scholarly journals Interference coloration as an anti-predator defence

2015 ◽  
Vol 11 (4) ◽  
pp. 20150159 ◽  
Author(s):  
Thomas W. Pike
Keyword(s):  
Animal Groups ◽  
Exact Location ◽  
Avian Predators ◽  
Poor Understanding ◽  
Mechanistic Basis ◽  
Predator Defence ◽  
Prey Items

Interference coloration, in which the perceived colour varies predictably with the angle of illumination or observation, is extremely widespread across animal groups. However, despite considerable advances in our understanding of the mechanistic basis of interference coloration in animals, we still have a poor understanding of its function. Here, I show, using avian predators hunting dynamic virtual prey, that the presence of interference coloration can significantly reduce a predator's attack success. Predators required more pecks to successfully catch interference-coloured prey compared with otherwise identical prey items that lacked interference coloration, and attacks against prey with interference colours were less accurate, suggesting that changes in colour or brightness caused by prey movement hindered a predator's ability to pinpoint their exact location. The pronounced anti-predator benefits of interference coloration may explain why it has evolved independently so many times.

Iridescent blue and orange components contribute to the recognition of a multicomponent warning signal

Behaviour ◽  
2013 ◽  
Vol 150 (3-4) ◽  
pp. 321-336 ◽  
Author(s):  
Kimberly V. Pegram ◽  
Melissa J. Lillo ◽  
Ronald L. Rutowski
Keyword(s):  
Warning Signal ◽  
Animal Kingdom ◽  
Battus Philenor ◽  
Warning Signals ◽  
Long Wavelength ◽  
Avian Predators ◽  
Redundant Signal ◽  
Pipevine Swallowtail ◽  
Swallowtail Butterflies ◽  
Prey Items

Warning colouration functions to deter predators from attacking unprofitable (e.g., unpalatable or toxic) prey items. While warning colours are often characterized by long-wavelength components (e.g., orange, red or yellow), many distasteful animals across the animal kingdom display orange or red colour patches adjacent to or within a field of short-wavelength colouration such as blue (e.g., strawberry poison dart frogs, pipevine swallowtail and pyjama nudibranch), which yields a multicomponent visual warning signal. Here we show that, in such signals, blue and orange patches can function as redundant signal components; avian predators trained not to attack the intact blue and orange colouration of the pipevine swallowtail (Battus philenor) recognised the butterflies as distasteful even when the blue and orange were presented individually. Our results demonstrate that blue colouration and potential multiple, unimodal, signal components should be considered in research on visual warning signals, including in well-studied animals, such as dendrobatid frogs and swallowtail butterflies.

scholarly journals Subfossil lemur discoveries from the Beanka Protected Area in western Madagascar

2019 ◽  
Vol 93 ◽  
pp. 187-203 ◽  
Author(s):  
David A. Burney ◽  
Haingoson Andriamialison ◽  
Radosoa A. Andrianaivoarivelo ◽  
Steven Bourne ◽  
Brooke E. Crowley ◽  
...  
Keyword(s):  
Human Activity ◽  
Protected Area ◽  
Avian Predators ◽  
Extant Species ◽  
Fossil Site ◽  
Pottery Sherds ◽  
Human Predation ◽  
Considerable Range ◽  
Prey Items ◽  
Prolemur Simus

AbstractA new fossil site in a previously unexplored part of western Madagascar (the Beanka Protected Area) has yielded remains of many recently extinct vertebrates, including giant lemurs (Babakotia radofilai, Palaeopropithecus kelyus, Pachylemur sp., and Archaeolemur edwardsi), carnivores (Cryptoprocta spelea), the aardvark-like Plesiorycteropus sp., and giant ground cuckoos (Coua). Many of these represent considerable range extensions. Extant species that were extirpated from the region (e.g., Prolemur simus) are also present. Calibrated radiocarbon ages for 10 bones from extinct primates span the last three millennia. The largely undisturbed taphonomy of bone deposits supports the interpretation that many specimens fell in from a rock ledge above the entrance. Some primates and other mammals may have been prey items of avian predators, but human predation is also evident. Strontium isotope ratios (87Sr/86Sr) suggest that fossils were local to the area. Pottery sherds and bones of extinct and extant vertebrates with cut and chop marks indicate human activity in previous centuries. Scarcity of charcoal and human artifacts suggests only occasional visitation to the site by humans. The fossil assemblage from this site is unusual in that, while it contains many sloth lemurs, it lacks ratites, hippopotami, and crocodiles typical of nearly all other Holocene subfossil sites on Madagascar.

scholarly journals Increased and sex-selective avian predation of desert locusts Schistocerca gregaria treated with Metarhizium acridum

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244733
Author(s):  
Wim C. Mullié ◽  
Robert A. Cheke ◽  
Stephen Young ◽  
Abdou Baoua Ibrahim ◽  
Albertinka J. Murk
Keyword(s):  
Side Effects ◽  
Schistocerca Gregaria ◽  
Maximum Effect ◽  
Desert Locust ◽  
Metarhizium Acridum ◽  
Avian Predation ◽  
Avian Predators ◽  
Locust Control ◽  
The Impact ◽  
Prey Items

The entomopathogenic fungus Metarhizium acridum in oil-based formulations (Green Muscle® (GM)) is a biopesticide for locust control lacking side-effects on biodiversity, unlike chemical insecticides. Under controlled conditions, GM-treated locusts and grasshoppers attract predators, a complementary advantage in locust control. We assessed avian predation on a population of desert locusts in northern Niger aerially sprayed operationally with GM with 107 g viable conidia ha-1. Populations of adult locusts and birds and vegetation greenness were assessed simultaneously along two transects from 12 days before until 23 days after treatment. Common kestrels Falco tinnunculus and lanners F. biarmicus were the predominant avian predators. Regurgitated pellets and prey remains were collected daily beneath “plucking posts” of kestrels. Locusts started dying five days post-spray and GM had its maximum effect one-two weeks after the spray, with 80% efficacy at day 21. After spraying, bird numbers increased significantly (P<0.05) concurrent with decreasing desert locust densities. Locust numbers decreased significantly (P<0.001) with both time since spraying and decreasing greenness. Before spraying, kestrel food remains under plucking posts accounted for 34.3 ±13.4 prey items day-1, of which 31.0 ±11.9 were adult desert locusts (90.3%), reducing post-spray to 21.1 ±7.3 prey items day-1, of which19.5 ±6.7 were adult desert locusts (92.5%), attributable to decreased use of the plucking-posts by the kestrels rather than an effect of the spray. After spraying, kestrels took significantly (P<0.05) more larger female (75–80%) than smaller male (20–25%) locusts. Avian predation probably enhanced the impact of the GM on the desert locust population, especially by removing large adult females. No direct or indirect adverse side-effects were observed on non-target organisms including locust predators such as ants and birds. These substantial ecological advantages should also be considered when choosing between conventional chemical and biopesticide-based locust control.

scholarly journals Phenotype–environment matching in sand fleas

2015 ◽  
Vol 11 (8) ◽  
pp. 20150494 ◽  
Author(s):  
Martin Stevens ◽  
Annette C. Broderick ◽  
Brendan J. Godley ◽  
Alice E. Lown ◽  
Jolyon Troscianko ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Oceanic Island ◽  
Geographical Range ◽  
Genetic Adaptation ◽  
Ontogenetic Changes ◽  
Animal Coloration ◽  
Animal Groups ◽  
Past Work ◽  
Avian Vision ◽  
Avian Predators

Camouflage is perhaps the most widespread anti-predator strategy in nature, found in numerous animal groups. A long-standing prediction is that individuals should have camouflage tuned to the visual backgrounds where they live. However, while several studies have demonstrated phenotype–environment associations, few have directly shown that this confers an improvement in camouflage, particularly with respect to predator vision. Here, we show that an intertidal crustacean, the sand flea ( Hippa testudinaria ), has coloration tuned to the different substrates on which it occurs when viewed by potential avian predators. Individual sand fleas from a small, oceanic island (Ascension) matched the colour and luminance of their own beaches more closely than neighbouring beaches to a model of avian vision. Based on past work, this phenotype–environment matching is likely to be driven through ontogenetic changes rather than genetic adaptation. Our work provides some of the first direct evidence that animal coloration is tuned to provide camouflage to prospective predators against a range of visual backgrounds, in a population of animals occurring over a small geographical range.

Using the research on intergroup conflict in nonhuman animals to help inform patterns of human intergroup conflict

2019 ◽  
Vol 42 ◽  
Author(s):  
Amanda R. Ridley ◽  
Melanie O. Mirville
Keyword(s):  
Large Body ◽  
Nonhuman Animal ◽  
Intergroup Conflict ◽  
Costs And Benefits ◽  
Animal Groups ◽  
Interesting Article ◽  
Nonhuman Animals

Abstract There is a large body of research on conflict in nonhuman animal groups that measures the costs and benefits of intergroup conflict, and we suggest that much of this evidence is missing from De Dreu and Gross's interesting article. It is a shame this work has been missed, because it provides evidence for interesting ideas put forward in the article.

Towards the Integration of Faith, Love, and Praxis

2020 ◽  
Vol 47 (2) ◽  
pp. 5-27
Author(s):  
Monica Y. E. Chi
Keyword(s):  
Social Work ◽  
The Other ◽  
Intergroup Dialogue ◽  
Christian Spirituality ◽  
Social Work Educators ◽  
Dorothy Day ◽  
Jane Addams ◽  
Faith Based ◽  
Poor Understanding ◽  
Martin Luther King

Non-faith-based social work educators and researchers have a poor understanding of what might motivate Christians in social work and whether Christian motivations have any place in social work. On the other hand, Christians have difficulty articulating actions inspired by their faith in ways that others can comprehend despite feeling misunderstood. The focus of this article is to present the framework of faith-inspired praxis of love and lay the groundwork for intergroup dialogue. The framework draws from the works of Jane Addams, Dorothy Day, Martin Luther King, Jr., Jean Vanier, and Mary Jo Leddy, five notable leaders in Christian spirituality and public initiatives, to discuss their conceptualization of faith, love, and praxis. Practice and research implications of this framework for social work are discussed.

Decision aids for alternative techniques in urban storm management

1995 ◽  
Vol 32 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Y. Azzout ◽  
S. Barraud ◽  
F. N. Cres ◽  
E. Alfakih
Keyword(s):  
Decision Making ◽  
Decision Aids ◽  
Decision Making Process ◽  
Urban Stormwater ◽  
Elimination Phase ◽  
Poor Understanding ◽  
Preliminary Study ◽  
Alternative Techniques ◽  
Urban Storm ◽  
Decision Making Tool

The choice of alternative techniques in urban stormwater drainage (infiltration and detention systems), in the course of a project, is most often made with a poor understanding of site constraints, and the possibilities afforded by these techniques. This gives rise to extra costs and also subsequent malfunctioning. To arrive at feasible choices, we have formalised the decision-making process, taking account of the multiple criteria and the large number of partners involved. At present, we are developing a decision-making tool for alternative techniques in urban stormwater management at the preliminary study stage. The first phase makes it possible to eliminate solutions which are unworkable (elimination phase). It is aimed at the designer. Work on the next phase (the decision-making phase), which is more complex, is in progress. It will make it possible, in collaboration with all the partners involved, to choose a stormwater drainage strategy which will best suit the objectives and the wishes of the partners. It uses multi-criteria methods.

An Introduction to Nonlinear Chemical Dynamics

1998 ◽  
Author(s):  
Irving R. Epstein ◽  
John A. Pojman
Keyword(s):  
Flow Reactor ◽  
Chemical Dynamics ◽  
Design Data ◽  
Chemical Oscillators ◽  
Starting Point ◽  
Hands On ◽  
Undergraduate Laboratory ◽  
History Of ◽  
Mechanistic Basis ◽  
Nonlinear Chemical Dynamics

Just a few decades ago, chemical oscillations were thought to be exotic reactions of only theoretical interest. Now known to govern an array of physical and biological processes, including the regulation of the heart, these oscillations are being studied by a diverse group across the sciences. This book is the first introduction to nonlinear chemical dynamics written specifically for chemists. It covers oscillating reactions, chaos, and chemical pattern formation, and includes numerous practical suggestions on reactor design, data analysis, and computer simulations. Assuming only an undergraduate knowledge of chemistry, the book is an ideal starting point for research in the field. The book begins with a brief history of nonlinear chemical dynamics and a review of the basic mathematics and chemistry. The authors then provide an extensive overview of nonlinear dynamics, starting with the flow reactor and moving on to a detailed discussion of chemical oscillators. Throughout the authors emphasize the chemical mechanistic basis for self-organization. The overview is followed by a series of chapters on more advanced topics, including complex oscillations, biological systems, polymers, interactions between fields and waves, and Turing patterns. Underscoring the hands-on nature of the material, the book concludes with a series of classroom-tested demonstrations and experiments appropriate for an undergraduate laboratory.

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