Eviction-driven infanticide and sexually selected adoption and infanticide in a neotropical parrot.

Infanticide and adoption have been attributed to sexual selection, where an individual later reproduces with the parent whose offspring it killed or adopted. While sexually selected infanticide is well known, evidence for sexually selected adoption is anecdotal. We report on both behaviors at 346 nests over 27 y in green-rumped parrotlets (Forpus passerinus) in Venezuela. Parrotlets are monogamous with long-term pair bonds, exhibit a strongly male-biased adult sex ratio, and nest in cavities that are in short supply, creating intense competition for nest sites and mates. Infanticide attacks occurred at 256 nests in two distinct contexts: 1) Attacks were primarily committed by nonbreeding pairs (69%) attempting to evict parents from the cavity. Infanticide attacks per nest were positively correlated with population size and evicting pairs never adopted abandoned offspring. Competition for limited nest sites was a primary cause of eviction-driven infanticide, and 2) attacks occurred less frequently at nests where one mate died (31%), was perpetrated primarily by stepparents of both sexes, and was independent of population size. Thus, within a single species and mating system, infanticide occurred in multiple contexts due to multiple drivers. Nevertheless, 48% of stepparents of both sexes adopted offspring, and another 23% of stepfathers exhibited both infanticide and long-term care. Stepfathers were often young males who subsequently nested with widows, reaching earlier ages of first breeding than competitors and demonstrating sexually selected adoption. Adoption and infanticide conferred similar fitness benefits to stepfathers and appeared to be equivalent strategies driven by limited breeding opportunities, male-biased sex ratios, and long-term monogamy.

The criminalization of women with postpartum psychosis: "a call for action" for judicial change.

PURPOSE: To prevent the incarceration and influence outcomes when criminal culpability is linked to postpartum psychosis. METHODS: Infanticide, neonaticide and filicide are most often linked with postpartum psychosis, which affects 1-2 women per 1,000 births or 4,000 women each year in the United States. Multiple genetic, hormonal and psychosocial factors surrounding childbirth result in a 1 to 4% risk of infanticide in women with postpartum psychosis. The authors seek to increase awareness of postpartum psychosis and postpartum depression in state legislatures. Others are working to have it recognized in the Diagnostic and Statistical Manual of Mental Disorders (DSM) as a specific illness. Specific postpartum legislation for those charged with crimes related to maternal mental illness is necessary. RESULTS: In Illinois, the very first criminal law in the nation recognizing the pernicious effects of this illness went into effect in 2018. The authors and others are attempting to cause similar or broader legislation to be brought in other states. Several women have been released from extended incarceration utilizing this law. CONCLUSIONS: This temporary mental illness can lead to tragic outcomes when hospitalization and crisis intervention is delayed or the illness is misdiagnosed. The legal/judicial system has not utilized the growing body of scientific developments that medical researchers have discovered in recent decades. The lack of a unique diagnostic classification in the DSM and the lack of postpartum criminal laws, lead to mentally ill mothers in the U.S. receiving excessively harsh sentences when prosecuted, evidenced both in trial and sentencing.

Intentional child and adolescent homicides in Milan (Italy): A 30-year interdisciplinary study.

This study aims to discuss the forensic and criminological implications of child homicides in the territory of Milan, Italy. The authors present a retrospective study on all the cases of child and adolescent homicides, that were observed at the Institute of Legal Medicine of Milan (Italy) in the last 30 years (from January 1991 to December 2020). A total of 46 child homicides were collected, focusing on the sociological features, by highlighting peculiar cases, risk factors, potential changing social trends, and comparing our cases with the current literature. The analysis revealed a statistically significant relationship (p < 0.05) for male adolescents and indicated that adolescent homicides were more frequently perpetrated in extrafamilial contexts. In contrast, neonaticides and infanticides were mainly committed at home. Furthermore, the Fisher's Exact test revealed that child murders were mainly committed by immigrants in the Milan district after 2005 (p < 0.05). The two main causes of death were due to sharp and firearm injuries. While the relationship between homicide clusters and homicides committed by sharp objects was not significant, adolescent homicides were mainly committed using firearms (p < 0.05). The present study may help to identify risk factors for homicides against child and adolescent. Consequently, policies that identify, prevent, and minimize this extreme violence should be designed to interrupt the vicious circle of such dreadful murderous events. Child and adolescent homicides deserve additional focus and better education for healthcare professionals and further research should be carried out to develop therapeutic and caring strategies.

Domestic violence as a risk factor of maternal filicide.

PURPOSE: This paper will investigate precursors to maternal filicide, focusing on domestic violence. While psychosis is often well described, less frequently explored are the connections between prior trauma, domestic violence, depression, and filicide. We will discuss reasons why a woman may not disclose domestic violence and suggest possible areas for intervention. METHODS: We present a case involving domestic violence, its impact on mental health, and eventual filicide. We then present an alternative scenario of the same case where filicide is considered, but is avoided. RESULTS: The case of the mother who experienced domestic violence and was accused and sentenced for filicide is seen in greater relief by presenting the case in an alternative scenario with effective interventions. It is clear the availability and the ability to access community supports, such as obstetric and pediatric screening, psychiatric treatment, domestic violence shelters, intimate partner violence outreach services, parenting support groups, and hospital social work case management, tragedies such as filicide can be prevented. CONCLUSION: Traumatic early childhood experiences predispose people to a stress-response system that is more prone to inactivity and impulsivity. This can cause women in domestic violence relationships to stay, limit their options for family planning, become increasingly depressed, not seek community support, and risk impulsive action of harming their child. This risk can be mitigated by building stable relationships with their medical team, treating depression, connecting with home visitation programs, and being empowered to access contraception.

Bibliometric analysis on cannibalism/infanticide and maternal aggression towards pups in laboratory rodents.

Animal welfare has evolved during the past decades to improve not only the quality of life of laboratory rodents but also the quality and reproducibility of scientific investigations. Bibliometric analysis has become an important tool to complete the current knowledge with academic databases. Our objective was to investigate whether scientific research on cannibalism/infanticide is connected with maternal aggression towards the offspring in laboratory rodents. To carry out our research, we performed a specific search for published articles on each concept. Results were analyzed in the open-source environment RStudio with the package Bibliometrix. We obtained 253 and 134 articles for the first search (cannibalism/infanticide) and the second search (maternal aggression towards the pups) respectively. We observed that the interest in infanticide/cannibalism started in the 1950s, while researchers started showing interest in maternal aggression towards the pups 30 years later. Our analyses indicated that maternal aggression had better citations in scientific literature. In addition, although our results showed some common features (e.g. oxytocin or medial preoptic area in the brain), we observed a gap between cannibalism/infanticide and maternal aggression towards the pups with only 14 published articles in common for both the searches. Therefore, we recommend researchers to combine both concepts in further investigations in the context of cannibalism for better dissemination and higher impact in laboratory rodents' welfare research.

Counter-strategies to infanticide: The importance of cubs in determining lion habitat selection and social interactions.

Animal social and spatial behaviours are inextricably linked. Animal movements are driven by environmental factors and social interactions. Habitat structure and changing patterns of animal space use can also shape social interactions. Animals adjust their social and spatial behaviours to reduce the risk of offspring mortality. In territorial infanticidal species, two strategies are possible for males: they can stay close to offspring to protect them against rivals (infant-defence hypothesis) or patrol the territory more intensively to prevent rival intrusions (territorial-defence hypothesis). Here, we tested these hypotheses in African lions (Panthera leo) by investigating how males and females adjust their social and spatial behaviours in the presence of offspring. We combined datasets on the demography and movement of lions, collected between 2002 and 2016 in Hwange National Park (Zimbabwe), to document the presence of cubs (field observations) and the simultaneous movements of groupmates and competitors (GPS tracking). We showed a spatial response of lions to the presence of offspring, with females with cubs less likely to select areas close to waterholes or in the periphery of the territory than females without cubs. In contrast, these areas were more selected by males when there were cubs in the pride. We also found social responses. Males spent more time with females as habitat openness increased but the presence of cubs in the pride did not influence the average likelihood of observing males with females. Furthermore, rival males relocated further after an encounter with pride males when cubs were present in the prides, suggesting that the presence of cubs leads to a more vigorous repulsion of competitors. Males with cubs in their pride were more likely to interact with male competitors on the edge of the pride's home range and far from the waterholes, suggesting that they are particularly assiduous in detecting and repelling rival males during these periods. In general, the strategies to avoid infanticide exhibited by male lions supported the territorial-defence hypothesis. Our study contributes to answer the recent call for a behavioural ecology at the spatial-social interface.

Intergroup encounters in pair-living primates: Comparative analysis and a case study of pair-living and monogamous owl monkeys (Aotus azarae) of Argentina.

The function of intergroup encounters (IGEs) may differ substantially among species of different group sizes and social organizations. Research in group-living primates has shown that the behavioral responses during IGEs can vary widely from affiliative to neutral or aggressive interactions; still, little is known about IGEs in pair-living taxa. We conducted a systematic literature review to find relevant studies on the functions of IGEs in pair-living nonhuman primates that could inform analyses of IGE data (n = 242 IGEs, 21 groups and 10 solitary individuals, 1997-2020) from wild owl monkeys, a pair-living, monogamous primate with extensive biparental care. We identified 1315 studies published between 1965 and 2021; only 13 of them (n = 10 species) contained raw data on the number of IGEs. Our review of those studies showed that IGEs are common, but highly variable in their nature and characteristics in pair-living primates. To examine the non-mutually exclusive hypotheses of resource-, and mate defense, and infanticide avoidance we analyzed data from the Owl Monkey Project 27-year long database to build first an a priori model set. To incorporate prior knowledge from the literature review, we conducted our analyses as a consecutive series of binomial logistic regressions. All IGEs including all biologically relevant parameters (N = 156) were codified into three different behavioral categories (Reaction, Agonism, and Physical Aggression). The analysis showed that owl monkeys regularly engaged in IGEs, most of which were agonistic. They showed more reaction when infants were present, but reactions were less physically aggressive when infants and pregnant females were involved. Overall, our results lend more support for the infant and mate defense hypotheses than they do for the resource defense one.

Reproductive success of Bornean orangutan males: scattered in time but clustered in space.

Abstract: The social and mating systems of orangutans, one of our closest relatives, remain poorly understood. Orangutans (Pongo spp.) are highly sexually dimorphic and females are philopatric and maintain individual, but overlapping home ranges, whereas males disperse, are non-territorial and wide-ranging, and show bimaturism, with many years between reaching sexual maturity and attaining full secondary sexual characteristics (including cheek pads (flanges) and emitting long calls). We report on 21 assigned paternities, among 35 flanged and 15 unflanged, genotyped male Bornean orangutans (Pongo pygmaeus wurmbii), studied from 2003 to 2018 in Tuanan (Central Kalimantan, Indonesia). All 10 infants born since mid-2003 with an already identified sire were sired by flanged males. All adult males ranged well beyond the study area (c. 1000 ha), and their dominance relations fluctuated even within short periods. However, 5 of the 10 identified sires had multiple offspring within the monitored area. Several sired over a period of c. 10 years, which overlapped with siring periods of other males. The long-calling behavior of sires indicated they were not consistently dominant over other males in the area around the time of known conceptions. Instead, when they were seen in the area, the known sires spent most of their time within the home ranges of the females whose offspring they sired. Overall, successful sires were older and more often resident than others. Significance statement: It is difficult to assess reproductive success for individuals of long-lived species, especially for dispersing males, who cannot be monitored throughout their lives. Due to extremely long interbirth intervals, orangutans have highly male-skewed operational sex ratios and thus intensive male-male competition for every conception. Paternity analyses matched 21 immature Bornean orangutans with their most likely sire (only 10 of 50 genotyped males) in a natural population. Half of these identified sires had multiple offspring in the study area spread over periods of at least 10 years, despite frequently ranging outside this area. Dominance was a poor predictor of success, but, consistent with female mating tactics to reduce the risk of infanticide, known "sires" tended to have relatively high local presence, which seems to contribute to the males' siring success. The results highlight the importance of large protected areas to enable a natural pattern of dispersal and ranging. Supplementary Information: The online version contains supplementary material available at 10.1007/s00265-023-03407-6.

A case-control study of filicide/infanticide in 90 mothers.

This study aims to explore the clinical and socio-demographic characteristics of 30 women who committed filicide and compare them to those of 60 postpartum women who did not commit filicide, including 30 with severe postpartum mental illness and 30 without a known history of psychiatric disorders. Clinical assessment included a face-to-face interview with the Structured Clinical Interviews for DSM-IV Axis I and Axis II Disorders. Information on socio-economic, medical, and personal factors was collected using the Clinical Interview for DSM-IV and organized in a clinical vignette and OPCRIT ratings. Consensus best-estimate diagnoses were made according to DSM-V criteria. Inference was conducted using Fisher's exact test for categorical variables and Mann-Whitney U rank test for continuous variables. Family history of violent death, psychotic symptoms (OR 8.3; CI 95% 2.26-36.13), severe insomnia (9.8; 2.28-61.75), and a schizophrenia spectrum or bipolar diathesis (4.8; 1.22-23.86) were associated with history of filicide. Rates of history of sexual abuse in childhood were higher in both the filicide and the severe postpartum mental illness groups compared to healthy controls (6.7; 1.25-70.46 and 7.8; 1.47; 80.47 respectively). Conversely, we did not observe any difference in the rates of history of sexual abuse in adulthood across groups. The lack of adequate postpartum psychiatric care was an important precipitating factor in many cases of infanticide and even late filicide. This study underscores the need for increasing awareness by health care professionals and the wider society of the complex dynamics and psychiatric risks associated with motherhood.

The Prevalence and Characteristics of Intrafamilial Child and Adolescent Homicides in Greece over 11 Years (2010-2020).

Intrafamilial child/adolescent homicide is the murder of a child/adolescent by one or more family members. This study delves into the medical and sociological consequences of child homicide, shedding light on the broader impact beyond individual families, which extends into the local community. Two Internet search engines and the search engines of major national news websites were surveyed to identify the number of intrafamilial child/adolescent homicide cases that occurred in Greece from January 2010 to December 2020. Over the study period, 34 victims of intrafamilial child/adolescent homicides were identified. The above deaths reflect an intrafamilial child/adolescent homicide rate of 0.15 homicides per year per 100,000 inhabitants. Most of the perpetrators (51.4%) were male, and the victims were equally divided into males and females. The ages of the perpetrators ranged from 13 to 61 years, and the ages of the victims ranged between 0 and 17 years. Most perpetrators (54.5%) had a previous psychiatric history and in many cases, they committed (33.3%) or attempted (15.2%) suicide after the homicide. The most common method of homicide was strangulation (usually combined with suffocation) (25%), followed by abandonment (15.6%). The most commonly reported motives were spousal revenge (26.5%) and psychotic disorders (26.5%). Raising awareness for intrafamilial child and adolescent homicide is of the utmost importance for the prevention of this dreadful phenomenon.

Unidentified Intracranial Foreign Body in an Epileptic Child: Infanticide or Child Abuse?

Although intracranial foreign bodies are typically associated with penetrating injuries or surgical interventions, they can also occur as a result of rare instances of child abuse. Enduring such abuse and neglect as an infant can lead to life-long neurological problems, developmental delays, and impairments. The present case involved a 14-year-old male adolescent who was brought to the emergency room due to recurrent generalized tonic seizures. A computed tomography (CT) scan revealed a ring-like metallic object within the right temporal lobe. The neurosurgeon declined the surgical removal of the object due to its position and orientation, as well as the patient's guardian's refusal to consent to surgery. Instead, drug treatment and care are advised. In infants, foreign objects are typically inserted through cranial sutures, fontanelles and less frequently into the orbits, often with the intention of harming unwanted children. However, no history of such an attempt is present in this case. The incidental discovery of intracranial foreign bodies typically occurs during investigations when patients present with neurological symptoms such as epileptic seizures (foreign body-induced epilepsy). The selection of an ideal treatment regimen is often challenging in such cases. If a patient can be effectively treated with drugs, surgical removal is usually avoided.

A case report of infanticide in rural Nepal: Sociocultural perspectives and forensic considerations.

This case highlights the complex interplay of mental health, stigma, and lack of contraceptive access underlying tragic instances of infanticide. Comprehensive medicolegal investigation paired with cross-sector efforts to expand reproductive services and transform cultural attitudes is crucial to protect vulnerable women and children.

Single fathers sacrifice their broods and re-mate quickly in a socially monogamous cichlid.

When one of two parents disappears in the midst of caring for offspring, the remaining parent is left with several options. They can either (1) desert the brood, (2) continue caring on their own and reject propositions from new potential partners, or (3) continue caring but remain receptive to re-mating opportunities. The presence of a brood may increase re-mating success of single parents, either because brood care is perceived as a signal of partner quality, or because prospective mates perceive the brood as potential energy source. In this field experiment, we used the socially monogamous, biparental cichlid fish Variabilichromis moorii to examine the re-mating strategy of males with or without dependent offspring after the loss of their female partner. Partner vacancies were filled quickly by new females, and these females engaged in high levels of affiliative behavior with the males. The new females engaged in territorial defense, but focused primarily against intruding conspecifics, likely as a means to repel rivals. The males, in turn, took over the majority of territorial defense against intruding heterospecifics. Interestingly, males that still had offspring from their previous partnerships did not show aggression toward their new female partners, even when those females were infanticidal and cannibalizing the males' current offspring. Overall, our experiment shows that single fathers of a biparental species will re-mate quickly even at the detriment to their current offspring.

takeout gene expression is associated with temporal kin recognition.

A key component of parental care is avoiding killing and eating one's own offspring. Many organisms commit infanticide but switch to parental care when their own offspring are expected, known as temporal kin recognition. It is unclear why such types of indirect kin recognition are so common across taxa. One possibility is that temporal kin recognition may evolve through alteration of simple mechanisms, such as co-opting mechanisms that influence the regulation of timing and feeding in other contexts. Here, we determine whether takeout, a gene implicated in coordinating feeding, influences temporal kin recognition in Nicrophorus orbicollis. We found that takeout expression was not associated with non-parental feeding changes resulting from hunger, or a general transition to the full parental care repertoire. However, beetles that accepted and provided care to their offspring had a higher takeout expression than beetles that committed infanticide. Together, these data support the idea that the evolution of temporal kin recognition may be enabled by co-option of mechanisms that integrate feeding behaviour in other contexts.

A case of intercommunity lethal aggression by chimpanzees in an open and dry landscape, Issa Valley, western Tanzania.

Intercommunity (lethal) aggression is a familiar component of the behavioural repertoire of many forest-dwelling chimpanzee (Pan troglodytes) communities. However, until now, the absence of intercommunity attacks - including killings - in communities that live in open, mosaic environments has supported hypotheses of reduced resource competition in drier habitats, and informed referential models of early hominin social dynamics in a similar habitat. In June 2020, we observed the first instance of intercommunity lethal aggression, a male-committed infanticide, by the Issa chimpanzee community, which live in a savannah-mosaic habitat in the Issa Valley, western Tanzania. The carcass was recovered by researchers after it was abandoned by the attackers. Here, we give a detailed account of the events leading up to and including the infanticide, and contextualise our observations with what has been described for other chimpanzee communities. Notably, in contrast to the majority of reported intercommunity infanticides, the infant male victim was castrated (and not cannibalised), making this the youngest reported castration. This observation of intercommunity aggression disproves its hypothesised absence in savannah-dwelling chimpanzees, which by extension, has implications for early hominin evolution. We suggest that the near absence of observations of intercommunity aggression in savannah chimpanzee communities is most likely due to the lack of long-term study communities, and in some cases geographic isolation. We hypothesise that food-rich areas within a habitat with otherwise widely distributed food sources may select for intense intercommunity aggression despite the low population density characteristic of savannah communities. Anecdotes such as this add to the comparative database available on intercommunity killings in chimpanzee society, improving our ability to draw inferences about their evolutionary significance.

Mating-induced prolactin surge is not required for subsequent neurogenesis in male mice.

Parenting involves major behavioral transitions that are supported by coordinated neuroendocrine and physiological changes to promote the onset of novel offspring-directed behaviors. In comparison to maternal care, however, the mechanisms underlying the transition to paternal care are less understood. Male laboratory mice are predominantly infanticidal as virgins but show paternal responses 2 weeks after mating. Interestingly, males show a mating-induced surge of prolactin, which we hypothesized may be involved in initiating this behavioral transition. During pregnancy, prolactin stimulates olfactory bulb neurogenesis, which is essential for maternal behavior. Mating induces olfactory bulb neurogenesis in males, but it is unknown whether this is driven by prolactin or is important for subsequent paternal care. New olfactory neurons are generated from cells in the subventricular zone (SVZ) and take about 2 weeks to migrate to the olfactory bulb, which may account for the delayed behavioral change in mated males. We investigated whether mating increases cell proliferation at the SVZ. Males were either mated, exposed to receptive female cues, or left alone (control) and injected with Bromodeoxyuridine (BrdU, a marker of cell division). Contrary to our hypothesis, we found that mating decreased cell proliferation in the caudal lateral portion of the SVZ. Next, we tested whether prolactin itself mediates cell proliferation in the SVZ and/or new cell survival in the olfactory bulb by administering bromocriptine (prolactin inhibitor), vehicle, or bromocriptine + prolactin prior to mating. While suppressing prolactin had no effect on cell proliferation in the SVZ, administering exogenous prolactin resulted in significantly higher BrdU-labeled cells in mated but not virgin male mice. No effects of prolactin were observed on new olfactory cell survival. Taken together, prolactin may have context-dependent effects on new cell division in the SVZ, while other unknown mechanisms may be driving the effects on new olfactory cell survival following mating.

Involvement of Serotonergic Projections from the Dorsal Raphe to the Medial Preoptic Area in the Regulation of the Pup-Directed Paternal Response of Male Mandarin Voles.

Male mammals display different paternal responses to pups, either attacking or killing the young offspring, or contrastingly, caring for them. The neural circuit mechanism underlying the between-individual variation in the pup-directed responsiveness of male mammals remains unclear. Monogamous mandarin voles were used to complete the present study. The male individuals were identified as paternal and infanticidal voles, according their behavioral responses to pups. It was found that the serotonin release in the medial preoptic area (MPOA), as well as the serotonergic neuron activity, significantly increased upon licking the pups, but showed no changes after attacking the pups, as revealed by the in vivo fiber photometry of the fluorescence signal from the 5-HT 1.0 sensor and the calcium imaging indicator, respectively. It was verified that the 5-HTergic neural projections to the MPOA originated mainly from the ventral part of the dorsal raphe (vDR). Furthermore, the chemogenetic inhibition of serotonergic projections from the vDR to the MPOA decreased the paternal behaviors and shortened the latency to attack the pups. In contrast, the activation of serotonergic neurons via optogenetics extended the licking duration and inhibited infanticide. Collectively, these results elucidate that the serotonergic projections from the vDR to the MPOA, a previously unrecognized pathway, regulate the paternal responses of virgin male mandarin voles to pups.

Monstrous Mothering: Understanding the Causes of and Responses to Infanticide.

The deliberate killing of a child by its mother is abhorrent and is associated in the minds of many with mental illness and in particular with postnatal depression. However, at least 50% of perpetrators are neither "mad" nor "bad", and mothers who kill children are not "unhinged" by pregnancy or childbirth. We propose a different explanation: "blind rage" or "overwhelmed syndrome", whereby parents, stressed to breaking point by sleep deprivation or incessant baby crying, respond by lethally harming their child contrary to previous behaviour. The roots of this blind rage may be found in psychosocial disturbances, including the mother's own unsatisfactory experience of parenting which has caused attachment disorders. The legal framework guiding decisions to prosecute and structuring sentencing decision-making following conviction should acknowledge the exceptional stress experienced by such mothers postnatally. Health professionals including midwives and obstetricians should increase their vigilance and arrange referrals for mothers at risk of causing harm or committing infanticide.

Perinatal mental health and the justice delivery system in India.

On 20 April 2022 the Sessions Court of Greater Mumbai sentenced a postpartum depressed woman to lifetime imprisonment for abandoning and murdering her twin girl child (In re: The State of Maharashtra). In the absence of a diagnosis or treatment for postpartum depression at the time when the crime was committed, a plea of insanity was denied. This article considers how the absence of services for perinatal mental health in India may challenge the delivery of criminal justice in cases of infanticide.