Animals regularly experience periods of food uncertainty due to seasonal changes and environmental variability. Further, the changing climate is leading to more variable weather patterns, which alter environmental conditions, and can result in resource distributions being less predictable in space and time. How animals respond to uncertain conditions, and in particular a changing distribution of food resources, remains largely unclear and is an important question in the field of movement and animal ecology. We used an experimental approach to study how Merino sheep (Ovis aries) respond to different levels of food location uncertainty in a drought-impacted region of the Australian arid zone. Sheep were unfamiliar with the experimental food locations at the start and progressively decreased their uncertainty (i.e., increased their environmental knowledge) when discovering an increasing number of foraging patches. We tracked 50 sheep with GPS collars (1 location every 15 s) and deduced their movement and space use behaviour. When food uncertainty decreased, individuals moved more directionally (greater step length, smaller turn angles) and moved greater distances per day. They also had larger daily ranges. Displacement (distance between first and last location of the day) increased once and otherwise remained similar across levels of uncertainty. Our study demonstrates how an arid zone ungulate, in a large 600 ha enclosed paddock, adjusted its movement and space use behaviour as it gained environmental information on food distribution. Our study provides important insights into how animals cope with variable environments in order to forage efficiently during periods of uncertainty. Food distributions are often unpredictable over time, with climate change exacerbating variability. Understanding how animals respond to periods of environmental uncertainty is crucial to predict animal movement in space and time. We used an experimental approach and investigated how different levels of food location uncertainty affected the movement and space-use behaviour in sheep freely moving in a large 600 ha paddock. We used the number of discovered experimental food patches as a proxy for environmental knowledge (inverse of uncertainty). Movement was faster and more directional, and daily range size increased as food uncertainty decreased and sheep gained knowledge about the food locations. Our study demonstrates how an arid zone ungulate adjusted its movement and space use behaviour as it gained environmental information about food patch distributions.

Theory predicts that high population density leads to more strongly connected spatial and social networks, but how local density drives individuals' positions within their networks is unclear. This gap reduces our ability to understand and predict density-dependent processes. Here we show that density drives greater network connectedness at the scale of individuals within wild animal populations. Across 36 datasets of spatial and social behaviour in >58,000 individual animals, spanning 30 species of fish, reptiles, birds, mammals and insects, 80% of systems exhibit strong positive relationships between local density and network centrality. However, >80% of relationships are nonlinear and 75% are shallower at higher values, indicating saturating trends that probably emerge as a result of demographic and behavioural processes that counteract density's effects. These are stronger and less saturating in spatial compared with social networks, as individuals become disproportionately spatially connected rather than socially connected at higher densities. Consequently, ecological processes that depend on spatial connections are probably more density dependent than those involving social interactions. These findings suggest fundamental scaling rules governing animal social dynamics, which could help to predict network structures in novel systems.

Host personality can markedly affect parasite transmission. Especially for parasites with indirect transmission through the environment, the effects of consistent among-individual differences in behavior may have both direct and indirect components. For example, personality may mediate both how hosts respond to infected individuals and the likelihood that hosts indirectly interact with infected conspecifics (e.g., by visiting patches infected hosts have previously contaminated). Integrating parasites, personality, and these different kinds of interaction networks constitutes a key step toward understanding transmission in natural systems. We evaluated these elements using a 5-year field study of a wild population of sleepy lizards, Tiliqua rugosa, and their tick parasites, which transmit among lizards through lizards' shared use of refuges. Using Bayesian models, we evaluated (1) predictors of lizard infestation probability and intensity (i.e., average tick count when infested) and (2) relationships among the predictors. We used the latter set of models to assess indirect relationships between the predictors and the infestation metrics. As predictors, we used lizards' infestation "risk" (derived from a time-lagged refuge sharing transmission network), traits (sex, mass, and the personality axes aggression and boldness), space use (number of unique refuges used and home range overlap with other lizards), and measures of synchronous social interactions (i.e., edge weight and degree). We found both indirect and direct connections between our predictors and tick infestation. For example, boldness was positively directly associated with infection intensity and indirectly positively associated with both infestation probability and intensity via intermediary connections with social network interaction and risk. Using more unique refuges, on the other hand, was indirectly negatively associated with infestation probability (via reduced risk), but directly positively associated with infestation probability, indicating a potential trade-off in the anti-parasite benefits of using more refuges. Our results emphasize that (1) multiple aspects of host behavior may associate with parasite infection, (2) these components may proceed through both direct and indirect pathways, and (3) multiple pathways should be considered together because the pathways may have compounding or counteracting effects.

ABSTRACT Individual recognition is an important element of social interactions among animals. While the presence of individually distinct vocalisations (providing a basis for individual recognition) has been widely tested across species, information about which components of a call encode this information is lacking. We investigated whether female alpaca ( Vicugna pacos ) vocalisations, particularly their hums, encode information about individual identity and explored which parameters contribute to this encoding. We recorded vocalisations from 9 adult female alpaca and extracted both spectro-temporal features (frequencies and duration) and mel-frequency cepstral coefficients (MFCC). Random forest analyses revealed clear individual differences in both datasets, with the spectro-temporal features allowing for slightly more accurate classification than MFCC (71% and 66.5% accuracy for spectro-temporal features and MFCC, respectively). These robust acoustic identities have the potential to provide a basis for individual recognition in alpaca, which could have important flow on effects for alpaca communication, as it allows receivers to modulate their response to the caller’s identity. Alpaca, as herd-living and vocal animals, provide an excellent model system for better understanding the mechanisms, causes and consequences of recognition and inter-individual communication.

Animal gut microbiomes can be very diverse, and enteric bacteria can profoundly affect the physiology of their host. The gut microbiome can be related to host health and digestion, which ultimately contribute to host body condition. However, we have a limited understanding of the co-occurrence patterns of gut bacteria in their host, and how co-occurrence and bacterial diversity change over time. This notion is especially important to animals living in groups as bacteria can transmit through social interactions. We investigated the co-occurrence patterns of gut bacteria in a lizard host. We repeatedly collected cloacal swabs from 87 sleepy lizards (Tiliqua rugosa) from two different study sites over their activity season. We determined the richness and prevalence of 82 enteric bacterial strains and used a probabilistic model to investigate their co-occurrence. At both study sites, richness and prevalence generally increased over time. We suggest that the lizards acquire strains throughout their activity season by moving through the landscape and inspecting conspecific scats. Lizards continuously tongue-flick while moving, and thereby ingest bacteria when they move through areas where other animals defaecated. Temperature, rainfall and diet change seasonally, influencing lizard activity, and may influence the observed increase in enterobacterial richness and prevalence. Further, albeit with some exceptions, most strain pairs did not occur significantly more often or less often than expected by chance. This finding shows a lack of structured co-occurrence, which may imply that most bacterial strains did not facilitate or inhibit each other. The absence of a co-occurrence pattern could also be driven by random encounters of bacteria shed by other lizards within the habitat. Our results suggest that behaviour (movement patterns, tongue-flicking), activity patterns and environmental factors collectively drive the temporal pattern of the gut bacterial community in sleepy lizards and potentially other wild reptiles.

Knowledge about the environment is fundamentally important to move, find resources and forage efficiently. This information can either be acquired through individual exploration (personal information) or from other group members (social information). We experimentally assessed the use of social information and its influence on foraging efficiency in sheep, Ovis aries. Naïve individuals paired with an informed partner that knew the food patch location, found the patch significantly faster compared to naïve individuals paired with another naïve individual. Similarly, they spent a significantly lower proportion of time exploring areas away from the food patch. We further found that the outcome of using social information in one directly previous trial (success = access to feed vs failure = no access to feed) had no impact and sheep continued to use social information in the subsequent foraging trial and foraged similarly efficient. Our results suggest, naïve sheep that are unfamiliar with resource locations, forage more efficiently when informed individuals are present compared to when all individuals are naïve. If informed individuals play a similar role in larger groups, new management practices that integrate informed sheep could be developed to improve foraging efficiency when sheep are moved to new paddocks or in paddocks with heterogenous and dynamic resource distribution.

Abstract Extreme weather conditions, like heatwave events, are becoming more frequent with climate change. Animals often modify their behaviour to cope with environmental changes and extremes. During heat stress conditions, individuals change their spatial behaviour and increase the use of shaded areas to assist with thermoregulation. Here, we suggest that for social species, these behavioural changes and ambient conditions have the potential to influence an individual's position in its social network, and the social network structure as a whole. We investigated whether heat stress conditions (quantified through the temperature humidity index) and the resulting use of shaded areas, influence the social network structure and an individual's connectivity in it. We studied this in free‐ranging sheep in the arid zone of Australia, GPS‐tracking all 48 individuals in a flock. When heat stress conditions worsened, individuals spent more time in the shade and the network was more connected (higher density) and less structured (lower modularity). Furthermore, we then identified the behavioural change that drove the altered network structure and showed that an individual's shade use behaviour affected its social connectivity. Interestingly, individuals with intermediate shade use were most strongly connected (degree, strength, betweenness), indicating their importance for the connectivity of the social network during heat stress conditions. Heat stress conditions, which are predicted to increase in severity and frequency due to climate change, influence resource use within the ecological environment. Importantly, our study shows that these heat stress conditions also affect the animal's social environment through the changed social network structure. Ultimately, this could have further flow on effects for social foraging and individual health since social structure drives information and disease transmission.

High population density should drive individuals to more frequently share space and interact, producing better-connected spatial and social networks. Despite this widely-held assumption, it remains unconfirmed how local density generally drives individuals' positions within wild animal networks. We analysed 34 datasets of simultaneous spatial and social behaviour in >55,000 individual animals, spanning 28 species of fish, reptiles, birds, mammals, and insects. >80% of systems exhibited strongly positive relationships between local density and network centrality, providing broad empirical evidence that local density increases connectedness at the individual level. However, >75% of density-connectedness relationships were nonlinear, and density's importance declined at higher values in >70% of systems, signifying saturating effects. Density's effect was much stronger and less saturating for spatial than social networks, suggesting population density drives individuals to become disproportionately spatially connected rather than socially. These findings reveal fundamental trends underlying societal structuring, with widespread behavioural, ecological, and evolutionary implications. ### Competing Interest Statement The authors have declared no competing interest.

Livestock heat stress threatens production, particularly in semi-arid, arid and tropical regions. Using established temperature thresholds for sheep, we modelled +1 °C and +3 °C temperature increases over the historical baseline, estimating that 2.1 million potential lambs are lost annually due to heat stress alone, increasing to 2.5 and 3.3 million, respectively, as temperatures rise. Heat stress poses risks at key periods of the reproductive cycle, with consequences across the Australian sheep flock.

Fission–fusion events, i.e. changes to the size and composition of animal social groups, are a mechanism to adjust the social environment in response to short-term changes in the cost–benefit ratio of group living. Furthermore, the time and location of fission–fusion events provide insight into the underlying drivers of these dynamics. Here, we describe a method for identifying group membership over time and for extracting fission–fusion events from animal tracking data. We applied this method to high-resolution GPS data of free-ranging sheep (Ovis aries). Group size was highest during times when sheep typically rest (midday and at night), and when anti-predator benefits of grouping are high while costs of competition are low. Consistent with this, fission and fusion frequencies were highest during early morning and late evening, suggesting that social restructuring occurs during periods of high activity. However, fission and fusion events were not more frequent near food patches and water resources when adjusted for overall space use. This suggests a limited role of resource competition. Our results elucidate the dynamics of grouping in response to social and ecological drivers, and we provide a tool for investigating these dynamics in other species.

Knowledge about the environment is fundamentally important to move, find resources and forage efficiently. This information can either be acquired through individual exploration (personal information) or from other group members (social information). We experimentally assessed the use of social information and its influence on foraging efficiency in sheep, Ovis aries . Naïve individuals paired with an informed partner that knew the food patch location, found the patch significantly faster compared to naïve individuals paired with another naïve individual. Similarly, they spent a significantly lower proportion of time exploring areas away from the food patch. We further found that the previous outcome of using social information (success = access to feed vs failure = no access to feed) had no impact and sheep continued to use social information in subsequent foraging trials and foraged similarly efficient. Our results suggest, naïve sheep that are unfamiliar with resource locations, forage more efficiently when informed individuals are present compared to when all individuals are naïve. If informed individuals play a similar role in larger groups, new management practices could be developed to improve foraging efficiency when sheep are moved to new paddocks or in paddocks with heterogenous and dynamic resource distribution.

Wild animals are often concurrently infected by multiple parasites, which are assumed to negatively affect their host by exploiting the host's resources. The cumulative effect of parasite infections is often not studied. Despite this assumption, many hosts do not suffer significant costs from parasitism in the wild. Hosts can adapt to parasitic infections by mounting physiological and behavioural defences. A commonly used behavioural defence by ectotherms is to frequently visit warm environments to increase body temperature (i.e., behavioural fever) and thereby mount an immune response to parasites. Using the Australian common garden skink (Lampropholis guichenoti), we investigated the cumulative effect of endo- and ectoparasites on host performance. First, we investigated whether endo- and ectoparasites were associated with whole-organism performance in the lizards. Second, we explored whether host individuals responded to their parasite infection through thermoregulatory behaviour. We found no significant relationship between parasitism and body condition. However, the infection with ectoparasitic mites was significantly related to reduced sprint speed, while the nematode infection had no significant relationship with any of our three performance measures (sprint speed, endurance and foraging efficiency). We showed no evidence of behavioural fever and infected lizards did not differ in their body temperature from uninfected lizards. Our findings suggest that short-lived lizards may simply endure parasitic infections. The study provides an important example of how multiple infections with endo- and ectoparasites affect their host. It adds to the growing evidence for a negligible effect of parasites on host whole-organism performance.

[This corrects the article DOI: 10.1098/10.1098/rsos.230402.][This corrects the article DOI: 10.1098/rspb.2021.1115.].

ABSTRACT Animals constantly experience periods of uncertainty due to seasonal changes in food distribution. The changing climate results in more variable weather patterns, which in turn alter environmental conditions, and can result in resource distribution being less predictable in space and time. How animals respond to these uncertain conditions, in particular the changing distribution of food resources, remains largely unclear and is an important question in the field of movement and animal ecology. Here we used an experimental approach to study how Merino sheep ( Ovis aries ) responded to different levels of environmental uncertainty in a drought-impacted region of the Australian arid zone. Sheep were unfamiliar with the experimental resource distribution at the start and progressively decreased their uncertainty (i.e., increased their environmental knowledge) when discovering an increasing number of foraging patches. We tracked 50 sheep with GPS collars (1 location every 15 sec) and deduced their movement and space use behaviour. When environmental uncertainty decreased, individuals moved more directionally (greater step length, smaller turn angles) and moved greater distances per day. They also had larger daily home ranges but rested in similar areas on consecutive nights (similar displacement, with the exception when five patches were discovered). Our study demonstrates how an arid zone, free-ranging ungulate adjusts its movement and space use behaviour as it gains environmental information in order to forage efficiently during periods of uncertainty. Our study provides important insights into how animals cope with variable environments and different levels of uncertainty.

Abstract Climate change threatens global livestock production1,2. We modelled the impact of recent temperatures and a 1°C and 3°C temperature increase over the historical baseline on risks of heat stress at key periods of the reproductive cycle and consequences for reproduction across the entire Australian sheep flock. We estimate that 2.1 million potential lambs are currently lost annually due to heat stress, increasing to 2.5 and 3.3 million as temperatures rise.

Parasite load can vary with seasonality, but this is rarely quantified. The garden skink (Lampropholis guichenoti) is host to multiple species of endoparasite. To measure seasonal effects of parasite transmission we established three captive groups of wild-caught individuals in which 2 of 16 individuals (12.5%) were initially infected with nematodes. We collected three faecal samples from each lizard, a sample at the beginning and at the end of the non-activity season and at the end of the following activity season. We measured parasite load (ascarid group) by counting parasite eggs per gram of faeces using a microscope. We found that parasite load was significantly higher in the activity season than in the non-activity season. The prevalence of parasites increased from 15.9% in the non-activity season to 72.5% in the activity season. The activity season is characterised by greater host activity and warmer ambient temperatures, which promote parasite egg survival in the environment as well as egg development. Taken together, this facilitates parasite transmission and could ultimately explain the higher parasite load during the activity season.

Home ranges (HRs), the regions within which animals interact with their environment, constitute a fundamental aspect of their ecology. HR sizes and locations commonly reflect costs and benefits associated with diverse social, biotic, and abiotic factors. Less is known, however, about how these factors affect intraspecific variation in HR size or fidelity (the individual's tendency to maintain the same HR location over time) or whether variation in these features emerge from consistent differences among individuals or among the sites they occupy. To address this knowledge gap, we used an extensive GPS-tracking data set of a long-lived lizard, the sleepy lizard (Tiliqua rugosa), which included repeated observations of multiple individuals across years. We tested how three categories of predictors-(1) lizard characteristics (sex, aggressiveness, and parasitic tick counts), (2) environmental characteristics (precipitation, food, and refuge quality), and (3) social conditions (conspecific overlap and number of neighbors)-affected HR size and fidelity. We found that individuals differed consistently in the size and fidelity of annual HRs (with a repeatability of 0.58 and 0.33, respectively), and that all three categories of predictors affected both HR size and fidelity. For example, HRs were smaller in areas with more food, and males had larger HRs than females. In addition, more aggressive lizards tended to have larger HRs. Conspecific overlap and number of individuals that a lizard interacted with (social network degree) had an interactive effect on HR size where individuals whose HRs overlapped more with neighbors had larger HRs, and this effect was particularly strong for individuals that interacted with more neighbors. HR fidelity declined over time (HR locations drifted from year to year), but individuals differed consistently in this rate of drift. The fact that HR size was consistent despite drifting locations suggests that lizard HRs reflect individual traits (e.g., habitat choice criteria that differ among individuals), rather than simple heterogeneity among sites. Overall, these findings demonstrate (1) both strong, long-term, within-individual consistency and between-individual differences in space use and (2) combined effects of individual traits, social conditions, and environmental characteristics on animal HRs, with implications for diverse ecological processes.

Remote-sensing technology facilitates longitudinal collection of body temperature during periods of hot or cold environmental stress without human interference, producing high-frequency measurements whilst reducing labour and stress to the animal. A pilot study was conducted to validate an improved, minimally invasive method for the continual measurement of vaginal temperature (VT) in female sheep. A silicon mould of a modified controlled internal drug release (CIDR) device (Zoetis Animal Health, Parsippany), was manufactured to securely house a temperature logger (Micro-T 16-bit; Star Oddi, Iceland) and allow direct contact at the collection site. These temperature-sensing CIDR devices were validated against manual rectal temperature (RT) measurements collected from 15 mature, non-pregnant, non-lactating Merino ewes. Rectal temperature was measured from each individual, six times per day in 2-h intervals for 14 consecutive days. The simultaneous measures of VT and RT did not differ significantly within each ewe (P > 0.05) and demonstrated a moderate linear relationship (R2 = 0.62, P < 0.05). The mean (± SEM) difference between RT and VT was small (0.010 ± 0.004 °C), with a 95% confidence interval of − 0.26 to 0.29 °C. Additionally, the coefficient of variation was lower on average for VT (0.49%) compared to RT (0.59%). Differences among paired readings were likely due to interval variation as well as penetration depth, air influx and faecal temperature when collecting RT. The initial silicone manufacturing costs were high (2200 AUD), with each unit costing 1.25 (AUD) thereafter; however, the temperature-sensing CIDR device was an effective and efficient research tool for the remote monitoring of body temperature. While further validation of these devices within extensive grazing environments is warranted, the collection and analysis of longitudinal physiological data from ewes has the potential to improve a variety of management aspects related to extensively grazed ewes maintained and joined in harsh conditions.

Dickcissel (Spiza americana) males occupying territories in cropland sites produced songs that were less similar on average to other Dickcissel songs in their neighborhood than did Dickcissels living in grasslands, where conformity to the local vocal culture was higher. Further, Dickcissel vocal culture changed more quickly over time in cropland sites relative to grassland sites. These differences may have resulted from the lower site fidelity we observed in Dickcissel males in cropland sites relative to grassland sites. We expected this link with site fidelity because we hypothesized that conformity to local culture in Oscine songbirds and the persistence of culture over time and space are promoted by habitats that facilitate stable populations. In contrast, sites in which habitat features cause rapid population turnover provide more territory vacancies and so more opportunities for colonization. Colonization should drive cultural change, either through adult colonists importing foreign cultural variants or young colonists making errors as they learn the local song. This potential link between population turnover and cultural stability may apply to animal cultures more broadly and so may be a fruitful area for further research. Besides the link between site fidelity and cultural change over time, we also investigated the possibility that habitats with different levels of site fidelity might show differences in the spatial scale of song similarity. However, we found no evidence of such a difference. Finally, although our conclusions regarding conformity and change in vocal culture were based on many recorded songs, automated assessments of song similarity imprecisely estimated the overall degree of song similarity. Thus, we may have underestimated the strength of the effects of time and distance on song similarity.

Individual variation in movement is profoundly important for fitness and offers key insights into the spatial and temporal dynamics of populations and communities. Nonetheless, individual variation in fine-scale movement behaviours is rarely examined even though animal tracking devices offer the long-term, high-resolution, repeatable data in natural conditions that are ideal for studying this variation. Furthermore, of the few studies that consider individual variation in movement, even fewer also consider the internal traits and environmental factors that drive movement behaviour which are necessary for contextualising individual differences in movement patterns. In this study, we GPS tracked a free-ranging population of sleepy lizards Tiliqua rugosa, each Austral spring over 5 years to examine consistent among-individual variation in movement patterns, as well as how these differences were mediated by key internal and ecological factors. We found that individuals consistently differed in a suite of weekly movement traits, and that these traits strongly covaried among-individuals, forming movement syndromes. Lizards fell on a primary movement continuum, from 'residents' that spent extended periods of time residing within smaller core areas of their home range, to 'explorers' that moved greater distances and explored vaster areas of the environment. Importantly, we also found that these consistent differences in lizard movement were related to two ecologically important animal personality traits (boldness and aggression), their sex, key features of the environment (including food availability, and a key water resource), habitat type and seasonal variation (cool/moist vs. hot/drier) in environmental conditions. Broadly, these movement specialisations likely reflect variation in life-history tactics including foraging and mating tactics that ultimately underlie key differences in space use. Such information can be used to connect phenotypic population structure to key ecological and evolutionary processes, for example social networks and disease-transmission pathways, further highlighting the value of examining individual variation in movement behaviour.