scholarly journals A Quantitative Analysis of Micrurus Coral Snakes Reveals Unexpected Variation in Stereotyped Anti-Predator Displays Within a Mimicry System

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
T Y Moore ◽  
S M Danforth ◽  
J G Larson ◽  
A R Davis Rabosky
Keyword(s):  
Stabilizing Selection ◽  
South American ◽  
Species Identity ◽  
Predator Prey ◽  
Signaling Systems ◽  
Curve Magnitude ◽  
Body Location ◽  
Critical Components ◽  
Common Signal ◽  
High Degree

Synopsis Warning signals in chemically defended organisms are critical components of predator–prey interactions, often requiring multiple coordinated display components for effective communication. When threatened by a predator, venomous coral snakes (genus Micrurus) display a vigorous, non-locomotory thrashing behavior that has previously been qualitatively described. Given the high contrast and colorful banding patterns of these snakes, this thrashing display is hypothesized to be a key component of a complex aposematic signal under strong stabilizing selection across species in a mimicry system. By experimentally testing snake response across simulated predator cues, we analyzed variation in the presence and expression of a thrashing display across five species of South American coral snakes. Although the major features of the thrash display were conserved across species, we found that predator cue type, snake body size, and species identity predict significant inter- and intraspecific variation in the propensity to perform a display, the duration of thrashing, and the curvature of snake bodies. We also found an interaction between curve magnitude and body location that clearly shows which parts of the display vary most across individuals and species. Our results suggest that contrary to the assumption that all Micrurus species and individuals perform the same display, a high degree of variation exists despite presumably strong selection to conserve a common signal. This quantitative behavioral characterization presents a new framework for analyzing the non-locomotory motions displayed by snakes in a broader ecological context, especially for signaling systems with complex interaction across multiple modalities.

scholarly journals A kinematic analysis of Micrurus coral snakes reveals unexpected variation in stereotyped anti-predator displays within a mimicry system

2019 ◽  
Author(s):  
Talia Y. Moore ◽  
Shannon M. Danforth ◽  
Joanna G. Larson ◽  
Alison R. Davis Rabosky
Keyword(s):  
Stabilizing Selection ◽  
List Type ◽  
South American ◽  
Species Identity ◽  
Predator Prey ◽  
Curve Magnitude ◽  
Body Location ◽  
Critical Components ◽  
Common Signal ◽  
High Degree

AbstractWarning signals in chemically defended organisms are critical components of predator-prey interactions, often requiring multiple coordinated display components for a signal to be effective. When threatened by a predator, venomous coral snakes (genus Micrurus) display a vigorous, non-locomotory thrashing behaviour that has been only qualitatively described. Given the high-contrast and often colourful banding patterns of these snakes, this thrashing display is hypothesized to be a key component of a complex aposematic signal under strong stabilizing selection across species in a mimicry system.By experimentally testing snake response across simulated predator cues, we analysed variation in the presence and expression of a thrashing display across five species of South American coral snakes.Although the major features of the thrash display were conserved across species, we found significant variation in the propensity to perform a display at all, the duration of thrashing, and the curvature of snake bodies that was mediated by predator cue type, snake body size, and species identity. We also found an interaction between curve magnitude and body location that clearly shows which parts of the display vary most across individuals and species.Our results suggest that contrary to the assumption in the literature that all species and individuals perform the same display, a high degree of variation persists in thrashing behaviour exhibited by Micrurus coral snakes despite presumably strong selection to converge on a common signal. This quantitative behavioural characterization presents a new framework for analysing the non-locomotory motions displayed by snakes in a broader ecological context, especially for signalling systems with complex interaction across multiple modalities.

SOD polymorphism in the Xiphinema americanum-group (Nematoda: Longidoridae)

Nematology ◽  
2004 ◽  
Vol 6 (6) ◽  
pp. 867-876 ◽  
Author(s):  
Robert Robbins ◽  
Rui Lemos ◽  
Peter Nagy ◽  
Michael McKenry ◽  
Franco Lamberti ◽  
...  
Keyword(s):  
North American ◽  
South American ◽  
Homogeneous Groups ◽  
The Usa ◽  
Geographic Separation ◽  
High Degree ◽  
First Time ◽  
Large Groups ◽  
Single Enzyme ◽  
Group 1

AbstractIsoelectrofocusing of superoxide dismutase (SOD) isoforms was carried out on the extracts of 117 nematode populations belonging to the so-called Xiphinema americanum-group. These populations came from the USA (77), Chile (5), Argentina (1), Venezuela (5), Portugal (15), Italy (2), Crete (1), Montenegro (1), Slovakia (4), Hungary (3), Egypt (1) and India (2). A total of 17 bands of enzyme activity were observed in the screening, whilst single enzyme phenotypes showed from two to eight bands. The high degree of SOD polymorphism of this nematode collection was grouped by cluster analysis into seven distinct homogeneous groups characterised by specific combinations of SOD markers. Sub-groups could be discriminated for larger groups. The small Groups 3 and 5 were constituted mostly by populations from USA east coast states (i.e., NY and PA, respectively). The larger Group 1 resulted from the association of populations coming from various and distant North American States. In other large groups, North American populations were associated with South American and European populations. Overall, the data presented here suggest that geographic separation and different hosts do not seem to be the source of genetic diversity for the X. americanum-group. When an adequate number of populations were collected from the same country, the variability expressed by such a sub-sample was comparable to that of the whole nematode collection. For the first time, homogeneous populations of a large collection of X. americanum-group populations were associated by molecular means in order to explore further approaches that may help resolve the recalcitrant taxonomy and phylogeny of this much debated group.

scholarly journals Predator-induced flow disturbances alert prey, from the onset of an attack

2014 ◽  
Vol 281 (1790) ◽  
pp. 20141083 ◽  
Author(s):  
Jérôme Casas ◽  
Thomas Steinmann
Keyword(s):  
Prey Capture ◽  
Ground Effect ◽  
Just In Time ◽  
Soil Arthropods ◽  
Predator Prey ◽  
Flow Sensing ◽  
Predator Attack ◽  
Flow Disturbances ◽  
A Minor ◽  
High Degree

Many prey species, from soil arthropods to fish, perceive the approach of predators, allowing them to escape just in time. Thus, prey capture is as important to predators as prey finding. We extend an existing framework for understanding the conjoint trajectories of predator and prey after encounters, by estimating the ratio of predator attack and prey danger perception distances, and apply it to wolf spiders attacking wood crickets. Disturbances to air flow upstream from running spiders, which are sensed by crickets, were assessed by computational fluid dynamics with the finite-elements method for a much simplified spider model: body size, speed and ground effect were all required to obtain a faithful representation of the aerodynamic signature of the spider, with the legs making only a minor contribution. The relationship between attack speed and the maximal distance at which the cricket can perceive the danger is parabolic; it splits the space defined by these two variables into regions differing in their values for this ratio. For this biological interaction, the ratio is no greater than one, implying immediate perception of the danger, from the onset of attack. Particular attention should be paid to the ecomechanical aspects of interactions with such small ratio, because of the high degree of bidirectional coupling of the behaviour of the two protagonists. This conclusion applies to several other predator–prey systems with sensory ecologies based on flow sensing, in air and water.

scholarly journals Direct evidence of megamammal-carnivore interaction decoded from bone marks in historical fossil collections from the Pampean region

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3117 ◽  
Author(s):  
Karina Vanesa Chichkoyan ◽  
Borja Figueirido ◽  
Margarita Belinchón ◽  
José Luis Lanata ◽  
Anne-Marie Moigne ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Popular Media ◽  
South American ◽  
Long Bones ◽  
Ecological Interactions ◽  
Predator Prey ◽  
Ecological Relationships ◽  
Pampean Region ◽  
Fossil Bones ◽  
Crucial Information

Pleistocene South American megafauna has traditionally attracted the interest of scientists and the popular media alike. However, ecological interactions between the species that inhabited these ecosystems, such as predator-prey relationships or interspecific competition, are poorly known. To this regard, carnivore marks imprinted on the fossil bones of megamammal remains are very useful for deciphering biological activity and, hence, potential interspecific relationships among taxa. In this article, we study historical fossil collections housed in different European and Argentinean museums that were excavated during the 19th and early 20th centuries in the Pampean region, Argentina, in order to detect carnivore marks on bones of megamammals and provide crucial information on the ecological relationships between South American taxa during the Pleistocene. Our results indicate that the long bones of megafauna from the Pampean region (e.g., the Mylodontidae and Toxodontidae families) exhibit carnivore marks. Furthermore, long bones of medium-sized species and indeterminate bones also present punctures, pits, scores and fractures. Members of the large-carnivore guild, such as ursids, canids and even felids, are recognised as the main agents that inflicted the marks. We hypothesize that the analysed carnivore marks represent the last stages of megaherbivore carcass exploitation, suggesting full consumption of these animals by the same or multiple taxa in a hunting and/or scavenging scenario. Moreover, our observations provide novel insights that help further our understanding of the palaeoecological relationships of these unique communities of megamammals.

Pinniped predation of birds: A cause for conservation concern?

The Condor ◽  
2020 ◽  
Vol 122 (2) ◽  
Author(s):  
George J F Swan ◽  
Eduardo A Silva-Rodríguez ◽  
Layla P Osman ◽  
Eduardo Jaramillo
Keyword(s):  
Mitigation Measures ◽  
South American ◽  
The Novel ◽  
Sea Lion ◽  
Predator Prey ◽  
Bird Populations ◽  
South American Sea Lion ◽  
Prey Interaction ◽  
Conservation Concern ◽  
Do So

Abstract Recovering predators can create challenges for conservation objectives when they prey on vulnerable species. Although largely uncommon, pinniped predation of birds presents one such challenge. Here, we describe the novel characteristics of this predator–prey interaction, its impact on bird populations, and possible mitigation responses. We do so both broadly, synthesizing the wider literature, and specifically, in reference to ongoing South American sea lion (Otaria flavescens) predation of Black-necked Swans (Cygnus melancoryphus) we are currently observing in southern Chile. Our review of the literature suggests that in most cases bird predation by pinnipeds is only exhibited by a small proportion of the population, spreads socially between individuals, can be temporally severe, and may rapidly threaten the viability of bird populations. We discuss feasibility and efficacy of potential mitigation measures highlighting that, as foraging specializations can be socially transmitted, any such actions need to be time conscious as bird-killing behaviors may be increasingly difficult to remove. The contrasting population trends of pinnipeds and seabirds suggests that pinniped predation of vulnerable waterbirds is going to be an increasingly common conservation challenge in the future.

Strength Calculation and Design Optimization of a Test Rig for Slide Ring Seals in the Scope of Rotary Manifolds

2016 ◽  
Vol 856 ◽  
pp. 166-173
Author(s):  
Julian Müller ◽  
Gordana Michos ◽  
Lukas Koch ◽  
Markus Hubert ◽  
Jörg Franke
Keyword(s):  
Design Optimization ◽  
Development Process ◽  
Pressure Chamber ◽  
Strength Calculation ◽  
Test Rig ◽  
Chamber Design ◽  
Functional Reliability ◽  
Critical Components ◽  
High Degree

An examination of machining centers with high degree of automation showed that rotatory manifolds are critical components regarding functional reliability and efficiency. In order to get a better understanding of the interrelationships and involved mechanisms of the sealing system inside the rotatory manifolds, a corresponding rotatory seal test rig was developed. This study presents the necessary development process. More importantly, both of the analytical and simulative strength verification of the pressure chamber design is elucidated.

scholarly journals Assessing display variability in wild brown anoles Anolis sagrei using a mechanical lizard model

2011 ◽  
Vol 57 (2) ◽  
pp. 140-152 ◽  
Author(s):  
Sarah R. Partan ◽  
Peter Otovic ◽  
Virginia L. Price ◽  
Scott E. Brown
Keyword(s):  
Temporal Structure ◽  
Adult Males ◽  
Anolis Sagrei ◽  
Species Identity ◽  
Social Responses ◽  
Nonbreeding Season ◽  
Putative Species ◽  
Brown Anole ◽  
Signature Pattern ◽  
High Degree

Abstract Signals used for species identity ought to be highly stereotyped so as to facilitate immediate recognition by con-specifics. It is surprising therefore to find variability in putative species signature displays. The brown anole Anolis sagrei has a high degree of variability in its signature bobbing display. In this study we collected descriptive data on variability in the temporal structure of wild brown anole bobbing patterns, finding that no two displays analyzed had the same temporal structure, and we also tested whether wild brown anoles prefer the signature display over an alternate display pattern by using mechanical robot playbacks in the field. As a response metric we assessed whether or not the lizards showed social responses (pushup, dewlap extension, or head-nod) in response to the robotic presentations. We found that the lizards responded slightly more to the signature than to the alternate pattern, providing support for the idea that despite the variability seen in displays, the signature pattern is meaningful to them. We tested two other independent variables: speed of the display and elevation of the robot during its display, neither of which was significant. Dewlap extensions were given predominantly by adult males and were more likely to be given in the breeding season than the nonbreeding season. Pushups and head-nods were given equally by males and a combined class of females and juveniles, and were not seasonal. Head-nods increased after the robot turned off, suggesting that they may be used in a conversational turn-taking style during communication.

scholarly journals Europe ‒ Latin America: Migratory Space Development

2021 ◽  
Vol 102 (2) ◽  
pp. 50-62
Author(s):  
Nadezhda Kudeyarova ◽  
Keyword(s):  
Latin America ◽  
Latin American ◽  
Large Scale ◽  
South American ◽  
Migration Flow ◽  
The Social ◽  
High Degree ◽  
Dramatic Growth ◽  
Space Concept ◽  
European Migration

The migration ties between Latin America and Europe at the beginning of the XXI century were manifested in a massive migration flow, resulting in the dramatic growth of the number of South American natives in Europe. The Migratory Space concept is applied to the current stage of transatlantic mobility, which makes it possible to determine the territorial limits of the involved states, to distinguish the transatlantic space from the general panorama of the Latin America migration movement as well as from the European migration context. At the present stage, the South American states are mainly the migration donors, while the European states are recipients. The historical ties between continents, their linguistic commonality and the social networks between migrants contributed to the transatlantic mobility. The majority of the Latin American migrants is localized in Spain and Italy. The high degree of integration into the host communities contributed to generally favorable public opinion about the migrants in the recipient countries. A large-scale migration presence also became an important factor in strengthening economic and political ties in the Iberoamerican Community of Nations.

Distribution of aquaporins in the colon of Octodon degus, a South American desert rodent

2002 ◽  
Vol 283 (3) ◽  
pp. R779-R788 ◽  
Author(s):  
Pedro Gallardo ◽  
Nancy Olea ◽  
Francisco V. Sepúlveda
Keyword(s):  
Water Absorption ◽  
Water Deprivation ◽  
Osmotic Gradient ◽  
South American ◽  
Muscularis Mucosae ◽  
Octodon Degus ◽  
Basolateral Membranes ◽  
Desert Rodent ◽  
High Degree

Octodon degus is a desert rodent of northern Chile, adapted to survive with a limited supply of water. This rodent has a high degree of fecal dehydration, related to colon water absorption. With the hypothesis that aquaporins (AQPs) might be present in the colon epithelium of O. degus and involved in fluid absorption, we studied colon water absorption in vivo and the distribution of AQPs and Na+ transporters by immunocytochemistry. AQP-1 was found in apical and basolateral membranes of surface-absorptive and crypt epithelial cells. AQP-8 was found in the cytoplasm of enterocytes of surface colon. AQP-3 immunolabeling, on the other hand, was absent from the epithelium but present in a subepithelial fibroblast layer, pericryptal cells, and muscularis mucosae. The hydration state did not modify the amount of immunostaining for any of the AQPs. Colon water absorption was markedly decreased by the mercurial agent p-chloromercuribenzenesulfonic acid and was not affected by water deprivation. The NHE3 isoform of Na+/H+exchanger and α-1 subunit of the Na+-K+-ATPase were found in apical and basolateral membranes of surface-absorptive cells, respectively. These results suggest that colon water absorption is mostly transcellular and mediated by water channels like AQP-1. Apical Na+/H+ exchanger and basolateral Na+-K+-ATPase in surface cells could be part of the Na+ absorption pathway. It is hypothesized that this transport is necessary to provide an osmotic gradient for water absorption. The roles of AQP-8 and AQP-3 in water absorption remain to be established.

scholarly journals Susceptibility of the egg parasitoid Trichogramma achaeae (Hymenoptera: Trichogrammatidae) to selected insecticides used in tomato greenhouses

2019 ◽  
Vol 17 (2) ◽  
pp. e1009 ◽  
Author(s):  
Juan R. Gallego ◽  
Jesús Guerrero-Manzano ◽  
Francisco J. Fernández-Maldonado ◽  
Tomas Cabello
Keyword(s):  
Biological Control ◽  
Egg Parasitoid ◽  
Economic Importance ◽  
South American ◽  
Pest Species ◽  
Biological Control Agents ◽  
Great Economic Importance ◽  
South American Tomato Moth ◽  
Trichogramma Achaeae ◽  
High Degree

The South American tomato moth Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a pest species of great economic importance in tomatoes, both in greenhouses and in open-air crops. This importance has increased in recent years because it has been introduced in many countries in Europe, Africa, and Asia. Insecticides different active ingredients and biological control agents are being used in the control of this pest species. This implies the need to make both groups compatible within IPM programmes. Therefore, the objective of this work was to study the compatibility between different insecticides and the use of the egg parasitoid Trichogramma achaeae Nagaraja and Nagakartti (Hymenoptera: Trichogrammatidae). Three groups of trials were carried out under laboratory and greenhouse conditions. Ten insecticides with the following active ingredient were evaluated: abamectin, azadirachtin, Bacillus thuringiensis, chlorantraniliprole, emamectin, flubendiamide, indoxacarb, methomyl, spinosad, and spiromesifen. In the results, three groups of insecticides were established based on their compatibility with the use of biological control: The first group (abamectin, B. thurigiensis, flubendiamide, indoxacarb and spiromesifen) showed a high degree of compatibility with egg parasitoid releases. The second group (azadirachtin and chlorantraniliprole, and methomyl) presented compatibility problems. Finally, the last group (emamectin, methomyl, and spinosad) did not apper to be compatible. The results found will allow a better application of IPM programmes in tomato crops for the control of this pest species.

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