scholarly journals Niche and neutral processes leave distinct structural imprints on indirect interactions in mutualistic networks

2020 ◽  
Author(s):  
Benno I. Simmons ◽  
Andrew P. Beckerman ◽  
Katrine Hansen ◽  
Pietro K. Maruyama ◽  
Constantinos Televantos ◽  
...  
Keyword(s):  
Detailed Analysis ◽  
Evolutionary Dynamics ◽  
Flowering Plants ◽  
Indirect Interactions ◽  
Indirect Interaction ◽  
Interaction Patterns ◽  
Bipartite Networks ◽  
Hummingbird Pollination ◽  
Generate Plant ◽  
Network Metrics

AbstractIndirect interactions are central to ecological and evolutionary dynamics in pollination communities, yet we have little understanding about the processes determining patterns of indirect interactions, such as those between pollinators through shared flowering plants. Instead, research has concentrated on the processes responsible for direct interactions and whole-network structures. This is partly due to a lack of appropriate tools for characterising indirect interaction structures, because traditional network metrics discard much of this information. The recent development of tools for counting motifs (subnetworks depicting interactions between a small number of species) in bipartite networks enable detailed analysis of indirect interaction patterns. Here we generate plant-hummingbird pollination networks based on three major assembly processes – neutral effects (species interacting in proportion to abundance), morphological matching and phenological overlap – and evaluate the motifs associated with each one. We find that different processes produce networks with significantly different patterns of indirect interactions. Neutral effects tend to produce densely-connected motifs, with short indirect interaction chains, and motifs where many specialists interact indirectly through a single generalist. Conversely, niche-based processes (morphology and phenology) produced motifs with a core of interacting generalists, supported by peripheral specialists. These results have important implications for understanding the processes determining indirect interaction structures.

scholarly journals Trait-mediated indirect interactions of ant shape on the attack of caterpillars and fruits

2016 ◽  
Vol 12 (8) ◽  
pp. 20160401 ◽  
Author(s):  
Wesley Dáttilo ◽  
Armando Aguirre ◽  
Pedro Luna De la Torre ◽  
Lucas A. Kaminski ◽  
Juan García-Chávez ◽  
...  
Keyword(s):  
Empirical Evidence ◽  
Visual Cues ◽  
Evolutionary Dynamics ◽  
Interspecific Interactions ◽  
Indirect Interactions ◽  
High Diversity

Mainly owing to their high diversity and abundance, ants are formidable as predators and defenders of foliage. Consequently, ants can exclude both invertebrate and vertebrate activity on plants via direct and indirect interactions as already shown in many previous studies. Here we present empirical evidence that objects resembling ant shape on dummy caterpillars were able to repel visually oriented predators. Moreover, we also show that rubber ants on dummy fruits can repel potential fruit dispersers. Our results have direct implications on the ecological and evolutionary dynamics of interactions in ant-based systems, as ant presence could affect the fitness of its partners. In short, our study highlights the importance of visual cues in interspecific interactions and opens a new way to study the effects of ant presence to test ecological and evolutionary hypotheses.

scholarly journals Bipartite networks improve understanding of effects of waterbody size and angling method on angler–fish interactions

2018 ◽  
Vol 75 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Christopher J. Chizinski ◽  
Dustin R. Martin ◽  
Daizaburo Shizuka ◽  
Kevin L. Pope
Keyword(s):  
Fish Species ◽  
Interaction Networks ◽  
Bipartite Networks ◽  
Recreational Fisheries ◽  
Fishery Science ◽  
Size Number ◽  
Catch Rates ◽  
Multiple Metrics ◽  
Network Metrics ◽  
Fish Interactions

Networks used to study interactions could provide insights to fisheries. We compiled data from 27 297 interviews of anglers across waterbodies that ranged in size from 1 to 12 113 ha. Catch rates of fish species among anglers grouped by species targeted generally differed between angling methods (bank or boat). We constructed angler–catch bipartite networks (angling method specific) between anglers and fish and measured several network metrics. There was considerable variation in networks among waterbodies, with multiple metrics influenced by waterbody size. Number of species-targeting angler groups and number of fish species caught increased with increasing waterbody size. Mean number of links for species-targeting angler groups and fish species caught also increased with waterbody size. Connectance (realized proportion of possible links) of angler–catch interaction networks decreased slower for boat anglers than for bank anglers with increasing waterbody size. Network specialization (deviation of number of interactions from expected) was not significantly related to waterbody size or angling methods. Application of bipartite networks in fishery science requires careful interpretation of outputs, especially considering the numerous confounding factors prevalent in recreational fisheries.

scholarly journals Pola Interaksi Anak dan Orangtua Selama Kebijakan Pembelajaran di Rumah

2020 ◽  
Vol 1 (1) ◽  
pp. 124-140
Author(s):  
Khamim Zarkasih Putro ◽  
Muhammad Adly Amri ◽  
Nuraisah Wulandari ◽  
Dedek Kurniawan
Keyword(s):  
Qualitative Study ◽  
Direct Interaction ◽  
Research Data ◽  
Learning Activities ◽  
Indirect Interaction ◽  
Interaction Patterns ◽  
Parents And Children ◽  
Patterns Of Interaction ◽  
Do So ◽  
At Home

This study aims to reveal the effectiveness of the implementation of learning from home, and patterns of interaction between parents and children during learning from home. Set the pattern of interaction between parents and children during the learning policy from home is very important to do, so that children can voluntarily learn, and parents can easily control and improve children's learning activities and outcomes at home. The method used in this research is a qualitative study based on descriptive studies, meaning that research methods require results in the form of descriptions, or a complete and complex depiction of research data and facts. In this case the depiction in question is the pattern of interaction between parents and children during distance learning or at home during the Covid-19 pandemic. The results showed that the position of parents in managing interactions with their children is very important for the continuity of learning. Interaction patterns of interaction between parents and children as the findings of this study show two patterns, direct interaction; in this case parents and children together follow the learning provided by the teacher. Indirect interaction in this case parents only as a facilitator, for the implementation of learning.

scholarly journals Indirect interactions influence contact network structure and diffusion dynamics

2019 ◽  
Vol 6 (8) ◽  
pp. 190845 ◽  
Author(s):  
Md Shahzamal ◽  
Raja Jurdak ◽  
Bernard Mans ◽  
Frank de Hoog
Keyword(s):  
Disease Transmission ◽  
Infected Individual ◽  
Indirect Interactions ◽  
Decay Rates ◽  
High Rate ◽  
Contact Network ◽  
Interaction Patterns ◽  
Contact Networks ◽  
Diffusion Dynamics ◽  
Airborne Disease

Interaction patterns at the individual level influence the behaviour of diffusion over contact networks. Most of the current diffusion models only consider direct interactions, capable of transferring infectious items among individuals, to build transmission networks of diffusion. However, delayed indirect interactions, where a susceptible individual interacts with infectious items after the infected individual has left the interaction space, can also cause transmission events. We define a diffusion model called the same place different time transmission (SPDT)-based diffusion that considers transmission links for these indirect interactions. Our SPDT model changes the network dynamics where the connectivity among individuals varies with the decay rates of link infectivity. We investigate SPDT diffusion behaviours by simulating airborne disease spreading on data-driven contact networks. The SPDT model significantly increases diffusion dynamics with a high rate of disease transmission. By making the underlying connectivity denser and stronger due to the inclusion of indirect transmissions, SPDT models are more realistic than same place same time transmission (SPST)-based models for the study of various airborne disease outbreaks. Importantly, we also find that the diffusion dynamics including indirect links are not reproducible by the current SPST models based on direct links, even if both SPDT and SPST networks assume the same underlying connectivity. This is because the transmission dynamics of indirect links are different from those of direct links. These outcomes highlight the importance of the indirect links for predicting outbreaks of airborne diseases.

scholarly journals Evolution of Cooperation in the Presence of Higher-Order Interactions: From Networks to Hypergraphs

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 744
Author(s):  
Giulio Burgio ◽  
Joan T. Matamalas ◽  
Sergio Gómez ◽  
Alex Arenas
Keyword(s):  
Evolutionary Dynamics ◽  
Higher Order ◽  
Structured Populations ◽  
Evolution Of Cooperation ◽  
Mathematical Representation ◽  
Interaction Patterns ◽  
Group Interactions ◽  
Cooperative Phenomena ◽  
Structured Population ◽  
Pairwise Models

Many real systems are strongly characterized by collective cooperative phenomena whose existence and properties still need a satisfactory explanation. Coherently with their collective nature, they call for new and more accurate descriptions going beyond pairwise models, such as graphs, in which all the interactions are considered as involving only two individuals at a time. Hypergraphs respond to this need, providing a mathematical representation of a system allowing from pairs to larger groups. In this work, through the use of different hypergraphs, we study how group interactions influence the evolution of cooperation in a structured population, by analyzing the evolutionary dynamics of the public goods game. Here we show that, likewise to network reciprocity, group interactions also promote cooperation. More importantly, by means of an invasion analysis in which the conditions for a strategy to survive are studied, we show how, in heterogeneously-structured populations, reciprocity among players is expected to grow with the increasing of the order of the interactions. This is due to the heterogeneity of connections and, particularly, to the presence of individuals standing out as hubs in the population. Our analysis represents a first step towards the study of evolutionary dynamics through higher-order interactions, and gives insights into why cooperation in heterogeneous higher-order structures is enhanced. Lastly, it also gives clues about the co-existence of cooperative and non-cooperative behaviors related to the structural properties of the interaction patterns.

scholarly journals Finding missing links in interaction networks

2019 ◽  
Author(s):  
J. Christopher D. Terry ◽  
Owen T. Lewis
Keyword(s):  
Network Structure ◽  
Research Effort ◽  
Structural Models ◽  
Ecological Communities ◽  
Bipartite Networks ◽  
Deficit Model ◽  
True Number ◽  
Underlying Network ◽  
Highly Correlated ◽  
Network Metrics

AbstractDocumenting which species interact within ecological communities is challenging and labour-intensive. As a result, many interactions remain unrecorded, potentially distorting our understanding of network structure and dynamics. We test the utility of four structural models and a new coverage-deficit model for predicting missing links in both simulated and empirical bipartite networks. We find they can perform well, but that the predictive power of structural models varies with the underlying network structure. Predictions can be improved by ensembling multiple models. Sample-coverage estimators of the number of missed interactions are highly correlated with the number of missed interactions, but strongly biased towards underestimating the true number of missing links. Augmenting observed networks with most-likely missing links improves estimates of qualitative network metrics. Tools to identify likely missing links can be simple to implement, allowing the prioritisation of research effort and more robust assessment of network properties.

scholarly journals Uncovering indirect interactions in bipartite ecological networks

2018 ◽  
Author(s):  
Benno I. Simmons ◽  
Alyssa R. Cirtwill ◽  
Nick J. Baker ◽  
Lynn V. Dicks ◽  
Daniel B. Stouffer ◽  
...  
Keyword(s):  
Ecological Networks ◽  
Indirect Interactions ◽  
Ecological Communities ◽  
Bipartite Networks ◽  
New Paradigm ◽  
Diverse Range ◽  
Constituent Species ◽  
Quantitative Analyses ◽  
Plant Pollinator ◽  
New Framework

AbstractIndirect interactions play an essential role in governing population, community and coevolutionary dynamics across a diverse range of ecological communities. Such communities are widely represented as bipartite networks: graphs depicting interactions between two groups of species, such as plants and pollinators or hosts and parasites. For over thirty years, studies have used indices, such as connectance and species degree, to characterise the structure of these networks and the roles of their constituent species. However, compressing a complex network into a single metric necessarily discards large amounts of information about indirect interactions. Given the large literature demonstrating the importance and ubiquity of indirect effects, many studies of network structure are likely missing a substantial piece of the ecological puzzle. Here we use the emerging concept of bipartite motifs to outline a new framework for bipartite networks that incorporates indirect interactions. While this framework is a significant departure from the current way of thinking about networks, we show that this shift is supported by quantitative analyses of simulated and empirical data. We use simulations to show how consideration of indirect interactions can highlight ecologically important differences missed by the current index paradigm. We extend this finding to empirical plant-pollinator communities, showing how two bee species, with similar direct interactions, differ in how specialised their competitors are. These examples underscore the need for a new paradigm for bipartite ecological networks: one incorporating indirect interactions.

Macro and micro network metrics as indicators of training tasks adjustment to players’ tactical level

2020 ◽  
pp. 174795412097956
Author(s):  
João Cláudio Machado ◽  
Rodrigo Aquino ◽  
Alberto Góes Júnior ◽  
João Bosco Júnior ◽  
Daniel Barreira ◽  
...  
Keyword(s):  
Social Networks ◽  
Clustering Coefficient ◽  
Soccer Players ◽  
Interaction Patterns ◽  
Training Context ◽  
Network Metrics ◽  
Level Group

We aimed to investigate if social networks measures can be used as indicators of training tasks' adjustment level to soccer players’ tactical skills. Twenty-four U17 male soccer players (16.89 ± 0.11 years) participated in this study. The System of Tactical Assessment in Football (FUT-SAT) was used to identify players’ tactical level and to organize them into three groups: Higher tactical level (Group 01), Intermediate tactical level (Group 02) and Lower tactical level (Group 03). Then, the players performed three High difficulty Small-Sided and Conditioned Games (HD-SSCG) and three Low difficulty Small-Sided and Conditioned Games (LD-SSCG). Teams’ interaction patterns and players’ prominence were analysed based on macro (Density – D and Clustering coefficient – CC) and micro networks (Indegree, Outdegree, Total links and Eigenvector) measures. We found that Group 01 presented higher D (p = .004 and ES = 1.189) and CC (p =.004 and ES = .785) at HD-SSCG than Group 03, whereas Group 03 presented higher values of D (p = .003 and ES = 1.200) and CC (p = .037 and ES = 1.180) at LD-SSCG than Group 01. When training tasks difficulty were adjusted to players’ tactical level, teams played more collectively and players were more actively engaged in ball circulation. We concluded that macro and micro networks measures can be applied in training context as indicators of training tasks adjustment to players' tactical level.

scholarly journals Species interactions in an Andean bird–flowering plant network: phenology is more important than abundance or morphology

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2789 ◽  
Author(s):  
Oscar Gonzalez ◽  
Bette A. Loiselle
Keyword(s):  
Species Interactions ◽  
Evolutionary Dynamics ◽  
Process Models ◽  
Flowering Plant ◽  
Forest Zone ◽  
Neutral Processes ◽  
Ideal System ◽  
Biological Constraints ◽  
Network Metrics ◽  
Plant Pollinator

Biological constraints and neutral processes have been proposed to explain the properties of plant–pollinator networks. Using interactions between nectarivorous birds (hummingbirds and flowerpiercers) and flowering plants in high elevation forests (i.e., “elfin” forests) of the Andes, we explore the importance of biological constraints and neutral processes (random interactions) to explain the observed species interactions and network metrics, such as connectance, specialization, nestedness and asymmetry. In cold environments of elfin forests, which are located at the top of the tropical montane forest zone, many plants are adapted for pollination by birds, making this an ideal system to study plant–pollinator networks. To build the network of interactions between birds and plants, we used direct field observations. We measured abundance of birds using mist-nets and flower abundance using transects, and phenology by scoring presence of birds and flowers over time. We compared the length of birds’ bills to flower length to identify “forbidden interactions”—those interactions that could not result in legitimate floral visits based on mis-match in morphology.Diglossaflowerpiercers, which are characterized as “illegitimate” flower visitors, were relatively abundant. We found that the elfin forest network was nested with phenology being the factor that best explained interaction frequencies and nestedness, providing support for biological constraints hypothesis. We did not find morphological constraints to be important in explaining observed interaction frequencies and network metrics. Other network metrics (connectance, evenness and asymmetry), however, were better predicted by abundance (neutral process) models. Flowerpiercers, which cut holes and access flowers at their base and, consequently, facilitate nectar access for other hummingbirds, explain why morphological mis-matches were relatively unimportant in this system. Future work should focus on how changes in abundance and phenology, likely results of climate change and habitat fragmentation, and the role of nectar robbers impact ecological and evolutionary dynamics of plant–pollinator (or flower-visitor) interactions.

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