Benefits and Costs of Mixed-Species Aggregations in Harvestmen (Arachnida: Opiliones)

Many animals form aggregations with individuals of the same species (single-species aggregations, SSA). Less frequently, individuals may also aggregate with individuals of other species (mixed-species aggregations, MSA). Although the benefits and costs of SSA have been intensively studied, the same is not true for MSA. Here, we first review the cases of MSA in harvestmen, an arachnid order in which the records of MSA are more frequent than other arthropod orders. We then propose several benefits and costs of MSA in harvestmen, and contrast them with those of SSA. Second, using field-gathered data we describe gregariousness in seven species of Prionostemma harvestmen from Costa Rica. These species form MSA, but individuals are also found solitarily or in SSA. We tested one possible benefit and one possible cost of gregariousness in Prionostemma harvestmen. Regarding the benefit, we hypothesized that individuals missing legs would be more exposed to predation than eight-legged individuals and thus they should be found preferentially in aggregations, where they would be more protected from predators. Our data, however, do not support this hypothesis. Regarding the cost, we hypothesized that gregariousness increases the chances of parasitism. We found no support for this hypothesis either because both mite prevalence and infestation intensity did not differ between solitary or aggregated individuals. Additionally, the type of aggregation (SSA or MSA) was not associated with the benefit or the cost we explored. This lack of effect may be explained by the fluid membership of the aggregations, as we found high turnover over time in the number of individuals and species composition of the aggregations. In conclusion, we hope our review and empirical data stimulate further studies on MSA, which remains one of the most elusive forms of group living in animals.

Hot-headed peckers: thermographic changes during aggression among juvenile pheasants ( Phasianus colchicus )

In group-living vertebrates, dominance status often covaries with physiological measurements (e.g. glucocorticoid levels), but it is unclear how dominance is linked to dynamic changes in physiological state over a shorter, behavioural timescale. In this observational study, we recorded spontaneous aggression among captive juvenile pheasants ( Phasianus colchicus ) alongside infrared thermographic measurements of their external temperature, a non-invasive technique previously used to examine stress responses in non-social contexts, where peripheral blood is redirected towards the body core. We found low but highly significant repeatability in maximum head temperature, suggesting individually consistent thermal profiles, and some indication of lower head temperatures in more active behavioural states (e.g. walking compared to resting). These individual differences were partly associated with sex, females being cooler on average than males, but unrelated to body size. During pairwise aggressive encounters, we observed a non-monotonic temperature change, with head temperature dropping rapidly immediately prior to an attack and increasing rapidly afterwards, before returning to baseline levels. This nonlinear pattern was similar for birds in aggressor and recipient roles, but aggressors were slightly hotter on average. Our findings show that aggressive interactions induce rapid temperature changes in dominants and subordinates alike, and highlight infrared thermography as a promising tool for investigating the physiological basis of pecking orders in galliforms. This article is part of the theme issue ‘The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies’.

Ecogeography of group size suggests differences in drivers of sociality among cooperatively breeding fairywrens

Cooperatively breeding species exhibit a range of social behaviors associated with different costs and benefits to group-living, often in association with different environmental conditions. For example, species in which collective-care of offspring reduces the cost of reproduction are more common in harsh environments (true cooperative breeding), while species that collectively defend resources are present in benign environments (family-living). Here, we examine whether environment also shapes sociality within cooperatively-breeding species. We illustrate that Purple-backed Fairywrens, which primarily gain intrinsic, or collective-care benefits, have larger groups in hot, dry environments and smaller groups in cool, wet environments, whereas Superb Fairywrens which primarily gain extrinsic, or resource defense benefits, exhibit the opposite trend. We suggest differences in the costs and benefits of sociality contribute to these opposing ecogeographic patterns, demonstrating that comparisons of intraspecific patterns of social variation across species can provide insight into how ecology shapes transitions between social systems.

Effects of Shopping Rehabilitation on Older People’s Daily Activities

In an aged society, the deterioration of physical and cognitive functions is prevalent. To motivate the rehabilitation of older persons, an initiative known as “shopping rehabilitation” incorporates shopping as an element of a nudge. The purpose of this study was to clarify motor function changes and cognitive functions of participants during shopping rehabilitation, through a semi-experimental study. We measured changes in the Kihon Checklist score before and after rehabilitation interventions. A paired t-test was used to analyze changes in the overall score of the basic checklist before and after the rehabilitation intervention. In December 2020, 59 participants answered the Kihon Checklist after their shopping rehabilitation intervention. During the 6-month intervention period, the number of participants with a checklist score of 8 or higher was significantly reduced after the intervention (p = 0.050). In the sub-analysis, the score improved significantly for the group with families (p = 0.050). Improvement was observed in the group living alone, but the difference was not significant (p = 0.428). The shopping rehabilitation intervention improved the Kihon Checklist score. Continuous observations and research are necessary to measure the long-term effects of shopping rehabilitation and the mechanisms that foster their maintenance and effects.

Should I stay or should I go? How activity synchronization affects fission decisions

Group-living animals need to deal with conflicting interests to maintain cohesion. When the costs of doing so outweigh the benefits, the group may (temporarily) split into two or more subgroups. Conflicting interests can concern what activity to pursue or the direction of travel. Temporary group separation is a common feature in species with a high degree of fission–fusion dynamics. We investigated the role activity synchronization played in fission decisions in a spider monkey group living in the Otoch Ma'ax Yetel Kooh Nature Reserve, Yucatan, Mexico. For 21 months, we recorded every fission event occurring in the followed subgroup, as well as the subgroup activity. We classified the activity as ‘synchronized’ when at least 75% of subgroup members performed the same activity (resting, foraging, socializing or travelling); otherwise, we classified it as ‘non-synchronized’. We found that fission events occurred more often when the activity was non-synchronized. In addition, when the activity was synchronized, fission events occurred more often when spider monkeys were travelling than when they were engaged in other subgroup activities. Our findings highlight the role of conflicting interests over the activity to pursue and travel direction in fission decisions.

Hadarat in Tual City Maluku: The Role of Arab Al-Katiri in Integration of Islam and Local Culture

<p>This paper examines the hadarat tradition as part of integrating Islam with local culture by the Al-Katiri Arab group in Tual City. Attendance is a unique ritual that the people of Tual City carry out in celebrating religious holidays such as Eid al-Fitr, Eid al-Adha, weddings, circumcisions, and other religious activities. The community conducts friendship around the village while dancing accompanied by chanting <em>shalawat</em> to the Prophet Muhammad with music (tambourine) in the hadarat. This article uses a qualitative descriptive method, with observations, interviews, and documentation as the data collection techniques. This article shows that the Al-Katiri Arab community played a role in the spread of Islam in Tual City through trade routes and social and cultural approaches. The descendants of the marriage between the Arab al-Katiri group and the Kei Community of Tual City have been considered one part of the Kei community of Tual City. The information was obtained using historical research methods. Appreciating the culture of the Kei people of Tual City as a form of preaching the spread of Islam is the key to the success of the Al-Katiri Arab group living in harmony amid society with local cultural traditions.</p><p><em>Tulisan ini mengkaji tentang tradisi hadarat sebagai bagian dari strategi mengintegrasikan Islam dengan kebudayaan lokal oleh kelompok Arab Al-Katiri di Kota Tual. Hadarat menjadi sebuah ritual unik yang dilakukan oleh masyarakat Kota Tual dalam merayakan hari besar keagamaan seperti Hari Raya Idul Fitri, Hari Raya Idul Adha, perkawinan, khitanan, dan kegiatan keagamaan lainnya. Masyarakat melakukan silaturahim mengelilingi kampung sambil menari diiringi lantunan shawat kepada Nabi Muhammad dengan musik (rebana) dalam hadarat. Artikel ini menggunakan metode deskriptif kualitatif, dengan observasi, wawancara, dan dokumentasi sebagai Teknik pengumpulan datanya. Hasil peneltian artikel ini menunjukkan bahwa komunitas Arab Al-Katiri berperan dalam penyebaran agama Islam di Kota Tual, melalui jalur perdagangan dan pendekatan sosial dan budaya. Keturunan dari hasil pernikahan antara kelompok Arab al-Katiri dengan Masyarakat Kei Kota Tual sudah dianggap sebagai satu bagian dengan masyarakat Kei Kota Tual. Informasi tersebut didapatkan dengan menggunakan metode penelitian sejarah. Menghargai kebudayaan masyarakat Kei Kota Tual sebagai suatu bentuk dakwah penyebaran agama Islam merupakan kunci kesuksesan kelompok Arab Al-Katiri hidup rukun di tengah-tengah masyarakat dengan tradisi budaya lokal. </em></p>

URBAN LOW-COST HOUSING EFFECT MENTAL HEALTH

As the number of people moving to urban areas increases by the year, it also increases the prevalence of mental health problems worldwide. Low-income groups in urban areas have had to choose to live in low-cost housing due to the higher cost of living. This study aims to understand the effect of living in lowcost housing. The objectives are to study and analyse mental health conditions for the low-income group living in low-cost housing in an urban area. This study was conducted at the Federal Territory of Kuala Lumpur, Malaysia. The questionnaire used is an adaptation of the Depression, Anxiety, and Stress Scale (DASS-21), and the sample selection used homogenous sampling. The site selection is based on the housing scheme's characteristics: location, density, property age, and surrounding land use. The data collected were analysed using correlation analysis to determine the relationship between urban low-cost housing living and mental health. The results have shown that 57.8 per cent of the respondents have depression, 65.7 per cent have anxiety, and 55.9 per cent have stress with various severity. The findings show that low-cost housing associated with poorer mental health is caused by several factors.

Naïve individuals promote collective exploration in homing pigeons

Group-living animals that rely on stable foraging or migratory routes can develop behavioural traditions to pass route information down to inexperienced individuals. Striking a balance between exploitation of social information and exploration for better alternatives is essential to prevent the spread of maladaptive traditions. We investigated this balance during cumulative route development in the homing pigeon Columba livia. We quantified information transfer within pairs of birds in a transmission-chain experiment and determined how birds with different levels of experience contributed to the exploration–exploitation trade-off. Newly introduced naïve individuals were initially more likely to initiate exploration than experienced birds, but the pair soon settled into a pattern of alternating leadership with both birds contributing equally. Experimental pairs showed an oscillating pattern of exploration over generations that might facilitate the discovery of more efficient routes. Our results introduce a new perspective on the roles of leadership and information pooling in the context of collective learning.

Oxytocin has ‘Tend-and-Defend’ Functionality in Group Conflict Across Social Vertebrates

Across vertebrate species, intergroup conflict confronts individuals with a tension between group interests best served by participation in conflict and personal interest best served by not participating. Here, we identify the neurohormone oxytocin as pivotal to the neurobiological regulation of this tension in distinctly different group-living vertebrates, including fish, birds, rodents, non-human primates, and humans. In the context of intergroup conflict, a review of emerging work on pro-sociality suggests that oxytocin and its fish and birds homologs, isotocin and mesotocin, respectively, can elicit participation in group conflict and aggression. This is because it amplifies (i) concern for the interests of genetically related or culturally similar ‘in- group’ others, and (ii) willingness to defend against outside intruders and enemy conspecifics. Across a range of social vertebrates, oxytocin can induce aggressive behaviour to ‘tend-and- defend’ the in-group during intergroup contests.

Flexibility in the social structure of male chimpanzees (Pan troglodytes schweinfurthii) in the Budongo Forest, Uganda

ABSTRACTIndividuals of social species face a trade-off between the competitive costs and social benefits of group living. Species show a range of social strategies to deal with this trade-off, for example atomistic fission-fusion dynamics in which temporary social groups of varying size and membership form and re-form; or molecular fission-fusion dynamics which contain stable sets of multilevel nested subgroups. Chimpanzees are considered an archetypical atomistic fission-fusion species, using dynamic changes in day-to-day association to moderate the costs of within-group competition. It has been argued that humans’ highly flexible social organisation allows us to live in extremely large groups. Using four years of association data from two neighbouring communities of East African chimpanzees (Pan troglodytes schweinfurthii), we describe new levels of flexibility in chimpanzee social organisation and confirm the presence of subgrouping in a second, large community of chimpanzees. We show that males from the larger Waibira community (N males 24-31) exhibited additional levels of semi-stable subgrouping, while males from the smaller Sonso community (N males 10-13) did not. Subgroup membership showed stability across some years, but flexibility across others. Our data support the hypothesis that chimpanzees can incorporate strategies other than fission-fusion to overcome costs of social living, and that their social organisation may be closer to that of modern humans than previously described.SIGNIFICANCE STATEMENTSocial living offers benefits and costs; groups can more easily locate and defend resources, but experience increased individual competition. Many species, or individuals, flexibly adjust their social organization when faced with different competitive pressures. It is argued that humans are unique among primates in combining multigroup social organisation with fission-fusion dynamics flexibly within and across groups, and that doing so allows us to live in extremely large groups. Using four-years of association data we show new levels of flexibility in chimpanzee social organization. Males from a typically-sized community employed atomistic fission-fusion dynamics, but males in an unusually large community incorporated additional semi-stable levels of subgrouping. Our data support the hypothesis that chimpanzee males combine social organization strategies, and that doing so may allow them, like humans, to mitigate individual costs at larger community sizes.