The effects of aposematic coloration on predation risk in bumblebees: a re-analysis of Stelzeret al. (2010)

2014 ◽  
Vol 292 (2) ◽  
pp. 125-132 ◽  
Author(s):  
R. E. Owen
2020 ◽  
Vol 31 (4) ◽  
pp. 1031-1039 ◽  
Author(s):  
Matthew E Nielsen ◽  
Johanna Mappes

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.


2020 ◽  
Vol 14 (2) ◽  
pp. 35
Author(s):  
Tatiane Bertuzzi ◽  
David Santos de Freitas ◽  
Luiz Liberato Costa Corrêa ◽  
Alice Pozza Rodrigues ◽  
Mateus De Oliveira ◽  
...  

Aposematism in an anti-predation mechanism that occurs when animals exhibit conspicuous signals, which are often of a contrasting color patterns, to alert potential predators of their unpalatability or toxicity. This study aims to test (in a short period) the effectiveness of aposematic coloration by comparing the predatory attack upon snakes models with and without an alert coloration on the body. To simulate snakes, we made 80 greenish plasticine snake models. Half of the models had a red strip on the dorsal part of the body, imitating an aposematic coloration. The other half of the models had only a greenish tint. The models were exposed to predators for 12 hours in an area with countryside vegetation.. Among the 20 models showing signs of predation, 65% were purely greenish models and 35% were models with red coloration on the back. Attaks at extremities (head and tail) were meaningly more frequent on models with red coloration. Our results suggest the efficiency of red coloration as a warning sign and anti-predation mechanism, since the models with red coloration, imitating aposematic preys, were less preyed and were attacked preferentially at the extremities, which suggests caution by the predator.


2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.


The Auk ◽  
2014 ◽  
Vol 131 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Jordi Pascual ◽  
Juan Carlos Senar ◽  
Jordi Domènech

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