Environmental, social, morphological, and behavioral constraints on opportunistic multiple paternity

Peer reviewedPostprin

Development of boldness and docility in yellow-bellied marmots

Peer reviewedPostprin

Commercial hatchery practices have long-lasting effects on laying hens' spatial behaviour and health.

The commercial hatchery process is globally standardized and exposes billions of day-old layer chicks to stress every year. By alleviating this early stress, on-farm hatching is thought to improve animal welfare, yet little is known about its effects throughout production. This study compared welfare indicators and spatial behaviours during the laying period of hens hatched in an on-farm environment (OFH) to those hatched in a commercial hatchery and transferred at one day-old to a rearing barn (STAN). In particular, we assessed how OFH and TRAN hens differed in space-use and movement behaviours following the transfer to the laying barn at 17 weeks of age, a similar stressor encountered by STAN hens early in life, and determined whether effects aligned more with the 'silver-spoon' or 'environmental matching' hypothesis. We found that for the first three months post-transfer into the laying barn, OFH hens, on average, transitioned less between the aviary's tiers and spent less time on the littered floor. Because OFH hens became behaviourally more similar to STAN hens over time, these results suggest that OFH hens required a prolonged period to establish their daily behavioural patterns. Furthermore, OFH hens had more severe keel bone fractures throughout the laying period but similar feather damage and body mass to STAN hens. No differences were found in hen mortality or the number of eggs per live hen. These findings support the environmental matching hypothesis and suggest that early-life stressors may have prepared hens for later-life stressors, underscoring the importance of both early-life and adult environments in enhancing animal welfare throughout production

Intra-individual variation of hen movements is associated with later keel bone fractures in a quasi-commercial aviary.

Measuring intra- and inter-individual variation in movement can bring important insights into the fundamental ecology of animals and their welfare. Although previous studies identified consistent differences in movements of laying hens within commercial aviaries, the level of consistency was not quantified, limiting our capacity to understand the importance of individual movements for welfare. We aimed to quantify the scope of intra- and inter-individual differences in movements of commercial laying hens and examined their associations with indicators of welfare at the end of production. We quantified individual differences in one composite daily movement score for 80 hens over 54 days post-transfer to a quasi-commercial aviary. Results showed consistent inter-individual differences in movement averages, explaining 44% of the variation, as well as individual variation in predictability and temporal plasticity (at the population-level, hens increased their movements for 39 days). Hens that were more predictable in their daily movements had more severe keel bone fractures at the end of production while we found no such correlation between daily movement averages (individual intercept) and welfare indicators. Our findings highlight the importance of inter-individual difference in intra-individual variation of movements to improve poultry welfare

The Causes and Maintenance of Personality in Yellow-bellied Marmots (Marmota flaviventris)

Animal personality, or consistent individual behavior, is wide spread across taxa, and is now being linked to ecology and evolutionary dynamics. Despite interest in the ecological and evolutionary consequences of personality, few studies have used a Tinbergian approach to understanding the causes and maintenance of personality. Furthermore, there is a large amount of variation within personality traits, and as evolutionary biologists, we are keenly interested in how variation is caused, develops, and is maintained within a population. My dissertation use Tinbergian principles to try and explain personality using yellow-bellied marmots (Marmota flaviventris) as a study system. First, I explore the methodology that describes personality traits by testing whether unacquainted raters could reliably assess subjects using subjective ratings. I found that raters could reliably measure subjects, and some of these measures were valid when compared to behavioral codings. I then focus on the development of personality and found that docility and boldness do not follow the same ontogenetic path. These traits become repeatable at different life stages, and this may reflect differences in stage-specific life history strategies. I also found that boldness and docility do not form a behavioral syndrome, and that this is most likely due to the differences in development. My next chapter focuses on the causes and maintenance of personality. I test three major theoretical hypotheses — growth-mortality tradeoffs, residual reproductive value, and state-dependent safety — and found no evidence for any. I did, however, find that different environmental variables differentially influence the same personality traits across contexts suggesting that selection can influence the same personality trait through different variables depending on the context. Finally, I explore the quantitative genetics of personality. To fully understand the evolution of personality, we need to know the heritability and correlations underlying these traits. I found low heritability in most personality traits with some correlations. This dissertation shows, that in marmots, personality is heavily influenced by environment and that personality is linked to life history strategy

The Causes and Maintenance of Personality in Yellow-bellied Marmots (Marmota flaviventris)

Animal personality, or consistent individual behavior, is wide spread across taxa, and is now being linked to ecology and evolutionary dynamics. Despite interest in the ecological and evolutionary consequences of personality, few studies have used a Tinbergian approach to understanding the causes and maintenance of personality. Furthermore, there is a large amount of variation within personality traits, and as evolutionary biologists, we are keenly interested in how variation is caused, develops, and is maintained within a population. My dissertation use Tinbergian principles to try and explain personality using yellow-bellied marmots (Marmota flaviventris) as a study system. First, I explore the methodology that describes personality traits by testing whether unacquainted raters could reliably assess subjects using subjective ratings. I found that raters could reliably measure subjects, and some of these measures were valid when compared to behavioral codings. I then focus on the development of personality and found that docility and boldness do not follow the same ontogenetic path. These traits become repeatable at different life stages, and this may reflect differences in stage-specific life history strategies. I also found that boldness and docility do not form a behavioral syndrome, and that this is most likely due to the differences in development. My next chapter focuses on the causes and maintenance of personality. I test three major theoretical hypotheses — growth-mortality tradeoffs, residual reproductive value, and state-dependent safety — and found no evidence for any. I did, however, find that different environmental variables differentially influence the same personality traits across contexts suggesting that selection can influence the same personality trait through different variables depending on the context. Finally, I explore the quantitative genetics of personality. To fully understand the evolution of personality, we need to know the heritability and correlations underlying these traits. I found low heritability in most personality traits with some correlations. This dissertation shows, that in marmots, personality is heavily influenced by environment and that personality is linked to life history strategy

Innovative problem-solving in a small, wild canid.

Innovation - the ability to solve problems in a novel way - is not only associated with cognitive abilities and relative brain size, but also by noncognitive traits, such as personality and motivation. We used a novel foraging task with three access options to determine how neophobia, exploration, and persistence influence innovation in 12 habituated bat-eared foxes (Otocyon megalotis) in the Kalahari Desert. Bat-eared foxes offer a unique system to understand cognition as they have the smallest relative brain size of measured canids and a specialized, termite-based diet, yet have displayed foraging innovations. Interestingly, most of our individuals solved the task at least once and six individuals solved the task in every trial. Neophobia did not influence success on the first trial, but both exploration and persistence influenced success across all trials. Those individuals that solved the puzzle over multiple trials became faster over time, suggesting that they learned how to open the box more efficiently. We found some variation in the method to open the puzzle box with six individuals solving the puzzle using two methods and one individual using all three methods. This is the first study to show innovation in a novel foraging task in wild bat-eared foxes