The wintering period constitutes a critical stage in the annual cycle of waterbirds, during which sufficient food resources are essential for their survival and energy maintenance. Under anthropogenic disturbance, waterbird individuals must balance benefits of foraging against the risks of predation. With the degradation of natural wetlands, waterbirds have increasingly turned to artificial habitats, which often provide high energetic returns but expose them to more frequent human activity. To investigate the trade-off strategies of vulnerable Hooded Cranes (Grus monacha) during wintering, we monitored their behavioral patterns, habitat utilization, and associated disturbance factors in farmland and lake habitats of Caizi Lake, Anqing City, Anhui Province, China, from November 2024 to March 2025. We measured two key indicators of escape behavior: alert distance (AD) and flight initiation distance (FID), and employed linear mixed models to assess the effects of habitat and disturbance factors on these escape responses. Our results showed that Hooded Cranes exhibited significantly shorter AD and FID in farmland compared to lake habitats, indicating greater tolerance to human disturbance in farmland. Furthermore, AD and FID were negatively associated with food abundance, but positively correlated with distance to settlements and food burial depth. This finding suggests that Hooded Cranes were willing to tolerate greater human disturbance in resource-rich, easily accessible farmlands to maximize foraging opportunities and energy intake. In farmland habitats, cranes allocated more time to foraging activities and achieved a higher foraging success rate. To mitigate the elevated disturbance risks in this human-dominated habitat, they also allocated more total time to vigilance through more frequent but shorter scans. Wetland loss has forced many waterbirds to rely on farmlands, where food resources are abundant but human disturbance is intense. Our study on wintering Hooded Cranes indicates that they tolerate higher human disturbance in farmlands to access greater food resources, while increasing vigilance to compensate for the associated risks. These results demonstrate that Hooded Cranes exhibit remarkable behavioral plasticity in human-dominated landscapes, adopting a flexible risk–benefit trade-off rather than relying solely on disturbance tolerance. Our findings provide empirical evidence for the underlying mechanisms of habitat-specific behavioral adaptations in wintering Hooded Cranes. They also highlight the importance of protecting natural wetlands while reducing human disturbance in artificial habitats to ensure the long-term survival of threatened waterbird species in human-dominated ecosystems.
The social environment, characterised by interactions between individuals and their surrounding group, has a significant influence on behavioural and life-history traits in many animal species. This study investigates the impact of the social environment on the mating behaviour of the invasive pest Drosophila suzukii. We conducted experiments to examine how variations in density of individuals and sex ratio - two main characteristics of the social environment - affect mating behaviours. First, our observations confirm that both male and female flies were attracted by fruits and aggregate around them, suggesting that fruits may serve as social hubs. We then tested the influence of male density and ratio of males to females on mating behaviour. Results showed a clear mate-finding Allee effect at low densities, with a lower mating probability and an increase of the latency before mating, when male density decreases. The general pattern of results highlights male density as the key determinant of reproductive success, while we were not able to detect effects of female density and sex ratio on mating outcomes. Conversely, high density environments facilitated mating probability and increased male-male competition. Thus, physical interactions among males, primarily in the form of aggressive attempts to dislodge copulating pairs, were prevalent at high males’ densities. These results strongly suggest that D. suzukii uses social information to modulate reproductive strategies, a flexibility likely contributing to its invasion success. Even in non-social animals, the social environment can influence behaviour and reproductive success. Here, we examined the impact of two parameters that characterise the social environment (i.e. male density and ratio of males to females) on mating probability in the pest fruit fly, Drosophila suzukii. We demonstrate a component Allee effect, whereby mating probability decreases with decreasing males’ density, with an increase of male-male competition at high males’ densities, resulting in copulation disruptions.
Predator pressure and competition constitute fundamental ecological forces shaping amphibian life-histories and population dynamics. We investigated how risk-induced behavioural responses and temporal segregation between prey and predator may facilitate the coexistence in sympatric, closely related spadefoot species (genus Pelobates). The two spadefoot species differ in size, making juveniles of both species and adults of P. fuscus potential prey for P. balcanicus adults. In an experimental setup where a visual cue of a predator (an adult P. balcanicus) was either present or absent, we measured the response to interspecific interactions, involving paired encounters between adult P. balcanicus and either adult or juvenile P. fuscus, and conspecific interactions, involving adult and juvenile P. balcanicus. Pelobates fuscus juveniles displayed higher emergence probability, i.e., taking more risk, but reduced their activity by covering shorter distances when the potential predator was visible. In contrast, P. balcanicus juveniles and P. fuscus adults showed no difference in emergence probability or distance covered in the presence of the visual cue. Emergence probability decreased with increasing potential prey size, regardless of the potential predator visual cue. We found high levels of temporal overlap in activity patterns, except between juveniles of the two species. Moreover, adult P. fuscus showed a reduced activity time frame in the presence of a predator visual cue. Our results suggest that P. fuscus displays life-stage dependent antipredator responses, with the direction and magnitude of these responses varying according to the perceived risk. Such anti-predator adaptations may contribute to the coexistence of closely related species. The study investigates potential species coexistence mechanisms by examining the response to perceived predation risk in sympatric populations of two closely related spadefoot toads whose ranges narrowly overlap. By exposing “prey” (i.e. animals of small size) to the visual stimuli of “predators” (i.e. adults of the larger species), our study revealed life-stage-dependent behavioural shifts, predation risk triggering specific antipredator responses, particularly in smaller juveniles. Smaller toads balanced survival and growth by emerging more frequently to forage. In the presence of a potential predator, juveniles of the smaller species increased their proclivity to emerge while simultaneously reducing their movement to avoid detection by a strictly visual hunter. Despite a general temporal overlap, potential prey tended to segregate their activity from that of their predators. Our study provides a deeper understanding of the intricate mechanisms that allow species coexistence and allow for niche partitioning.
Sexual advertisement often involves multimodal signals whose expression may be integrated differently among and within individuals. When signals overlap in function, patterns of covariation in signaling effort can indicate whether they operate as coordinated components of a complex display, alternative tactics, or independently evolving traits. However, these patterns can be obscured by plasticity in signaling effort in response to fluctuations in environments and individuals’ internal states. Using a katydid species (Docidocercus gigliotosi) that produces both airborne and substrate-borne sexual advertisement signals, we tested whether multimodel signaling efforts were more strongly influenced by persistent individual differences or short-term intra-individual plasticity. We recorded wild-caught males for repeated 24-hour periods over multiple weeks and examined how individual identity, experimentally manipulated mating history, and other factors affected signaling effort in each modality. We found that plasticity during a transient refractory period after mating accounted for most of the overall variation in signal production. Over six weeks, unmated males increased stridulation effort more than males that had mated immediately before the first week of recording, suggesting a more persistent effect of mating history on sexual advertisement behavior. Male body condition, moonlight intensity, and recording location were also associated with variation in calling effort. Together, these results indicate that multimodal signaling effort in D. gigliotosi is shaped more by coordinated within-individual plasticity than by fixed among-individual signaling strategies. They also suggest that airborne and substrate-borne calls function as complementary components of mate advertisement over daily timescales rather than full functional equivalents. Many animals advertise for mates using multiple signals, and these signals may not vary independently. Signalers could consistently specialize in one signal type, or coordinate multiple signals as part of a flexible, integrated display. We tested these alternatives in a katydid with separate airborne sound and substrate-borne vibration advertisement signals, observing recently mated and unmated males over several weeks to test whether plasticity or persistent differences between individuals better accounted for variation in signaling behavior. Individuals showed higher airborne calling effort on nights when they also produced more substrate-borne signals. They also plastically adjusted signaling in response to changes in both internal state and environmental conditions. Our results support a joint role in mate advertisement for these signals, despite a lack of stereotyped temporal coordination.
