Publications by authors named "Eens M"

Humans show remarkable differences in social behaviour between families, groups, communities and cultures, whereas such group-level within-species variation in socio-behavioural propensities is typically overlooked in other species. Studies on intraspecific variation in animal social structures are needed to inform an evolutionary account of human sociality. Here, we study multiple independent bonobo populations ( = 6) in zoological settings to investigate if and how bonobos ( = 70) show group-specific signatures in sociality.

View Article and Find Full Text PDF

Artificial light at night (ALAN) and noise pollution are two important stressors associated with urbanisation that can have a profound impact on animal behaviour and physiology, potentially disrupting biological rhythms. Although the influence of ALAN and noise pollution on daily activity patterns of songbirds has been clearly demonstrated, studies often focus on males, and the few that examined females have not included the potential influence of males on female activity patterns. Using free-living pairs of great tits () as a model, we examined for the first time the effects of ALAN and noise pollution and their interaction on the onset of (vocal) activity in both members of a pair.

View Article and Find Full Text PDF

Wild animals are exposed to a variety of anthropogenic stressors that may result in loss of physiological homeostasis. One main consequence of this stress exposure is the increased vulnerability to pathogens. We addressed the hypothesis that energetic unbalance and alterations of immune effectors are key proximate mechanisms underlying this vulnerability, by quantifying the gene expression of magnificent frigatebird Fregata magnificens chicks affected by a highly lethal viral disease, whose appearance is favoured by food limitation in this species.

View Article and Find Full Text PDF

Birds have evolved a variety of antipredator strategies, which have been extensively studied during day-time. Yet, how diurnal birds directly respond to nocturnal predation threats remains largely elusive, despite that predation risk can be high during both night- and day-time. One form of antipredator behaviour found in several tit species when confronted with a predator at the nest is the hissing display.

View Article and Find Full Text PDF

In many socially monogamous bird species with biparental care, occasional social polygyny has been detected. We provide information about a case of facultative polygyny in the European Nightjar (). The male nightjar (I96) formed a pair with two females (I95: the presumed primary female with whom he already bred since 2018; M042: the presumed secondary female, an inexperienced yearling).

View Article and Find Full Text PDF
Article Synopsis
  • Anthropogenic environmental changes, like noise pollution and artificial light at night, affect animal behavior, particularly the timing of daily activities known as chronotypes.
  • Researchers studied suburban female great tits to track their emergence times from nest boxes, finding that these patterns were consistent across seasons and life stages, hinting at established chronotypes.
  • They discovered that higher levels of noise and light disturbances reduced the consistency of these behaviors, implying that such environmental factors could hinder the selection for behavioral traits like chronotype in affected populations.
View Article and Find Full Text PDF
Article Synopsis
  • The study explores the impact of PFAS (per- and polyfluoroalkyl substances) on the reproductive health of great tit and blue tit birds near a PFAS hotspot in Belgium, as previous studies were limited.
  • Researchers collected eggs and blood samples and found more PFAS types in eggs than in plasma, but the differences between the bird species were minor.
  • Despite high PFAS levels in both species, there was only limited evidence of reproductive impairment, suggesting that great tits and blue tits might be less affected by PFAS pollution, with other environmental factors playing a bigger role in their health.
View Article and Find Full Text PDF

Homegrown crops can present a significant exposure source of per- and polyfluoroalkyl substances (PFAS) to humans. Field studies studying PFAS accumulation in multiple vegetable food categories and examining the potential influence of soil characteristics on vegetable bioavailability under realistic exposure conditions are very scarce. Crop PFAS accumulation depends on a complex combination of factors.

View Article and Find Full Text PDF

Human evaluation of animal emotional expressivity can inform animal welfare. Qualitative Behavioural Assessment (QBA) has been applied to domesticated and some non-domesticated animals, but its use in primates is limited despite their emotional expressivity. We aimed to develop and apply a QBA for bonobos () through two consecutive studies.

View Article and Find Full Text PDF

Homegrown food serves as an important human exposure source of per- and polyfluoroalkyl substances (PFAS), yet little is known about their spatiotemporal distribution within and among private gardens. This knowledge is essential for more accurate site-specific risk assessment, identification of new sources and evaluating the effectiveness of regulations. The present study evaluated spatiotemporal changes of legacy and emerging PFAS in surface soil from vegetable gardens (N = 78) and chicken enclosures (N = 102), as well as in homegrown eggs (N = 134) of private gardens, across the Province of Antwerp (Belgium).

View Article and Find Full Text PDF

Bonobos are typically portrayed as more socially tolerant than chimpanzees, yet the current evidence supporting such a species-level categorization is equivocal. Here, we used validated group-level co-feeding assays to systematically test expressions of social tolerance in sixteen groups of zoo- and sanctuary-housed bonobos and chimpanzees. We found that co-feeding tolerance substantially overlaps between the species, thus precluding categorical inference at the species level.

View Article and Find Full Text PDF

Chemical pollution is a global concern as contaminants are transported and reach even the remote regions of Antarctica. Seabirds serve as important sentinels of pollution due to their high trophic position and wide distribution. This study examines the influence of migration and trophic ecology on the exposure of two Antarctic seabirds, Wilson's storm petrel (Oceanites oceanicus - Ooc), and Cape petrel (Daption capense - Dca), to chemical elements and perfluoroalkyl substances (PFAS).

View Article and Find Full Text PDF

Homegrown eggs from free-ranging laying hens often contain elevated concentrations of perfluoroalkyl acids (PFAAs). However, it is unclear which factors contribute to these relatively large exposure risk scenarios. Moreover, existing bioavailability and modeling concepts of conventional organic pollutants cannot be generalized to PFAAs due to their different physicochemical soil interactions.

View Article and Find Full Text PDF

Aggression plays a crucial role in deterring predators and securing resources to promote fitness. Nevertheless, studies focussing on female aggression remain scarce. In songbirds, aggression is prevalent during the breeding season, when same-sex individuals compete for limited resources.

View Article and Find Full Text PDF

Many food contact materials (FCMs) and reusable plastics in the food industry contain poly- and perfluoroalkyl substances (PFAS), a group of synthetic pollutants that are known to be potentially harmful for wildlife, humans, and the environment. PFAS may migrate from FCMs to food consumed by humans. As a replacement for plastics, often paper and other plant-based materials are used in commercial settings.

View Article and Find Full Text PDF

For the past 7 decades, PFAS have been used in many different products and applications, which has led to a widespread contamination of these compounds. Nevertheless at present, little is known about the effects of these compounds on avian wildlife. Therefore, this study investigated associations between PFAS concentrations in the plasma and the oxidative status (i.

View Article and Find Full Text PDF

Body condition, a measure for relative fat mass, is associated with primate health, fitness, and overall welfare. Body condition is often influenced by dietary factors, age, and/or sex, but several body condition measures (body weight, weight-to-height ratios, and so on) also show high heritability across primate species, indicating a role of genetic effects. Although different measures for body condition exist, many require direct handling of animals, which is invasive, time-consuming, and expensive, making them impractical in wild and captive settings.

View Article and Find Full Text PDF

Artificial light at night significantly alters the predictability of the natural light cycles that most animals use as an essential Zeitgeber for daily activity. Direct light has well-documented local impacts on activity patterns of diurnal and nocturnal organisms. However, artificial light at night also contributes to an indirect illumination of the night sky, called skyglow, which is rapidly increasing.

View Article and Find Full Text PDF

Anthropogenic stressors, such as artificial light at night (ALAN), increasingly affect the sleep behaviour and physiology of wild birds, particularly in areas where human activity is prevalent. To understand the consequences of the resulting sleep deprivation, it is essential to investigate whether the effects of sleep deprivation on cognitive performance, observed in humans, also occur in birds. Here, we studied the impact of sleep deprivation, induced by intermittent exposure to ALAN, on inhibitory control, vigilance behaviour, and exploratory behaviour in great tits.

View Article and Find Full Text PDF

The replacement of long-chained per- and polyfluoroalkyl substances (PFAS) with their short-chained homologues may have an impact on the accumulation in plants. The extent to which PFAS are absorbed by plants may differ among species and may depend on environmental factors, including temperature. The effect of an increased temperature on root uptake and translocation of PFAS in plants has been poorly studied.

View Article and Find Full Text PDF

Individual variation in complex social behavioral traits, like primate grooming, can be influenced by the characteristics of the individual and those of its social group. To better grasp this complexity, social network analysis can be used to quantify direct and indirect grooming relationships. However, multi-group social network studies remain rare, despite their importance to disentangle individual from group-level trait effects on grooming strategies.

View Article and Find Full Text PDF

Exposure to persistent organic pollutants (POPs), such as organochlorines (OCs) and polybrominated diphenyl ethers (PBDEs), is associated with adverse health effects in wildlife. Many POPs have been banned and consequently their environmental concentrations have declined. To assess both temporal trends of POPs and their detrimental impacts, raptors are extensively used as biomonitors due to their high food web position and high contaminant levels.

View Article and Find Full Text PDF

Perfluoralkyl acids (PFAS) have been regarded as global pollutants for at least twenty years, with potentially negative physiological effects on multiple vertebrate species including humans. Here we analyze the effects of the administration of environmentally-relevant levels of PFAS on caged canaries (Serinus canaria) by using a combination of physiological, immunological, and transcriptomic analyses. This constitutes a completely new approach to understand the toxicity pathway of PFAS in birds.

View Article and Find Full Text PDF

During the breeding season, aggression is expressed to gain access to resources such as territories and mates and protect offspring. Female aggressiveness has received much less attention than male aggressiveness, and few studies have examined female and male aggressiveness towards intruders of both sexes in the same species. We compared female and male aggressiveness towards same- and opposite-sex intruders during the egg-laying period in blue tits () using simulated territorial intrusions.

View Article and Find Full Text PDF

Species persistence in the Anthropocene is dramatically threatened by global climate change. Large emissions of carbon dioxide (CO) from human activities are driving increases in mean temperature, intensity of heatwaves, and acidification of oceans and freshwater bodies. Ectotherms are particularly sensitive to CO-induced stressors, because the rate of their metabolic reactions, as well as their immunological performance, are affected by environmental temperatures and water pH.

View Article and Find Full Text PDF