It’s a Matter of Taste: Avian Predators Taste Reject Mimetic Prey in Relation to Signal Reliability

2021 ◽  
Author(s):  
Ruchuan He ◽  
Craig Barnett ◽  
Emilio Pagani-Núñez ◽  
Eben Goodale
Keyword(s):  
Field Experiment ◽  
Associative Learning ◽  
Frequency Ratio ◽  
Visual Signals ◽  
Warning Signals ◽  
Signal Reliability ◽  
Quinine Sulphate ◽  
Avian Predators ◽  
Prey System ◽  
First Time

Abstract Aposematic organisms defend themselves through various means to increase their unprofitability to predators which they advertise with conspicuous warning signals. Predators learn to avoid aposematic prey through associative learning that leads to lower predation. However, when these visual signals become unreliable (e.g., through automimicry or Batesian mimicry), predators may switch from using visual signals to taste sampling prey to choose among them (‘go-slow’ behaviour). In this experiment, we tested this possibility in a field experiment where we released a total of 9600 mealworm prey of two types: (i) undefended prey (injected with water) and (ii) model-mimics (injected with either quinine sulphate [models] or water [mimics]). Prey were deployed at 12 sites, each with a mimic frequency ratio between 0 to 1, at 0.2 intervals. We found that taste rejection peaked at moderate mimic frequencies (0.4 and 0.6), supporting the idea that taste sampling and rejection of prey is related to signal reliability and predator uncertainty. This is the first time that taste-rejection has been shown to be related to the reliability of prey signals in a mimetic prey system.

Social interactions in a neotropical stream frog reveal a complex repertoire of visual signals and the use of multimodal communication

Behaviour ◽  
2014 ◽  
Vol 151 (6) ◽  
pp. 719-739 ◽  
Author(s):  
Vinícius Matheus Caldart ◽  
Samanta Iop ◽  
Sonia Zanini Cechin
Keyword(s):  
Social Interactions ◽  
Ecological Factors ◽  
Acoustic Signals ◽  
Multimodal Communication ◽  
Visual Signals ◽  
Agonistic Interactions ◽  
Intraspecific Communication ◽  
Neotropical Stream ◽  
First Time

Visual communication has evolved independently in several families of frogs and is complex in diurnal stream frogs. In addition to isolated visual and acoustic signals, some species may emit multimodal displays characterized by the association of these signals. Through the analysis of focal recordings obtained in situ in southern Brazil, we investigated the visual and multimodal communication in the diurnal stream frog Crossodactylus schmidti. We found a complex visual repertoire of nine signals used in intraspecific communication, of which the signal Both legs kicking was described for the first time. Males, females and juveniles emitted visual signals, but males had a larger repertoire and used most signals in agonistic interactions. The four most common visual signals, Toe flagging, Limb lifting, Body jerking and Running-jumping, were emitted predominantly upon rocks in the stream bed. The emission of isolated visual and acoustic signals, as well as audiovisual displays with simultaneous or temporally coupled components, demonstrates that the communication in C. schmidti is complex and that the multimodal displays may have different functions. We discuss the historical, behavioural, ecological factors which may have influenced the evolution of the visual repertoire of C. schmidti, and how the ritualization of derived activities similar to visual signals may have led to the evolution of part of the repertoire. This study provides novel results on visual and multimodal communication for the genus Crossodactylus and demonstrates that C. schmidti represents an appropriate model for studies of complex displays.

Associative learning in hatchlings of the lizard Calotes versicolor: taste and colour discrimination

2010 ◽  
Vol 31 (4) ◽  
pp. 475-481 ◽  
Author(s):  
Bhagyashri Shanbhag ◽  
Veena Ammanna ◽  
Srinivas Saidapur
Keyword(s):  
Associative Learning ◽  
Colour Discrimination ◽  
Learning Behaviour ◽  
New Born ◽  
Silk Moth ◽  
Calotes Versicolor ◽  
Taste Discrimination ◽  
The One ◽  
First Time

AbstractThe study examined whether newly born hatchlings of Calotes versicolor discriminate between tastes and exhibit associative learning. The one-day-old hatchlings ate 2nd instar silk-moth larvae (prey) placed in non-painted, orange or green dishes without any bias for the background colour. They ate sucrose coated sweetened prey, but given a choice preferred natural larvae. But they spat bitter tasting chloroquine phosphate (CP)-coated prey and exhibited aversion behaviour. Hatchlings fed on natural larvae from non-painted or orange dishes for 10 days preferred food from the dish to which they were accustomed when choice of both colour backgrounds was given suggesting they also remember different tastes in association with background colour cues. Upon swapping sucrose and CP-coated prey/dish colours the hatchlings were misled and they attempted to eat from the dishes to which they were accustomed prior to the trials regardless of whether food/prey was coated with sucrose or CP. However, bitter prey was immediately spat and aversion behaviour followed. The study shows for the first time, taste discrimination and associative learning behaviour in new-born lizard hatchlings.

scholarly journals Visual Warning Signals Optimized for Human Perception: What the Eye Sees Fastest

2005 ◽  
Vol 2 (1) ◽  
pp. 45-52 ◽  
Author(s):  
B. L. Gros ◽  
D. S. Greenhouse ◽  
T. E. Cohn
Keyword(s):  
Human Perception ◽  
Warning Signal ◽  
Sensitivity Function ◽  
Visual Signals ◽  
Temporal Contrast ◽  
Warning Signals ◽  
Moving Stimuli ◽  
Classic Problem ◽  
Speed Advantage ◽  
Spatio Temporal

This study aimed to answer the question of how to design a visual warning signal that is most easily seen and produces the quickest reaction time. This is a classic problem of bionic optimization—if one knows the properties of the receiver one can most easily find a suitable solution. Because the peak of the spatio-temporal contrast sensitivity function of the human visual system occurs at non-zero spatial and temporal frequencies, it is likely that movement enhances the detectability of threshold visual signals. Earlier studies employing extended drifting sinewave gratings bear out this prediction. We have studied the ability of human observers to detect threshold visual signals for both moving and stationary stimuli. We used discrete, localized signals such as might be employed in aerospace or automotive warning signal displays. Moving stimuli show a superior detectability to non-moving stimuli of the same integrated energy. Moving stimuli at threshold detectability are seen faster than non-moving threshold stimuli. Under some conditions the speed advantage is over 0.25 seconds. Similar advantages have also been shown to occur for suprathreshold signals.

scholarly journals How do predators generalize warning signals in simple and complex prey communities? Insights from a videogame

2020 ◽  
Vol 287 (1921) ◽  
pp. 20200014
Author(s):  
Mónica Arias ◽  
John W. Davey ◽  
Simon Martin ◽  
Chris Jiggins ◽  
Nicola Nadeau ◽  
...  
Keyword(s):  
Natural Populations ◽  
Computer Game ◽  
Butterfly Species ◽  
Warning Signals ◽  
Identical Stimulus ◽  
Toxic Species ◽  
Avian Predators ◽  
Colour Patterns

The persistence of distinct warning signals within and between sympatric mimetic communities is a puzzling evolutionary question because selection favours convergence of colour patterns among toxic species. Such convergence is partly shaped by predators' reaction to similar but not identical stimulus (i.e. generalization behaviour), and generalization by predators is likely to be shaped by the diversity of local prey. However, studying generalization behaviour is generally limited to simple variations of prey colour patterns. Here, we used a computer game played by humans as surrogate predators to investigate generalization behaviours in simple (4 morphs) and complex (10 morphs) communities of unprofitable (associated with a penalty) and profitable butterflies. Colour patterns used in the game are observed in the natural populations of unprofitable butterfly species such as Heliconius numata . Analyses of 449 game participants' behaviours show that players avoided unprofitable prey more readily in simple than in complex communities. However, generalization was observed only in players that faced complex communities, enhancing the protection of profitable prey that looked similar to at least one unprofitable morph. Additionally, similarity among unprofitable prey also reduced attack rates only in complex communities. These results are consistent with previous studies using avian predators but artificial colour patterns and suggest that mimicry is more likely to evolve in complex communities where increases in similarity are more likely to be advantageous.

Foraging and associative learning of visual signals in a parasitic wasp

2008 ◽  
Vol 11 (3) ◽  
pp. 525-533 ◽  
Author(s):  
Patrice Lucchetta ◽  
Carlos Bernstein ◽  
Marc Théry ◽  
Claudio Lazzari ◽  
Emmanuel Desouhant
Keyword(s):  
Associative Learning ◽  
Parasitic Wasp ◽  
Visual Signals

scholarly journals Effect of tree harvest intervals on the removal of heavy metals from a contaminated soil in a field experiment

2018 ◽  
Vol 64 (No. 3) ◽  
pp. 132-137 ◽  
Author(s):  
Kubátová Pavla ◽  
Száková Jiřina ◽  
Břendová Kateřina ◽  
Kroulíková-Vondráčková Stanislava ◽  
Drešlová Markéta ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Field Experiment ◽  
Metal Concentration ◽  
Contaminated Soil ◽  
Metal Removal ◽  
Salix Viminalis ◽  
Short Rotation ◽  
Removal Of Heavy Metals ◽  
Harvest Intervals ◽  
First Time

Four clones of short rotation coppice (SRCs) were investigated for phytoextraction of soil contaminated by risk elements (REs), especially Cd, Pb and Zn. As a main experimental factor, the influence of rotation length on the removal of REs was assessed. The field experiment with two Salix clones (S1 – (Salix schwerinii × Salix viminalis) ×S. viminalis; S2 – S. × smithiana) and two Populus clones (P1 – Populus maximowiczii × Populus nigra; P2 – P. nigra) was established in April 2008 on moderately contaminated soil. For the first time, all clones were harvested in February 2012 (2012<sub>4y</sub>) after 4 years. Subsequently each plot was equally split into halves. The first half of the SRC clones was harvested in February 2014 after 2 years (2014<sub>2y</sub>) and again it was harvested in February 2016 after further 2 years (2016<sub>2y</sub>). The second half was harvested in February 2016 after 4 years (2016<sub>4y</sub>). The results showed that the biomass production for the second 4-year harvest period was significantly higher for all clones but the metal concentration was lower in the mentioned period. 4-year rotation seems to be more advantageous for the phytoextraction than two 2-year rotations. The highest metal removal presented by remediation factors (RFs) per 4 years for Cd (6.39%) and for Zn (2.55%) were found for S2 in the harvest 2016<sub>4y</sub> treatment. Removal of Pb was the highest by P1 clone with very low RF per 4 years (0.04%). Longer rotation is also economically superior.

scholarly journals Limpet disturbance effects on barnacle recruitment are related to recruitment intensity but not recruit size

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9190
Author(s):  
Julius A. Ellrich ◽  
Takefumi Yorisue ◽  
Kyosuke Momota
Keyword(s):  
Field Experiment ◽  
Pacific Coast ◽  
Demographic Variable ◽  
Balanus Glandula ◽  
Disturbance Effects ◽  
The Pacific ◽  
Population Establishment ◽  
First Time ◽  
High Recruitment ◽  
Chthamalus Dalli

Intertidal limpets are important grazers along rocky coastlines worldwide that not only control algae but also influence invertebrates such as common barnacles. For instance, grazing limpets ingest settling barnacle cyprid larvae (hereafter cyprids) and push cyprids and barnacle recruits off the substrate. Such limpet disturbance effects (LDEs) can limit barnacle recruitment, a key demographic variable affecting barnacle population establishment and persistence. In this study, we examined limpet (Lottia cassis) disturbance to barnacle (Chthamalus dalli, Balanus glandula) recruitment on the Pacific coast of Hokkaido, Japan, as information on limpet-barnacle interactions from this region is missing. We investigated, for the first time, whether barnacle size and recruitment intensity influence LDEs on barnacle recruitment. Small barnacles may be less susceptible to LDEs than larger barnacles, because small size may reduce the propbability of limpet disturbance. Moreover, recruitment intensity can influence LDEs, as high recruitment can compensate for LDEs on barnacle recruitment density. In Hokkaido, C. dalli cyprids are smaller than B. glandula cyprids, and C. dalli recruitment is higher than B. glandula recruitment. Thus, we hypothesized that LDEs on C. dalli recruitment would be weaker than those on B. glandula recruitment. To test our hypothesis, we conducted a field experiment during which we manipulated limpet presence/absence on the interior surfaces of ring-shaped cages. After four weeks, we measured barnacle recruitment and recruit size on the interior surfaces of the cages and found negative LDEs on C. dalli and B. glandula recruitment and recruit size. As hypothesized, the LDEs on C. dalli recruitment were weaker than the LDEs on B. glandula recruitment. Additionally, C. dalli recruits were smaller than B. glandula recruits. However, the LDEs on C. dalli recruit size were as strong as the LDEs on B. glandula recruit size, indicating that the smaller C. dalli recruits are not less susceptible to LDEs than B. glandula recruits. Since C. dalli recruitment was higher than B. glandula recruitment, we propose that the higher C. dalli recruitment compensated for the LDEs on C. dalli recruitment. Our findings indicate that the detected differences in LDEs on barnacle recruitment are related to barnacle recruitment intensity but not recruit size.

scholarly journals Geographic mosaic of selection by avian predators on hindwing warning colour in a polymorphic aposematic moth

2020 ◽  
Author(s):  
Katja Rönkä ◽  
Janne K. Valkonen ◽  
Ossi Nokelainen ◽  
Bibiana Rojas ◽  
Swanne Gordon ◽  
...  
Keyword(s):  
Large Scale ◽  
Avian Community ◽  
Warning Coloration ◽  
Warning Signals ◽  
Geographic Mosaic ◽  
Frequency Dependent Selection ◽  
Avian Predators ◽  
Morph Frequency ◽  
Predator Community ◽  
Positive Frequency

AbstractWarning signals are predicted to develop signal monomorphism via positive frequency-dependent selection (+FDS) albeit many aposematic systems exhibit signal polymorphism. To understand this mismatch, we conducted a large-scale predation experiment in four locations, among which the frequencies of hindwing warning coloration of aposematic Arctia plantaginis differ. Here we show that selection by avian predators on warning colour is predicted by local morph frequency and predator community composition. We found +FDS to be strongest in monomorphic Scotland, and in contrast, lowest in polymorphic Finland, where different predators favour different male morphs. +FDS was also found in Georgia, where the predator community was the least diverse, whereas in the most diverse avian community in Estonia, hardly any models were attacked. Our results support the idea that spatial variation in predator and prey communities alters the strength or direction of selection on warning signals, thus facilitating a geographic mosaic of selection.

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