Why Care: Complex Evolutionary History of Human Healthcare Networks

Wound-dependent leg amputations to combat infections in an ant society

Open wounds pose major infection and mortality risks in animals.1,2 To reduce these risks, many animal species apply antimicrobial compounds on their wounds.1,2,3,4 Ant societies use antimicrobial secretions from the metapleural gland to combat pathogens,5,6,7,8,9,10 but this gland has been lost over evolutionary time in several genera, including Camponotus.11 To understand how infected wounds are handled without the use of antimicrobial secretions from the metapleural gland, we conducted behavioral and microbiological experiments in Camponotus floridanus. When we experimentally injured a worker's leg at the femur, nestmates amputated the injured limb by biting the base (trochanter) of the leg until it was severed, thereby significantly increasing survival compared to ants that did not receive amputations. However, when the experimental injury was more distal (at the tibia), nestmates did not amputate the leg and instead directed more wound care to the injury site. Experimental amputations also failed to improve survival in ants with infected tibia injuries unless the leg was amputated immediately after pathogen exposure. Micro-CT scans revealed that the muscles likely responsible for leg hemolymph circulation are predominantly in the femur. Thus, it is likely that femur injuries, by attenuating hemolymph flow, provide sufficient time for workers to perform amputations before pathogen spread. Overall, this study provides the first example of the use of amputations to treat infected individuals in a non-human animal and demonstrates that ants can adapt their type of treatment depending on the location of wounds.

Taking Stock and Looking Forward to the Future of Pathogen Politics in Light of New Insights and Recommendations: COVID-19 Threat Was Meaningfully Associated With Support for Liberal Policies in the United States

Infectious disease outbreaks are expected to predict support for conservative policies. However, earlier studies (January-June, 2020) reached conflicting findings regarding the association between COVID-19 threat and policy preferences in the United States. We revisit this issue by analyzing five nationally representative surveys conducted during the relatively severe periods of the pandemic (August 2020-December, 2020; total N = 82,753). Using Bayesian inference, we find strong evidence that subjective (e.g., fear of infection and pandemic outrage) but not objective (e.g., local cases and deaths) threat predicted support for liberal policies (e.g., immigration and universal health care). Meta-analyses revealed that the estimates depend on the type of subjective (.05 ≥ r ≤ .60) or objective (.00 ≥ r ≤ .14) COVID-19 threat. We propose an emotion-mediated dual-process model of pathogen management suggesting that infectious disease outbreaks activate both avoidance and caregiving motives that translate, respectively, into support for right-wing and left-wing policies.

Could care giving have altered the evolution of human immune strategies?

Life history theory indicates that individuals/species with a slow pace of life invest more in acquired than innate immunity. Factors that decrease the pace of life and predict greater investment in acquired immunity include increased nutritional resources, increased pathogen exposure and decreased risk of extrinsic mortality. Common care behaviors given to sick individuals produce exactly these effects: provisioning increases nutritional resources; hygiene assistance increases disease exposure of carers; and protection can reduce the risk of extrinsic mortality to sick individuals. This study, therefore, investigated under what conditions care giving behaviors might impact immune strategy and pace of life. The study employed an agent-based model approach that simulated populations with varying levels of care giving, disease mortality, disease transmissibility, and extrinsic mortality, enabling measurements of how the immune strategy and age structure of the populations changed over evolutionary time. We used multiple regressions to examine the effects of these variables on immune strategy and the age structure of the population. The findings supported our predictions that care was selected for an acquired immunity. However, the pace of life did not slow as expected. Instead, the population shifted to a faster, but also more cost-intensive reproductive strategy in which care improved child survival by subsidizing the development of acquired immune responses.

Targeted treatment of injured nestmates with antimicrobial compounds in an ant society

Infected wounds pose a major mortality risk in animals. Injuries are common in the ant Megaponera analis, which raids pugnacious prey. Here we show that M. analis can determine when wounds are infected and treat them accordingly. By applying a variety of antimicrobial compounds and proteins secreted from the metapleural gland to infected wounds, workers reduce the mortality of infected individuals by 90%. Chemical analyses showed that wound infection is associated with specific changes in the cuticular hydrocarbon profile, thereby likely allowing nestmates to diagnose the infection state of injured individuals and apply the appropriate antimicrobial treatment. This study demonstrates that M. analis ant societies use antimicrobial compounds produced in the metapleural glands to treat infected wounds and reduce nestmate mortality.

The role of the behavioural immune system on covid-19 lockdown attitudes: The relationship with authoritarianism and collectivism

Background and objectives

The behavioural immune system (BIS) is a motivational system that facilitates the avoidance of pathogens and is thought to have evolved as a less costly mechanism to combat infectious diseases compared to the physiological immune system. The Parasite Stress Theory of Social Values predicts that authoritarianism and collectivist attitudes may impact the BIS by predisposing people to support disease control measures, including severe restrictions like lockdowns or stay-at-home orders. This study investigates the relationship between authoritarianism, collectivism and Covid-19 worry on support for lockdown measures during the Covid-19 pandemic.

Methodology

A total of 187 UK participants were recruited to complete an online survey, which was administered between 22 June and 7 July 2020. The survey included measures of authoritarianism, collectivism, Covid-19 worry and support for lockdown measures. The data were analysed using moderated parallel mediation analysis.

Results

Covid-19 worry had a direct effect on support for and enforcement of lockdown measures, but not on the idea that adherence to lockdown rules should be an individual choice. The relationship between Covid Worry and Support for and Enforcement of lockdown measures was not mediated by authoritarianism, nor was it moderated by Collectivism. Collectivism and Authoritarianism were related to increased levels of support for lockdown independently from Covid Worry but were not related to enforcement.

Conclusions and implications

Support for lockdown restrictions and enforcement was mainly associated with covid worry. Our findings do not support the parasite stress theory of social values and indicate that the BIS manifested in a more direct way, and not through social values.

The suffering ape hypothesis

The "fearful ape hypothesis" could be regarded as one aspect of a more general "suffering ape hypothesis": Humans are more likely to experience negative emotions (e.g., fear, sadness), aversive symptoms (e.g., pain, fever), and to engage in self-harming behavior (e.g., cutting, suicide attempts) because these might motivate affiliative, consolatory, and supportive behavior from their prosocial environment thereby enhancing evolutionary fitness.

The evolution of the human healthcare system and implications for understanding our responses to COVID-19

The COVID-19 pandemic has revealed an urgent need for a comprehensive, multidisciplinary understanding of how healthcare systems respond successfully to infectious pathogens-and how they fail. This study contributes a novel perspective that focuses on the selective pressures that shape healthcare systems over evolutionary time. We use a comparative approach to trace the evolution of care-giving and disease control behaviours across species and then map their integration into the contemporary human healthcare system. Self-care and pro-health environmental modification are ubiquitous across animals, while derived behaviours like care for kin, for strangers, and group-level organizational responses have evolved via different selection pressures. We then apply this framework to our behavioural responses to COVID-19 and demonstrate that three types of conflicts are occurring: (1) conflicting selection pressures on individuals, (2) evolutionary mismatches between the context in which our healthcare behaviours evolved and our globalized world of today and (3) evolutionary displacements in which older forms of care are currently dispensed through more derived forms. We discuss the significance of understanding how healthcare systems evolve and change for thinking about the role of healthcare systems in society during and after the time of COVID-19-and for us as a species as we continue to face selection from infectious diseases.

Traditional plant use during lactation and postpartum recovery: Infant development and maternal health roles

ETHNOPHARMACOLOGICAL RELEVANCE

Evidence of phytochemical roles in infant development and maternal recovery offers insights into beneficial functions of traditional plant use during lactation and the postpartum period. Ethnopharmacological research has relevance to global priorities on maternal and child health, to understanding origins and determinants of human self-medication, and for reconciling traditional postpartum practices and mainstream healthcare.

AIM OF THE STUDY

Present emerging evidence, within evolutionary and socio-cultural contexts, on the role of maternal consumption on transfer of phytochemicals into breast milk with impacts on maternal and child health, and on infant development. Establish current state of knowledge and an ethnopharmacological research agenda that is attentive to cross-cultural and regional differences in postpartum plant use.

MATERIALS AND METHODS

An extensive literature review using Medline, Scopus, and Web of Science focused on traditional and contemporary use and socio-cultural context, as well as physiological, pharmacological, toxicological, and behavioral activities of plants used medicinally by women during postpartum recovery and lactation.

RESULTS

The most widely reported postpartum plants show antimicrobial, anti-inflammatory, immunological, and neurophysiological activities, with low toxicity. Phytochemicals transfer from maternal consumption into breast milk in physiological concentrations, while animal studies demonstrate immunomodulation and other actions of medicinal plants during lactation. Reporting on the use and diverse traditional knowledge of women about plants during the postpartum period is obscured by the marginal place of obstetric issues and by gender biases in ethnobotanical research. In many contemporary contexts use is prejudiced by precautionary risk warnings in health literature and practice that confound lactation with pregnancy.

CONCLUSIONS

Although systematic investigation of postpartum plant use is lacking, known pharmacological activities support potential benefits on infant development and maternal health with immediate and long-term consequences in relation to allergic, inflammatory, autoimmune, and other diseases. An ethnopharmacological agenda focused on the perinatal period requires directed methodologies and a regional approach in relation to culturally-specific knowledge and practices, traditional plant use, and local health needs. Testing the hypothesis that phytochemicals transferred from medicinal plants into breast milk impact the human immune system and other aspects of infant development requires extended analysis of phytochemicals in human milk and infant lumen and plasma, as well as effects on gastrointestinal and milk microbiome.

Recent selection of candidate genes for mammal domestication in Europeans and language change in Europe: a hypothesis

BACKGROUND AND AIM

Human evolution resulted from changes in our biology, behaviour, and culture. One source of these changes has been hypothesised to be our self-domestication (that is, the development in humans of features commonly found in domesticated strains of mammals, seemingly as a result of selection for reduced aggression). Signals of domestication, notably brain size reduction, have increased in recent times.

METHODS

In this paper, we compare whole-genome data between the Late Neolithic/Bronze Age individuals and modern Europeans.

RESULTS

We show that genes associated with mammal domestication and with neural crest development and function are significantly differently enriched in nonsynonymous single nucleotide polymorphisms between these two groups.

CONCLUSION

We hypothesise that these changes might account for the increased features of self-domestication in modern humans and, ultimately, for subtle recent changes in human cognition and behaviour, including language.

Creating a Compassionate World: Addressing the Conflicts Between Sharing and Caring Versus Controlling and Holding Evolved Strategies

For thousands of years, various spiritual traditions and social activists have appealed to humans to adopt compassionate ways of living to address the suffering of life. Yet, along with our potential for compassion and self-sacrifice, the last few thousand years of wars, slavery, tortures, and holocausts have shown humans can be extraordinarily selfish, callous, vicious, and cruel. While there has been considerable engagement with these issues, particularly in the area of moral psychology and ethics, this paper explores an evolutionary analysis relating to evolved resource-regulation strategies that can be called "care and share" versus "control and hold." Control and hold are typical of primates that operate through intimidatory social hierarchies. Care and share are less common in non-human primates, but evolved radically in humans during our hunter-gatherer stage when our ancestors lived in relatively interdependent, small, mobile groups. In these groups, individualistic, self-focus, and self-promoting control and hold strategies (trying to secure and accumulate more than others) were shunned and shamed. These caring and sharing hunter-gatherer lifestyles also created the social contexts for the evolution of new forms of childcare and complex human competencies for language, reasoning, planning, empathy, and self-awareness. As a result of our new 'intelligence', our ancestors developed agriculture that reduced mobility, increased group size, resource availability and storage, and resource competition. These re-introduced competing for, rather than sharing of, resources and advantaged those who now pursue (often aggressively) control and hold strategies. Many of our most typical forms of oppressive and anti-compassionate behavior are the result of these strategies. Rather than (just) thinking about individuals competing with one another, we can also consider these different resource regulation strategies as competing within populations shaping psychophysiological patterns; both wealth and poverty change the brain. One of the challenges to creating a more compassionate society is to find ways to create the social and economic conditions that regulate control and hold strategies and promote care and share. No easy task.

Compassion: From Its Evolution to a Psychotherapy

The concept, benefits and recommendations for the cultivation of compassion have been recognized in the contemplative traditions for thousands of years. In the last 30 years or so, the study of compassion has revealed it to have major physiological and psychological effects influencing well-being, addressing mental health difficulties, and promoting prosocial behavior. This paper outlines an evolution informed biopsychosocial, multicomponent model to caring behavior and its derivative "compassion" that underpins newer approaches to psychotherapy. The paper explores the origins of caring motives and the nature and biopsychosocial functions of caring-attachment behavior. These include providing a secure base (sources of protection, validation, encouragement and guidance) and safe haven (source of soothing and comfort) for offspring along with physiological regulating functions, which are also central for compassion focused therapy. Second, it suggests that it is the way recent human cognitive competencies give rise to different types of "mind awareness" and "knowing intentionality" that transform basic caring motives into potentials for compassion. While we can care for our gardens and treasured objects, the concept of compassion is only used for sentient beings who can "suffer." As psychotherapy addresses mental suffering, cultivating the motives and competencies of compassion to self and others can be a central focus for psychotherapy.