scholarly journals A spatiotemporal analysis of the food dissemination process and the trophallactic network in the ant Lasius niger

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Joffrey Planckaert ◽  
Stamatios C. Nicolis ◽  
Jean-Louis Deneubourg ◽  
Cédric Sueur ◽  
Olivier Bles
Keyword(s):  
Network Theory ◽  
Random Network ◽  
Spatiotemporal Analysis ◽  
Lasius Niger ◽  
Ant Colonies ◽  
Interindividual Differences ◽  
Food Management ◽  
Dissemination Process ◽  
Underlying Mechanisms ◽  
Spatial Locations

Abstract Intranidal food dissemination through trophallactic exchanges is a fundamental issue in social insect colonies but its underlying mechanisms are far from being clear. In light of the division of work, network theory and collective food management we develop a framework to investigate the spatiotemporal dynamics of the trophallactic network in starved Lasius niger ant colonies. Thanks to tracking methods we are able to record spatial locations of the trophallactic interactions in the nest. We highlight quantitative differences between the foragers and non-foragers concerning their contributions, their roles (donor/recipient) and their spatial distributions. Moreover, at the intracaste level, we show interindividual differences in all activities and we characterise their nature. In particular, within each caste, all the individuals have the same probability to start their food exchange activity but their probability to exchange differs after their first trophallactic event. Interestingly, despite the highlighted interindividual differences, the trophallactic network does not differ from a random network.

scholarly journals Rational time investment during collective decision making in Temnothorax ants

2019 ◽  
Vol 15 (10) ◽  
pp. 20190542 ◽  
Author(s):  
Takao Sasaki ◽  
Benjamin Stott ◽  
Stephen C. Pratt
Keyword(s):  
Decision Making ◽  
Collective Decision ◽  
Collective Decision Making ◽  
Ant Colonies ◽  
Temnothorax Albipennis ◽  
Time Investment ◽  
Decision Outcomes ◽  
Nest Site Choice ◽  
The Difference ◽  
Underlying Mechanisms

The study of rational choice in humans and other animals typically focuses on decision outcomes, but rationality also applies to decision latencies, especially when time is scarce and valuable. For example, the smaller the difference in quality between two options, the faster a rational actor should decide between them. This is because the consequences of choosing the inferior option are less severe if the options are similar. Experiments have shown, however, that humans irrationally spend more time choosing between similar options. In this study, we assessed the rationality of time investment during nest-site choice by the rock ant, Temnothorax albipennis . Previous studies have shown that collective decision-making allows ant colonies to avoid certain irrational errors. Here we show that the same is true for time investment. Individual ants, like humans, irrationally took more time to complete an emigration when choosing between two similar nests than when choosing between two less similar nests. Whole colonies, by contrast, rationally made faster decisions when the options were more similar. We discuss the underlying mechanisms of decision-making in individuals and colonies and how they lead to irrational and rational time investment, respectively.

Vitreous borate networks containing superstructural units: a challenge to the random network theory?

1995 ◽  
Vol 192-193 ◽  
pp. 92-97 ◽  
Author(s):  
Adrian C. Wright ◽  
Natalia M. Vedishcheva ◽  
Boris A. Shakhmatkin
Keyword(s):  
Network Theory ◽  
Random Network

scholarly journals Impact of Interference Competition on Exploration and Food Exploitation in the AntLasius niger

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Vincent Fourcassié ◽  
Tristan Schmitt ◽  
Claire Detrain
Keyword(s):  
Interference Competition ◽  
Lasius Niger ◽  
Ant Colonies ◽  
Individual Level ◽  
Temporal Predictability ◽  
Food Exploitation ◽  
Local Recruitment ◽  
The Individual ◽  
Behavioral Mechanisms ◽  
Physical Access

Competition acts as a major force in shaping spatially and/or temporally the foraging activity of ant colonies. Interference competition between colonies in particular is widespread in ants where it can prevent the physical access of competitors to a resource, either directly by fighting or indirectly, by segregating the colony foraging areas. Although the consequences of interference competition on ant distribution have been well studied in the literature, the behavioral mechanisms underlying interference competition have been less explored. Little is known on how ants modify their exploration patterns or the choice of a feeding place after experiencing aggressive encounters. In this paper, we show that, at the individual level, the aphid-tending antLasius nigerreacts to the presence of an alien conspecific through direct aggressive behavior and local recruitment in the vicinity of fights. At the colony level, however, no defensive recruitment is triggered and the “risky” area where aggressive encounters occur is not specifically avoided during further exploration or food exploitation. We discuss how between-species differences in sensitivity to interference competition could be related to the spatial and temporal predictability of food resources at stake.

scholarly journals Know your foe: synanthropic spiders are deterred by semiochemicals of European fire ants

2021 ◽  
Vol 8 (5) ◽  
pp. 210279
Author(s):  
Andreas Fischer ◽  
Yerin Lee ◽  
T'ea Dong ◽  
Gerhard Gries
Keyword(s):  
Filter Paper ◽  
Fire Ants ◽  
Deterrent Effect ◽  
Lasius Niger ◽  
Community Members ◽  
Black Widow ◽  
Latrodectus Hesperus ◽  
Ant Colonies ◽  
Carpenter Ants ◽  
Web Building

Many ants prey on spiders, suggesting that web-building spiders may avoid micro-locations near ant colonies or frequented by foraging ants. Here we tested the hypothesis that ant-derived semiochemicals deter synanthropic spiders. To generate stimuli, we exposed filter paper for 12 h to workers of European fire ants, Myrmica rubra, black garden ants, Lasius niger, or western carpenter ants, Camponotus modoc , and then offered select urban spiders in three-chamber olfactometer bioassays a choice between ant-exposed filter paper and unexposed control filter paper. Semiochemical deposits of M. rubra , but not of L. niger or C. modoc , had a significant deterrent effect on subadults of the false black widow, Steatoda grossa, the black widow, Latrodectus hesperus , and the hobo spider, Eratigena agrestis, as well as a moderate (but statistically not significant) deterrent effect on the cross spider, Araneus diadematus . The deterrent effect caused by semiochemical deposits of M. rubra may be attributable to the aggressive nature and efficient foraging of M. rubra in its invaded North American range, exerting selection pressure on community members to recognize M. rubra semiochemicals and to avoid micro-locations occupied by M. rubra .

A Relational Approach to Lexical Borrowings in the Discourse of Romanian Bilingual Immigrants in Spain

2021 ◽  
Vol 66 (4) ◽  
pp. 13-32
Author(s):  
Paul Buzilă ◽  
Keyword(s):  
Network Theory ◽  
Linguistic Processing ◽  
Lexical Borrowing ◽  
Relational Approach ◽  
Bilingual Speakers ◽  
Linguistic Interference ◽  
Romanian Immigrants ◽  
Underlying Mechanisms ◽  
Relational Network ◽  
Hybrid Forms

A Relational Approach to Lexical Borrowings in the Discourse of Romanian Bilingual Immigrants in Spain. This paper is a neurocognitive analysis of idiosyncratic lexical borrowings recorded in the discourse of bilingual Romanian immigrants living in Spain. The neurocognitive approach, also known as Relational Network Theory (RNT), conceives language as an interconnected relational network composed of nodes and lines, part of and connected to the general cognitive system. Linguistic processing is a result of spreading activation through the network and of interaction of the system with other biological systems. The model elegantly describes real and inferred linguistic behaviors, both well-formed and erroneous. We use this approach to explore the underlying mechanisms that trigger the emergence of linguistic interference in the discourse of bilingual speakers. We focus on several lexical borrowings selected from corpora of Romanian spoken in Spain, and we model them, using the NeuroLab tool, in relational network terms. The network modeling of these hybrid forms pinpoints new ways of understanding the differences between adapted and non-adapted, and between necessary and luxury borrowings. We conclude that the RNT model is well suited for explaining bilingual processing and, arguably, one of the few models that can account for the hybrid forms emerging in the discourse of bilingual speakers. Keywords: Relational Network Theory, lexical borrowing, Romanian, Spanish, Rumañol, neurocognitive linguistics.

ON CONNECTED COMPONENT DISTRIBUTION OF RANDOM BLOCK-HIERARCHICAL NETWORKS USING THE AUTOMATED SYSTEM $ \textit{XRANDNET} $

2018 ◽  
Vol 52 (1 (245)) ◽  
pp. 34-40
Author(s):  
A.G. Kocharyan
Keyword(s):  
Network Theory ◽  
Hierarchical Models ◽  
Random Network ◽  
Automated System ◽  
Random Networks ◽  
Topological Properties ◽  
Connected Component ◽  
Hierarchical Networks ◽  
Component Distribution ◽  
Random Block

In the paper the result of a research done by using the automated system xRandNet is presented, which is designed and implemented for generating and analyzing the main topological properties of some hierarchical models of random networks. The research is related to the connected component distribution of random block-hierarchical networks, which are quite new objects in the random network theory.

scholarly journals Network analysis of whole-brain fMRI dynamics: A new framework based on dynamic communicability

2018 ◽  
Author(s):  
Matthieu Gilson ◽  
Nikos E. Kouvaris ◽  
Gustavo Deco ◽  
Jean-François Mangin ◽  
Cyril Poupon ◽  
...  
Keyword(s):  
Network Analysis ◽  
Network Theory ◽  
Random Network ◽  
Effective Connectivity ◽  
Structural Connectivity ◽  
Real Data ◽  
Brain Regions ◽  
Network Activity ◽  
Whole Brain ◽  
The Brain

AbstractNeuroimaging techniques such as MRI have been widely used to explore the associations between brain areas. Structural connectivity (SC) captures the anatomical pathways across the brain and functional connectivity (FC) measures the correlation between the activity of brain regions. These connectivity measures have been much studied using network theory in order to uncover the distributed organization of brain structures, in particular FC for task-specific brain communication. However, the application of network theory to study FC matrices is often “static” despite the dynamic nature of time series obtained from fMRI. The present study aims to overcome this limitation by introducing a network-oriented analysis applied to whole-brain effective connectivity (EC) useful to interpret the brain dynamics. Technically, we tune a multivariate Ornstein-Uhlenbeck (MOU) process to reproduce the statistics of the whole-brain resting-state fMRI signals, which provides estimates for MOU-EC as well as input properties (similar to local excitabilities). The network analysis is then based on the Green function (or network impulse response) that describes the interactions between nodes across time for the estimated dynamics. This model-based approach provides time-dependent graph-like descriptor, named communicability, that characterize the roles that either nodes or connections play in the propagation of activity within the network. They can be used at both global and local levels, and also enables the comparison of estimates from real data with surrogates (e.g. random network or ring lattice). In contrast to classical graph approaches to study SC or FC, our framework stresses the importance of taking the temporal aspect of fMRI signals into account. Our results show a merging of functional communities over time (in which input properties play a role), moving from segregated to global integration of the network activity. Our formalism sets a solid ground for the analysis and interpretation of fMRI data, including task-evoked activity.

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