scholarly journals Neither ant dominance nor abundance explain ant-plant network structure in Mexican temperate forests

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10435
Author(s):  
Brenda Juárez-Juárez ◽  
Mariana Cuautle ◽  
Citlalli Castillo-Guevara ◽  
Karla López-Vázquez ◽  
María Gómez-Ortigoza ◽  
...  
Keyword(s):  
Trophic Level ◽  
Network Structure ◽  
Dominance Hierarchy ◽  
Ecological Factors ◽  
Interaction Network ◽  
Oak Forest ◽  
Plant Interactions ◽  
The Core ◽  
Core Species ◽  
Dominant Ant

Background Ant-plant mutualistic networks tend to have a nested structure that contributes to their stability, but the ecological factors that give rise to this structure are not fully understood. Here, we evaluate whether ant abundance and dominance hierarchy determine the structure of the ant-plant networks in two types of vegetation: oak and grassland, in two temperate environments of Mexico: Flor del Bosque State Park (FBSP) and La Malinche National Park (MNP). We predicted that dominant and abundant ant species make up the core, and submissives, the periphery of the network. We also expected a higher specialization level in the ant trophic level than in plant trophic level due to competition among the ant species for the plant-derived resources. Methods The ant-plant interaction network was obtained from the frequency of ant-plant interactions. We calculated a dominance hierarchy index for the ants using sampling with baits and evaluated their abundance using pitfall traps. Results In MNP, the Formica spp. species complex formed the core of the network (in both the oak forest and the grassland), while in FBSP, the core species were Prenolepis imparis (oak forest) and Camponotus rubrithorax (grassland). Although these core species were dominant in their respective sites, they were not necessarily the most dominant ant species. Three of the four networks (oak forest and grassland in FBSP, and oak forest in MNP) were nested and had a higher number of plant species than ant species. Although greater specialization was observed in the ant trophic level in the two sites and vegetations, possibly due to competition with the more dominant ant species, this was not statistically significant. In three of these networks (grassland and oak forest of MNP and oak forest of FBSP), we found no correlation between the dominance hierarchy and abundance of the ant species and their position within the network. However, a positive correlation was found between the nestedness contribution value and ant dominance hierarchy in the grassland of the site FBSP, which could be due to the richer ant-plant network and higher dominance index of this community. Conclusions Our evidence suggests that ant abundance and dominance hierarchy have little influence on network structure in temperate ecosystems, probably due to the species-poor ant-plant network and a dominance hierarchy formed only by the presence of dominant and submissive species with no intermediate dominant species between them (absence of gradient in hierarchy) in these ecosystems.

scholarly journals Temporal dynamics of the hummingbird-plant interaction network of a dry forest in Chamela, Mexico: a 30-year follow-up after two hurricanes

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8338
Author(s):  
Sergio Díaz Infante ◽  
Carlos Lara ◽  
Maria del Coro Arizmendi
Keyword(s):  
Plant Species ◽  
Network Structure ◽  
Temporal Dynamics ◽  
Interaction Network ◽  
Dry Forest ◽  
Interaction Networks ◽  
Severe Drought ◽  
Plant Interactions ◽  
Temporal Perspective ◽  
Plant Interaction

Background Interactions among species are a driving force of community structure. The species composition of animal-plant interaction networks can be highly dynamic on a temporal scale, even though the general network structure is usually not altered. However, few studies have examined how interaction networks change over long periods of time, particularly after extreme natural events. We analyzed herein the structure of the hummingbird-plant interaction network in a dry forest of Chamela, Mexico, comparing the structure in 1985–1986 with that in 2016–2017 following the passage of two hurricanes (category 2 Jova in 2011 and category 4 Patricia in 2015). Methods The fieldwork was carried out in the Chamela-Cuixmala Biosphere Reserve in Jalisco, Mexico. In the last 30 years, three severe drought events and two hurricanes have affected this region. Previously, from 1985–1986, hummingbird-plant interactions were recorded monthly for one year in the study area. Then, from 2016–2017, we replicated the sampling in the same localities. We compared the network parameters describing the plant-hummingbird interactions of each period using adjacency matrices. Results We found differences in the number and identity of interacting species, especially plants. The plant species missing in 2016–2017 were either the least connected in the original network (1985–1986) or belonged to groups such as cacti, epiphytes, or trees. The new plant species incorporated in the 2016–2017 network were herbs, vines, and shrubs, or other species barely connected. These changes in the composition are consistent with reports on vegetation damage after strong hurricanes at other study sites. Conversely, all hummingbird species remained in the network, with the exception of Heliomaster constantii, which was primarily connected to a plant species absent in the 2016–2017 network. Migratory and habitat generalist species (i.e., Archilochus spp.) showed higher abundances following the disturbance events. Conclusions Most of the parameters describing the hummingbird-plant network structure remained unchanged after 30 years, with the exception of an increase in plant robustness and hummingbird niche overlap. However, the network’s generalist core was affected by the loss of some species. Also, core plant species such as Ipomoea bracteata, Combretum farinosum, and Justicia candicans were found to be important for maintaining the hummingbird-plant interaction network. The temporal perspective of this study provides unique insights into the conservation of plant-hummingbird networks across time and extreme natural events.

Weak-Tie Confidants

2017 ◽  
Author(s):  
Mario Luis Small
Keyword(s):  
Social Interaction ◽  
Graduate Students ◽  
Network Structure ◽  
Relative Importance ◽  
The Core ◽  
Structure Versus

This chapter examines the “core discussion networks” of graduate students in three departments and shows that, contrary to traditional expectations, many of the ties appear to be weak rather than strong. It considers how the students relate to those they have considered their confidants after six months, and more specifically whether they would as a whole report the same confidants. Three perspectives on the relative importance of network structure versus social interaction are discussed based on the students’ different experiences: the students will keep most confidants, they will drop many of their confidants, or they will drop many confidants but quickly replace them. In general, the students replaced their confidants often.

The Primacy of Experience

2019 ◽  
pp. 64-81
Author(s):  
Andrea Schiavio
Keyword(s):  
Ecological Factors ◽  
Assessment Practices ◽  
Flexible Systems ◽  
Phenomenological Philosophy ◽  
The Core ◽  
Learning Contexts ◽  
Grading Systems ◽  
Recent Developments ◽  
Core Issue ◽  
Event Based

This chapter explores a possible alternative to traditional “paper-and-pencil” assessment practices in music classes. It argues that an approach based on phenomenological philosophy and inspired by recent developments in cognitive science may shed new light on learning and help educators reconsider grading systems accordingly. After individuating the core issue in an unresolved tension between subjective-objective methodologies relevant to certain learning contexts, the chapter proposes a possible remedy by appealing to three principles central to “embodied” approaches to cognition. Such principles may help educators reframe cognitive phenomena (learning described as a measurable event based on “information processing”) in terms of cognitive ecosystems (learning understood as a negotiating and transformative activity codetermined by diverse embodied and ecological factors connected in recurrent fashion). Accommodating this shift implies transforming assessment practices into more open and flexible systems that take seriously the challenge of cooperative learning and phenomenological reflections.

scholarly journals Non-random associations in group housed rats (Rattus norvegicus)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Leanne Proops ◽  
Camille A. Troisi ◽  
Tanja K. Kleinhappel ◽  
Teresa Romero
Keyword(s):  
Network Analysis ◽  
Empirical Evidence ◽  
Rattus Norvegicus ◽  
Dominance Hierarchy ◽  
Group Living ◽  
Ecological Factors ◽  
Limited Evidence ◽  
Rat Strains ◽  
Social Species ◽  
Over Time

AbstractEcological factors, such as predation, have traditionally been used to explain sociability. However, it is increasingly recognised that individuals within a group do not associate randomly, and that these non-random associations can generate fitness advantages. The majority of the empirical evidence on differentiated associations in group-living mammals, however, comes from a limited number of taxa and we still know very little about their occurrence and characteristics in some highly social species, such as rats (Rattus spp.). Here, using network analysis, we quantified association patterns in four groups of male fancy rats. We found that the associations between rats were not randomly distributed and that most individuals had significantly more preferred/avoided associates than expected by random. We also found that these preferences can be stable over time, and that they were not influenced by individuals’ rank position in the dominance hierarchy. Our findings are consistent with work in other mammals, but contrast with the limited evidence available for other rat strains. While further studies in groups with different demographic composition are warranted to confirm our findings, the occurrence of differentiated associations in all male groups of rats have important implications for the management and welfare of captive rat populations.

scholarly journals Mechanism of Compound Houttuynia Mixture as an Anti-COVID-19 Drug Based on Network Pharmacology and Molecular Docking

2021 ◽  
Vol 16 (5) ◽  
pp. 1934578X2110167
Author(s):  
Xing-Pan Wu ◽  
Tian-Shun Wang ◽  
Zi-Xin Yuan ◽  
Yan-Fang Yang ◽  
He-Zhen Wu
Keyword(s):  
Molecular Docking ◽  
Target Prediction ◽  
Interaction Network ◽  
Scientific Basis ◽  
Network Pharmacology ◽  
Chemical Components ◽  
Active Components ◽  
Discovery Studio ◽  
The Core ◽  
Pathway Annotation

Objective To explore the anti-COVID-19 active components and mechanism of Compound Houttuynia mixture by using network pharmacology and molecular docking. Methods First, the main chemical components of Compound Houttuynia mixture were obtained by using the TCMSP database and referring to relevant chemical composition literature. The components were screened for OB ≥30% and DL ≥0.18 as the threshold values. Then Swiss Target Prediction database was used to predict the target of the active components and map the targets of COVID-19 obtained through GeneCards database to obtain the gene pool of the potential target of COVID-19 resistance of the active components of Compound Houttuynia mixture. Next, DAVID database was used for GO enrichment and KEGG pathway annotation of targets function. Cytoscape 3.8.0 software was used to construct a “components-targets-pathways” network. Then String database was used to construct a “protein-protein interaction” network. Finally, the core targets, SARS-COV-2 3 Cl, ACE2 and the core active components of Compound Houttuyna Mixture were imported into the Discovery Studio 2016 Client database for molecular docking verification. Results Eighty-two active compounds, including Xylostosidine, Arctiin, ZINC12153652 and ZINC338038, were screened from Compound Houttuyniae mixture. The key targets involved 128 targets, including MAPK1, MAPK3, MAPK8, MAPK14, TP53, TNF, and IL6. The HIF-1 signaling, VEGF signaling, TNF signaling and another 127 signaling pathways associated with COVID-19 were affected ( P < 0.05). From the results of molecular docking, the binding ability between the selected active components and the core targets was strong. Conclusion Through the combination of network pharmacology and molecular docking technology, this study revealed that the therapeutic effect of Compound Houttuynia mixture on COVID-19 was realized through multiple components, multiple targets and multiple pathways, which provided a certain scientific basis of the clinical application of Compound Houttuynia mixture.

scholarly journals Effect of agricultural land-use change on ant dominance hierarchy and food preferences in a temperate oak forest

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6255 ◽  
Author(s):  
Citlalli Castillo-Guevara ◽  
Mariana Cuautle ◽  
Carlos Lara ◽  
Brenda Juárez-Juárez
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Dominance Hierarchy ◽  
Agricultural Land ◽  
Food Preferences ◽  
Cold Climate ◽  
Agricultural Land Use ◽  
Oak Forest ◽  
Ant Communities ◽  
Trade Off

Background The discovery-dominance trade-off is the inverse relationship between the ability of a species to discover resources and the species’ dominance of those resources; a paradigm used to explain species coexistence in ant communities dependent on similar resources. However, factors such as stress (e.g., temperature) or disturbance (e.g., removal of biomass) associated with the change in land use, can modify this trade-off. Here, we aimed to determine the potential effects of land use change on dominance hierarchy, food preferences and on the discovery-dominance trade-off. Methods An experiment with baits was used to investigate the dominance hierarchies of ant communities in a temperate mountain habitat in central Mexico. We evaluated the dominance index (DI), food preferences and discovery-dominance trade-offs of ants inhabiting two types of vegetation: a native oak forest and agricultural land resulting from agricultural land use and grazing. Results The ant communities in both environments were comprised of three species of ants (Monomorium minimum, Myrmica mexicana, and Camponotus picipes pilosulus), four morphospecies (Pheidole sp.1 and Pheidole sp.2, Temnothorax sp. and Lasius sp.) and one genus (Formica spp.). All Formicidae showed values of intermediate to low DI, and this factor did not seem to be influenced by the change in land use. Ants in the modified vegetation (i.e., agricultural land) were found to be numerically greater. Overall, a higher number of visits were registered to the tuna bait, although the duration of foraging events to the honey baits was longer. However, foraging times were dependent on the species considered: the generalized Myrmicinae, M. minimum, the ant species with highest DI, foraged for longer periods of time in the agricultural land and on the tuna bait. Meanwhile, the cold-climate specialist Formica spp., with a lower DI, foraged for longer periods of time in the oak (although not significant) and on the honey bait. We found little evidence of the discovery-dominance trade-off; instead, we found considerable diversity in the strategies used by the different species to access resources. This range of strategies is well represented by the generalized Myrmicinae M. minimum, the cold-climate specialists Formica spp. and Temnothorax sp., and the rare species, as the cold climate specialist Lasius sp. (insinuators). Conclusions Our evaluation shows that transformation of the original habitat does not appear to affect the hierarchical dominance of the ant communities, but it does affect their food preferences. Species with higher DI values such as the generalized Myrmicinae are more skilled at resource acquisition in modified habitats. Our results suggest that change in land use promotes an increase in the diversity of foraging strategies used by different ant species. This diversity may contribute to resource partitioning which favors coexistence.

scholarly journals Cooperative optimality principals in differential games on networks

2020 ◽  
Vol 12 (4) ◽  
pp. 93-111
Author(s):  
Анна Тур ◽  
Anna Tur ◽  
Леон Аганесович Петросян ◽  
Leon Petrosyan
Keyword(s):  
Characteristic Function ◽  
Differential Games ◽  
Network Structure ◽  
Shapley Value ◽  
The Core ◽  
Investment Game ◽  
The Shapley Value ◽  
Research Investment ◽  
Optimality Principles

The paper describes a class of differential games on networks. The construction of cooperative optimality principles using a special type of characteristic function that takes into account the network structure of the game is investigated. The core, the Shapley value and the tau-value are used as cooperative optimality principles. The results are demonstrated on a model of a differential research investment game, where the Shapley value and the tau-value are explicitly constructed.

scholarly journals Structural and Spatial Associations between Fe, O, and C in the Network Structure of the Leptothrix ochracea Sheath Surface

2011 ◽  
Vol 77 (21) ◽  
pp. 7873-7875 ◽  
Author(s):  
Tomoko Suzuki ◽  
Hideki Hashimoto ◽  
Hiromichi Ishihara ◽  
Tomonari Kasai ◽  
Hitoshi Kunoh ◽  
...  
Keyword(s):  
Network Structure ◽  
Outer Coat ◽  
Content Type ◽  
Spatial Associations ◽  
The Core ◽  
Bacterial Origin ◽  
Gallionella Ferruginea

ABSTRACTThe structural and spatial associations of Fe with O and C in the outer coat fibers of theLeptothrix ochraceasheath were shown to be substantially similar to the stalk fibers ofGallionella ferruginea, i.e., a central C core, probably of bacterial origin, and aquatic Fe interacting with O at the surface of the core.

scholarly journals Field studies reveal functions of chemical mediators in plant interactions

2018 ◽  
Vol 47 (14) ◽  
pp. 5338-5353 ◽  
Author(s):  
Meredith C. Schuman ◽  
Ian T. Baldwin
Keyword(s):  
Interaction Network ◽  
Field Studies ◽  
Plant Interactions ◽  
Chemical Mediators

Chemistry structures plant interactions, providing information and instructions to other organisms; and may be traceable through an interaction network.

scholarly journals The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region—taxonomy of the T. bessonii, T. bonibony, T. dysalum, T. marginatum, T. tsingy, and T. weitzeckeri species groups

Zootaxa ◽  
2012 ◽  
Vol 3365 (1) ◽  
pp. 1 ◽  
Author(s):  
FRANCISCO HITA GARCIA ◽  
BRIAN L. FISHER
Keyword(s):  
New Species ◽  
Single Species ◽  
Species Level ◽  
The Other ◽  
Current Status ◽  
Species Status ◽  
The Core ◽  
Core Species ◽  
Species Groups ◽  
Level Identification

The taxonomy of the T. bessonii, T. bonibony, T. dysalum, T. marginatum, T. tsingy, and T. weitzeckeri species groups isrevised. A total of 33 species is treated, of which 27 are newly described and one is raised to species status. The T.weitzeckeri group contains the single species T. humbloti Forel, which is of Afrotropical origin and the only representativeof the group in the Malagasy region. The species T. bessonii Forel, T. dysalum Bolton, T. marginatum Forel, and T. stein-heili Forel, which were originally members of the T. weitzeckeri group, are now placed in other groups. Tetramorium bes-sonii is the core species of the T. bessonii group, which also contains the four newly described species T. artemis sp. n., T.malagasy sp. n., T. ryanphelanae sp. n., T. wardi sp. n., and T. orientale Forel stat. n., which was a junior synonym of T.bessonii but is now raised to species rank. The T. dysalum group is a moderately-sized group with ten species, of whichonly T. dysalum and T. steinheili were previously known; the other eight species are all newly described. The newly described species in this group are: T. ambatovy sp. n., T. macki sp. n., T. mallenseana sp. n., T. orc sp. n., T. robitika sp. n.,T. sargina sp. n., T. yammer sp. n., and T. vohitra sp. n. A lectotype and several paralectotypes of T. steinheili are desig-nated. Tetramorium marginatum is the central species of the T. marginatum group, which also includes the five newly de-scribed species T. valky sp. n., T. hector sp. n., T. norvigi sp. n., T. shamshir sp. n., and T. silvicola sp. n. The T. bonibonyand T. tsingy groups represent completely new groups that consist entirely of previously unknown, undescribed species.The first group holds the new species T. bonibony sp. n., T. kali sp. n., T. sada sp. n., T. nosybe sp. n., T. olana sp. n., T.popell sp. n., and T. trafo sp. n. and T. vony sp. n. The last group, the T. tsingy group, only contains the two species T. tyrionsp. n. and T. tsingy sp. n., both among the rarest Tetramorium species in Madagascar. All groups are fully revised withillustrated species-level identification keys, and all species are described/re-described and illustrated with high qualitymontage images. In addition, the current status of the Malagasy Tetramorium species groups is discussed and further modifications are proposed.

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