Biology subjects

Cook, C. N.

Publications and source records attributed to Cook, C. N..

10 recordsLinked to original sources

bioRxiv2026

Behavioral compensation preserves collective behavior when individual members are compromised

Collective behavior in animal societies can buffer individual costs and confer resilience to environmental challenges. However, the mechanisms by which groups sustain function when members are compromised remain poorly understood. In the presented study, we investigate how social context shapes collective fanning, a thermoregulatory behavior critical for colony function, in Western honeybees (Apis mellifera). Using oxytetracycline (OTC), a known physiologically disruptive antibiotic to honeybees, to selectively impair certain group members, we tested our hypothesis that the presence of untreated bees would rescue the fanning response in mixed-composition groups. We show that groups containing untreated individuals fan at levels comparable to fully untreated groups, despite the presence of OTC-impaired bees. This preservation of collective thermoregulatory function was correlated with both treated and untreated individuals in mixed groups shifting their interaction dynamics and social network positions. These findings reveal a decentralized mechanism of collective resilience, whereby behavioral compensation by individuals sustains group-level thermoregulation under partial disruption. Our results provide a framework for understanding how social insect colonies maintain function in the face of individual-level perturbations, with broader implications for predicting the limits of collective resilience in animal societies experiencing increasing environmental pressures.

animal behavior and cognition↗

bioRxiv2024

Disruption of Collective Behavior Correlates with Reduced Interaction Efficiency

Group-living organisms commonly engage in collective behavior to respond to an ever-changing environment. How individuals utilize local information to produce such large-scale, cohesive behaviors and the factors that impact these dynamics are of high research interest, especially since animals face increasingly challenging environmental conditions due to pollution and climate change. Western honeybees (Apis mellifera) are highly social insects that depend on the tight coordination of many individuals to ensure optimum colony function. We used fanning, a collective thermoregulatory behavior in honeybees that depends on both social and thermal contexts, as a case study for collective behavior. To elucidate the mechanisms behind the coordination of fanning, we used oxytetracycline, an antibiotic historically used in apiculture and known environmental pollutant that impairs bee physiology and behavior. Specifically, we hypothesized that oxytetracycline will interfere social interactions which will lead to a disruption in honeybee fanning behavior. We found that longer exposure to antibiotics decreases fanning in honeybees. Using an automated tracking software, we show that antibiotic treatment lowers the number of interactions bees have despite increasing average movement velocity, thereby impeding the social dynamics within these small bee groups. Our results contribute strong evidence that interactions between individuals may drive the collective thermoregulatory fanning response in honeybees. This work emphasizes the importance of understanding the social mechanisms that underlie critical collective animal coordination and how the effects of a common environmental pollutant on an individual can scale to affect populations.

animal behavior and cognition↗

bioRxiv2024

Physical Interactions Drive Collective Thermoregulatory Behavior in Honey Bees

Social animals can coordinate complex behaviors, which can affect massive change on the environment. Within groups, individuals can sense the environment and communicate that information with others. Direct contact, like physical touch, is a key method of communication among social animals, and may be a mechanism to facilitate the coordination of collective behaviors that buffer environmental change. Here, we use a collective thermoregulatory fanning behavior in honey bees (Apis mellifera) to test the hypothesis that direct physical contact is necessary to perform this behavior. By modulating their ability to engage in physical contact, we establish that honey bee workers must touch each other to coordinate the fanning response. We then manipulated social density by changing the physical space the bees occupied to modulate likelihood of contact and found that in high social densities, honey bees are more likely to fan. Using video tracking, we then verified that bees in higher social density indeed have more direct physical interactions. This work identifies a mechanism of communication and potentially information synthesis in an ecologically relevant collective behavior. By understanding the ways in which animals communicate, we may be able to pinpoint the mechanisms of resilience that social insects evolved to manage a changing world.

animal behavior and cognition↗

bioRxiv2024

Development and characterization of phospho-ubiquitin antibodies to monitor PINK1-PRKN signaling in cells and tissue

The selective removal of dysfunctional mitochondria, a process termed mitophagy, is critical for cellular health and impairments have been linked to aging, Parkinson disease, and other neurodegenerative conditions. A central mitophagy pathway is orchestrated by the ubiquitin (Ub) kinase PINK1 together with the E3 Ub ligase PRKN/Parkin. The decoration of damaged mitochondrial domains with phosphorylated Ub (p-S65-Ub) mediates their elimination though the autophagy system. As such p-S65-Ub has emerged as a highly specific and quantitative marker of mitochondrial damage with significant disease relevance. Existing p-S65-Ub antibodies have been successfully employed as research tools in a range of applications including western blot, immunocytochemistry, immunohistochemistry, and ELISA. However, physiological levels of p-S65-Ub in the absence of exogenous stress are very low, therefore difficult to detect and require reliable and ultrasensitive methods. Here we generated and characterized a collection of novel recombinant, rabbit monoclonal p-S65-Ub antibodies with high specificity and affinity in certain applications that allow the field to better understand the molecular mechanisms and disease relevance of PINK1-PRKN signaling. These antibodies may also serve as novel diagnostic or prognostic tools to monitor mitochondrial damage in various clinical and pathological specimens.

neuroscience↗

bioRxiv2023

Vi polysaccharide and conjugated vaccines afford similar early, IgM or IgG-independent control of infection but boosting with conjugated Vi vaccines sustains the efficacy of immune responses

Vaccination with Vi capsular polysaccharide (Vi-PS) or protein-Vi typhoid conjugate vaccine (TCV) can protect adults against Salmonella Typhi infections. TCVs offer better protection than Vi-PS in infants and may offer better protection in adults. Potential reasons for why TCV may be superior in adults are not fully understood. Here, we immunized wild-type (WT) mice and mice deficient in IgG or IgM with Vi-PS or TCVs (Vi conjugated to tetanus toxoid or CRM197) for up to seven months, with and without subsequent challenge with Vi-expressing Salmonella Typhimurium. Unexpectedly, IgM or IgG alone were similarly able to reduce bacterial burdens in tissues, and this was observed in response to conjugated or unconjugated Vi vaccines and was independent of antibody being of high affinity. Only in the longer-term after immunization (>5 months) were differences observed in tissue bacterial burdens of mice immunized with Vi-PS or TCV. These differences related to the maintenance of antibody responses at higher levels in mice boosted with TCV, with the rate of fall in IgG titres induced to Vi-PS being greater than for TCV. Therefore, Vi-specific IgM or IgG are independently capable of protecting from infection and any superior protection from vaccination with TCV in adults may relate to responses being able to persist better rather than from differences in the antibody isotypes induced. These findings suggest that enhancing our understanding of how responses to vaccines are maintained may inform on how to maximize protection afforded by conjugate vaccines against encapsulated pathogens such as S. Typhi.

immunology↗

bioRxiv2022

Tyramine and its AmTYR1 receptor modulate attention in honey bees (Apis mellifera)

Animals must learn to ignore stimuli that are irrelevant to survival and attend to ones that enhance survival. When a stimulus regularly fails to be associated with an important consequence, subsequent excitatory learning about that stimulus can be delayed, which is a form of non-associative conditioning called latent inhibition. Honey bees show latent inhibition toward an odor they have experienced without association with food reinforcement. Moreover, individual honey bees from the same colony differ in the degree to which they show latent inhibition, and these individual differences have a genetic basis. To investigate the mechanisms that underly individual differences in latent inhibition, we selected two honey bee lines for high and low latent inhibition, respectively. We crossed those lines and mapped a Quantitative Trait Locus (QTL) for latent inhibition to a region of the genome that contains the tyramine receptor gene Amtyr11. We then show that disruption of Amtyr1 signaling either pharmacologically or through RNAi qualitatively changes the expression of latent inhibition but has little effect on appetitive conditioning, and these results suggest that AmTYR1 modulates inhibitory processing in the CNS. Electrophysiological recordings from the brain during pharmacological blockade are consistent with a model that AmTYR1 indirectly regulates Hebbian plasticity at inhibitory synapses in the CNS. Finally, sequencing Amtyr1 and its up and downstream genomic region for high and low line workers suggested that individual differences might arise from variation in transcriptional control rather than structural changes in the coding region. Our results therefore identify a distinct modulatory pathway for this type of non-associative learning, and we propose a model for how it modulates Hebbian plasticity at defined synapses in the CNS. We have shown elsewhere how this modulation also underlies potentially adaptive intracolonial learning differences among individuals that benefit colony survival.

animal behavior and cognition↗

bioRxiv2021

Cooperative breeding and the emergence of multilevel societies in birds

Multilevel societies (MLSs), where social levels are hierarchically nested within each other, are considered one of the most complex forms of animal societies. Although thought to mainly occur in mammals, it is suggested that MLSs could be under-detected in birds. Here we propose that the emergence of MLSs could be common in cooperatively breeding birds, as both systems are favoured by similar ecological and social drivers. We first investigate this proposition by systematically comparing evidence for multilevel social structure in cooperative and non-cooperative birds in Australia and New Zealand, global hotspots for cooperative breeding. We then analyse non-breeding social networks of cooperatively breeding superb fairy-wrens (Malurus cyaneus) to reveal their structured multilevel society, with three hierarchical social levels that are stable across years. Our results confirm recent predictions that MLSs are likely to be widespread in birds and suggest that these societies could be particularly common in cooperatively breeding birds.

ecology↗

bioRxiv2021

Role of molecular polymorphism in defining tau filament structures in neurodegenerative diseases

Misfolding and aggregation of tau protein is implicated in many neurodegenerative diseases that are typified by the presence of large, filamentous tau inclusions. The aggregation of tau in human brain is disease-specific with characteristic filaments defining the neuropathology. An understanding of how identical tau isoforms aggregate into disparate filament morphologies in phenotypically distinct tau-related diseases remains elusive. Here, we determine the structure of a brain-derived twisted tau filament in progressive supranuclear palsy and compare it to a dissimilar tau fold found in corticobasal degeneration. While the tau filament core in both diseases is comprised of residues 274 to 380, molecular-level polymorphism exists. Potential origins of the molecular polymorphism, such as noncovalent cofactor binding, are identified and predicted to modulate tau filament structures in the brain.

biophysics↗

bioRxiv2019

The effect of individual learning on collective foraging in honey bees in complex environments

The trade-off between exploiting known resources and exploring for new ones is a complex decision-making challenge, particularly when resource patches are variable in quality and heterogeneously distributed in the landscape. Social insect colonies navigate this challenge, in the absence of centralized control, by allocating different individuals to each of these tasks based on variation in individual behavior. To investigate how heritable differences in individual learning affect a colonys collective ability to locate and choose among different quality food resources, we develop an agent based model and test its predictions using two genetic lines of honey bees, selected for differences in their learning behavior. Here we show that, paradoxically, colonies containing individuals that are better at learning to ignore unrewarding stimuli are worse at choosing the highest quality resource at the collective level. This work highlights the importance of individual variation within groups on the emergence of collective behavior.

animal behavior and cognition↗

bioRxiv2019

Heritable Variation in Learning Phenotypes Drive Collective Cognition

Variation in cognition can influence how individuals respond to and communicate about their environment, which may scale to shape how a collective solves a cognitive task. However, few empirical examples of variation in collective cognition emerges from variation in individual cognition exist. Here, we show that interactions among individuals that differ in the performance of a cognitive task drives collective foraging behavior in honey bee colonies by utilizing a naturally variable and heritable learning behavior called latent inhibition (LI). We artificially selected two distinct phenotypes: high LI bees that are better at ignoring previously unrewarding familiar stimuli, and low LI bees that can learn previously unrewarding and novel stimuli equally well. We then provided colonies composed of these distinct phenotypes with a choice between a familiar feeder or a novel feeder. Colonies of high LI individuals preferred to visit familiar food locations, while low LI colonies visited novel and familiar food locations equally. However, in colonies of mixed learning phenotypes, the low LI bees showed a preference to visiting familiar feeders, which contrasts with their behavior when in a uniform low LI group. We show that the shift in feeder preference of low LI bees is driven by foragers of the high LI phenotype dancing more intensely and attracting more followers. Our results reveal that cognitive abilities of individuals and their interactions drive emergent collective outcomes. Significance StatementVariation in individual cognition affects how animals perceive their environment and which information they share with others. Here we provide empirical evidence that how individual honey bees learn contributes to collective cognition of a colony. By creating colonies of distinct learning phenotypes, we evaluated how bees make foraging choices in the field. Colonies containing individuals that learn to ignore unimportant information preferred familiar food locations, however colonies of individuals that are unable to ignore familiar information visit novel and familiar feeders equally. A 50/50 mix of these phenotypes prefer familiar food locations, because individuals who learn the familiar location recruit nestmates by dancing more intensely. Our results reveal that variation in individual cognition scales non-linearly to shape collective outcomes.

animal behavior and cognition↗