Search results for "mimikry"

Biased predation could promote convergence yet maintain diversity within Müllerian mimicry rings of Oreina leaf beetles.

2019

Mullerian mimicry is a classic example of adaptation, yet Muller's original theory does not account for the diversity often observed in mimicry rings. Here, we aimed to assess how well classical Mullerian mimicry can account for the colour polymorphism found in chemically defended Oreina leaf beetles by using field data and laboratory assays of predator behaviour. We also evaluated the hypothesis that thermoregulation can explain diversity between Oreina mimicry rings. We found that frequencies of each colour morph were positively correlated among species, a critical prediction of Mullerian mimicry. Predators learned to associate colour with chemical defences. Learned avoidance of the green…

Ecological conditions alter cooperative behaviour and its costs in a chemically defended sawfly

2018

The evolution of cooperation and social behaviour is often studied in isolation from the ecology of organisms. Yet, the selective environment under which individuals evolve is much more complex in nature, consisting of ecological and abiotic interactions in addition to social ones. Here, we measured the life-history costs of cooperative chemical defence in a gregarious social herbivore, Diprion pini pine sawfly larvae, and how these costs vary under different ecological conditions. We ran a rearing experiment where we manipulated diet (resin content) and attack intensity by repeatedly harassing larvae to produce a chemical defence. We show that forcing individuals to allocate more to coope…

Can multiple-model mimicry explain warning signal polymorphism in the wood tiger moth, Arctia plantaginis (Lepidoptera: Erebidae)?

2018

Social information use about novel aposematic prey is not influenced by a predator’s previous experience with toxins

2019

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…

Why aren't warning signals everywhere? : On the prevalence of aposematism and mimicry in communities

2021

Warning signals are a striking example of natural selection present in almost every ecological community - from Nordic meadows to tropical rainforests, defended prey species and their mimics ward off potential predators before they attack. Yet despite the wide distribution of warning signals, they are relatively scarce as a proportion of the total prey available, and more so in some biomes than others. Classically, warning signals are thought to be governed by positive density-dependent selection, i.e. they succeed better when they are more common. Therefore, after surmounting this initial barrier to their evolution, it is puzzling that they remain uncommon on the scale of the community. He…

Evaluating the potential for evolutionary mismatch in Batesian mimics: A case study in the endangered smooth snake (Coronella austriaca)

2018

Many harmless organisms gain a survival advantage by mimicking venomous species. This is the case of the endangered smooth snake (Coronella austriaca), which mimics venomous vipers. Although this may protect the smooth snake against most of its natural predators, it may render them at greater risk of mortality from humans, who are more inclined to kill species, such as vipers, that they consider dangerous. This may cause an evolutionary mismatch, whereby humans may counteract the natural advantage of mimicry. We explore this possibility of evaluating the willingness of humans to kill smooth snakes versus the adder (Vipera berus), as well as their ability to discern them in the Åland Islands…

‘World-class’ fantasies : A neocolonial analysis of international branch campuses

2018

In this article, we build on postcolonial studies and discourse analytical research exploring how the ‘world-class’ discourse as an ideology and a fantasy structures neocolonial relations in international branch campuses. We empirically examine how international branch campuses reproduce the fantasy of being so-called world-class operators and how the onsite faculty members identify with or resist this world-class fantasy through mimicry. Our research material originates from fieldwork conducted in business-school international branch campuses operating in the United Arab Emirates. Our findings show the ambivalent nature of mimicry towards the world-class fantasy to include both compliance …

Experiments on defensive mimicry : linkages between predator behaviour and qualities of the prey

2006

Myrkylliset tai pahanmakuiset lajit voivat puolustautua saalistajia vastaan mainostamalla syömäkelvottomuuttaan näkyvin varoitussignaalein kuten värein. Saalistajien on tavallisesti opittava kokeilemalla välttämään pahoja ja signaloivia eli aposemaattisia lajeja. Varoitussignaaleja myös jäljitellään luonnossa. Batesin mimikria on ilmiö, jossa syömäkelpoinen matkijalaji suojautuu saalistajilta jäljittelemällä aposemaattisen mallilajin signaalia. Müllerin mimikriassa taas aposemaattiset ja ”näköislajit” käyttävät keskenään samanlaisia signaaleja.Loisteliaimmat esimerkit mimikriasta ovat trooppisia perhosia. Väitöskirjassaan Ihalainen tutki, miten samanlainen signalointi ja maku vaikuttavat sa…

The Effect of Predator Population Dynamics on Batesian Mimicry Complexes.

2022

Understanding Batesian mimicry is a classic problem in evolutionary biology. In Batesian mimicry, a defended species (the model) is mimicked by an undefended species (the mimic). Prior theories have emphasized the role of predator behavior and learning as well as evolution in model-mimic complexes but have not examined the role of population dynamics in potentially governing the relative abundances and even persistence of model-mimic systems. Here, we examined the effect of the population dynamics of predators and alternative prey on the prevalence of warning-signaling prey composed of models and mimics. Using optimal foraging theory and signal detection theory, we found that the inclusion …

Evolution of signal diversity: predator-prey interactions and the maintenance of warning colour polymorphism in the wood tiger moth Arctia plantaginis

2017

Aposematic organisms avoid predation by advertising defences with warning signals. The theory of aposematism predicts warning signal uniformity, yet variation in warning coloration is widespread. The chemically defended wood tiger moth Arctia plantaginis shows both geographic variation and local polymorphism in warning coloration. In this thesis, I studied whether predation by local avian predators is driving the evolution of wood tiger moth warning colours. The close relatives of the wood tiger moth designated here to genus Arctia do not show similar colour polymorphism. The wood tiger moth is thus apparently under evolutionary radiation and provides a natural laboratory for observing curr…