scholarly journals Predation by avian predators may have initiated the evolution of myrmecomorph spiders

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Petr Veselý ◽  
Juraj Dobrovodský ◽  
Roman Fuchs
Keyword(s):  
Predator Avoidance ◽  
Selective Pressure ◽  
Parus Major ◽  
Avian Predators ◽  
Invertebrate Predators

AbstractMyrmecomorphy is a strategy utilized by a variety of species, among which spiders are the most common. It is supposed that myrmecomorphy tends to be selected by predator avoidance of preying on ants rather than by blind ant workers. To date, this hypothesis has been tested mainly on invertebrate predators (mantises and spiders). We are the first to test whether an imperfect myrmecomorph spider (Phrurolithus festivus) gains protection against avian predators (wild adult great tits—Parus major) through its appearance. In a set of preferential trials, we showed that the ant model and the myrmecomorph spider are equally well protected against attack, though the attacked myrmecomorphs are usually eaten. This suggests that the mimicry of the myrmecomorph spiders is effective against avian predators and works in a Batesian manner. In this study, we have provided evidence toward the evolution of myrmecomorphy in response to selective pressure elicited by visually-oriented predators like birds.

Avian predators avoid attacking artificial aposematic millipedes in Brazilian Atlantic Forest

2016 ◽  
Vol 33 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Luiz F. M. Iniesta ◽  
Pedro Ratton ◽  
Tadeu J. Guerra
Keyword(s):  
Atlantic Forest ◽  
Predator Avoidance ◽  
Selective Pressure ◽  
Natural Habitat ◽  
Neotropical Forests ◽  
Average Percentage ◽  
Chemical Defences ◽  
Avian Predators ◽  
Colouration Pattern

Abstract:Avian predators may represent an important selective pressure favouring the evolution of aposematic colouration in millipedes that present chemical defences. However, the role of their warning colouration in predator avoidance remains poorly explored under field conditions, especially in Neotropical forests. Thus, to evaluate the hypothesis of the predator avoidance, we conducted a factorial experiment utilizing artificial replicas of millipedes constructed from plasticine and placed in the natural habitat of Odontopeltis aleijadinho (Polydesmida, Chelodesmidae), an Atlantic Forest endemic aposematic millipede. We assessed patterns of attack to aposematic and non-aposematic replicas applied with repugnant fluid extracted from living millipedes and two control treatments, distributed as a total of 300 replicas exposed for 48 h on the forest floor. The average percentage of replicas attacked was nearly 10-fold higher on those non-aposematic control replicas (13.3% ± 3.3%) than on aposematic replicas (1.3% ± 0.9%). In 24 replicas attacked by avian predators, no effect of millipede repugnant fluid was found, but the effect of colouration pattern was statistically significant. Our data support the hypothesis that a warning colouration pattern involving yellow spots symmetrically distributed along the millipede body can mediate avian predator avoidance.

scholarly journals Defense against predators incurs high reproductive costs for the aposematic moth Arctia plantaginis

2020 ◽  
Vol 31 (3) ◽  
pp. 844-850
Author(s):  
Carita Lindstedt ◽  
Kaisa Suisto ◽  
Emily Burdfield-Steel ◽  
Anne E Winters ◽  
Johanna Mappes
Keyword(s):  
Chemical Defense ◽  
Reproductive Output ◽  
Defensive Secretion ◽  
Reproductive Costs ◽  
Heritable Variation ◽  
White Males ◽  
Avian Predators ◽  
Invertebrate Predators ◽  
Color Morphs ◽  
Tiger Moth

Abstract To understand how variation in warning displays evolves and is maintained, we need to understand not only how perceivers of these traits select color and toxicity but also the sources of the genetic and phenotypic variation exposed to selection by them. We studied these aspects in the wood tiger moth Arctia plantaginis, which has two locally co-occurring male color morphs in Europe: yellow and white. When threatened, both morphs produce defensive secretions from their abdomen and from thoracic glands. Abdominal fluid has shown to be more important against invertebrate predators than avian predators, and the defensive secretion of the yellow morph is more effective against ants. Here, we focused on the morph-linked reproductive costs of secretion of the abdominal fluid and quantified the proportion of phenotypic and genetic variation in it. We hypothesized that, if yellow males pay higher reproductive costs for their more effective aposematic display, the subsequent higher mating success of white males could offer one explanation for the maintenance of the polymorphism. We first found that the heritable variation in the quantity of abdominal secretion was very low (h2 = 0.006) and the quantity of defensive secretion was not dependent on the male morph. Second, deploying the abdominal defensive secretion decreased the reproductive output of both color morphs equally. This suggests that potential costs of pigment production and chemical defense against invertebrates are not linked in A. plantaginis. Furthermore, our results indicate that environmentally induced variation in chemical defense can alter an individual’s fitness significantly.

scholarly journals Out in the open: behavior’s effect on predation risk and thermoregulation by aposematic caterpillars

2020 ◽  
Vol 31 (4) ◽  
pp. 1031-1039 ◽  
Author(s):  
Matthew E Nielsen ◽  
Johanna Mappes
Keyword(s):  
Predation Risk ◽  
Predator Avoidance ◽  
Parus Major ◽  
Black Body ◽  
Stabilizing Selection ◽  
Warning Coloration ◽  
Small Patch ◽  
Potential Explanation ◽  
Aposematic Coloration ◽  
Tiger Moth

Abstract Warning coloration should be under strong stabilizing selection but often displays considerable intraspecific variation. Opposing selection on color by predators and temperature is one potential explanation for this seeming paradox. Despite the importance of behavior for both predator avoidance and thermoregulation, its role in mediating selection by predators and temperature on warning coloration has received little attention. Wood tiger moth caterpillars, Arctia plantaginis, have aposematic coloration, an orange patch on the black body. The size of the orange patch varies considerably: individuals with larger patches are safer from predators, but having a small patch is beneficial in cool environments. We investigated microhabitat preference by these caterpillars and how it interacted with their coloration. We expected caterpillar behavior to reflect a balance between spending time exposed to maximize basking and spending time concealed to avoid detection by predators. Instead, we found that caterpillars preferred exposed locations regardless of their coloration. Whether caterpillars were exposed or concealed had a strong effect on both temperature and predation risk, but caterpillars in exposed locations were both much warmer and less likely to be attacked by a bird predator (great tits, Parus major). This shared optimum may explain why we observed so little variation in caterpillar behavior and demonstrates the important effects of behavior on multiple functions of coloration.

scholarly journals Transparency, a better camouflage than crypsis in cryptically coloured moths

2019 ◽  
Author(s):  
Mónica Arias ◽  
Marianne Elias ◽  
Christine Andraud ◽  
Serge Berthier ◽  
Doris Gomez
Keyword(s):  
Selective Pressure ◽  
Future Studies ◽  
Animal Body ◽  
Avian Predators ◽  
Strong Selective Pressure ◽  
Potential Benefits ◽  
Living Organisms ◽  
Transparent Windows

AbstractPredation is a ubiquitous and strong selective pressure on living organisms. Transparency is a predation defence widespread in water but rare on land. Some Lepidoptera display transparent patches combined with already cryptic opaque patches. While transparency has recently been shown to reduce detectability in conspicuous prey, we here test whether transparency decreases detectability in already cryptically-coloured terrestrial prey, by conducting field predation experiments with free avian predators and artificial moths. We monitored and compared survival of a fully opaque grey artificial form (cryptic), a form including transparent windows and a wingless artificial butterfly body. Survival of the transparent forms was similar to that of wingless bodies and higher than that of fully opaque forms, suggesting a reduction of detectability conferred by transparency. This is the first evidence that transparency decreases detectability in cryptic terrestrial prey. Future studies should explore the organisation of transparent and opaque patches on the animal body and their interplay on survival, as well as the costs and other potential benefits associated to transparency on land.

Gregariousness as a defence strategy of moderately defended prey: experiments with Pyrrhocoris apterus and avian predators

Behaviour ◽  
2014 ◽  
Vol 151 (11) ◽  
pp. 1617-1640 ◽  
Author(s):  
Kateřina Hotová Svádová ◽  
Alice Exnerová ◽  
Pavel Štys
Keyword(s):  
Avoidance Training ◽  
Chemical Defence ◽  
Parus Major ◽  
Learning Criterion ◽  
Pyrrhocoris Apterus ◽  
Aposematic Coloration ◽  
Avian Predators ◽  
Defence Strategy ◽  
Prey Handling ◽  
Predator Behaviour

Aggregations in insects carry out diverse functions, and gregariousness may also act as an antipredatory strategy, especially when combined with warning signalling. Despite many studies focused on the antipredatory function of gregariousness, there are still aspects needing further investigation: What aspects of predator behaviour are affected by prey gregariousness? Which of the antipredatory effects of aggregations are linked with aposematic coloration, and which will also work for non-aposematic prey? Does gregariousness of an aposematic species affect its mimetic relationships? We have studied these topics in the firebug, Pyrrhocoris apterus (Heteroptera), an aposematic red-and-black true bug with moderate chemical defence. Firebugs alternate between solitary and gregarious lifestyles throughout the year. We used hand-reared great tits (Parus major) as naive predators, and subjected them to avoidance training with either solitarily or gregariously presented firebugs, followed by a memory test with solitary individuals. To test whether effects of gregariousness are specific for the aposematic firebugs, we tested another group of birds with brown-painted firebugs. Our results show that the gregarious lifestyle of the firebug is a part of its antipredatory strategy. Compared to solitary individuals, aggregations benefited in several ways, some exclusive for aposematic firebugs, others working irrespective of coloration. Aggregations induced greater innate wariness, leading to longer attack latencies and more cautious prey handling, including complete attack avoidance in some birds. Despite the fact that the birds mostly attacked only one or two individuals from an aggregation, they needed fewer trials to reach the avoidance-learning criterion than the birds learning to avoid solitary firebugs. Birds’ experience with firebug aggregations reduced the predation risk of subsequently encountered solitary individuals, as the birds hesitated longer before attacking a solitary firebug if their previous aversive experience had been with aggregations rather than with solitary individuals. Predators’ experience with firebug aggregations may compensate for the firebugs’ moderate chemical defence, and as a consequence, gregariousness may change the firebugs’ mimetic relationships with better defended red-and-black true bug species from quasi-Batesian to Müllerian.

Seaweed traits linked to wave exposure determine predator avoidance

2013 ◽  
Vol 483 ◽  
pp. 143-151 ◽  
Author(s):  
JD Long ◽  
L Porturas ◽  
E Jones ◽  
C Kwan ◽  
GC Trussell
Keyword(s):  
Predator Avoidance ◽  
Wave Exposure

Effects of marine reserves on predator-prey interactions in central California kelp forests

2020 ◽  
Vol 655 ◽  
pp. 139-155
Author(s):  
DC Yates ◽  
SI Lonhart ◽  
SL Hamilton
Keyword(s):  
Species Interactions ◽  
Size Structure ◽  
Marine Reserves ◽  
Mortality Rates ◽  
Kelp Forests ◽  
Negative Effects ◽  
Central California ◽  
Invertebrate Predators ◽  
Predatory Fishes ◽  
Density And Biomass

Marine reserves are often designed to increase density, biomass, size structure, and biodiversity by prohibiting extractive activities. However, the recovery of predators following the establishment of marine reserves and the consequent cessation of fishing may have indirect negative effects on prey populations by increasing prey mortality. We coupled field surveys with empirical predation assays (i.e. tethering experiments) inside and outside of 3 no-take marine reserves in kelp forests along the central California coast to quantify the strength of interactions between predatory fishes and their crustacean prey. Results indicated elevated densities and biomass of invertebrate predators inside marine reserves compared to nearby fished sites, but no significant differences in prey densities. The increased abundance of predators inside marine reserves translated to a significant increase in mortality of 2 species of decapod crustaceans, the dock shrimp Pandalus danae and the cryptic kelp crab Pugettia richii, in tethering experiments. Shrimp mortality rates were 4.6 times greater, while crab mortality rates were 7 times greater inside reserves. For both prey species, the time to 50% mortality was negatively associated with the density and biomass of invertebrate predators (i.e. higher mortality rates where predators were more abundant). Video analyses indicated that macro-invertivore fishes arrived 2 times faster to tethering arrays at sites inside marine reserves and began attacking tethered prey more rapidly. The results indicate that marine reserves can have direct and indirect effects on predators and their prey, respectively, and highlight the importance of considering species interactions in making management decisions.

Study of Alnus incana L. Moench fruit extract biologically active substances influence on resistance development in mls-resistant staphylococci skin isolates

2018 ◽  
Vol 22 (2) ◽  
pp. 263-266
Author(s):  
R.V. Kutsyk ◽  
O.I. Yurchyshyn
Keyword(s):  
Selective Pressure ◽  
Biological Response ◽  
Biologically Active Substances ◽  
Biologically Active ◽  
Alnus Incana ◽  
Fruit Extract ◽  
Antimicrobial Drugs ◽  
Resistance Development ◽  
Subinhibitory Concentrations ◽  
Active Substances

The emergence of microorganisms resistant strains is a natural biological response to the use of antimicrobial drugs that creates selective pressure, contributing to pathogens selection, survival and reproduction. The purpose of the investigation was to study the resistance development of staphylococci skin isolates to erythromycin and influence on it Alnus incana L. fruit extract subinhibitory concentrations. Development of resistance to erythromycin and influence on it Alnus incana L. fruit extract (extraction by 90% ethanol) subinhibitory concentrations were conducted with S epidermidis strains: sensitive and resistant to 14 and 15-membered macrolides. The study was carried out within 30 days by multiple consecutive passages of staphylococci test strains (concentration 1×107 CFU/ml) into test tubes containing broth and erythromycin ranging from 3 doubling dilutions above to doubling dilutions below the minimum inhibitory concentration. Statistical analysis of the results was carried out by one-and two-factor analysis of variance (ANOVA) and Microsoft Office Excel 2011. Rapid increase of resistance from 32 to 1024 μg/ml (F=34.2804; F> Fstand. max = 5.9874; p=0.0011) for S.epidermidis with a low level of resistance to 14 and 15-membered macrolides resistance to the erythromycine was observed. In the presence of Alnus incana L. fruit extract subinhibitory concentrations (¼ MIC), the initial MIC of erythromycin was decreased by 32 times to 1 μg/ml (F = 9.7497; F> Fstand. max = 5.9874; p = 0.0205). The sensitive strain after 30 passages did not develop resistance to erythromycin. Under the influence of erythromycin selective pressure, S.epidermidis strain with low initial level of MLS-resistance rapidly reaches a high-level resistance. Biologically active substances of the Alnus incana L. fruit extract significantly inhibit the resistance development in S. epidermidis to macrolides and eliminate it phenotypic features.

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