A5027736161- Animal Behavior and Reproduction
- Plant and animal studies
- Avian ecology and behavior
- Parasite Biology and Host Interactions
- Helminth infection and control
- Parasites and Host Interactions
- Animal Vocal Communication and Behavior
- Plant Parasitism and Resistance
- Aquaculture disease management and microbiota
- Physiological and biochemical adaptations
- Insect and Arachnid Ecology and Behavior
University of Pretoria
2015-2024
Princeton University
2021-2024
University of Cambridge
2021-2024
University of Exeter
2013-2021
University of Bristol
2011-2014
It is well established that the lunar cycle can affect behaviour of nocturnal animals, but its potential to have a similar influence on diurnal species has received less research attention. Here, we demonstrate dawn song cooperative songbird, white-browed sparrow weaver ( Plocepasser mahali ), varies with moon phase. When was above horizon at dawn, males began singing average 10 min earlier, if there full compared new moon, resulting in 67% mean increase performance period and greater total...
Sex-biased dispersal is pervasive and has diverse evolutionary implications, but the fundamental drivers of sex biases remain unresolved. This due in part to limited diversity within taxonomic groups direction biases, which leaves hypothesis testing critically dependent upon identifying rare reversals norms. Here, we use a combination observational genetic data demonstrate reversal avian bias cooperatively breeding white-browed sparrow weaver (Plocepasser mahali). Direct observations...
The immune system provides vital protection against pathogens, but extensive evidence suggests that mounting responses can entail survival and fecundity costs. physiological mechanisms underpin these costs remain poorly understood, despite their potentially important role in shaping life-histories. Recent studies involving laboratory models highlight the possibility oxidative stress could mediate costs, as immune-activation increase production of reactive oxygen species leading to stress....
In many cooperatively breeding species, females mate extra-group, the adaptive value of which remains poorly understood. One hypothesis posits that employ extra-group mating to access mates whose genotypes are more dissimilar their own than social mates, so as increase offspring heterozygosity. We test this using life history and genetic data from 36 white-browed sparrow weaver (Plocepasser mahali) groups. Contrary prediction, a dominant female's relatedness her did not drive decisions and,...
Explaining the evolution of sex differences in cooperation remains a major challenge. Comparative studies highlight that offspring more philopatric tend to be cooperative within their family groups than those dispersive but we do not understand why. The leading "Philopatry hypothesis" proposes cooperates because higher likelihood natal breeding increases direct fitness benefits cooperation. However, "Dispersal trade-off less preparations for dispersal, such as extra-territorial prospecting,...
SUMMARY Factors affecting survival of parasites introduced to new geographical regions include changes in environmental temperature. Protopolystoma xenopodis is a monogenean with the amphibian Xenopus laevis from South Africa Wales (probably 1960s) where low water temperatures impose major constraints on life-cycle processes. Effects were quantified by maintenance eggs infections under controlled conditions at 10, 12, 15, 18, 20 and 25°C. The threshold for egg viability/ development was...
SUMMARY The monogenean Protopolystoma xenopodis has been established in Wales for >40 years following introduction with Xenopus laevis from South Africa. This provides an experimental system determining constraints affecting introduced species novel environments. Parasite development post-infection was followed at 15, 20 and 25°C 15 weeks 10°C ⩾1 year correlated temperatures recorded Wales. Development slowed/arrested ⩽10°C which reflects habitat conditions >6 months/year. There wide...
Predators have profound effects on prey behavior and some adult brood parasites use predator resemblance to exploit the antipredator defenses of their hosts. Clarifying host perception such stimuli is important for understanding adaptive significance parasite characteristics, mechanisms by which they misdirect Here I review literature explore basis in avian parasites, natural variation responses these stimuli. also provide a framework information ecology resemblance, based principles signal...
Abstract The existence of adult sexual dimorphism is typically explained as a consequence selection, yet coevolutionary drivers frequently remain untested. Here, I investigate the role in host–parasite interactions brood parasitic diederik cuckoo, Chrysococcyx caprius . Female cuckoos are more cryptic appearance and pose threat to clutch, while male conspicuous not direct threat. Specifically, examine whether provokes threat‐level sensitive responses Southern red bishop, Euplectes orix ,...
Abstract Explaining the evolution of sex differences in cooperation remains a major challenge. Comparative studies highlight that offspring more philopatric tend to be cooperative within their family groups than those dispersive but we do not understand why. The leading ‘Philopatry hypothesis’ proposes cooperates because higher likelihood natal breeding increases direct fitness benefits cooperation. However, ‘Dispersal trade-off less preparations for dispersal, such as extra-territorial...
ABSTRACT In many cooperatively breeding species non-breeding individuals help to rear the offspring of breeders. The physiological mechanisms that regulate such cooperative helping behavior are poorly understood, but may have been co-opted, during evolution breeding, from pre-existing regulated parental care. Key among these be a role for prolactin. Here we investigate whether natural variation in circulating prolactin levels predicts both and helper contributions nestling provisioning...
The existence of adult sexual dimorphism is typically explained as a consequence selection, yet coevolutionary drivers frequently remain untested. Here, I investigate the role in host-parasite interactions brood parasitic diederik cuckoo, Chrysococcyx caprius. Female cuckoos are more cryptic appearance and pose threat to clutch, while male conspicuous not direct threat. Specifically, examine whether provokes threat-level sensitive responses Southern red bishop, Euplectes orix, hosts. use...