Biology subjects

Thorogood, R.

Publications and source records attributed to Thorogood, R..

15 recordsLinked to original sources

bioRxiv2026

The effect of parental provisioning on the development of prey preferences in great tit (Parus major)

To make adaptive foraging decisions, naive individuals need to gather information about the local prey community. Besides sampling prey personally, the young could gather information about prey profitability by observing the foraging behaviour of other individuals, and parental provisioning provides the first opportunity to acquire this social information. Still, previous research on vertical transmission of prey preferences from parents has provided mixed results that are often confounded with other information sources, such as siblings and peers. It is also not known whether information from parents can change potential innate biases against certain prey types, such as avoidance of warningly coloured insects. Here, we tested whether social information acquired by offspring during parental provisioning influences the development of prey preferences in a generalist predator, the Great Tit (Parus major). We brought 15 great tit broods and their parents into captivity at late nestling stage (14 days old) and divided them into three social information treatments where parents were provided with either brown, red or yellow palatable maggots to feed to their dependent young for 8 days. Once foraging independently from parents, we conducted a preference test where juveniles were offered the full array of coloured maggots. Regardless of palatable exposure to typical warning-coloured maggots (i.e. red and yellow), juveniles consistently preferred yellow over red, and preferred brown maggots the most (i.e. lacking warning coloration). This supports the existence of innate biases against typical warning colours, and that social information from parents is unlikely to override these, at least when alternative prey is easily available.

animal behavior and cognition↗

bioRxiv2025

Signatures of genomic adaptation to Cuckoo brood parasitism in Reed Warbler hosts across Europe

Behaviour is a fundamental defence mechanism for animals facing enemies, yet its plasticity makes finding associated genomic evidence for coevolution challenging. As a solution, we apply landscape genomics methods more typically deployed with abiotic variables to a coevolutionary model system: Reed Warblers (Acrocephalus scirpaceus) and their Cuckoo (Cuculus canorus) brood parasites. Using continental sampling of genome-wide data from hosts breeding under varying brood parasitism rates, we reveal that gene flow varies among populations, and, controlling for variation due to environmental differences, identify genomic regions and putative genes that differ with exposure to brood parasitism. Therefore, our results suggest that variable host responses to selection are possible, even by highly mobile and connected populations, supporting long-held assumptions that behavioural defences may reflect genomic adaptation despite their plasticity. Further studies, including those linking genetic variation to individual-level behaviours involved in parental responses to brood parasitism, are required to confirm a genetic basis to specific coevolutionary adaptations, and to test for other biotic or abiotic variables potentially confounding with local parasitism rate.

evolutionary biology↗

bioRxiv2025

High genetic diversity and no detectable founder effects following a rapid range expansion of a long-distance migrant (Acrocephalus scirpaceus)

Many species are currently experiencing range shifts in response to changing environmental conditions, but with potentially serious genetic consequences. Repeated founder events and strong genetic drift are expected to erode genetic variation at the range front, reducing adaptive potential and slowing or even halting the expansion. However, the severity of these consequences for the more common and highly mobile species undergoing environment-driven range shifts (c.f. invasions) is less clear. Here we combined historical observations and contemporary movement data of the common reed warbler (Acrocephalus scirpaceus) with genomic evidence from across its European breeding range to (1) infer the origin and (2) quantify the genetic consequences of a recent and rapid northward range expansion. While there were no reductions in levels of nucleotide diversity or allelic richness, nor a signal of founder effect in the directionality index ({psi}), our combined dataset approach was able to infer an expansion origin from the southwest. Furthermore, we found that private allelic richness retained a slight but significant linear decline along the colonisation route. These results suggest that high dispersal capabilities can allow even philopatric species to avoid the loss of genetic diversity during rapid range expansions. Nevertheless, if multiple lines of evidence enable identification of an expansion pathway, we may still detect genetic signals of expansion.

evolutionary biology↗

bioRxiv2024

Multispecies relations shape bird-feeding practices

While humans often feed birds in their backyards, there is growing awareness that this has positive and negative effects on local biodiversity. Whether the observed species assemblage shapes human activities has, however, rarely been investigated. We analyzed 15,088 open-ended answers from 9,473 Finnish respondents about why they have increased or reduced feeding birds. They mentioned 58 avian and non-avian species linked to changed practices. The main reasons for change were 1) respondents relation to non-human species, 2) respondents relation to other humans and 3) relations between non-human species. Most taxa and reasons could lead to both increase or decrease in feeding, although the direction was context-dependent. We suggest that bird-feeding is an interactive process where the species community strongly affects feeding practices, which in turn can affect community composition. Recognising this process is crucial for understanding the effects of bird-feeding on both humans and nature and providing more nuanced guidance.

scientific communication and education↗

bioRxiv2024

Common cuckoo female host selection is not determined by host quality but can affect cuckoo nestling growth when parasitising Common redstarts

Common cuckoo (Cuculus canorus) females lay their eggs in the nests of other avian hosts, relying on parental care provided by parasitised hosts. Therefore, it would benefit cuckoo females to target high-quality individual hosts, able to provide optimal parental care. Attempts at testing cuckoo female host selection have so far shown mixed results. However, this might be because studies have rarely considered the host nests that are available in space and time during each cuckoo egg-laying event, as well as the implications of host choice on the cuckoo nestling growth. Here we combined long-term monitoring data with an experiment to test whether cuckoo females parasitising Common redstarts (Phoenicurus phoenicurus) target individual hosts to optimise their nestling[s] growth. Making use of data collected between 2013 and 2022 from 350+ nest boxes in Oulu (Finland), we first explored whether there is a range of available host nests for the cuckoo female to choose from. Second, we tested if hosts are targeted according to individual quality (using clutch size as a proxy). And third, we investigated the outcomes of cuckoo female host-selection on nestling growth (mass, tarsus length, and wing length) between 2014 and 2019. We conducted a cross-fostering experiment where we either left cuckoo eggs to hatch and be raised in the nest their mother originally chose for them or moved cuckoo eggs to non-parasitised nests. Additionally, we conducted an exploratory analysis to test the quality of the parents caring for the cross-fostered cuckoo nestlings. After accounting for how many host nests were available to the cuckoo female to choose from, we found that nests with bigger clutches were not more likely to be parasitised, and cross-fostering did not affect mass and tarsus length growth. However, both in the wing length growth and in our exploratory analysis of host parental care on cuckoo nestling growth we found that cuckoo nestlings that grew in the nest selected by their mothers, reached higher asymptotic growth at a slower rate. This suggests that while cuckoos may not choose redstart hosts based on their individual quality when parasitising common redstarts, cuckoo female host selection might improve cuckoo nestling growth and thus, have an adaptive significance.

animal behavior and cognition↗

bioRxiv2024

Can social interactions rescue "lost" behavioural defences in an allopatric cuckoo host?

Behavioral defenses are a key adaptation across animals, but confirming decay under relaxed selection is challenging. If expression involves decision-making, then defenses may only be expressed when the right environmental cues are available (i.e. cryptic plasticity). Even if defenses wane, they could be quickly restored once selection resumes as animals can learn by observing others (i.e. social memory). Here we tested cryptic plasticity and social memory under relaxed selection in a cuckoo host, the Common Reed Warbler, by manipulating perceived parasitism risk with social information in geographically-distinct areas differing in allopatry (100 to 1000 years). Despite predicting social information of a cuckoo vs. a control would elicit otherwise cryptic behavioral defenses, only birds that mobbed model cuckoos prior to manipulation upregulated this defense, and only in the recently allopatric population. Social information also had no effect on low-to-absent rates of foreign egg rejection, a second line of defense common to cuckoo host species. These results contrast with parasitized locations where similar methods provoke mobbing and increase egg rejection ten-fold. Our study therefore suggests that, even when manipulating information to account for reaction norms, behavioral defenses may degrade rapidly under relaxed selection, demonstrating a process facilitating a geographic mosaic of coevolution.

animal behavior and cognition↗

bioRxiv2024

Species-associated bacterial diversity increases along a gradient of habitat degradation

Alterations of microbial communities have evident impacts on development, digestion, fecundity, metabolism, immunity, and diverse other biological functions of their hosts. Yet, the factors affecting microbial communities associated with wild species often remain uncharacterized. For example, the impact of the hosts habitat degradation due to anthropogenic activities has received little attention, which contrasts with the large literature showing how such habitat degradation is at least partly responsible for the on-going global patterns of macro-biodiversity erosion. Here, we use metacommunities of herbivorous insect species specialized in feeding on Plantago lanceolata in the fragmented landscape of the [A]land Islands, Finland, as a model system to test whether and how bacterial communities associated with wild species change along a gradient of habitat degradation. We evaluated microbial species diversity and community composition in two sympatric insect species sampled from local meadow habitats with various levels of human disturbance within or around these habitats (e.g. forests, roads, agriculture fields, buildings). Counter to our expectations, we found that bacterial diversity can increase with habitat degradation, with individuals from more degraded habitats hosting more rare bacterial species. In contrast, as the dominant microbial species remain similar across habitats, the community composition and function of the microbiota persist under habitat degradation. In this system, the strength of human activities might induce changes in habitat heterogeneity rather than changes in overall habitat quality, thus allowing local insects to encounter and host more rare microbes rather than trigger local microbial extinction.

microbiology↗

bioRxiv2022

Genomic consequences of range expansion and colonisation in the reed warbler (Acrocephalus scirpaceus)

Range expansion is a common natural phenomenon, which may be intensified by human-induced drivers such as climate change and alterations of habitat. The genetic consequences of range expansion are potentially major, and it is important to study known cases of range expansion to understand how human activities affect contemporary evolution, and to learn more about the genetic adaptive potential of species. The reed warbler (Acrocephalus scirpaceus) is a long-distance migratory bird breeding in Eurasia and wintering south of Sahara. It is currently expanding its range northwards, likely as a consequence of climate change. Interestingly, however, reed warblers have also recently colonised new territory southwards, following habitat restoration at the southern range margin. In this study, we investigate the genetic consequences of these two-directional range expansions with RAD-seq, looking at 10 populations from north to south in Europe. We investigate population structure and genome diversity, and assess the role of selection in divergence between populations across the species range. We do not find evidence of strong genetic structure in the reed warbler populations, and the youngest edge populations do not exhibit any substantial loss in genetic diversity, suggesting ongoing gene flow. On a smaller scale, the edge populations are the most genetically distinct, and we identify environmental disparity, especially in precipitation variability, as the main barrier of gene flow, to a greater extent than geographic distance. We find no evidence that the loci involved in population divergence and adaptation in the core populations are the same that are involved in adaptation at the range edges. Using three genome scan methods to identify selection, we found 49 SNPs putatively under selection, of which 33 were located in introns of 28 unique genes. Most of these are correlated with differences in climatic variables of temperature and precipitation. Some genome scan outliers show signs of being part of nascent selective sweeps, especially one which is distinct for the northern range edge. Our results suggest that in the reed warbler, contemporary range expansion has had little effect on molecular diversity and has been rapidly followed by local adaptation to climatic conditions, which could further corroborate the rapid pace at which colonisation of novel environments has occurred both northwards and southwards.

evolutionary biology↗

bioRxiv2022

Intergenerational effects from spatial and genetic environment predict early-life social network structure

Early independence is a crucial stage in the ontogeny of social environments, but it is often challenging to study in the wild. Genetics may structure groups if young animals associate with familiar kin, but association opportunities also develop as a by-product of environmental processes such as spatial resource distribution. The contribution of these alternate factors in initial opportunities for bonding outside direct relatives is difficult to pick apart, despite its importance in shaping later life. However, species where genetics and spatial structure are less closely coupled (for example, via extra-pair mating) provide a natural opportunity to disentangle these effects. We addressed this gap by investigating the contribution of relatedness versus spatiotemporal synchrony (natal nest-box location and fledge timing) to early-life social structure in newly-independent young hihi (Notiomystis cincta). We also investigated the contribution of inbreeding in both juveniles and their parents, to individual-level sociality, as this genetic factor has had limited focus in studies of social structure. Using a long-term genetic pedigree, detailed breeding records, and social network data collected across three cohorts, we found that juvenile social associations were predicted by natal nest-box location, irrespective of relatedness between juveniles. Therefore, the physical environment can create initial opportunities for associations to develop once young animals disperse from natal sites. Furthermore, juvenile sociability was predicted by their fathers (but not mothers) inbreeding, highlighting how genetics may have indirect and intergenerational effects on social behaviour. Overall, social structure in wild animals can emerge early in life if the natal environment determines association opportunities. These patterns may even be pre-determined across generations if breeding and settlement decisions made by parents affect the physical and social environments experienced by their offspring. Ultimately, our study highlights how influences on early life social structure may have important consequences for population dynamics and evolutionary potential.

animal behavior and cognition↗

bioRxiv2021

A Chromosome-level Genome Assembly of the Reed Warbler (Acrocephalus scirpaceus)

The reed warbler (Acrocephalus scirpaceus) is a long-distance migrant passerine with a wide distribution across Eurasia. This species has fascinated researchers for decades, especially its role as host of a brood parasite, and its capacity for rapid phenotypic change in the face of climate change. Currently, it is expanding its range northwards in Europe, and is altering its migratory behaviour in certain areas. Thus, there is great potential to discover signs of recent evolution and its impact on the genomic composition of the reed warbler. Here we present a high-quality reference genome for the reed warbler, based on PacBio, 10X and Hi-C sequencing. The genome has an assembly size of 1,075,083,815 bp with a scaffold N50 of 74,438,198 bp and a contig N50 of 12,742,779 bp. BUSCO analysis using aves_odb10 as a model showed that 95.7% of genes in the assembly were complete. We found unequivocal evidence of two separate macrochromosomal fusions in the reed warbler genome, in addition to the previously identified fusion between chromosome Z and a part of chromosome 4A in the Sylvioidea superfamily. We annotated 14,645 protein-coding genes, of which 97.5% were complete BUSCO orthologs. This reference genome will serve as an important resource, and will provide new insights into the genomic effects of evolutionary drivers such as coevolution, range expansion, and adaptations to climate change, as well as chromosomal rearrangements in birds. Significance statementThe reed warbler (Acrocephalus scirpaceus) has been lacking a genomic resource, despite having been broadly researched in studies of coevolution, ecology and adaptations to climate change. Here, we generated a chromosome-length genome assembly of the reed warbler, and found evidence of macrochromosomal fusions in its genome, which are likely of recent origin. This genome will provide the opportunity for a deeper understanding of the evolution of genomes in birds, as well as the evolutionary path and possible future of the reed warbler.

genomics↗

bioRxiv2021

Darwin's finches can have taste preferences, but not for human foods

Urbanization is rapidly changing ecological niches. On the inhabited Galapagos Islands, Darwins finches consume human-introduced foods preferentially; however, it remains unclear why. Here we presented pastry with flavour profiles typical of human foods (oily, salty, sweet) to small ground finches (Geospiza fuliginosa) and medium ground finches (Geospiza fortis) to test if latent taste preferences might drive selection of human foods. If human-food flavours were consumed more than a neutral or bitter control only at sites with human foods, then we predicted tastes were acquired after urbanization; however, if no site-differences were found then this would indicate latent taste preferences. Contrary to both predictions, we found little evidence that human-food flavours were preferred compared to control flavours at any site. Instead, finches showed a weak aversion to oily foods, but only at remote (no human foods present) sites. This was further supported by behavioural responses, with beak wiping occurring more often at remote sites after finches tasted flavours associated with human foods. Our results suggest, therefore, that while Darwins finches may have acquired a tolerance to the flavours of human food, latent taste preferences are unlikely to have played a major role in their dietary response to increased urbanization.

animal behavior and cognition↗

bioRxiv2020

Sociality enhances survival in science, especially for female researchers

Intense competition for limited opportunities means the career path of a scientist is a challenging one, and female scientists in particular are less likely to survive in academia. Collaboration is a key factor in scientific advances, and in social species enhanced sociality improves fitness and longevity. Yet whether sociality influences career progression and survival in science, and how this might differ between genders, is largely unknown. We built authorship social networks from publication records to test how sociality predicts career progression and survival in a cohort of biologists contributing to three international conferences in the 1990s. We show that sociality has the strongest effect for female researchers but, regardless of gender, publishing with many diverse co-authors significantly reduces time to become a principal investigator and increases career duration. Publishing repeatedly with co-authors also enhances career progression in both genders, but reduces career length for men. These findings demonstrate that the value of collaboration extends beyond scientific advances, and can directly benefit the career progression and longevity of research scientists themselves. Efforts to encourage researchers at all levels to invest in collaborations, particularly with female researchers, will help to close the gender gap in science and academia.

scientific communication and education↗

bioRxiv2018

One of the gang: social group dynamics in a juvenile passerine bird

Living in groups comes with many potential benefits, especially for juveniles. Naive individuals may learn how to forage, or avoid predators through group vigilance. Understanding these benefits, however, requires an appreciation of the opportunities juveniles have to associate with (and learn from) others. Here we describe social groups in terms of residency, movement, relatedness, and social associations from the perspective of juvenile hihi, a threatened New Zealand passerine bird. Over three years, we identified individuals in groups, their relatedness, and behavioural interactions. Using multistate analysis, we compared movement and residency of adults and juveniles and found that groups were composed predominately of juveniles which remained at group sites for longer than more transient adults. Movement of juveniles between groups did occur but was generally low. There was no evidence that siblings and parents were likely to be seen in groups together. With an initial understanding of group structure, we next asked what characteristics predicted assortment in social network associations. By identifying groups of co-occurring juveniles from time-stamped observations of individual hihi and building a social network, we found that juveniles were most likely to associate with other juveniles. Associations were also predominantly based on locations where hihi spent the most time, reflecting limited movement among separate groups. We suggest groups are best described as \"gangs\" where young hihi have little interaction with adults. These spatially-separated groups of juveniles may have consequences for social information use during the first few months of independence in young birds.

animal behavior and cognition↗

bioRxiv2018

Copy parents or follow friends? Juvenile foraging behaviour changes with social environment

The first few months of juvenile independence is a critical period for survival as young must learn new behaviours to forage efficiently. Social learning by observing parents (vertical transmission) or others (horizontal/oblique transmission) may be important to overcome naivety, but these tutors are likely to differ in their reliability due to variation in their own experience. How young animals use different social information sources, however, has received little attention. Here we tested if wild juvenile hihi (Notiomystis cincta, a New Zealand passerine) retained foraging behaviours learned from parents, or if behaviour changed after independence in response to peers. We first trained parents with feeders during chick rearing: one-third could access food from any direction, one-third could access food from one side only, and the remaining third had no feeder. During post-fledge parental care, juveniles chose the same side as their parents. Once independent, juveniles formed mixed-treatment groups naturally so we then presented feeders with two equally profitable sides. Juveniles with natal feeder experience were quicker to use these feeders initially, but side choice was now random. Over time, however, juveniles converged on using one side of the feeder (which differed between groups). This apparent conformity was because juvenile hihi paid attention to the behaviour of their group and were more likely to choose the locally-favoured side as the number of visits to that side increased. They did not copy the choice of specific individuals, even when they were more social or more familiar with the preceding bird. Our study shows that early social experiences with parents affect foraging decisions, but later social environments lead juveniles to modify their behaviour.

animal behavior and cognition↗

bioRxiv2018

Changes in social groups across reintroductions and effects on post-release survival

Reintroductions are essential to many conservation programmes, and thus much research has focussed on understanding what determines the success of these translocation interventions. However, while reintroductions disrupt both the abiotic and social environments, there has been less focus on the consequences of social disruption. Therefore, here we investigate if moving familiar social groups may help animals (particularly naive juveniles) adjust to their new environment and increase the chances of population establishment. We used social network analysis to study changes in group composition and individual sociality across a reintroduction of 40 juvenile hihi (Notiomystis cincta), a threatened New Zealand passerine. We collected observations of groups before a translocation to explore whether social behaviour before the reintroduction predicted associations after, and whether reintroduction influenced individual sociality (degree). We also assessed whether grouping familiar birds during temporary captivity in aviaries maintained group structure and individual sociality, compared to our normal translocation method (aviaries of random familiarity). Following release, we measured if survival depended on how individual sociality had changed. By comparing these analyses with birds that remained at the source site, we found that translocation lead to re-assortment of groups: non-translocated birds maintained their groups, but translocated juveniles formed groups with both familiar and unfamiliar birds. Aviary holding did not improve group cohesion; instead, juveniles were less likely to associate with aviary-mates. Finally, we found that translocated juveniles that lost the most associates experienced a small but significant tendency for higher mortality. This suggests sociality loss may have represented a disruption that affected their ability to adapt to a new site.

animal behavior and cognition↗