scholarly journals Foraging behavior and extended phenotype independently affect foraging success in spiders

2020 ◽  
Vol 31 (5) ◽  
pp. 1242-1249 ◽  
Author(s):  
N DiRienzo ◽  
H A Schraft ◽  
P O Montiglio ◽  
C T Bradley ◽  
A Dornhaus
Keyword(s):  
Prey Capture ◽  
Phenotypic Traits ◽  
Foraging Success ◽  
Black Widow ◽  
Live Prey ◽  
Correlational Selection ◽  
Web Structure ◽  
Functional Consequences ◽  
Black Widow Spiders ◽  
Insight Into

Abstract Multiple phenotypic traits often interact with each other to determine an individual’s fitness. Behavioral and extended phenotypic traits, such as architectural constructions, can contribute to fitness in an integrated way. The goal of this study was to understand how the interaction between behavioral and extended phenotypic traits can affect foraging success. We tested this question using black widow spiders, where spiders that are aggressive in a foraging context tend to build more gumfooted silk lines that aid in prey capture, while non-aggressive spiders build webs with fewer gumfooted lines. We repeatedly assessed behavior and web structure to quantify relationships between these traits, and then allowed spiders to forage for live prey on their own web or the web of a conspecific that differed in structure. Thus, we assessed how varying combinations of behavior and web structure affect foraging success, and if correlational selection might act on them. We confirmed that aggressiveness and number of gumfooted lines are positively correlated and found that capture success increased with both aggressiveness and the number of gumfooted lines. Yet, we did not find any evidence for correlational selection: aggressiveness and number of gumfooted lines appeared to affect foraging success independently of each other. These findings highlight that a correlation between traits that contribute towards the same ecological function does not necessarily imply correlational selection. Taking advantage of the experimental convenience afforded by extended phenotypic traits can provide insight into the functional consequences of phenotypic variation within and between individuals.

scholarly journals Posture controls mechanical tuning in the black widow spider mechanosensory system

2018 ◽  
Author(s):  
Natasha Mhatre ◽  
Senthurran Sivalinghem ◽  
Andrew C Mason
Keyword(s):  
Prey Capture ◽  
Abdominal Mass ◽  
Mechanical Vibration ◽  
The Body ◽  
Black Widow ◽  
Vibration Sensing ◽  
Black Widow Spiders ◽  
Freely Suspended ◽  
Pendulous Abdomen ◽  
Mechanical Tuning

Spiders rely on mechanical vibration sensing for sexual signalling, prey capture and predator evasion. The sensory organs underlying vibration detection, called slit sensilla, resemble cracks in the spider's exoskeleton, and are distributed all over the spider body. Those crucial to sensing web- and other substrate-borne vibrations are called lyriform organs and are densely distributed around leg joints. It has been shown that forces that cause bending at leg joints also activate these lyriform organs. Little is known of how the biomechanics of the body of a freely-suspended spider in its natural posture interact with vibrations introduced into the body and how this affects vibration perception. Female black widow spiders, in particular, have a striking body-form; their long thin legs support a large pendulous abdomen. Here, we show that in their natural posture, the large abdominal mass of black widow females, interacts with the spring-like behaviour of their leg joints and determines the mechanical behaviour of different leg joints. Furthermore, we find that adopting different body postures enables females to alter both the level and tuning of the mechanical input to lyriform organs. Therefore, we suggest that posture may be used to flexibly and reversibly focus attention to different classes or components of web vibration. Postural effects thus emphasize the dynamic loop of interactions between behaviour and perception, i.e. between 'brain' and body.

scholarly journals Game of webs: species and web structure influence contest outcome in black widow spiders

2019 ◽  
Vol 31 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Cameron Jones ◽  
Lea Pollack ◽  
Nicholas DiRienzo
Keyword(s):  
Individual Variation ◽  
Native Species ◽  
Interspecific Interactions ◽  
Population Level ◽  
Black Widow ◽  
Trait Variation ◽  
Web Structure ◽  
Contest Outcome ◽  
Black Widow Spiders ◽  
The Web

Abstract Population-level trait variation within species plays an often-overlooked role in interspecific interactions. In this study, we compared among-individual variation in web phenotype and foraging behavior between native black widows (Latrodectus hesperus) and invasive brown widows (Latrodectus geometricus). We staged repeated contests whereby native widows defended their webs against intruders of both species to 1) investigate how trait variation mediates web contest outcome among native widows and 2) see whether widow behavior differs in response to an invasive spider. In only one trait, the average number of foraging lines, did black widows differ from brown widows. Black widow residents that built more structural lines were more likely to successfully defend their webs from conspecific intruders (i.e., be the sole spider remaining on the web postinteraction). This association between web structure and contest outcome did not exist in trials between black widows and invasive brown widows; however, in interspecific interactions, these same residents were more likely to have intruders remain on the web rather than drive them away. Surprisingly, brown widows did not usurp black widows. Brown widows were never observed signaling, yet black widow residents signaled equally to intruders of both species. Our results suggest that among-individual variation among native species can influence the response toward invasive competitors and outcome of these interactions.

Black widow spiders in an urban desert: Population variation in an arthropod pest across metropolitan Phoenix, AZ

2011 ◽  
Vol 15 (3) ◽  
pp. 599-609 ◽  
Author(s):  
Patricia Trubl ◽  
Theresa Gburek ◽  
Lindsay Miles ◽  
J. Chadwick Johnson
Keyword(s):  
Population Variation ◽  
Black Widow ◽  
Black Widow Spiders ◽  
Arthropod Pest

scholarly journals Exploring genetic programming systems with MAP-Elites

2018 ◽  
Author(s):  
Emily Dolson ◽  
Alexander Lalejini ◽  
Charles Ofria
Keyword(s):  
Neural Networks ◽  
Genetic Programming ◽  
Pareto Front ◽  
Underlying Structure ◽  
Phenotypic Traits ◽  
Computation Technique ◽  
Phenotype Space ◽  
Programming Systems ◽  
Insight Into ◽  
Connection Cost

MAP-Elites is an evolutionary computation technique that has proven valuable for exploring and illuminating the genotype-phenotype space of a computational problem. In MAP-Elites, a population is structured based on phenotypic traits of prospective solutions; each cell represents a distinct combination of traits and maintains only the most fit organism found with those traits. The resulting map of trait combinations allows the user to develop a better understanding of how each trait relates to fitness and how traits interact. While MAP-Elites has not been demonstrated to be competitive for identifying the optimal Pareto front, the insights it provides do allow users to better understand the underlying problem. In particular, MAP-Elites has provided insight into the underlying structure of problem representations, such as the value of connection cost or modularity to evolving neural networks. Here, we extend the use of MAP-Elites to examine genetic programming representations, using aspects of program architecture as traits to explore. We demonstrate that MAP-Elites can generate programs with a much wider range of architectures than other evolutionary algorithms do (even those that are highly successful at maintaining diversity), which is not surprising as this is the purpose of MAP-Elites. Ultimately, we propose that MAP-Elites is a useful tool for understanding why genetic programming representations succeed or fail and we suggest that it should be used to choose selection techniques and tune parameters.

scholarly journals Network Analysis Provides Insight into Tomato Lipid Metabolism

Metabolites ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 152 ◽  
Author(s):  
Anastasiya Kuhalskaya ◽  
Micha Wijesingha Ahchige ◽  
Leonardo Perez de Souza ◽  
José Vallarino ◽  
Yariv Brotman ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Network Analysis ◽  
Volatile Compounds ◽  
Tomato Fruit ◽  
Major Influence ◽  
Phenotypic Traits ◽  
Solanum Pennellii ◽  
Metabolic Network Analysis ◽  
Wide Range ◽  
Insight Into

Metabolic correlation networks have been used in several instances to obtain a deeper insight into the complexity of plant metabolism as a whole. In tomato (Solanum lycopersicum), metabolites have a major influence on taste and overall fruit quality traits. Previously a broad spectrum of metabolic and phenotypic traits has been described using a Solanum pennellii introgression-lines (ILs) population. To obtain insights into tomato fruit metabolism, we performed metabolic network analysis from existing data, covering a wide range of metabolic traits, including lipophilic and volatile compounds, for the first time. We provide a comprehensive fruit correlation network and show how primary, secondary, lipophilic, and volatile compounds connect to each other and how the individual metabolic classes are linked to yield-related phenotypic traits. Results revealed a high connectivity within and between different classes of lipophilic compounds, as well as between lipophilic and secondary metabolites. We focused on lipid metabolism and generated a gene-expression network with lipophilic metabolites to identify new putative lipid-related genes. Metabolite–transcript correlation analysis revealed key putative genes involved in lipid biosynthesis pathways. The overall results will help to deepen our understanding of tomato metabolism and provide candidate genes for transgenic approaches toward improving nutritional qualities in tomato.

Application of a Three-Dimensional Computational Wrist Model to Proximal Row Carpectomy

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Jennifer S. Wayne ◽  
Afsarul Q. Mir
Keyword(s):  
Wrist Joint ◽  
Three Dimensional ◽  
Proximal Row Carpectomy ◽  
Clinical Tool ◽  
Additional Insight ◽  
Bony Anatomy ◽  
Muscle Loading ◽  
Functional Consequences ◽  
Triangular Fibrocartilage ◽  
Insight Into

A three-dimensional (3D) computational model of the wrist examined the biomechanical effects of the proximal row carpectomy (PRC), a surgical treatment of certain wrist degenerative conditions but with functional consequences. Model simulations, replicating the 3D bony anatomy, soft tissue restraints, muscle loading, and applied perturbations, demonstrated quantitatively accurate responses for the decreased motions subsequent to the surgical procedure. It also yielded some knowledge of alterations in radiocarpal contact force which likely increase contact pressure as well as additional insight into the importance of the triangular fibrocartilage complex and retinacular/capsular structures for stabilizing the deficient wrist. As better understanding of the wrist joint is achieved, this model could serve as a useful clinical tool.

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