Charlie Cornwallis | Lund University (original) (raw)

Papers by Charlie Cornwallis

For several years we took repeated thermal images of ostriches at a research farm in South Africa... more For several years we took repeated thermal images of ostriches at a research farm in South Africa. We also recorded ambient temperatures at the time of each picture, allowing us to relate surface temperatures to ambient temperatures (Thermal-Plasticity-Evolution.csv). In some instances ostriches were incubating, giving the opportunity to compare surface temperatures between incubating and standing individuals (Incubation-vs-Standing.csv). We only monitored a single females change in surface temperatures throughout and after incubation (Single-Female-Incubating.csv).

Cooperative breeding societies allow the costs of reproduction to be shared. However, as groups b... more Cooperative breeding societies allow the costs of reproduction to be shared. However, as groups become larger, such benefits often decrease and competition increases. This is predicted to select for an optimal group size, yet variation in groups is a ubiquitous feature of cooperative breeding animals. Here we experimentally established groups (ngroups=96) of cooperative breeding ostriches, Struthio camelus, with different numbers of males and females and manipulated the potential for cooperation over incubation. There was a clear optimal group size for males. Their reproductive success was maximized in groups with four or more females and no other males, irrespective of cooperation over incubation. Conversely, female reproductive success was strongly dependent on the benefits of cooperating over incubation, being maximized in groups with either many males or many females. In intermediate sized groups, both male and female reproductive success was reduced by sexual conflict over the ...

Additional file 6. Supplementary Table S5. Intestinal and environmental samples metadata.

Additional file 2. Supplementary Table S1. Significant differentially abundant OTUs in the ileum.

Additional file 4. Supplementary Table S3. Significant differentially abundant OTUs in the cecum.

For over 300 million years, insects have relied on symbiotic microbes for nutrition and defense. ... more For over 300 million years, insects have relied on symbiotic microbes for nutrition and defense. We used data on 1844 microbe-insect symbioses, across 400 insect families, to examine the causes and consequences of symbiosis for the evolution of insect diversity. We found that the acquisition of bacterial symbionts allowed insects to specialize on a range of niches that were low in B vitamins, including phloem, blood and wood. In some cases, such as herbivorous insects, shifts to new niches have facilitated spectacular adaptive radiations. In other niches, such as strict blood feeding, diversification has been severely constrained. Symbioses therefore appear to solve universal nutrient deficiencies for insects, but the consequences for insect diversification depend on the feeding niche invaded.

Parasite and host trait data for each cichlid specimen included in the stud

Patterns of Nucleotide Diversity and Linkage Disequilibrium along the Ostrich Pseudoautosomal Region

eLife, 2021

Living with relatives can be highly beneficial, enhancing reproduction and survival. High related... more Living with relatives can be highly beneficial, enhancing reproduction and survival. High relatedness can, however, increase susceptibility to pathogens. Here, we examine whether the benefits of living with relatives offset the harm caused by pathogens, and if this depends on whether species typically live with kin. Using comparative meta-analysis of plants, animals, and a bacterium (nspecies = 56), we show that high within-group relatedness increases mortality when pathogens are present. In contrast, mortality decreased with relatedness when pathogens were rare, particularly in species that live with kin. Furthermore, across groups variation in mortality was lower when relatedness was high, but abundances of pathogens were more variable. The effects of within-group relatedness were only evident when pathogens were experimentally manipulated, suggesting that the harm caused by pathogens is masked by the benefits of living with relatives in nature. These results highlight the importa...

For over 300 million years, insects have relied on symbiotic microbes for nutrition and defence1,... more For over 300 million years, insects have relied on symbiotic microbes for nutrition and defence1,2. However, it is unclear whether specific ecological conditions have repeatedly favoured the evolution of symbioses, and how this has influenced insect diversification1,3,4. Using data on 1844 microbe-insect symbioses across 400 insect families, we found that symbionts have allowed insects to radiate into a range of feeding niches deficient in B vitamins, including phloem, blood and wood. In some cases, such as herbivorous insects, the shift to a new niche has resulted in spectacular species proliferation. In other niches, such as strict blood feeding, diversification has been severely constrained. Symbioses therefore appear to solve universal nutrient deficiencies for insects, but the consequences for insect diversification depend on the feeding niche invaded.

Proceedings of the Royal Society B: Biological Sciences, 2021

Individuals are expected to avoid mating with relatives as inbreeding can reduce offspring fitnes... more Individuals are expected to avoid mating with relatives as inbreeding can reduce offspring fitness, a phenomenon known as inbreeding depression. This has led to the widespread assumption that selection will favour individuals that avoid mating with relatives. However, the strength of inbreeding avoidance is variable across species and there are numerous cases where related mates are not avoided. Here we test if the frequency that related males and females encounter each other explains variation in inbreeding avoidance using phylogenetic meta-analysis of 41 different species from six classes across the animal kingdom. In species reported to mate randomly with respect to relatedness, individuals were either unlikely to encounter relatives, or inbreeding had negligible effects on offspring fitness. Mechanisms for avoiding inbreeding, including active mate choice, post-copulatory processes and sex-biased dispersal, were only found in species with inbreeding depression. These results hel...

Live birth is a key innovation that has evolved from egg laying ancestors over 100 times in repti... more Live birth is a key innovation that has evolved from egg laying ancestors over 100 times in reptiles. However, egg-laying lizards and snakes often have preferred body temperatures that are lethal to developing embryos and should prevent egg retention: how has viviparity repeatedly evolved in the face of this pervasive mismatch? We resolve this paradox by conducting phylogenetic analyses of adult and embryo thermal preferences across 224 species. Thermal mismatches between mothers and offspring are widespread but resolved by gravid females down-regulating their body temperature towards the thermal optimum of embryos. Importantly, this thermoregulatory behaviour evolved in ancestral egg-laying species before the evolution of live birth. Maternal thermoregulatory behaviour therefore bypasses the constraints imposed by a slowly evolving thermal physiology and is likely to have been a key requirement for repeated transitions to live birth.

The American Naturalist, 2020

In birds that breed cooperatively in family groups, adult offspring often delay dispersal to assi... more In birds that breed cooperatively in family groups, adult offspring often delay dispersal to assist the breeding pair in raising their young. Kin selection is thought to play an important role in the evolution of this breeding system. However, evidence supporting the underlying assumption that helpers increase the reproductive success of breeders is inconsistent. In 10 out of 19 species where the effect of helpers on breeder reproductive success has been estimated while controlling for the effects of breeder and territory quality, no benefits of help were detected. Here, we use phylogenetic meta-analysis to show that the inconsistent evidence for helper benefits across species is explained by study design. After accounting for low sample sizes and the different study designs used to control for breeder and territory quality, we found that helpers consistently enhanced the reproductive success of breeders. Therefore, the assumption that helpers increase breeder reproductive success is supported by evidence across cooperatively breeding birds.

Nature Ecology & Evolution, 2020

Group-living species show a diversity of social organisation, from simple mated pairs to complex ... more Group-living species show a diversity of social organisation, from simple mated pairs to complex communities of interdependent individuals performing specialized tasks. The advantages of living in cooperative groups are well understood, but why some species breed in small aggregations while others evolve large, complex groups with clearly divided roles is unclear. We address this problem by reconstructing the evolutionary pathways to cooperative breeding across 4730 bird species. We show that differences in the way groups form at the origin of cooperative breeding predicts the level of group complexity that emerges. Groups that originate through the retention of offspring have a clear reproductive divide with distinct breeder and helper roles. This is associated with reproductive specialization, where breeders invest more in fecundity and less in care. In 2 contrast, groups formed through the aggregation of unrelated adults are smaller and lack specialization. These results help explain why some species have not transitioned beyond simple groups, while others have taken the path to increased group complexity. Main Text: Cooperatively breeding animals have provided us with profound insights into the evolution of cooperation and group living 1-3. Decades of research has shown that breeding in cooperative groups can increase reproductive success 4,5 , especially under conditions where independent breeding is difficult 6-8. This has allowed species to expand into new ecological niches and persist in environments uninhabitable for less social species 9-11. Detailed accounts of cooperative breeders have also revealed that there is remarkable unexplained variation in the complexity of social groups across species 12,13. Complex groups are those in which there is a clear division of reproduction, group members are specialized in breeding and helping roles and groups are large 2. Why do animal societies vary dramatically in group size, and why are tasks such as reproduction and offspring care partitioned amongst group members in some species but not others (Fig. 1) 5,14-18 ? Evolutionary theory predicts that differences in the complexity of social groups can arise because of differences in the way they form 19. Groups formed by offspring staying with their parents ('family groups') have relatively high average relatedness between

Proceedings of the National Academy of Sciences, 2018

Nature ecology & evolution, 2018

Colonization and migration have a crucial effect on patterns of biodiversity, with disease predic... more Colonization and migration have a crucial effect on patterns of biodiversity, with disease predicted to play an important role in these processes. However, evidence of the effect of pathogens on broad patterns of colonization and migration is limited. Here, using phylogenetic analyses of 1,311 species of Afro-Palaearctic songbirds, we show that colonization events from regions of high (sub-Saharan Africa) to low (the Palaearctic) pathogen diversity were up to 20 times more frequent than the reverse, and that migration has evolved 3 times more frequently from African- as opposed to Palaearctic-resident species. We also found that resident species that colonized the Palaearctic from Africa, as well as African species that evolved long-distance migration to breed in the Palaearctic, have reduced diversity of key immune genes associated with pathogen recognition (major histocompatibility complex class I). These results suggest that changes in the pathogen community that occur during col...

Nature Ecology & Evolution, 2017

Animals living in harsh environments, where temperatures are hot and rainfall is unpredictable, a... more Animals living in harsh environments, where temperatures are hot and rainfall is unpredictable, are more likely to breed in cooperative groups. As a result, harsh environmental conditions have been accepted as a key factor explaining the evolution of cooperation. However, this is based on evidence that has not investigated the order of evolutionary events, so the inferred causality could be incorrect. We resolved this problem using phylogenetic analyses of 4,707 bird species and found that causation was in the opposite direction to that previously assumed. Rather than harsh environments favouring cooperation, cooperative breeding has facilitated the colonization of harsh environments. Cooperative breeding was, in fact, more likely to evolve from ancestors occupying relatively cool environmental niches with predictable rainfall, which had low levels of polyandry and hence high within-group relatedness. We also found that polyandry increased after cooperative breeders invaded harsh environments, suggesting that when helpers have limited options to breed independently, polyandry no longer destabilizes cooperation. This provides an explanation for the puzzling cases of polyandrous cooperative breeding birds. More generally, this illustrates how cooperation can play a key role in invading ecological niches, a pattern observed across all levels of biological organization from cells to animal societies.