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Antagonistic co-evolution can be asymmetric, where one species lags behind another. Asymmetry in a predator–prey context is expressed by the 'life–dinner principle', a classic informal model predicting that prey should be in some sense ahead in this arms race, since prey are running for their lives, while predators lag as they only run for their dinner. The model has undergone surprisingly little theoretical scrutiny. We derive analytical models that show coevolutionary outcomes do not always align with the life–dinner principle. Our results show that other important asymmetries can easily reverse the outcome, especially the rare-enemy principle: predators are usually outnumbered by their prey, sometimes substantially (trophic asymmetry), which can make selection on prey relatively weak. We additionally show that the antagonists typically exhibit different evolutionary responses to a situation where both predator and prey start out as equally fast runners. Although predators sometimes become so efficient that attacks always succeed, attack success often reaches a stable intermediate value. We conclude that the life–dinner principle has some validity as a metaphor, but its effect is of an 'all else being equal' type, which is surprisingly easily overridden by other features of the evolutionary dynamics. [ABSTRACT FROM AUTHOR]

The colours of insects function in intraspecific communication such as sexual signalling, interspecific communication such as protection from predators, and in physiological processes, such as thermoregulation. The expression of melanin‐based colours is temperature‐dependent and thus likely to be impacted by a changing climate. However, it is unclear how climate change drives changes in body and wing colour may impact insect physiology and their interactions with conspecifics (e.g. mates) or heterospecific (e.g. predators or prey). The aim of this review is to synthesise the current knowledge of the consequences of climate‐driven colour change on insects. Here, we discuss the environmental factors that affect insect colours, and then we outline the adaptive mechanisms in terms of phenotypic plasticity and microevolutionary response. Throughout we discuss the impact of climate‐related colour change on insect physiology, and interactions with con‐and‐heterospecifics. [ABSTRACT FROM AUTHOR]

Host–parasite interactions are impacted by climate, which may result in variation of parasitism across landscapes and time. Understanding how parasitism varies across these spatio‐temporal scales is crucial to predicting how organisms will respond to and cope under a rapidly changing climate. Empirical work on how parasitism varies across climates is limited. Here, we examine the variation of parasitism across seasons and identify the likely climatic factors that explain this variation using Agriocnemis femina damselflies and Arrenurus water mite ectoparasites as a host–parasite study system. We assessed parasitism in a natural population in Sylhet, Bangladesh which is located in subtropical climate between 2021 and 2023. We calculated prevalence (proportion of infected individuals) and intensity (the number of parasites on an infected individual) of parasitism across different seasons. Parasite prevalence and intensity were greater during cooler seasons (autumn and winter) compared to hotter seasons (spring and summer). Mean temperature and precipitation were negatively correlated with parasite prevalence, whereas only mean precipitation was negatively correlated with parasite intensity. Tropical, subtropical and mediterranean regions are predicted to experience extreme climatic events (extreme temperature, less precipitation and frequent drought) as a consequence of anthropogenic climate change, and our finding suggests that this might alter patterns of parasitism in aquatic insects. [ABSTRACT FROM AUTHOR]

Aposematic prey advertise their unprofitability with conspicuous warning signals that are often composed of multiple color patterns. Many species show intraspecific variation in these patterns even though selection is expected to favor invariable warning signals that enhance predator learning. However, if predators acquire avoidance to specific signal components, this might relax selection on other aposematic traits and explain variability. Here, we investigated this idea in the aposematic moth Amata nigriceps that has conspicuous black and orange coloration. The size of the orange spots in the wings is highly variable between individuals, whereas the number and width of orange abdominal stripes remains consistent. We produced artificial moths that varied in the proportion of orange in the wings or the presence of abdominal stripes. We presented these to a natural avian predator, the noisy miner (Manorina melanocephala) , and recorded how different warning signal components influenced their attack decisions. When moth models had orange stripes on the abdomen, birds did not discriminate between different wing signals. However, when the stripes on the abdomen were removed, birds chose the model with smaller wing spots. In addition, we found that birds were more likely to attack moths with a smaller number of abdominal stripes. Together, our results suggest that bird predators primarily pay attention to the abdominal stripes of A. nigriceps, and this could relax selection on wing coloration. Our study highlights the importance of considering individual warning signal components if we are to understand how predation shapes selection on prey warning coloration. [ABSTRACT FROM AUTHOR]

Many prey species employ multiple defenses during interactions with predators. Multiple defenses can provide a selective advantage against a single predator at different stages of the interaction or attack, as well as against multiple predator types. However, the efficacy of multiple defenses both during different sequences of an attack and against multiple predator types, remains poorly understood. We measured and classified defensive traits used by five mimics (Müllerian and Batesian) of the myrmecomorphic golden mimicry complex and one non-mimetic species. We then performed predatory trials using two different predators that differed markedly in their body size, trophic specialization, and how they handle prey—one being an ant specialist (spider) and the other a generalist which avoided ants (skink). We identified 12 defensive traits and classified them into four groups (primary, chemical, mechanical, and behavioral), which were strongly correlated. Skinks were much less likely to attack and capture mimics than the ant-eating spider predators. Our results show that multiple defenses (five or six) were used against each predator. The defensive behaviors and features that were most effective against skinks included appendage waving and large body size, whereas the golden "shine" warning signal, large body size, cuticle thickness, and defensive gland size were most effective against spiders. Most defenses appeared to be predator-specific. We conclude that potential prey in the golden mimicry complex have been selected for multiple defenses because of their vulnerability to different predator types and consequently, the efficacy of some of these defenses likely represents a trade-off. [ABSTRACT FROM AUTHOR]

Prey seldom rely on a single type of antipredator defence, often using multiple defences to avoid predation. In many cases, selection in different contexts may favour the evolution of multiple defences in a prey. However, a prey may use multiple defences to protect itself during a single predator encounter. Such "defence portfolios" that defend prey against a single instance of predation are distributed across and within successive stages of the predation sequence (encounter, detection, identification, approach (attack), subjugation and consumption). We contend that at present, our understanding of defence portfolio evolution is incomplete, and seen from the fragmentary perspective of specific sensory systems (e.g., visual) or specific types of defences (especially aposematism). In this review, we aim to build a comprehensive framework for conceptualizing the evolution of multiple prey defences, beginning with hypotheses for the evolution of multiple defences in general, and defence portfolios in particular. We then examine idealized models of resource trade‐offs and functional interactions between traits, along with evidence supporting them. We find that defence portfolios are constrained by resource allocation to other aspects of life history, as well as functional incompatibilities between different defences. We also find that selection is likely to favour combinations of defences that have synergistic effects on predator behaviour and prey survival. Next, we examine specific aspects of prey ecology, genetics and development, and predator cognition that modify the predictions of current hypotheses or introduce competing hypotheses. We outline schema for gathering data on the distribution of prey defences across species and geography, determining how multiple defences are produced, and testing the proximate mechanisms by which multiple prey defences impact predator behaviour. Adopting these approaches will strengthen our understanding of multiple defensive strategies. [ABSTRACT FROM AUTHOR]