Testing the Effect of Relative Pollen Productivity on the REVEALS Model : A Validated Reconstruction of Europe-Wide Holocene Vegetation

Reliable quantitative vegetation reconstructions for Europe during the Holocene are crucial to improving our understanding of landscape dynamics, making it possible to assess the past effects of environmental variables and land-use change on ecosystems and biodiversity, and mitigating their effects in the future. We present here the most spatially extensive and temporally continuous pollen-based reconstructions of plant cover in Europe (at a spatial resolution of 1° × 1°) over the Holocene (last 11.7 ka BP) using the 'Regional Estimates of VEgetation Abundance from Large Sites' (REVEALS) model. This study has three main aims. First, to present the most accurate and reliable generation of REVEALS reconstructions across Europe so far. This has been achieved by including a larger number of pollen records compared to former analyses, in particular from the Mediterranean area. Second, to discuss methodological issues in the quantification of past land cover by using alternative datasets of relative pollen productivities (RPPs), one of the key input parameters of REVEALS, to test model sensitivity. Finally, to validate our reconstructions with the global forest change dataset. The results suggest that the RPPs.st1 (31 taxa) dataset is best suited to producing regional vegetation cover estimates for Europe. These reconstructions offer a long-term perspective providing unique possibilities to explore spatial-temporal changes in past land cover and biodiversity

Learning and Judgment Can Be Affected by Predisposed Fearfulness in Laying Hens

High fearfulness could disrupt learning and likely affects judgment in animals, especially when it is part of an animals’ personality, i.e., trait anxiety. Here, we tested whether high fearfulness affects discrimination learning and judgment bias (JB) in laying hens. Based on the response to an open field at 5 weeks of age, birds were categorized as fearful (FC) by showing no walking or vocalizing or non-fearful (NFC) by showing walking and vocalizing. At adult age, birds (n = 24) were trained in a go–go task to discriminate two cues (white or black) with a small or large reward. Birds that reached training criteria were exposed to three unrewarded ambiguous cues (25, 50, and 75% black) to assess JB. Task acquisition took longer for FC birds than for NFC birds, due to a left side bias, and more sessions were needed to unlearn this side bias. Changes in trial setup increased response latencies for FC birds but not for NFC birds. A larger number of FC birds than NFC birds chose optimistically in the last ambiguous trial (25% black). FC birds had a longer latency to choose in the ambiguous trial (75% black) compared to NFC birds. Prior choice in ambiguous trials and a preceding large or small trial affected latencies and choices for both types of birds. Our study showed that fearfulness was associated with differences in discrimination learning ability and JB. It appeared that FC birds used a rigid response strategy during early learning phases by choosing a specific side repeatedly irrespective of success. FC birds were more affected by changes in the setup of the trials in comparison to NFC birds. We speculate that FC birds are more sensitive to changes in environmental cues and reward expectancy. These factors could explain how high fearfulness affects learning

Of nature and nurture : The role of genetics and environment in behavioural development of laying hens

Behavioural development of birds is shaped by the complex interplay between genetics and environment. It is becoming increasingly clear that experiences of previous generations are transferred to the offspring through epigenetic and hormonal effects and result in lasting changes in behaviour. After hatching, social and physical conditions during early life have marked effects on bird behaviour of both the current and following generations. Aspects like the presence or absence of maternal care, the composition of the social environment and the behavioural stimulation offered by the physical environment all have strong influences on the behavioural development of a bird. Research approaches that focus on manipulations during the early-life period and investigate effects on epigenetics, maternal hormones and behavioural development should be encouraged

Learning and judgment can be affected by predisposed fearfulness in laying hens

High fearfulness could disrupt learning and likely affects judgment in animals, especially when it is part of an animals' personality, i.e., trait anxiety. Here, we tested whether high fearfulness affects discrimination learning and judgment bias (JB) in laying hens. Based on the response to an open field at 5 weeks of age, birds were categorized as fearful (FC) by showing no walking or vocalizing or non-fearful (NFC) by showing walking and vocalizing. At adult age, birds (n = 24) were trained in a go-go task to discriminate two cues (white or black) with a small or large reward. Birds that reached training criteria were exposed to three unrewarded ambiguous cues (25, 50, and 75% black) to assess JB. Task acquisition took longer for FC birds than for NFC birds, due to a left side bias, and more sessions were needed to unlearn this side bias. Changes in trial setup increased response latencies for FC birds but not for NFC birds. A larger number of FC birds than NFC birds chose optimistically in the last ambiguous trial (25% black). FC birds had a longer latency to choose in the ambiguous trial (75% black) compared to NFC birds. Prior choice in ambiguous trials and a preceding large or small trial affected latencies and choices for both types of birds. Our study showed that fearfulness was associated with differences in discrimination learning ability and JB. It appeared that FC birds used a rigid response strategy during early learning phases by choosing a specific side repeatedly irrespective of success. FC birds were more affected by changes in the setup of the trials in comparison to NFC birds. We speculate that FC birds are more sensitive to changes in environmental cues and reward expectancy. These factors could explain how high fearfulness affects learning

Where in the serotonergic system does it go wrong? Unravelling the route by which the serotonergic system affects feather pecking in chickens

A deficient serotonergic system is associated with psychopathological behaviors in various species, among which, feather pecking (FP) in chickens. Deficiency in the serotonergic system can predispose birds to develop FP, while the serotonergic system is affected in birds that feather peck. Serotonin (5-HT) can further influence dopamine (DA) activity. Lines with high FP tendency generally have low central 5-HT and DA turnovers at a young age, but high turnovers at an adult age in brain areas involved in somato-motor regulation and goal-directed behavior. Agonizing 5-HT1A and 5-HT1B receptors increases FP, while antagonizing D2 receptor reduces FP. Genetic associations exist between FP, 5-HT1A and 5-HT1B receptor functioning and metabolism of 5-HT and DA. Birds with deficient functioning of the somatodendritic 5-HT1A autoreceptor and 5-HT metabolism appear predisposed to develop FP. Birds which feather peck often eat feathers, have low whole-blood 5-HT, different gut-microbiota composition and immune competence compared to non-peckers. FP and feather eating likely affect the interaction between gut microbiota, immune system and serotonergic system, but this needs further investigation.</p

Fearfulness and feather damage in laying hens divergently selected for high and low feather pecking

International audienceFeather pecking (FP) remains a major welfare and economic problem in laying hens. FP has been found to be related to other behavioural characteristics, such as fearfulness. There are indications that fearful birds are more likely to develop FP. Furthermore, FP can lead to increased fearfulness in the victims. To investigate further the relationship between FP and fearfulness, feather damage and behavioural fear responses were recorded in three White Leghorn lines of laying hens: a line selected for high FP (HFP line), a line selected for low FP (LFP line) and an unselected control line (10th generation of selection). We used 64 birds per line housed in 16 four-bird cages (cage was the experimental unit). At 25 weeks of age, birds were subjected to a tonic immobility (TI) test and a combined human approach (HA) and novel object (NO) test, and plumage condition was recorded. Line differences in fear responses between the HFP and LFP lines were not found, neither in the TI-test, nor in the HA or NO test. As expected, birds from the HFP line had considerably more feather damage than birds from the LFP line and birds from the unselected control line were intermediate. Cages that withdrew from the NO 30 s after placement had more feather damage on the back compared with cages that did not show a withdrawal response. These results suggest that although relationships were found between feather damage and fear response at cage level, lines divergently selected on feather pecking behaviour do not differ in their fear responses. Divergent selection on feather pecking may have altered pecking motivation rather than fearfulness

Effects of early and later life environmental enrichment and personality on attention bias in pigs (Sus scrofa domesticus)

We investigated effects of early and later life housing on attention bias, as an indicator of affective state, in pigs differing in coping style [reactive (LR) vs. proactive (HR)]. Pigs (n = 128) in barren or enriched housing from birth (B1 vs. E1) that experienced either a switch in housing at 7 weeks of age or not (creating B1B2, B1E2, E1E2, and E1B2 treatments), were studied in a 180-s attention bias test at 11 weeks. Pigs exposed to a 10-s-auditory-and-sudden-motion threat in the test arena paid more attention to the location of the threat, were more vigilant, showed less eating, more walking and were more likely to utter high-pitched vocalisations than non-threat pigs. During threat presence, HR pigs from post-switch enriched housing (E2-HR, i.e., B1E2 + E1E2) showed more vigilance but less exploration than others. After threat removal, no effects were found on time spent paying attention to the threat, vigilance, and eating, but E2-HR pigs paid attention to the threat more frequently, were more likely to utter high-pitched vocalisations and walked more compared to (part of) other groups, suggesting the most negative affective state in these animals. E2 pigs grunted more than B2 pigs. Thus, current housing, but not early life housing, affected behaviour in a personality-dependent manner in this attention bias test. Housing effects were opposite to expectation, possibly due to the short-term effect of the relative contrast between the home pens of the pigs and the test room. This potentially overruled putative long-term effects of environmental conditions on attention bias.</p

Parents and Early Life Environment Affect Behavioral Development of Laying Hen Chickens

Severe feather pecking (SFP) in commercial laying hens is a maladaptive behavior which is associated with anxiety traits. Many experimental studies have shown that stress in the parents can affect anxiety in the offspring, but until now these effects have been neglected in addressing the problem of SFP in commercially kept laying hens. We therefore studied whether parental stock (PS) affected the development of SFP and anxiety in their offspring. We used flocks from a brown and white genetic hybrid because genetic background can affect SFP and anxiety. As SFP can also be influenced by housing conditions on the rearing farm, we included effects of housing system and litter availability in the analysis. Forty-seven rearing flocks, originating from ten PS flocks were followed. Behavioral and physiological parameters related to anxiety and SFP were studied in the PS at 40 weeks of age and in the rearing flocks at one, five, ten and fifteen weeks of age. We found that PS had an effect on SFP at one week of age and on anxiety at one and five weeks of age. In the white hybrid, but not in the brown hybrid, high levels of maternal corticosterone, maternal feather damage and maternal whole-blood serotonin levels showed positive relations with offsprings’ SFP at one week and offsprings’ anxiety at one and five weeks of age. Disruption and limitation of litter supply at an early age on the rearing farms increased SFP, feather damage and fearfulness. These effects were most prominent in the brown hybrid. It appeared that hens from a brown hybrid are more affected by environmental conditions, while hens from a white hybrid were more strongly affected by parental effects. These results are important for designing measures to prevent the development of SFP, which may require a different approach in brown and white flocks.

Transgenerational epigenetic inheritance in birds

While it has been shown that epigenetics accounts for a portion of the variability of complex traits linked to interactions with the environment, the real contribution of epigenetics to phenotypic variation remains to be assessed. In recent years, a growing number of studies have revealed that epigenetic modifications can be transmitted across generations in several animal species. Numerous studies have demonstrated inter- or multi-generational effects of changing environment in birds, but very few studies have been published showing epigenetic transgenerational inheritance in these species. In this review, we mention work conducted in parent-to-offspring transmission analyses in bird species, with a focus on the impact of early stressors on behaviour. We then present recent advances in transgenerational epigenetics in birds, which involve germline linked non-Mendelian inheritance, underline the advantages and drawbacks of working on birds in this field andcomment on future directions of transgenerational studies in bird species