Ambush Predators on Flowers at Night: Predation Pressure on Moths

Striped and unstriped colour morphs of the eastern red-backed salamander,Plethodon cinereus, vary in their pre-attack behavioural response to predators, but it is unknown whether the morphs vary in post-attack strategies. Both morphs employ tail autotomy, a post-attack defensive mechanism enabling an individual to release a portion of their tail to facilitate escape from predation. Postautotomy tail movement diverts attention of a predator away from the individual’s body, so natural selection should favor vigorous tail movement in both colour morphs ofP. cinereus. We compared the degree of postautotomy tail movement between morphs following simulated predation. Striped individuals exhibited substantially longer and faster tail movement than unstriped individuals. Divergence in postautotomy tail movement may be a direct evolved response to variable predation pressure between colour morphs. Alternatively, tail movement may be constrained in the unstriped morph due to a genetic correlation with colouration (e.g., pleiotropy).

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Vigilance and foraging patterns of American elk during the rut in habitats with and without predators

Canadian Journal of Zoology ◽

10.1139/z03-011 ◽

2003 ◽

Vol 81 (2) ◽

pp. 266-271 ◽

Cited By ~ 78

Author(s):

Jerry O Wolff ◽

Toni Van Horn

Keyword(s):

Cervus Elaphus ◽

National Park ◽

Forest Cover ◽

Hot Springs ◽

Rocky Mountain ◽

Predation Pressure ◽

Risk Avoidance ◽

Foraging Patterns ◽

Survival And Reproduction ◽

Free Environment

Animal behavior is often optimized as a trade-off between survival and reproduction. During the breeding season, mammals tend to maximize their reproductive effort within the constraints of predation pressure. When predation pressure is reduced, greater effort can be allocated to reproductive behavior and less to vigilance and predator avoidance. The objective of this study was to test the hypothesis that elk, Cervus elaphus, in Yellowstone National Park (YNP), with predators, would spend more time in vigilance and risk-avoidance behavior than would elk in Rocky Mountain National Park (RMNP), a predator-free environment. We further predicted that elk at Mammoth Hot Springs (MAM) in YNP would behave similarly to those at RMNP because predators were absent in that area of the park. Cow elk in YNP spent more time in vigilance and less in foraging during activity periods than did cows in RMNP or MAM. Also, elk in YNP retreated to forest cover during the midday inactive period, whereas elk in RMNP and MAM remained in open habitat. Vigilance was not correlated with group size at either site. Cows with calves spent more time in vigilance and less in foraging than did cows without calves in RMNP and YNP. Bull elk spent most of their time in courtship at all sites, but foraged more at RMNP than in YNP or MAM. Mean harem sizes were similar among the three sites: 17.0 in RMNP, 15.7 in YNP, and 19.0 in MAM. The proportion of cows with calves was significantly lower in the area with predators, YNP (0.10), than in the predator-free areas (0.24 in RMNP and 0.37 in MAM), probably because of greater calf mortality in YNP. Elk in YNP behaved in accordance with a predation risk, whereas those in RMNP and MAM showed less vigilance behavior.

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Beak marks on the wings of butterflies and predation pressure in the field

Entomological Science ◽

10.1111/ens.12076 ◽

2014 ◽

Vol 17 (4) ◽

pp. 371-375 ◽

Cited By ~ 5

Author(s):

Masato Ota ◽

Masahide Yuma ◽

Yoshito Mitsuo ◽

Yuki Togo

Keyword(s):

Predation Pressure

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Social transmission in the wild can reduce predation pressure on novel prey signals

Nature Communications ◽

10.1038/s41467-021-24154-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Liisa Hämäläinen ◽

William Hoppitt ◽

Hannah M. Rowland ◽

Johanna Mappes ◽

Anthony J. Fulford ◽

...

Keyword(s):

Evolutionary Dynamics ◽

Parus Major ◽

Predation Pressure ◽

Social Transmission ◽

Blue Tit ◽

Cyanistes Caeruleus ◽

Novel Approach ◽

Transmission Of Information ◽

In The Wild ◽

Animal Communities

AbstractSocial transmission of information is taxonomically widespread and could have profound effects on the ecological and evolutionary dynamics of animal communities. Demonstrating this in the wild, however, has been challenging. Here we show by field experiment that social transmission among predators can shape how selection acts on prey defences. Using artificial prey and a novel approach in statistical analyses of social networks, we find that blue tit (Cyanistes caeruleus) and great tit (Parus major) predators learn about prey defences by watching others. This shifts population preferences rapidly to match changes in prey profitability, and reduces predation pressure from naïve predators. Our results may help resolve how costly prey defences are maintained despite influxes of naïve juvenile predators, and suggest that accounting for social transmission is essential if we are to understand coevolutionary processes.

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Functional implications of supercontracting muscle in the chameleon tongue retractors

Journal of Experimental Biology ◽

10.1242/jeb.204.21.3621 ◽

2001 ◽

Vol 204 (21) ◽

pp. 3621-3627 ◽

Cited By ~ 1

Author(s):

Anthony Herrel ◽

Jay J. Meyers ◽

Peter Aerts ◽

Kiisa C. Nishikawa

Keyword(s):

Prey Capture ◽

Three Dimensional ◽

Force Production ◽

Retractor Muscle ◽

Muscle Physiology ◽

Large Prey ◽

Wide Range ◽

Ambush Predators ◽

Full Body

SUMMARYChameleons capture prey items using a ballistic tongue projection mechanism that is unique among lizards. During prey capture, the tongue can be projected up to two full body lengths and may extend up to 600 % of its resting length. Being ambush predators, chameleons eat infrequently and take relatively large prey. The extreme tongue elongation (sixfold) and the need to be able to retract fairly heavy prey at any given distance from the mouth are likely to place constraints on the tongue retractor muscles. The data examined here show that in vivo retractor force production is almost constant for a wide range of projection distances. An examination of muscle physiology and of the ultrastructure of the tongue retractor muscle shows that this is the result (i) of active hyoid retraction, (ii) of large muscle filament overlap at maximal tongue extension and (iii) of the supercontractile properties of the tongue retractor muscles. We suggest that the chameleon tongue retractor muscles may have evolved supercontractile properties to enable a substantial force to be produced over a wide range of tongue projection distances. This enables chameleons successfully to retract even large prey from a variety of distances in their complex three-dimensional habitat.

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