Making a Bee-Line for Food with Octopamine

How do you find the newest, trendiest restaurants with the best food in your neighborhood (that is, of course, during non-pandemic times when restaurants are all open)? Well, one way that you may notice the new hip spot is to follow the crowds. If you wander by a spot filled with folks enjoying mouth-wateringly delicious food, you will likely be drawn to visit that restaurant yourself. But, how does your brain process these signals about food resources and quality? Tianfei Peng and two of his colleagues from the University of Mainz in Germany dug into this question by looking at the inner-workings of a slightly simpler brain – that of the stingless bee – to uncover the brain's role in social animal foraging.The trio suspected that the compound octopamine could play a role in how both individuals and social groups find food and perceive its value. Octopamine is a major player in the brain function of invertebrate animals, including many insects, equivalent to the fight-or-flight hormone noradrenaline in vertebrates, including human

Flies Walk the Line for Serotonin

In the grand scheme of the animal kingdom, insects are often overlooked for their impressive locomotor skills. They can walk forwards, backwards and even upside down, traversing challenging environments with relative ease. But how do insects achieve this coordination? Clare Howard (Columbia University) and colleagues teach us that the insect nervous system employs a multifaceted signalling network to optimize their speed, gait and reaction timing to gracefully navigate through life.Using the vinegar fly (Drosophila melanogaster), Howard and colleagues surveyed the fly nervous system to establish the sequence of signals involved in locomotion

Serotonin: Octopus Love Potion?

When you think about human social behaviour, what animals do you immediately think of as most similar to us? Apes, dolphins, wolves? Sure, these animals display incredibly complex social interactions, just like us. But Eric Edsinger from the Marine Biological Laboratory, USA, and Gül Dölen from Johns Hopkins University, USA, teach us in their latest study that we aren't actually all that different from our more distant cousin: the octopus. While octopuses typically hang out by themselves and fight when they come across each other, they let bygones be bygones during the mating season. Until now, we had no idea why octopuses suddenly set aside their aggressive tendencies during this ‘special’ time. Using a unique combination of molecular and behavioural studies, Edsinger and Dölen delved into the brain of the octopus to uncover the neurological mechanisms that regulate their social behaviour.<br/

Birds Ruffled by Big-City Lights

The blazing lights of Times Square in New York City may be impressive for tourists, yet this blindingly bright attraction can cause problems for urban wildlife. Artificial light at night, typical of cities and suburban areas around the globe, can cause problems for the animals that we share space with, although the impact on local wildlife is often disregarded. Given the current global COVID-19 pandemic, understanding how stressors, such as artificial nocturnal light, alter infectious disease transmission is now even more pressing. So, Daniel Becker and colleagues from Indiana University in the USA delved into this question, looking at how persistent artificial light at night alters immunity and infection risk in wild animal communities

The role of physiological traits in assortment among and within fish shoals

Individuals of gregarious species often group with conspecifics to which they are phenotypically similar. This among-group assortment has been studied for body size, sex and relatedness. However, the role of physiological traits has been largely overlooked. Here, we discuss mechanisms by which physiological traits—particularly those related to metabolism and locomotor performance—may result in phenotypic assortment not only among but also within animal groups. At the among-group level, varying combinations of passive assortment, active assortment, phenotypic plasticity and selective mortality may generate phenotypic differences among groups. Even within groups, however, individual variation in energy requirements, aerobic and anaerobic capacity, neurological lateralization and tolerance to environmental stressors are likely to produce differences in the spatial location of individuals or associations between group-mates with specific physiological phenotypes. Owing to the greater availability of empirical research, we focus on groups of fishes (i.e. shoals and schools). Increased knowledge of physiological mechanisms influencing among- and within-group assortment will enhance our understanding of fundamental concepts regarding optimal group size, predator avoidance, group cohesion, information transfer, life-history strategies and the evolutionary effects of group membership. In a broader perspective, predicting animal responses to environmental change will be impossible without a comprehensive understanding of the physiological basis of the formation and functioning of animal social groups. This article is part of the themed issue ‘Physiological determinants of social behaviour in animals’

Protein kinase C-dependent signaling controls the midgut epithelial barrier to malaria parasite infection in anopheline mosquitoes.

Anopheline mosquitoes are the primary vectors of parasites in the genus Plasmodium, the causative agents of malaria. Malaria parasites undergo a series of complex transformations upon ingestion by the mosquito host. During this process, the physical barrier of the midgut epithelium, along with innate immune defenses, functionally restrict parasite development. Although these defenses have been studied for some time, the regulatory factors that control them are poorly understood. The protein kinase C (PKC) gene family consists of serine/threonine kinases that serve as central signaling molecules and regulators of a broad spectrum of cellular processes including epithelial barrier function and immunity. Indeed, PKCs are highly conserved, ranging from 7 isoforms in Drosophila to 16 isoforms in mammals, yet none have been identified in mosquitoes. Despite conservation of the PKC gene family and their potential as targets for transmission-blocking strategies for malaria, no direct connections between PKCs, the mosquito immune response or epithelial barrier integrity are known. Here, we identify and characterize six PKC gene family members--PKCδ, PKCε, PKCζ, PKD, PKN, and an indeterminate conventional PKC--in Anopheles gambiae and Anopheles stephensi. Sequence and phylogenetic analyses of the anopheline PKCs support most subfamily assignments. All six PKCs are expressed in the midgut epithelia of A. gambiae and A. stephensi post-blood feeding, indicating availability for signaling in a tissue that is critical for malaria parasite development. Although inhibition of PKC enzymatic activity decreased NF-κB-regulated anti-microbial peptide expression in mosquito cells in vitro, PKC inhibition had no effect on expression of a panel of immune genes in the midgut epithelium in vivo. PKC inhibition did, however, significantly increase midgut barrier integrity and decrease development of P. falciparum oocysts in A. stephensi, suggesting that PKC-dependent signaling is a negative regulator of epithelial barrier function and a potential new target for transmission-blocking strategies

The Role of Physiological Traits in Assortment Among and Within Fish Shoals

Individuals of gregarious species often group with conspecifics to which they are phenotypically similar. This among-group assortment has been studied for body size, sex and relatedness. However, the role of physiological traits has been largely overlooked. Here, we discuss mechanisms by which physiological traits—particularly those related to metabolism and locomotor performance—may result in phenotypic assortment not only among but also within animal groups. At the among-group level, varying combinations of passive assortment, active assortment, phenotypic plasticity and selective mortality may generate phenotypic differences among groups. Even within groups, however, individual variation in energy requirements, aerobic and anaerobic capacity, neurological lateralization and tolerance to environmental stressors are likely to produce differences in the spatial location of individuals or associations between group-mates with specific physiological phenotypes. Owing to the greater availability of empirical research, we focus on groups of fishes (i.e. shoals and schools). Increased knowledge of physiological mechanisms influencing among- and within-group assortment will enhance our understanding of fundamental concepts regarding optimal group size, predator avoidance, group cohesion, information transfer, life-history strategies and the evolutionary effects of group membership. In a broader perspective, predicting animal responses to environmental change will be impossible without a comprehensive understanding of the physiological basis of the formation and functioning of animal social groups

Social familiarity improves fast-start escape performance in schooling fish

Using social groups (i.e. schools) of the tropical damselfish Chromis viridis, we test how familiarity through repeated social interactions influences fast-start responses, the primary defensive behaviour in a range of taxa, including fish, sharks, and larval amphibians. We focus on reactivity through response latency and kinematic performance (i.e. agility and propulsion) following a simulated predator attack, while distinguishing between first and subsequent responders (direct response to stimulation versus response triggered by integrated direct and social stimulation, respectively). In familiar schools, first and subsequent responders exhibit shorter latency than unfamiliar individuals, demonstrating that familiarity increases reactivity to direct and, potentially, social stimulation. Further, familiarity modulates kinematic performance in subsequent responders, demonstrated by increased agility and propulsion. These findings demonstrate that the benefits of social recognition and memory may enhance individual fitness through greater survival of predator attacks

Role of Water Flow Regime in the Swimming Behaviour and Escape Performance of a Schooling Fish

Animals are exposed to variable and rapidly changing environmental flow conditions, such as wind in terrestrial habitats and currents in aquatic systems. For fishes, previous work suggests that individuals exhibit flow-induced changes in aerobic swimming performance. Yet, no one has examined whether similar plasticity is found in fast-start escape responses, which are modulated by anaerobic swimming performance, sensory stimuli and neural control. In this study, we used fish from wild schools of the tropical damselfish Chromis viridis from shallow reefs surrounding Lizard Island in the Great Barrier Reef, Australia. The flow regime at each site was measured to ascertain differences in mean water flow speed and its temporal variability. Swimming and escape behaviour in fish schools were video-recorded in a laminar-flow swim tunnel. Though each school\u27s swimming behaviour (i.e. alignment and cohesion) was not associated with local flow conditions, traits linked with fast-start performance (particularly turning rate and the distance travelled with the response) were significantly greater in individuals from high-flow habitats. This stronger performance may occur due to a number of mechanisms, such as an in situ training effect or greater selection pressure for faster performance phenotypes in areas with high flow speed