Human-induced environmental change increases unpredictability, disrupting habitats and social structures in ways that many animals are poorly adapted to. This may also reduce the reliability of information faster as contingencies shift. While independently acquired information is often more accurate, increased unpredictability may make recency the key to reliability, increasing the value of social information, which is cheaper and faster to update. Unpredictability might thus shift the balance between the values of these types of information, increasing reliance on more recent social information. Thus, independent of information quality, the predictability of background conditions may affect how animals make decisions. To test whether living in an unstable environment changes the inherent value of information, zebrafish (Danio rerio) were housed for 3 mo under either highly unpredictable Dynamic (water temperature, feeding times, habitat complexity, group size and membership fluctuated) or Stable conditions. Across 6 behavioral assays, Dynamic condition fish showed more information-seeking, greater attention to social stimuli, more sensitivity to social cues, and were less coordinated but swam closer together in shoals. When personal and social information conflicted, they were also more likely to prioritize recent social information over previously learned personal information. Together, these results indicate that long-term housing in an unpredictable environment diminishes the value of information faster, raises the value of social information to allow for faster updating, shifts decision-making strategies independent of the quality of information itself, and disrupts coordinated schooling in zebrafish. This sensitivity may fundamentally alter how animal collectives navigate an increasingly unpredictable world.

Abstract Just as for predators, many animals have developed a suite of defenses to counter the ubiquitous threat posed by parasites. Behavioral avoidance is a key strategy to reduce the likelihood of encountering situations with a relatively high degree of risk. However, because such avoidance likely incurs costs (i.e., non-consumptive effects), individuals should engage in risk assessment to gauge their threat of parasitism based on relevant cues. Combinations of cues may signal particularly risky situations, especially as animals often face concurrent natural enemies. In the first study to consider host choice in the presence of different parasites, we investigated behavioral avoidance in red flour beetles (Tribolium castaneum) given various foraging options involving two entomopathogens, the fungus Beauveria bassiana and the nematode Steinernema carpocapsae. Combinations included single and dual parasite threats, as well as whether parasites were represented by the presence of infectious stages and/or conspecific cadavers that were euthanized or killed by infection. Beetles generally did not exhibit behavioral avoidance of either parasite or the parasite-killed conspecifics, but rather, tended to be attracted to the latter if nematode-infected. They also did not avoid conditions with mixed cues related to the threat of infection, suggesting that they do not gauge or respond to parasitism risk in this way. Our findings have implications for understanding avoidance as an anti-parasite behavior across different host taxa, but also for the use of biocontrols such as fungi and nematodes for pest insects.

Seemingly irrelevant options, such as inferior or unavailable “decoys”, can shift decisions people and captive animals make in simplified environments. But do decoys influence animals in messy, complex, natural environments? Here, we explored this question in a foraging context, a process involving countless daily decisions that ultimately underpins animal fitness. We tested whether a “phantom decoy” (inaccessible but preferred food) influenced food choice of free-ranging swamp wallabies across 3 scenarios; Binary—2 available, equally preferred foods differing nutritionally; Phantom—2 available foods plus an inaccessible phantom decoy nutritionally similar to one; Trinary—all 3 foods available. We analysed data using a new approach that overcame cross-level bias, when individual choices shift in opposite directions leading to no overall shifts. We found that the phantom decoy made wallabies more likely to switch their choice away from the nutritionally similar food—a net reactance effect. Unexpectedly, when all foods were available, wallaby choices appeared random and haphazard, suggesting cognitive overload. These findings demonstrate that decoys can shape ecologically relevant foraging decisions, so their influence is not simply an inadvertent byproduct of stylized simplistic settings. As such, traditional foraging models may better predict real-world foraging decisions by incorporating decoy effects.

Injuries are common in animals and represent a major threat to individual survival. They can result from inter- or intraspecific conflict, predation, or pugnacious prey. Despite their potential ecological and evolutionary importance, injury patterns remain poorly documented in animal populations. To test whether a species’ feeding ecology or habitat can predict injury patterns, we quantified injury rates and affected body regions among native ant species collected from different habitats in Bavaria, Germany. Specimens were sampled using pitfall traps, which proved to be an efficient method for injury assessment. Injury rates varied substantially among species and genera, ranging from 0% to 38%. Predatory ant species exhibited higher frequencies of leg injuries, whereas omnivorous species were more frequently injured at the antennae. The distribution of injuries likely reflects both foraging ecology and species-specific wound care behaviors, with a high frequency of trochanter injuries potentially indicating prior amputation events to cope with infected leg injuries, as observed in Lasius alienus. Our findings demonstrate that injury propensity and distribution are shaped by feeding habits and behavioral adaptations, providing comparative evidence that the costs and management of injuries vary systematically among ant species. Our study thus highlights injuries as a measurable axis of selection that may have contributed to the emergence of wound care and other forms of social immunity in ants.

Male bees navigate complex tradeoffs between energy acquisition and reproductive signaling, yet their movement strategies remain understudied. Unlike workers that optimize foraging to support the colony, male bumblebees (Bombus terrestris) forage independently to collect nectar and deposit sex pheromones on selected plants. Using high-resolution 3D tracking in an indoor flight cage, we investigated how the spatial arrangement of nectar and scent-marking sites, along with nectar availability, influence male movement patterns. We manipulated the distribution of feeders (artificial flowers) and scent-marking locations (branches), and varied nectar delivery rates, to assess effects on foraging, scent-marking, and patrolling. Males responded strongly to spatial structure: in clumped arrays with evenly spaced resources, movements between consecutive visits were shorter and more localized, while in dispersed arrays with irregular spacing, transitions were longer and more variable. The combination of dispersed spacing and low nectar availability imposed the highest foraging demands, resulting in fewer feeding events and reduced total feeding time. Despite these increased costs, males maintained consistent investment in reproductive behaviors, suggesting a prioritization of mate-seeking over energy gain. Rather than reducing signaling, males adjusted their foraging strategy—favoring fewer but prolonged feeding bouts when nectar availability allowed. These findings reveal a unidirectional behavioral adjustment, in which foraging is modulated to sustain reproductive effort, and show how spatial resource structure and nectar availability together shape movement decisions in male pollinators.

Animals employ diverse coloration strategies to reduce predation risk, with patterns playing a key role in camouflage or for signaling unprofitability. Snakes exhibit various markings, but the specific antipredator functions of these patterns remain debated. We investigated how different snake patterns interact with habitat background and predator viewing conditions to influence camouflage. Using artificial snake models with 4 patterns (uniform, stripe, spot, zigzag) and 2 body colors (brown, gray), we assessed detectability across different natural habitats in southwest UK. We used visual modeling to simulate mammalian and avian predators and quantified background matching and edge disruption across varying visual distance and angles. Our results show that patterns affect camouflage depending on habitat and observer perspective. Spot and zigzag patterns increased edge disruption, particularly at greater distances, while striped patterns provided less effective concealment. However, zigzag patterns increased the contrast of snakes with conspicuous coloration in open habitats, suggesting potential aposematism. Viewing angle significantly influenced camouflage, with higher angles breaking edge disruption of zigzag and spot patterns, which also decreases as an observer approaches. Our findings highlight the multifunctionality of varied snake patterns, demonstrating their ability to facilitate both crypsis and aposematism depending on the ecological context. These results emphasize the importance of integrating habitat, body color, and predator perspective in understanding antipredator adaptations.

Courtship is often a multimodal process involving several signals of different modalities occurring simultaneously. Male nursery web spiders (Pisaura mirabilis) perform substrate-borne vibrations while offering a nuptial gift (a nutritional donation which also serves as a visual and olfactory signal) as they court females. The nuptial gift, consisting of a prey item wrapped in silk, is a considerable investment for the male, and vibration is also likely an energetically costly signal. In this study, we investigate how these 2 expensive mate attraction tactics interact in order to explore how investment might be partitioned between them. We conducted behavioral experiments where male P. mirabilis were provided with nuptial gifts in 3 treatments—no gift, medium gift, large gift—and recorded their courtship vibrations in repeated trials (once with each nuptial gift treatment). We found that calling duration (the total amount of time spent signaling) is longer when males have a nuptial gift vs. when they do not, but the duration is not plastic in response to the mass of the gift. Pulse rate is not affected by the quality of the nuptial gift. In trials where a gift is present, only pulse interval consistency changes based on gift quality, with intervals becoming more consistent (putatively more attractive) as gifts increase in mass. Our results suggest that male spiders do adjust their investment in vibratory courtship signals at a general level, though the plasticity is slight.

Sexual selection has sculpted diverse and intricate courtship displays throughout the animal kingdom, where failure to achieve the choreographic standards of a potential partner can be highly costly for reproductive success. Yet this raises a paradox: if there is strong selection for optimal display choreography within species, how do courtship displays begin to diverge? To address this, we measure how the choreography of courtship changes among three populations of the dancing dune fly—Apotropina ornatipennis Malloch (Diptera: Chloropidae)—a species in which males and females spend their days cavorting on Australia's hot sandy beaches. Merging population genetics with detailed quantification of the courtship display, we explore which elements of the display are the first to diverge between isolated populations, whether new behaviors arise rapidly, and whether sequence rearrangements occur in the modular structure of the display. We find that these tiny flies express courtship repertoires that rival some of the most sophisticated displays in the animal kingdom. Yet despite clear genetic and geographic isolation, the complex choreography of courtship is largely stable—with the frequency of “wing sweep” emerging as the only display element showing evidence of divergence among populations. In contrast to the notion that courtship behavior should be highly evolvable and rapidly diverge among allopatric populations, our findings suggest that complex courtship displays can remain remarkably stable over short evolutionary timescales.

Deimatic behavior is an antipredator defense such as a sudden movement or sounds performed by prey upon perceiving a threat from a predator. Such behaviors can cause predators to slow or stop their attack, but how different components of deimatic behavior influence predator responses remains untested. We investigated the effect of prey movement, size, and size change on predator attack behavior using a robotic moth and wild Australian magpies (Gymnorhina tibicen) as predators. We first tested birds' responses to a nonmoving control moth and then presented them with a moving moth displaying deimatic behavior. The experiment included 3 different deimatic behavior treatments with the moving prey: a small moth, a large moth, and a moth that increased in size from small to large. We found that all deimatic behavior treatments were more effective at stopping the first approach compared with the nonmoving control moth, and that no treatment was more effective than another. There was no significant difference in attack latency among the treatments, although birds tended to attack the prey more quickly after the display when the moving prey remained small, compared with moving prey that increased in size during the movement. The robotic moth did not include warning colors or chemical defenses. Our results therefore indicate that protective value is conferred by movement alone, supporting the “startle-first” hypothesis that the behavioral component of deimatism can evolve before other defenses.

While much is known about the functions of avian nests in reproduction, the role of experience in nest building has often been overlooked, especially in natural populations. Increasing evidence from captive birds suggests that the environment an individual experiences affects nest-building decisions, as does reproductive experience. Here we asked whether in a wild population of blue tits Cyanistes caeruleus, experience affected: (i) the materials and/or amounts of material with which the birds chose to build, and/or (ii) the location in which they built. We investigated the material composition and effectiveness of nests built by female blue tits between 2016 and 2022. We found that (i) a high insulation: structure ratio was associated with higher hatching success; (ii) the rate at which nests cooled was faster the more offspring had fledged from that nest; (iii) individuals that successfully fledged at least 1 chick were more likely to reduce the amount of insulating material they put into their nest the following year than were blue tits that previously had been unsuccessful; (iv) for unsuccessful birds, changing the nest design the following year improved their fledgling success; and finally, (v) unsuccessful birds were also more likely to move to a different nestbox the following year. In sum, we find that wild blue tits used their experience of reproduction in 1 yr to change their building decisions the following year. This effect mirrors responses made by birds building in the laboratory but over a much longer time interval.