sponsors'' financial interests might bias the conclusions of scientific research. We examined whether financial industry funding or the disclosure of potential conflicts of interest influenced the results of published systematic reviews (SRs) conducted in the field of sugar-sweetened beverages (SSBs) and weight gain or obesity.

Methods and Findings

We conducted a search of the PubMed, Cochrane Library, and Scopus databases to identify published SRs from the inception of the databases to August 31, 2013, on the association between SSB consumption and weight gain or obesity. SR conclusions were independently classified by two researchers into two groups: those that found a positive association and those that did not. These two reviewers were blinded with respect to the stated source of funding and the disclosure of conflicts of interest.We identified 17 SRs (with 18 conclusions). In six of the SRs a financial conflict of interest with some food industry was disclosed. Among those reviews without any reported conflict of interest, 83.3% of the conclusions (10/12) were that SSB consumption could be a potential risk factor for weight gain. In contrast, the same percentage of conclusions, 83.3% (5/6), of those SRs disclosing some financial conflict of interest with the food industry were that the scientific evidence was insufficient to support a positive association between SSB consumption and weight gain or obesity. Those reviews with conflicts of interest were five times more likely to present a conclusion of no positive association than those without them (relative risk: 5.0, 95% CI: 1.3–19.3).An important limitation of this study is the impossibility of ruling out the existence of publication bias among those studies not declaring any conflict of interest. However, the best large randomized trials also support a direct association between SSB consumption and weight gain or obesity.

Conclusions

Financial conflicts of interest may bias conclusions from SRs on SSB consumption and weight gain or obesity. Please see later in the article for the Editors'' Summary     

Conflicts over host manipulation between different parasites and pathogens: Investigating the ecological and medical consequences

When parasites have different interests in regard to how their host should behave this can result in a conflict over host manipulation, i.e. parasite induced changes in host behaviour that enhance parasite fitness. Such a conflict can result in the alteration, or even complete suppression, of one parasite's host manipulation. Many parasites, and probably also symbionts and commensals, have the ability to manipulate the behaviour of their host. Non‐manipulating parasites should also have an interest in host behaviour. Given the frequency of multiple parasite infections in nature, potential conflicts of interest over host behaviour and manipulation may be common. This review summarizes the evidence on how parasites can alter other parasite's host manipulation. Host manipulation can have important ecological and medical consequences. I speculate on how a conflict over host manipulation could alter these consequences and potentially offer a new avenue of research to ameliorate harmful consequences of host manipulation.     

Sexual conflict over mating and fertilization: an overview

Sexual conflict is a conflict between the evolutionary interests of individuals of the two sexes. The sexes can have different trait optima but this need not imply conflict if their optima can be attained simultaneously. Conflict requires an interaction between males and females (e.g. mating or parental care), such that the optimal outcomes for each sex cannot be achieved simultaneously. It is important to distinguish between battleground models, which define the parameter space for conflict and resolution models, which seek solutions for how conflicts are resolved. Overt behavioural conflict may or may not be manifest at resolution. Following Fisherian principles, an immediate (i.e. direct) benefit to a male that has a direct cost to his female partner can have an indirect benefit to the female via her male progeny. Female resistance to mating has been claimed to represent concurrence rather than conflict, due to female benefits via sons (males with low mating advantage are screened out by resistance). However, the weight of current evidence (both theoretical and empirical) supports sexual conflict for many cases. I review (i) conflicts over mate quality, encounters between males and females of genetically diverged subpopulations, mating rate and inbreeding, (ii) the special features of postcopulatory sexual conflict and (iii) some general features of importance for conflict resolution.     

Sexual cannibalism and sperm competition in the golden orb-web spider Nephila plumipes (Araneoidea): female and male perspectives

Mating systems are frequently shaped by conflicts over reproductive interests between males and females. Sexual cannibalism canbe an especially dramatic manifestation of such conflicts.However, the resolutions of this conflict differ among sexuallycannibalistic spider species. Cannibalism may be in the interestof both sexes when females consume males as a foraging decisionto improve fecundity and/or males sacrifice their bodies toincrease fertilization success. In other species, females exertsequential choice of partner by selectively terminating copulationthrough cannibalism while males fail to obtain a paternityadvantage. Here, we investigate the adaptive value of cannibalismin the orb-web spider Nephila plumipes where 60% of males donot survive copulation. Virgin females in poor condition aremore frequently cannibalistic and more likely to kill largemales, but the frequency of cannibalism among mated femalesis not influenced by these factors. Instead, males that matewith mated females increase their fertilization success bybeing cannibalized. Cannibalized males generally mate for longer,but longer copulations correspond with increased paternity onlyin mated females. The amount of sperm from particular malesthat a female stored was not influenced by any of the measuredvariables. The number of sperm stored was not related to paternity,nor was there any detectable reduction in sperm number afterfemales had reproduced. Our data suggest that the conflict between the sexes differs between virgin and mated females.Females should always cannibalize a male, but males only gainfrom cannibalism when mating with mated females, not when matingwith virgin females. Interestingly, the frequencies of cannibalismare not different in matings with virgin or mated females.     

Ant versus fungus versus mutualism: ant-cultivar conflict and the deconstruction of the attine ant-fungus symbiosis

A century of research on fungus-growing ants (Attini, Formicidae) has ignored the cultivated fungi as passive domesticates and viewed the attine fungicultural symbiosis as an integrated unit dominated by the evolutionary interests of the ant farmers. This article takes a different perspective and explores first the evolutionary interests and leverages of the fungal cultivars, then dissects eight potential evolutionary conflicts between ants and cultivars. Three types of ant-cultivar conflict are examined in depth. First, ant-cultivar conflict over the ant sex ratio is predicted because the cultivars are dispersed by female foundresses but not by males; cultivars thus may be selected to bias the ant sex ratio toward females. Second, ant-cultivar conflict over fungal sexual reproduction exists if the fungi are able to escape from the symbiosis and live independently, as is implied by phylogenetic analyses of the fungi; this conflict is exacerbated in colonies that experience queen death or senescence. A literature review reveals that sexual fruiting of attine cultivars is more common than has been traditionally realized and often occurs in moribund colonies. Third, the routine transplanting of fungal mycelium by ants could generate, through sensory-biased symbiont choice, selection favoring fungal features that increase the likelihood of transplantation within nests (symbiont drive) but that are detrimental to the survival of the whole colony. A balanced perspective incorporating both ant and fungal interests emerges as a more appropriate framework than the traditional myrmicocentric perspective. Indeed, the attine symbiosis offers unique experimental opportunities (cultivar switch experiments) to unravel the evolutionary dynamics of conflict and cooperation between ant and fungal partners.     

Genomic conflict in scale insects: the causes and consequences of bizarre genetic systems

It is now clear that mechanisms of sex determination are extraordinarily labile, with considerable variation across all taxonomic levels. This variation is often expressed through differences in the genetic system (XX‐XY, XX‐XO, haplodiploidy, and so on). Why there is so much variation in such a seemingly fundamental process has attracted much attention, with recent ideas concentrating on the possible role of genomic conflicts of interest. Here we consider the role of inter‐ and intra‐genomic conflicts in one large insect taxon: the scale insects. Scale insects exhibit a dizzying array of genetic systems, and their biology promotes conflicts of interest over transmission and sex ratio between male‐ and female‐expressed genes, parental‐ and offspring‐expressed genes (both examples of intra‐genomic conflict) and between scale insects and their endosymbionts (inter‐genomic conflict). We first review the wide range of genetic systems found in scale insects and the possible evolutionary transitions between them. We then outline the theoretical opportunities for genomic conflicts in this group and how these might influence sex determination and sex ratio. We then consider the evidence for these conflicts in the evolution of sex determination in scale insects. Importantly, the evolution of novel genetic systems in scale insects has itself helped create new conflicts of interest, for instance over sex ratio. As a result, a major obstacle to our understanding of the role of conflict in the evolution of sex‐determination and genetic systems will be the difficulty in identifying the direction of causal relationships. We conclude by outlining possible experimental and comparative approaches to test more effectively how important genomic conflicts have been.     

Queen-controlled sex ratios and worker reproduction in the bumble bee Bombus hypnorum,as revealed by microsatellites

Social insect colonies provide model systems for the examination of conflicts among parties with different genetic interests. As such, they have provided the best tests of inclusive fitness theory. However, much remains unknown about in which party's favour such conflicts are resolved, partly as a result of the only recent advent of the molecular tools needed to examine the outcome of these conflicts. Two key conflicts in social insect colonies are over control of the reproductive sex ratio and the production of male offspring. Most studies have examined only one of these conflicts but in reality they occur in tandem and may influence each other. Using microsatellite analyses, the outcome of conflict over sex ratios and male production was examined in the bumble bee, Bombus hypnorum. The genotypes were determined for mother queens, their mates and males for each of 10 colonies. In contrast to other reports of mating frequency in this species, all of the queens were singly mated. The population sex ratio was consistent with queen control, suggesting that queens are winning this conflict. In contrast, workers produced over 20% of all males in queen-right colonies, suggesting that they are more effective in competing over male-production. Combining these results with previous work, it is suggested that worker reproduction is a labile trait that may well impose only small costs on queen fitness.     

Birds and people: from conflict to coexistence

Negative interactions between humans and animals are becoming increasingly frequent, as wild habitats shrink and human presence and activities expand throughout the world. Conflicts between people over conservation are one of the outcomes of this increased interaction, with severe consequences for both wildlife and people. Globally, conflicts can arise across diverse ecosystems, species and circumstances. Even if most attention in wildlife-related conflicts has been on mammals, birds are also often at the centre of such conflicts, but conflict research is still not explicitly present in ornithological literature. Examples of such conflicts include those related to birds and agriculture, forestry, hunting, fishing and public health interests. Conflicts are often more complex than initial assessments might suggest, involving ecological, economic, cultural, social and political elements. Reflecting the complexity of these issues and their increasing relevance to bird conservation, a British Ornithologists' Union conference was organized in November 2021 that aimed to highlight examples of conflicts that exist between people over birds and their conservation. Building on this conference, we provide here a review of key themes relating to the understanding of conflicts, including the importance of conflict perceptions, the collaboration between multiple disciplines and the different types of knowledge needed to better understand conflicts. We then consider the management of bird conservation conflicts, including the key issues of dealing with uncertainty, the role of technical solutions and the importance of collaboration and building trust, illustrating each theme with real-world examples. Finally, we outline potential future conflicts around bird conservation and how best to address them proactively.     

Chimpanzees coordinate in a negotiation game

A crucially important aspect of human cooperation is the ability to negotiate to cooperative outcomes when interests over resources conflict. Although chimpanzees and other social species may negotiate conflicting interests regarding travel direction or activity timing, very little is known about their ability to negotiate conflicting preferences over food. In the current study, we presented pairs of chimpanzees with a choice between two cooperative tasks—one with equal payoffs (e.g., 5-5) and one with unequal payoffs (higher and lower than in the equal option, e.g., 10-1). This created a conflict of interests between partners with failure to work together on the same cooperative task resulting in no payoff for either partner. The chimpanzee pairs cooperated successfully in as many as 78–94% of the trials across experiments. Even though dominant chimpanzees preferred the unequal option (as they would obtain the largest payoff), subordinate chimpanzees were able to get their way (the equal option) in 22–56% of trials across conditions. Various analyses showed that subjects were both strategic and also cognizant of the strategies used by their partners. These results demonstrate that one of our two closest primate relatives, the chimpanzee, can settle conflicts of interest over resources in mutually satisfying ways—even without the social norms of equity, planned strategies of reciprocity, and the complex communication characteristic of human negotiation.     

Does intragenomic conflict predict intrapersonal conflict?

Parts of the genome of a single individual can have conflicting interests, depending on which parent they were inherited from. One mechanism by which these conflicts are expressed in some taxa, including mammals, is genomic imprinting, which modulates the level of expression of some genes depending on their parent of origin. Imprinted gene expression is known to affect body size, brain size, and the relative development of various tissues in mammals. A high fraction of imprinted gene expression occurs in the brain. Biologists including Hamilton, Trivers and Haig have proposed that this may explain some intrapersonal conflict in humans. This speculation amounts to an inference from conflict within the genome (which is well-established) to conflict within the brain or mind. This is a provocative proposal, which deserves serious attention. In this paper I assess aspects of Haig’s version of the proposal. I argue, first, that the notion that intragenomic conflict predicts personal inconsistency should be rejected. Second, while it is unlikely that it credibly predicts sub-personal agents representing conflicting genetic interests, it is plausible that it predicts that the division of cognitive labour could be exploited to turn sub-systems into proxies for conflicting interests.     

Increased aggression during human group contests when competitive ability is more similar

Theoretical analyses and empirical studies have revealed that conflict escalation is more likely when individuals are more similar in resource-holding potential (RHP). Conflicts can also occur between groups, but it is unknown whether conflicts also escalate more when groups are more similar in RHP. We tested this hypothesis in humans, using data from two professional sports competitions: football (the Bundesliga, the German first division of football) and basketball (the NBA, the North American National Basketball Association). We defined RHP based on the league ranks of the teams involved in the competition (i.e. their competitive ability) and measured conflict escalation by the number of fouls committed. We found that in both sports the number of fouls committed increased when the difference in RHP was smaller. Thus, we provide what is to our best knowledge the first evidence that, as in conflicts between individuals, conflicts escalate more when groups are more similar in RHP.     

The quantitative genetic basis of offspring solicitation and parental response in a passerine bird with biparental care.

The coevolution of parental investment and offspring solicitation is driven by partly different evolutionary interests of genes expressed in parents and their offspring. In species with biparental care, the outcome of this conflict may be influenced by the sexual conflict over parental investment. Models for the resolution of such family conflicts have made so far untested assumptions about genetic variation and covariation in the parental resource provisioning response and the level of offspring solicitation. Using a combination of cross-fostering and begging playback experiments, we show that, in the great tit (Parus major), (i) the begging call intensity of nestlings depends on their common origin, suggesting genetic variation for this begging display, (ii) only mothers respond to begging calls by increased food provisioning, and (iii) the size of the parental response is positively related to the begging call intensity of nestlings in the maternal but not paternal line. This study indicates that genetic covariation, its differential expression in the maternal and paternal lines and/or early environmental and parental effects need to be taken into account when predicting the phenotypic outcome of the conflict over investment between genes expressed in each parent and the offspring.