Nesting Behavior Research Articles

Inventory, new records, and host association of cleptoparasitic bees (Apidae: Nomadinae) in Brazilian savanna region

ABSTRACT Brazil has a rich diversity of native bees, crucial as pollinators. This study aimed to inventory cleptoparasitic bees in the Cerrado region of Mato Grosso, specifically in three preserved areas, characterized by Cerrado vegetation. Species richness and distribution over time were evaluated, and new occurrences are reported for the study area. Biweekly sampling was used to collect specimens and monitor the nesting behaviour of bees (Apoidea). A total of 24 individuals from the subfamily Nomadinae, covering five genera and six species, were collected. Results showed new occurrences, including Acanthopus palmatus (Ericrocidini), Odyneropsis armata (Epeolini), and Rhathymus unicolour (Rhatimini). Seasonal variation was observed mainly at the beginning and end of the rainy season. For the first time, the interaction between the parasite and host species Mesoplia decorata and Epicharis maculata was reported. We conclude that long-term inventories are essential to reveal rare species and describe new associations in understudied areas.

The deer mouse (Peromyscus maniculatus bairdii) as a model organism to explore the naturalistic psychobiological mechanisms contributing to compulsive-like rigidity: A narrative overview of advances and opportunities

Deer mice (Peromyscus maniculatus bairdii), a wildtype species native to North America, have been investigated for their spontaneous compulsive-like behaviour. The repetitive and persistence nature of three unique compulsive-like phenotypes in deer mice, i.e., high stereotypy (HS), large nesting behaviour (LNB) and high marble burying (HMB), are characterized by behavioural and cognitive rigidity. In this narrative review, we summarize key advances in the model's application to obsessive-compulsive disorder (OCD), emphasizing how it may be used to study neurobiological and neurocognitive aspects of rigidity. Indeed, deer mice provide the field with a unique naturalistic and spontaneous model system of behavioural and cognitive rigidity, that is useful for investigating the psychobiological mechanisms that underpin a range of compulsive-like phenotypes. Throughout the review, we highlight new opportunities for future research.

PSII-4 How to define good mothering ability using computer vision of free farrowing sows?

Abstract In modern swine production, most of the sows are housed in a cage system in the farrowing unit. Although this system is intended to reduce preweaning mortality, the welfare of the sow might be compromised as it greatly restricts their natural behavior. Free farrowing systems allow sows to move around in the farrowing pen, which might stimulate their nesting behavior, shorten the farrowing duration and improve locomotion score, therefore, optimizing the longevity of the sows. However, the risk of increased preweaning mortality in free farrowing systems is greater compared with cage systems. Previous studies suggested that sow behavior, also known as mothering ability, can influence preweaning mortality as an increased level of posture changes could lead to increased mortality. With grunts, a sow could initiate the suckling of the piglets but also terminate it by hiding her udder from the piglets. However, there is conflicting evidence on what characteristics of maternal ability are correlated with piglet mortality, and most studies relied on limited manual observations, which might be biased. Using computer vision algorithms, the behavior and the movement pattern of a large number of sows could be monitored at a high density and on a continuous basis. Hence, this study intended to investigate the mothering ability of sows in free farrowing systems based on large quantities and unbiased observations using computer vision. Forty cameras were installed above free farrowing pens to observe the behavior of the sow. The dataset is continuously growing and will add data of 8 sows every week, totaling 416 sows on a yearly basis. The performance of the sows and their piglets are recorded, including body weight (BW), backfat, total number born, number weaned, birth weight, and weaning weight. Computer vision algorithms (YOLO) will be trained to estimate the contour and posture of the sow and the position of the piglets. Preliminary results based on a small subset of animals showed that the algorithm is able to detect the sows and their postures accurately, and it is now being extended to detect piglet locations. This will allow us to find beneficial behavior of sow and piglets, estimate genetic parameters for potential implementation in breeding programs, and eventually improve sow performance in a welfare-friendly free farrowing system.

Seabirds as biovectors in the transport of plastic debris across ecosystem borders: A case study from the Humboldt Current Upwelling System

Seabirds have become biovectors of plastic pollutants between marine and terrestrial ecosystems, and transport of plastics to their nesting sites becomes relevant due to increasing levels of pollution. To determine the pathways by which plastic reaches their colonies, we analysed the abundance of plastics at the nesting sites of five seabird species (Humboldt penguin Spheniscus humboldti, Peruvian booby Sula variegata, kelp gull Larus dominicanus, grey gull Leucophaeus modestus, Markham's storm-petrel Hydrobates markhami) nesting in northern Chile. Seabirds were primarily grouped according to their nesting behaviour, but two species foraging in contrasting habitats (kelp gull and Markham's storm-petrel) were also compared directly. The abundance, type, and polymer of macro-, meso- and microplastics were analysed in the soil of colonies and control sites, and microplastic ingestion was evaluated for selected species. Densities of plastics in colonies of surface-nesting seabirds ranged from 0 to 21.4 items m−2 (mainly plastic bags and thin films), and 0.002 to 19.7 items m−2 (mainly hard fragments) in colonies of burrow-nesting seabirds. Mean microplastic loads in the stomachs of seabirds were between 3.7 ± 4.2 plastic items individual−1. Overall, the abundances of plastic items in all seabird colonies were low, suggesting a limited transfer of plastics from sea to land. For kelp gulls, the results indicate transfer of macroplastic items to colonies, reaching the colony via regurgitates, with landfills considered as the main plastic source. Our results suggest that contrasting nesting behaviour and foraging habitats among species can explain differential plastic accumulation in seabird colonies, but also other factors, such as wind, contribute to the accumulation of plastic debris in colonies. Proper management of sanitary landfills are key to reduce plastic contamination of coastal seabirds and their colonies.

Nesting and mating behaviours, and the development time of three solitary digger wasps of the genus Ammophila (Hymenoptera: Sphecidae)

Abstract Nesting and mating behaviours and the development time of Ammophila clavus (Fabricius), Ammophila globifrontalis Q.Li & Ch.Yang, and Ammophila laevigata F.Smith from Vietnam are presented. All three dig their nests in the ground. The nest entrance is round. The nest burrow is nearly vertical and ends with an elliptical cell. The cell contains 1–2 caterpillars. The egg is usually glued on the third abdominal segment of prey. The three wasps temporarily close their nest burrows just below the entrance when provisioning, but permanently close them above or at the nest cells when full provision is complete. As the last stage of nest construction, the nest entrance is camouflaged with small sticks and several pebbles. Males of both Ammophila clavus and Ammophila laevigata patrol nesting areas, pursue females searching for their nest sites, pounce upon them, and mate with them on the ground. The development time from egg to the emergence of adult wasps is more than one month, males always emerging before females. The nesting behaviour of the three Ammophila species is compared and discussed.

First report of Trypoxylon clavicerum (Crabronidae: Hymenoptera) from the Indian subcontinent: its nesting behaviour and prey preference

Abstract A study was conducted to document the nesting behaviour and prey composition of a crabronid wasp, Trypoxylon sp. The wasp was molecularly characterised as T. clavicerum (NCBI Accession No. OQ913679.1). Nest acceptance rate was significantly higher in the reeds of Ipomea carnea (79.20%) and bamboo (84.80%). The mean number of brood cells (4.40 ± 0.89 cells/nest) and vestibular cells (1.06 cells/nest) built by the wasp was significantly higher in the reeds of I. carnea. Brood parasitisation by the nest parasite Amobia sp. was significantly higher in nests built by the wasp in paper straws (58.57%) compared to the nests built in the reeds of bamboo (23.33%). The mean durations of the egg, larval and pupal stages of T. clavicerum were 2.60 ± 0.55, 6.01 ± 0.71 and 4.80 ± 0.84 days. The number of nests recovered was observed to be the highest during the months of August (3.66 ± 1.53 nests), September (5.00 ± 4.36 nests), October (8.67 ± 2.89 nests) and November (6.00 ± 2.10 nests). The major species of spider from the occupied nests belonged to two families, viz. Salticidae (81%) and Oxyopidae (19%). During the nesting period the adult wasp provisioned a greater number of spiderlings (3.25 to 3.60 spiderlings/cell) than adult spiders (1.20 to 1.60 adult spiders/cell) to her brood. The time taken to complete a single nest provisioned with adult spiders and spiderlings (13.20 ± 6.83 hr/single nest) was significantly less than for the nests provisioned with adult spiders (46.80 ± 14.80 hr/single nest) only. This study is the first ever report of nesting behaviour and prey composition of the spider-hunting wasp T. clavicerum from India.

Adult Offspring of Deer Mouse Breeding Pairs Selected for Normal and Compulsive-Like Large Nesting Expression Invariably Show the Same Behavior Without Prior In-Breeding.

Obsessive-compulsive disorder is a neuropsychiatric condition with notable genetic involvement. Against this background, laboratory-housed deer mice of both sexes varyingly present with excessive and persistent large nesting behavior (LNB), which has been validated for its resemblance of clinical compulsivity. Although LNB differs from normal nesting behavior (NNB) on both a biological and cognitive level, it is unknown to what extent the expression of LNB and NNB is related to familial background. Here, we randomly selected 14 NNB- and 14 LNB-expressing mice (equally distributed between sexes) to constitute 7 breeding pairs of each phenotype. Pairs were allowed to breed two successive generations of offspring, which were raised until adulthood (12 weeks) and assessed for nesting expression. Remarkably, our findings show that offspring from LNB-expressing pairs build significantly larger nests compared to offspring from NNB-expressing pairs and the nesting expression of the offspring of each breeding pair, irrespective of parental phenotype or litter, is family specific. Collectively, the results of this investigation indicate that LNB can be explored for its potential to shed light on heritable neurocognitive mechanisms that may underlie the expression of specific persistent behavioral phenotypes.

Distinct, common and synergistic effects of insulin and IGF-1 receptors on healthy murine ageing

ObjectiveReduced IGF-1 signalling is an evolutionarily conserved mediator of longevity, yet the magnitude of this effect is substantially larger in organisms retaining a common insulin and IGF-1 receptor. Whether this reflects the failure to simultaneously reduce IGF-1 and insulin signalling in mammalian model systems remains unexplored, as is the associated impact on markers of healthy ageing. We set out to address these uncertainties. MethodsWe compared the duration of healthy life (healthspan) in male mice with haploinsufficiency of the insulin receptor (IRKO), IGF-1 receptor (IGF-1RKO), or both (DKO), versus wildtype (WT) littermates. Cognitive performance was defined using nesting studies at 3- and 24-months of age. Brain transcriptome was characterised at 3- and 18-months of age using RNA-seq. ResultsHealthspan was longer in DKO versus WT, with IRKO and IGF-1RKO being intermediate. At 2 years of age, DKO also exhibited preserved nesting behaviour in contrast with all other genotypes. Differential insulin sensitivity or weight gain during ageing did not explain the preserved healthspan of DKO, since these were comparable to IRKO littermates. Brain transcriptomics at 18 months of age revealed lower expression of canonical ageing-associated genes in DKO versus WT, although many of these findings were replicated in IRKO versus WT or IGF-1RKO vs WT. ConclusionsReduced insulin and IGF-1 receptor expression have both common and synergistic effects upon elements of healthy mammalian ageing, suggesting future ageing studies should consider targeting both insulin and IGF-1 signalling.

Ecological drivers of nesting behavior in a subtropical city: An observational study on spotted doves.

Due to rapid homogenization in habitat types as a result of urbanization, some urban birds adapt their nesting strategies to changes in local habitat characteristics. Bird nesting decisions might have been mainly linked to resource constraints and ensuring reproductive success. In this study, we examined patterns of nesting behavior by spotted doves (Spilopelia chinensis) in a rapidly urbanizing area of Nanchang, China using ArcGIS 10.8, satellite tracking, camera traps, and field survey. To explore the mechanisms underlying nesting behavior in urban habitats, we assessed the correlations between nest reuse and reproductive success, and between nest reuse and nest predation. From December 2018 to December 2021, a total of 302 breeding nests were surveyed. The results revealed that the nest reuse rate was 38.08% (n = 115). Nests closer to trunk, with lower nest position and higher large-scale urbanization score tended to have higher reuse rate. In addition, nests with the higher the nest height and percent of canopy cover, and the lower small-scale urbanization score were more likely to reproduce successfully, and the reused nests also reproduce more successfully. The reproductive success associated with nest reuse was significantly higher than that associated with new nests (χ 2 = 8.461, p = .004). High degree of urbanization promoted nest reuse of spotted doves (large-scale urbanization score, z = 2.094, p = .036), which apparently enhanced their reproductive success (nest reuse, z = 2.737, p = .006). In conclusion, a nest structure with good permeability is the material basis for the nest reuse in spotted dove, while the relatively low risk of predation in urban habitat and the scarcity of nest site resources due to urbanization increase the tendency of birds to reuse old nests, which is associated with their reproductive success and evolutionary fitness.

Notes on the Nesting Behavior of Four Solitary Wasps (Insecta: Hymenoptera) in India

India is one of countries that has the highest biodiversity level of Hymenoptera in the Oriental region, as well as in the world. Hence, studies of its biology have received a large consideration of entomologists. In a course of study on Hymenoptera in Odisha state of the country in 2015, we observed the nesting behavior of several wasps and recorded their new nesting sites. Therefore, this study presents notes on the nesting behavior of the four Indian wasps, namely, Chalybion bengalense (Dahlbom) (Sphecidae), Trypoxylon petiolatum F. Smith (Crabronidae), Delta esuriens (Fabricius) and Xenorhynchium nitidulum (Fabricius) (both, Vespidae: Eumeninae). The first two wasps used man-made holes on the walls of a big temple for their nesting sites, fully stored paralyzed spiders in the nest cells for offspring and plugged them with mud, in a case of Chalybion bengalense, females added a white layer of unknown material on the outside surface of covers. Delta esuriens chose its nesting site beneath the thatched roof of a human house, built a linear series of pot-shaped mud cells that were firmly attached to some rice blades hung loosely beneath the roof and provisioned caterpillars in these nest cells. The latter built a mud nest on a wall of a human house. Xenorhynchium nitidulum made a nest cell oblique a 30° angle from the vertical surface of the wall, plastered the outside surface of the cell with tree resin of a certain plant species after completion of building and then stored prey of an unknown caterpillar in the cell. The female of Xenorhynchium nitidulum sit in the nest cell after provisioning of the first prey to the following morning suggesting that the wasp progressively provisions its nest and the egg is laid prior to provisioning.

Taxonomic notes on the Zethus olmecus de Saussure, 1875 species group (Hymenoptera, Vespidae, Eumeninae), with the description of five new species

Zethus Fabricius is the largest genus within Vespidae with nearly 300 species. The genus has a central role on discussion of social evolution, once some species share behavioral features between solitary and social representatives of vespids and the genus has been recovered as phylogenetically closer to social wasps than to other Eumeninae. The Zethus olmecus species group is even more remarkable since there are observations of communal nesting behavior, a fact misused as support for the hypothesis of closer relationship to social wasps. Herein we closely investigate the taxonomy of this group of species, the first step needed for future studies to properly approach its evolution. The taxonomic approach involved examination of external morphology and male genitalia. Five new species are described for the group: Z. bolivari n. sp., Z. hermesi n. sp., Z. hexacirratus n. sp., Z. perilloi n. sp., and Z. utingensis n. sp. The unknown female of Z. peruvicus is also described. An illustrated taxonomic key is presented. Geographical distribution is expanded for Z. peruvicus, Z. pygmaeus, Z. thoracicus, and Z. toltecus. Finally, additional notes and corrections of existing literature are given.

Ant communities and their trophobionts shape the incidence of pests and diseases in Indonesia’s coffee agroforestry system

Abstract. Muhammad FN, Rizali A, Rahardjo BT. 2024. Ant communities and their trophobionts shape the incidence of pests and diseases in Indonesia’s coffee agroforestry system. Biodiversitas 25: 1127-1134. Ants play various roles in a coffee agroecosystem, and their presence may impact biological control in coffee plantations. Despite the pantropical economic importance of coffee, most research is focused on the Americas. This study investigates how ant communities and their trophobionts shape the incidences of pests and diseases in the Indonesian shade coffee agroecosystem. Three 30 m x 30 m plots consisting of a total of 256 coffee plants were observed from January to March 2022. Ant communities and their trophobiont were observed using three methods: visual, tuna bait, and live bait. The ants found were classified into dominant and non-dominant based on their nesting behavior and dominance in the bait trap. Pest damage and disease intensity observation were also conducted three times. Generalized linear models were used to test the relationships between ant, hemipteran, coffee berry borer, twig borer damage and leaf rust disease intensity. Twenty-one species of ants were found, and five of them were categorized as dominant ants. Ants correlate coffee pest damage and disease intensity, their hemipteran trophobionts, or both. Dolichoderus thoracicus ant positively correlated with all trophobiont hemipteran and negatively correlated with twig borer damage. Technomyrmex albipes positively correlated with aphids but negatively with flatids. Meanwhile, Tetraponera sp.1 ant only positively correlated with flatids. In trophobiont hemipteran group, all except aphids positively correlated with coffee pests and disease. Scale insect Coccus viridis positively correlated with coffee leaf rust and twig borer infestation intensity, while flatid presence even positively correlated with all coffee plant pest and disease intensity. Indirectly, ants may reduce coffee pests and diseases through hemipteran suppression. The results suggest that the interaction of ants and their trophobiont hemipteran can act as a biological control agent for coffee pests and diseases.

Dangerous neighbours: Birds and bird-eating bats sharing tree cavities.

Mounting evidence indicates the non-consumptive effects of predators significantly impact prey physiology, ecology and behaviour. Passerine birds experience adverse effects on nesting and reproductive success when in proximity to predators. Fear of predators is context-dependent and influenced by hunting habitats and foraging strategies. While some bat species prey on birds, the greater noctule (Nyctalus lasiopterus) stands out by specialising in avian prey, especially during peak bird migration. N. lasiopterus is thought to seize avian prey in flight, but direct evidence is lacking. If birds were taken from nests, they would likely avoid nesting near these bats. However, no observations support this view. This study documents the successful reproduction of Eurasian blue tits (Cyanistes caeruleus) nesting alongside a colony of approximately 25 greater noctules. This bird species is a prey species for greater noctules in Italy. Over about 1 month (April-May 2023), we observed parent birds provisioning food to chicks, with at least two chicks alive and fed outside the tree cavity by the end of the period. While acknowledging the limitations of a single observation, we propose that this previously unknown behaviour indirectly supports the idea that greater noctules only capture avian prey in flight, not within confined spaces. This observation challenges the perception that these bats pose a threat when sharing roosting spaces in trees, as evidenced in our observed case. We hope this novel observation inspires future research on variations in bird nesting behaviour and reproductive success in the presence of bird-eating bats, as well as an assessment of the long-term impact on population dynamics and reproductive success of nesting birds sharing such roosting spaces.

Higher offspring mortality in deer mice (Peromyscus maniculatus bairdii) that spontaneously present with large nest building behaviour

Nesting is a normal, evolutionary conserved rodent behavioural phenotype that is expressed for purposes of breeding, safety, and thermal regulation. Further, nesting is commonly assessed as marker of overall rodent health and wellbeing, with poorer nesting performance generally proposed to resemble a worse state of health. Deer mice can be bidirectionally separated with 30 % of mice presenting with excessively large nesting behaviour (LNB). All laboratory-housed deer mice are exposed to identical environmental conditions. Thus, the functional purpose of LNB remains unknown. Considering the evolutionary functions of nesting, we hypothesized that LNB will be related to an inflated drive to breed and nurse offspring. After breeding two generations of offspring from six ‘normal’ nesting (NNB) and seven LNB expressing pairs, our data showed that while as fertile as NNB expressing pairs, offspring survival of LNB mice were notably worse (67.9 % vs. 98.3 %). In conclusion, variance in nesting behaviour should be considered when animal health and wellbeing is considered, since it may point to underlying biobehavioural perturbations.

Updating Chimpanzee Nesting Data at Mount Assirik (Niokolo Koba National Park, Senegal): Implications for Conservation.

The Niokolo Koba National Park (NKNP) is the largest protected area in Senegal and lies at the northern limit of the chimpanzee's range in West Africa. Recent information on nesting behavior and factors influencing nesting behavior is available for several sites outside NKNP. However, the information available for NKNP is obsolete. Considering that the adequate management of chimpanzee populations cannot be achieved without strong scientific knowledge, it is essential to update data on chimpanzee, Pan troglodytes verus, nesting behavior in NKNP. For this reason, we surveyed their habitat in Mt. Assirik and recorded 626 chimpanzee nests. The results of the study showed that chimpanzees nest more often in closed-canopy habitats such as gallery forests. The average nest height observed in this study was 8.07 ± 0.36 m, varying between 2 and 20 m, which is well below the heights described in most sites where chimpanzees cohabit with large carnivores. Botanical surveys confirmed that chimpanzees select tree species bearing their nests. In Assirik, 12 of the 37 tree species bearing nests are the most used. The nest decay rate (or the time it takes for a nest to go from the fresh to the skeletal stage) at Assirik averaged 68.8 ± 5.8 days.

Uncovering floral composition of paper wasp nests (Hymenoptera: Vespidae: Polistes) through DNA metabarcoding

As the social organism, Polistes wasps build a communal nest using woody fibers with saliva for sustaining brood and adult population throughout the season. Limited information exists regarding the identification specific plant materials employed in wasp nest building. Thus, we firstly tested if the DNA metabarcoding approach utilizing rbcL and trnL molecular markers could identify the plant species quantitatively and qualitatively inform the mixed-origin woody samples. A threshold of 0.01 proportion of reads was applied for rbcL and trnL molecular markers, while this threshold for median proportion was 0.0025. In assessing taxa richness, the median proportion demonstrated superior performance, exhibiting higher taxa detection power, however, rbcL marker outperformed in quantitative analysis. Subsequently, we applied DNA metabarcoding to identify the plant materials from the nests of two Polistes species, P. mandarinus and P. rothneyi. The results showed that higher preference of Quercus and Robinia as the major nest building materials regardless of the surrounding plant communities, by two wasp species. Material diversity was higher for P. rothneyi than P. mandarinus, which may explain the abundance of this species possibly with heightened adaptive capacities in their nesting behavior. This study demonstrated that DNA metabarcoding could identify the complex nest-building plant materials of paper wasps and provide insights into their ecological interactions in the natural ecosystem.

Nesting trends and predation risks among yellow-spotted river turtles in Essequibo River Basin

The yellow-spotted river turtle (Podocnemis unifilis), inhabiting Amazon, Orinoco, and Essequibo River basins, is classified as vulnerable due to historical exploitation and current threats. Efforts have been made throughout the Amazon basin to understand the ecology of yellow-spotted river turtles and implement conservation measures, but the Essequibo River basin located in Guyana, remains the least studied part of the geographical range of the species. In this study we present data collected over a three-year period from 2020 to 2023, as part of a community driven conservation program by Yupukari village, in the North Rupununi, Guyana. We describe the nesting behavior of P. unifilis,and assess predation of eggs in the wild. A total number of nests in 9 beaches ranging from 59 (in 2021) to 76 (in 2023) (in averge 6.68 nest/beach, and 14.2 nests per ha) with an average number of 20.45 eggs per nest. Nesting locations were found to be predominantly situated within 1–20 m from the river, in proximity to vegetation, and on fine sand, with temperatures consistently falling within the 27–29 degrees Celsius range. Importantly, this study unravels the critical issue of nest predation, with lizards, human, and the birds emerging as the primary culprits, impacting nests located closer to vegetation to a greater extent. All nests in sites which potentially would be flooded were moved for a hatchery in the community of Yupukari in which the hatching success reached 83%.

Nesting behavior of greater eelpout (Lycodes esmarkii), identified through a predation event by spotted wolffish (Anarhichas minor).

The stomach of a spotted wolffish (Anarhichas minor) caught in Icelandic waters was found to contain ~727 greater eelpout larvae (Lycodes esmarkii). All the larvae were of similar size and at a similar state of digestion, indicating they were all consumed together. The likely explanation for this observation is that greater eelpout lay their eggs in a nest, with the larvae remaining in the nest for a short period after hatching. The larvae were then predated upon by the spotted wolffish while still in the nest. This study sheds new light on greater eelpout in Icelandic waters, with recently hatched larvae being present in March, breeding at a depth of ~200-250 m, and likely exhibiting nesting behavior, which has not previously been documented.

Nesting behavior is associated with body weight and grip strength loss in mice suffering from experimental arthritis

Objective animal health evaluation is essential to determine welfare and discomfort in preclinical in vivo research. Body condition scores, body weight, and grimace scales are commonly used to evaluate well-being in murine rheumatoid arthritis (RA) and osteoarthritis experiments. However, nest-building, a natural behavior in mice, has not yet been evaluated in wild type (WT) or genetically modified rodents suffering from collagen antibody-induced arthritis (CAIA). To address this, we analyzed nesting behavior in WT mice, calcitonin gene-related peptide alpha-deficient (αCGRP-/-) mice, and calcitonin receptor-deficient (Calcr-/-) mice suffering from experimental RA compared to healthy control (CTRL) groups of the same genotypes. CAIA was induced in 10–12-week-old male mice, and clinical parameters (body weight, grip strength, clinical arthritis score, ankle size) as well as nesting behavior were assessed over 10 or 48 days. A slight positive association between the nest score and body weight and grip strength was found for animals suffering from CAIA. For the clinical arthritis score and ankle size, no significant associations were observed. Mixed model analyses confirmed these associations. This study demonstrates that clinical effects of RA, such as loss of body weight and grip strength, might negatively affect nesting behavior in mice. Assessing nesting behavior in mice with arthritis could be an additional, non-invasive and thus valuable health parameter in future experiments to monitor welfare and discomfort in mice. During severe disease stages, pre-formed nest-building material may be provided to animals suffering from arthritis.

Evidence for a selective link between cooperation and individual recognition

The ability to recognize others is a frequent assumption of models of the evolution of cooperation. At the same time, cooperative behavior has been proposed as a selective agent favoring the evolution of individual recognition abilities. Although theory predicts that recognition and cooperation may co-evolve, data linking recognition abilities and cooperative behavior with evidence of selection are elusive. Here, we provide evidence of a selective link between individual recognition and cooperation in the paper wasp Polistes fuscatus through a combination of clinal, common garden, and population genomics analyses. We identified latitudinal clines in both rates of cooperative nesting and color pattern diversity, consistent with a selective link between recognition and cooperation. In behavioral experiments, we replicated previous results demonstrating individual recognition in cooperative and phenotypically diverse P.fuscatus from New York. In contrast, wasps from a less cooperative and phenotypically uniform Louisiana population showed no evidence of individual recognition. In a common garden experiment, groups of wasps from northern populations formed more stable and individually biased associations, indicating that recognition facilitates group stability. The strength of recent positive selection on cognition-associated loci likely to mediate individual recognition is substantially greater in northern compared with southern P.fuscatus populations. Collectively, these data suggest that individual recognition and cooperative nesting behavior have co-evolved in P.fuscatus because recognition helps stabilize social groups. This work provides evidence of a specific cognitive phenotype under selection because of social interactions, supporting the idea that social behavior can be a key driver of cognitive evolution.