Adaptive foraging of pollinators fosters gradual tipping under resource competition and rapid environmental change.

Plant and pollinator communities are vital for transnational food chains. Like many natural systems, they are affected by global change: rapidly deteriorating conditions threaten their numbers. Previous theoretical studies identified the potential for community-wide collapse above critical levels of environmental stressors-so-called bifurcation-induced tipping points.

Intermittent migration can induce pulses of speciation in a two-island system.

Geographic barriers can come and go depending on natural conditions. These fluctuations cause population cycles of expansion and contraction, introducing intermittent migrations that may not hinder speciation but rather promote diversification. Here, we study a neutral 2-island speciation model with intermittent migration driven by sea-level fluctuations.

Evolution of cooperation in a two-species system with a common resource pool.

Understanding the evolution of cooperation is a major question in Evolutionary Biology. Here, we extend a previously proposed mathematical model in Evolutionary Game Theory that investigated how resource use by a single species composed of cooperators and defectors may lead to its maintenance or extinction. We include another species in the model, so as to investigate how different intra and interspecific interactions of cooperative or competitive nature among individuals that share the same essential resource may drive the survival and evolution of the species.

Effect of Host-Switching on the Ecological and Evolutionary Patterns of Parasites.

Speciation via host-switching is a macroevolutionary process that emerges from a microevolutionary dynamic where individual parasites switch hosts, establish a new association, and reduce reproductive contact with the original parasite lineage. Phylogenetic distance and geographic distribution of the hosts have been shown to be determinants of the capacity and opportunity of the parasite to change hosts. Although speciation via host-switching has been reported in many host-parasite systems, its dynamic on the individual, population and community levels is poorly understood.

Diversity patterns and speciation processes in a two-island system with continuous migration.

Geographic isolation is a central mechanism of speciation, but perfect isolation of populations is rare. Although speciation can be hindered if gene flow is large, intermediate levels of migration can enhance speciation by introducing genetic novelty in the semi-isolated populations or founding small communities of migrants. Here, we consider a two-island neutral model of speciation with continuous migration and study diversity patterns as a function of the migration probability, population size, and number of genes involved in reproductive isolation (dubbed as genome size).

Model-based estimation of transmissibility and reinfection of SARS-CoV-2 P.1 variant.

Background: The SARS-CoV-2 variant of concern (VOC) P.1 (Gamma variant) emerged in the Amazonas State, Brazil, in November 2020. The epidemiological consequences of its mutations have not been widely studied, despite detection of P.

Shannon information criterion for low-high diversity transition in Moran and voter models.

Mutation and drift play opposite roles in genetics. While mutation creates diversity, drift can cause gene variants to disappear, especially when they are rare. In the absence of natural selection and migration, the balance between the drift and mutation in a well-mixed population defines its diversity.

Brazil in the face of new SARS-CoV-2 variants: emergencies and challenges in public health.

This article discusses the epidemic situation of Covid-19 in Brazil, in the face of the emergence of a new strain called P.1, which is more transmissible and may be associated with reinfection. Given the collapse of hospital care in Manaus in January 2021 and the results of three recent preprints, each that reports increased transmissibility of the P.

Interaction generalisation and demographic feedbacks drive the resilience of plant-insect networks to extinctions.

Understanding the processes driving ecological resilience, that is the extent to which systems retain their structure while absorbing perturbations, is a central challenge for theoretical and applied ecologists. Plant-insect assemblages are well-suited for the study of ecological resilience as they are species-rich and encompass a variety of ecological interactions that correspond to essential ecosystem functions. Mechanisms affecting community response to perturbations depend on both the natural history and structure of ecological interactions.

Signatures of Microevolutionary Processes in Phylogenetic Patterns.

Phylogenetic trees are representations of evolutionary relationships among species and contain signatures of the processes responsible for the speciation events they display. Inferring processes from tree properties, however, is challenging. To address this problem, we analyzed a spatially-explicit model of speciation where genome size and mating range can be controlled.

A genetic approach to the rock-paper-scissors game.

Polymorphisms are usually associated with defenses and mating strategies, affecting the individual's fitness. Coexistence of different morphs is, therefore, not expected, since the fittest morph should outcompete the others. Nevertheless, coexistence is observed in many natural systems.

Nestedness across biological scales.

Biological networks pervade nature. They describe systems throughout all levels of biological organization, from molecules regulating metabolism to species interactions that shape ecosystem dynamics. The network thinking revealed recurrent organizational patterns in complex biological systems, such as the formation of semi-independent groups of connected elements (modularity) and non-random distributions of interactions among elements.

Modelling the heart as a communication system.

Electrical communication between cardiomyocytes can be perturbed during arrhythmia, but these perturbations are not captured by conventional electrocardiographic metrics. We developed a theoretical framework to quantify electrical communication using information theory metrics in two-dimensional cell lattice models of cardiac excitation propagation. The time series generated by each cell was coarse-grained to 1 when excited or 0 when resting.

The structure of ant-plant ecological networks: is abundance enough?

Knowledge of the mechanisms that shape biodiversity is essential to understand the ecological and evolutionary dynamics of interacting species. Recent studies posit that most of the organization of mutualistic networks is shaped by differences in species abundance among interacting species. In this study, we examined the mutualism involving plants with extrafloral nectaries and their associated ants.

Structure and mechanism of diet specialisation: testing models of individual variation in resource use with sea otters.

Studies of consumer-resource interactions suggest that individual diet specialisation is empirically widespread and theoretically important to the organisation and dynamics of populations and communities. We used weighted networks to analyze the resource use by sea otters, testing three alternative models for how individual diet specialisation may arise. As expected, individual specialisation was absent when otter density was low, but increased at high-otter density.

Analysis of a hyper-diverse seed dispersal network: modularity and underlying mechanisms.

Mutualistic interactions involving pollination and ant-plant mutualistic networks typically feature tightly linked species grouped in modules. However, such modularity is infrequent in seed dispersal networks, presumably because research on those networks predominantly includes a single taxonomic animal group (e.g.

The modularity of seed dispersal: differences in structure and robustness between bat- and bird-fruit networks.

In networks of plant-animal mutualisms, different animal groups interact preferentially with different plants, thus forming distinct modules responsible for different parts of the service. However, what we currently know about seed dispersal networks is based only on birds. Therefore, we wished to fill this gap by studying bat-fruit networks and testing how they differ from bird-fruit networks.

The missing part of seed dispersal networks: structure and robustness of bat-fruit interactions.

Mutualistic networks are crucial to the maintenance of ecosystem services. Unfortunately, what we know about seed dispersal networks is based only on bird-fruit interactions. Therefore, we aimed at filling part of this gap by investigating bat-fruit networks.