0000000000627183
AUTHOR
Rose Thorogood
Social learning within and across predator species reduces attacks on novel aposematic prey
Abstract To make adaptive foraging decisions, predators need to gather information about the profitability of prey. As well as learning from prey encounters, recent studies show that predators can learn about prey defences by observing the negative foraging experiences of conspecifics. However, predator communities are complex. While observing heterospecifics may increase learning opportunities, we know little about how social information use varies across predator species.Social transmission of avoidance among predators also has potential consequences for defended prey. Conspicuous aposematic prey are assumed to be an easy target for naïve predators, but this cost may be reduced if multipl…
Can video playback provide social information for foraging blue tits?
Video playback is becoming a common method for manipulating social stimuli in experiments. Parid tits are one of the most commonly studied groups of wild birds. However, it is not yet clear if tits respond to video playback or how their behavioural responses should be measured. Behaviours may also differ depending on what they observe demonstrators encountering. Here we present blue tits (Cyanistes caeruleus) videos of demonstrators discovering palatable or aversive prey (injected with bittertasting Bitrex) from coloured feeding cups. First we quantify variation in demonstrators’ responses to the prey items: aversive prey provoked high rates of beak wiping and head shaking. We then show tha…
Social transmission in the wild can reduce predation pressure on novel prey signals
Funder: Suomen Kulttuurirahasto (Finnish Cultural Foundation); doi: https://doi.org/10.13039/501100003125
The effect of social information from live demonstrators compared to video playback on blue tit foraging decisions.
Video playback provides a promising method to study social interactions, and the number of video playback experiments has been growing in recent years. Using videos has advantages over live individuals as it increases the repeatability of demonstrations, and enables researchers to manipulate the features of the presented stimulus. How observers respond to video playback might, however, differ among species, and the efficacy of video playback should be validated by investigating if individuals’ responses to videos are comparable to their responses to live demonstrators. Here, we use a novel foraging task to compare blue tits’ (Cyanistes caeruleus) responses to social information from a live …
The evolution and ecology of multiple antipredator defences
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 speci…
Seeing red? Colour biases of foraging birds are context dependent.
Funder: Suomen Kulttuurirahasto; doi: http://dx.doi.org/10.13039/501100003125
Predators' consumption of unpalatable prey does not vary as a function of bitter taste perception
Many prey species contain defensive chemicals that are described as tasting bitter. Bitter taste perception is, therefore, assumed to be important when predators are learning about prey defenses. However, it is not known how individuals differ in their response to bitter taste, and how this influences their foraging decisions. We conducted taste perception assays in which wild-caught great tits (Parus major) were given water with increasing concentrations of bitter-tasting chloroquine diphosphate until they showed an aversive response to bitter taste. This response threshold was found to vary considerably among individuals, ranging from chloroquine concentrations of 0.01 mmol/L to 8 mmol/L.…
The signal detection problem of aposematic prey revisited: integrating prior social and personal experience
Ever since Alfred R. Wallace suggested brightly coloured, toxic insects warn predators about their unprofitability, evolutionary biologists have searched for an explanation of how these aposematic prey evolve and are maintained in natural populations. Understanding how predators learn about this widespread prey defence is fundamental to addressing the problem, yet individuals differ in their foraging decisions and the predominant application of associative learning theory largely ignores predators' foraging context. Here we revisit the suggestion made 15 years ago that signal detection theory provides a useful framework to model predator learning by emphasizing the integration of prior inf…
Social transmission of avoidance among predators facilitates the spread of novel prey.
Warning signals are an effective defence strategy for aposematic prey, but only if they are recognized by potential predators. If predators must eat prey to associate novel warning signals with unpalatability, how can aposematic prey ever evolve? Using experiments with great tits (Parus major) as predators, we show that social transmission enhances the acquisition of avoidance by a predator population. Observing another predator’s disgust towards tasting one novel conspicuous prey item led to fewer aposematic than cryptic prey being eaten for the predator population to learn. Despite reduced personal encounters with unpalatable prey, avoidance persisted and increased over subsequent trials.…
Social information use by predators : expanding the information ecology of prey defences
Social information use is well documented across the animal kingdom, but how it influences ecological and evolutionary processes is only just beginning to be investigated. Here we evaluate how social transmission may influence species interactions and potentially change or create novel selection pressures by focusing on predator-prey interactions, one of the best studied examples of species coevolution. There is extensive research into how prey can use social information to avoid predators, but little synthesis of how social transmission among predators can influence the outcome of different stages of predation. Here we review evidence that predators use social information during 1) encount…
Reed Warbler Hosts Do Not Fine-Tune Mobbing Defenses During the Breeding Season, Even When Cuckoos Are Rare
Hosts of brood parasitic cuckoos often employ mobbing attacks to defend their nests and, when mobbing is costly, hosts are predicted to adjust their mobbing to match parasitism risk. While evidence exists for fine-tuned plasticity, it remains unclear why mobbing does not track larger seasonal changes in parasitism risk. Here we test a possible explanation from parental investment theory: parents should defend their current brood more intensively as the opportunity to replace it declines (re-nesting potential), and therefore “counteract” any apparent seasonal decline to match parasitism risk. We take advantage of mobbing experiments conducted at two sites where reed warblers (Acrocephalus sc…
Social information use about novel aposematic prey is not influenced by a predator’s previous experience with toxins
Aposematism is an effective antipredator strategy. However, the initial evolution and maintenance of aposematism are paradoxical because conspicuous prey are vulnerable to attack by naive predators. Consequently, the evolution of aposematic signal mimicry is also difficult to explain. The cost of conspicuousness can be reduced if predators learn about novel aposematic prey by observing another predator's response to that same prey. On the other hand, observing positive foraging events might also inform predators about the presence of undefended mimics, accelerating predation on both mimics and their defended models. It is currently unknown, however, how personal and social information combi…
Supplementary tables of model estimates from The signal detection problem of aposematic prey revisited: integrating prior social and personal experience
Ever since Alfred R. Wallace suggested brightly coloured, toxic insects warn predators about their unprofitability, evolutionary biologists have searched for an explanation of how these aposematic prey evolve and are maintained in natural populations. Understanding how predators learn about this widespread prey defence is fundamental to addressing the problem, yet individuals differ in their foraging decisions and the predominant application of associative learning theory largely ignores predators' prior experience. Here we revisit the suggestion made almost 15 years ago that signal detection theory (SDT) provides a useful framework to model predator learning by emphasizing the integration …
Research data supporting "Social information use about novel aposematic prey is not influenced by a predator’s previous experience with toxins"
This data is from the experiment investigating social avoidance learning in wild-caught great tits, conducted at Konnevesi Research Station in Central Finland during winter 2017. Sheet 1 (���main data���) contains data from the main avoidance learning experiment, including individual attributes (sex, age, weight etc.), experimental treatments and individuals��� foraging choices in the learning trials. Sheet 2 (���preference test���) contains data from the initial preference test of the symbols that were used in the experiment, and Sheet 3 (���visibility test���) data from the initial visibility test of the same symbols.
Research data supporting "Social learning within and across predator species reduces attacks on novel aposematic prey"
This data is from the experiment that investigated how wild-caught blue tits and great tits use conspecific and heterospecific information about unpalatable prey, published at the Journal of Animal Ecology (2020). The experiment was conducted at the Konnevesi Research Station from October to December 2017. Sheet 1 (“Main experiment”) contains data from the main avoidance learning experiment. Sheets 2 (“Symbol preference blue tits”) and 3 ("Symbol visibility blue tits") contain data of blue tits' symbol choices in initial preference and visibility tests.
Data from: Predators’ consumption of unpalatable prey does not vary as a function of bitter taste perception
Many prey species contain defensive chemicals that are described as tasting bitter. Bitter taste perception is therefore assumed to be important when predators are learning about prey defenses. However, it is not known how individuals differ in their response to bitter taste, and how this influences their foraging decisions. We conducted taste perception assays in which wild-caught great tits (Parus major) were given water with increasing concentrations of bitter-tasting chloroquine diphosphate until they showed an aversive response to bitter taste. This response threshold was found to vary considerably among individuals, ranging from chloroquine concentrations of 0.01 mmol/l to 8 mmol/l. W…
Can dietary specialization be used for conservation? Foraging and ecological restoration by hihi (Notiomystis cincta)
While it is now widely acknowledged that individuals within species behave differently even when faced with similar environmental challenges, few studies have identified how this variation arises and what impacts it has on the environment itself. This is critical to consider given that the ecosystems species inhabit are often under threat. The hihi (Notiomystis cincta), a threatened New Zealand passerine and important pollinator of native plants, provides an excellent model for investigating the causes and consequences of specialization through the lens of foraging. Following near-extinction around 1890, hihi have been reintroduced to several island and mainland sites, but habitat suitabili…