Evolution, Methods papers

The Power of Infinity: Using 3D Fractal Geometry to Study Irregular Organisms

Post provided by Jessica Reichert, André R. Backes, Patrick Schubert and Thomas Wilke

The Problem with the Shape

More than anything else, the phenotype of an organism determines how it interacts with the environment. It’s subject to natural selection, and may help to unravel the underlying evolutionary processes. So shape traits are key elements in many ecological and biological studies.

The growth form of corals is highly variable. ©Jessica Reichert
The growth form of corals is highly variable. ©Jessica Reichert

Commonly, basic parameters like distances, areas, angles, or derived ratios are used to describe and compare the shapes of organisms. These parameters usually work well in organisms with a regular body plan. The shape of irregular organisms – such as many plants, fungi, sponges or corals – is mainly determined by environmental factors and often lacks the distinct landmarks needed for traditional morphometric methods. The application of these methods is problematic and shapes are more often categorised than actually measured.

As scientists though, we favour independent statistical analyses, and there’s an urgent need for reliable shape characterisation based on numerical approaches. So, scientists often determine complexity parameters such as surface/volume ratios, rugosity, or the level of branching. However, these parameters all share the same drawback: they are delineated to a univariate number, taking information from one or few spatial scales and because of this essential information is lost. Continue reading “The Power of Infinity: Using 3D Fractal Geometry to Study Irregular Organisms”

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Lab Methods, Methods papers

Animation Meets Biology: Shedding New Light on Animal Behaviour

Below is a press release about the Methods paper ‘Integrating evolutionary biology with digital arts to quantify ecological constraints on vision-based behaviour‘ taken from the La Trobe University.

Ctenophorus fionni (Peninsula Dragon), male push up display - Copyright Jose Ramos, La Trobe University
Ctenophorus fionni (Peninsula Dragon), male push up display. © Jose Ramos, La Trobe University

Many animals rely on movement to find prey and avoid predators. Movement is also an essential component of the territorial displays of lizards, comprising tail, limb, head and whole-body movements.

For the first time, digital animation has been used as a research tool to examine how the effectiveness of a lizard’s territorial display varies across ecological environments and conditions. The new research was published today in the journal Methods in Ecology and Evolution.

A team from La Trobe University’s School of Life Sciences, led by Dr Richard Peters, worked with academics from Monash University’s Faculty of IT to create, using 3D animation, a series of varied environmental settings and weather conditions, comprising different plant environments and wind conditions, to quantify how lizard displays are affected by this variation. Continue reading “Animation Meets Biology: Shedding New Light on Animal Behaviour”

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Editor Profiles, Journal updates

More New Associate Editors

Today we are welcoming another two Associate Editors to the Methods in Ecology and Evolution. Just like the seven AEs who joined last week, Michael Matschiner (of the University of Basel, Switzerland) and Tiago Bosisio Quental (of the University of São Paulo, Brazil) were both invited to work with the journal following our open call earlier this year. You can find out more about both of them … Continue reading More New Associate Editors

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Methods papers, Virtual Issues

Microbial Methods Virtual Issue

The BES Microbial Ecology Special Interest Group is running a workshop today (Thursday 2 November) on Novel Tools for Microbial Ecology. To compliment this workshop, Xavier Harrison has edited a Virtual Issue of the best Methods in Ecology and Evolution articles on advances in methods of studying microbial evolution and ecology from the past few years.

Advances in Next-Generation Sequencing (NGS) technology now allow us to study associations between hosts and their microbial communities in unprecedented detail. However, studies investigating host-microbe interactions in the field of ecology and evolution are dominated by 16S and ITS amplicon sequencing. While amplicon sequencing is a useful tool for describing microbial community composition, it is limited in its ability to quantify the function(s) performed by members of those communities. Characterising function is vital to understanding how microbes and their hosts interact, and consequently whether those interactions are adaptive for, or detrimental to, the host. The articles in this Virtual Issue cover a broad suite of approaches that allow us to study host-microbe and microbe-microbe interactions in novel ways.

All of the articles in the Microbial Methods Virtual Issue will be freely available for the next two months. You can find out a little more about each one below. Continue reading “Microbial Methods Virtual Issue”

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Editor Profiles, Journal updates

New Associate Editors

Today we are welcoming seven new people to the Methods in Ecology and Evolution Associate Editor Board. All of these new Associate Editors were invited to join the Board following our open call for applications a couple of months ago. You can find out more about them below.

Karen Bacon

Karen Bacon
Karen Bacon

“I am a plant ecologist and palaeoecologist with interests that span the present day to the Mesozoic. My particular interests include plant–atmosphere interactions, fossil plant taphonomy, mass extinctions, stable isotope ecology, and Anthropocene ecology. My current work focuses on the development of plant-based proxies to improve interpretations of plant responses to past environmental change and investigating plant functional traits that lead to success across environmental upheaval events in both the fossil record and present day.”

Torbjørn Ergon

Torbjørn Ergon

“I am a population/evolutionary ecologist with wide interests. My research has mostly been focused on variation in life-history traits and demographic rates within populations, and I have a strong interest in statistical modelling in this field. As an associate editor of Methods in Ecology and Evolution, I hope to promote novel papers that pay close attention to ecological/evolutionary theory in addition to study design and statistical modelling.” Continue reading “New Associate Editors”

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Conservation and management, Methods papers

Midwater Ocean Communities: Sounds Like Siphonophore Soup

Post provided by Roland Proud

How do we know how many fish there are in the ocean? 1000, 1 billion, 1000 billion? We can’t catch them all and count – that’s not practical. Nor can we make observations from Earth-orbiting satellites – light does not penetrate far into the ocean. What we can use is sound.

Sound travels well in water (faster and further than it does in air), so we can use scientific SONAR (echosounders) to produce sound waves and record backscatter from organisms and communities. This provides information concerning their biomass, distribution and behaviour. A recent study used echoes from the mesopelagic zone (200 – 1,000m) to predict global mesopelagic fish biomass to be between 11 and 15 billion tonnes (that’s a lot), suggesting that mesopelagic fish communities could potentially provide global food security.

Mesopelagic Biogeography

In a recent paper, we (the Pelagic Ecology Research Group, PERG at the University of St Andrews) divided the global ocean up into regions based on the properties of echoes from the mesopelagic zone (see below).

10 mesopelagic classes are shown for the open-ocean, echo intensity (a proxy for biomass) increases from blue to red. Coastal zones excluded. Longhurst provinces overlaid. Shapefile here. Proud et al. (2017)
10 mesopelagic classes are shown for the open-ocean, echo intensity (a proxy for biomass) increases from blue to red. Coastal zones excluded. Longhurst provinces overlaid. Shapefile here. Proud et al. (2017)

Continue reading “Midwater Ocean Communities: Sounds Like Siphonophore Soup”

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Evolution, Methods papers, Phylogenetic analysis

Phylogenies, Trait Evolution and Fancy Glasses

Post provided by Daniel S. Caetano

Phylogenetic trees represent the evolutionary relationships among different lineages. These trees give us two crucial pieces of information:

  1. the relationships between lineages (which we can tell from the pattern of the branches (i.e., topology))
  2. the point when lineages separated from a common ancestor (which we can tell from the length of the branches, when estimated from genetic sequences and fossils).
Phylogeny of insects inferred from genetic sequences showing the time of divergence between ants and bees.
Phylogeny of insects inferred from genetic sequences showing the time of divergence between ants and bees.

As systematic biologists, we are interested in the evolutionary history of life. We use phylogenetic trees to uncover the past, understand the present, and predict the future of biodiversity on the planet. Among the tools for this thrilling job are the comparative methods, a broad set of statistical tools built to help us understand and interpret the tree of life.

Here’s a Tree, Now Tell Me Something

The comparative methods we use to study the evolution of traits are mainly based on the idea that since species share a common evolutionary history, the traits observed on these lineages will share this same history. In the light of phylogenetics, we can always make a good bet about how a species will look if we know how closely related it is to another species or group. Comparative models aim to quantify the likelihood of our bet being right and use the same principle to estimate how fast evolutionary changes accumulate over time. Continue reading “Phylogenies, Trait Evolution and Fancy Glasses”

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Methods papers, Online extras

In Situ Measurements of Wildlife

Measurements of morphological features are important for ecological studies, especially on free-ranging wild animal species. Conventionally, specimens either dead or in captivity are used for morphometric studies, which is difficult in the case of wild species for several reasons.‘In situ measurements of animal morphological features: a non-invasive method’ presents a new way to estimate an individual’s morphometric measurements using metadata from digital photographs. Dr. Mylswamy Mahendiran and … Continue reading In Situ Measurements of Wildlife

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Journal updates

Issue 8.8

Issue 8.10 is now online!

The October issue of Methods is now online!

This double-sized issue contains three Applications articles and two Open Access articles. These five papers are freely available to everyone, no subscription required.

– Phylogenetic Trees: The fields of phylogenetic tree and network inference have advanced independently, with only a few attempts to bridge them. Schliep et al. provide a framework, implemented in R, to transfer information between trees and networks.

– Emon: Studies, surveys and monitoring are often costly, so small investments in preliminary data collection and systematic planning of these activities can help to make best use of resources. To meet recognised needs for accessible tools to plan some aspects of studies, surveys and monitoring, Barry et al. developed the R package emon, which includes routines for study design through power analysis and feature detection.

– Haplostrips: A tool to visualise polymorphisms of a given region of the genome in the form of independently clustered and sorted haplotypes. Haplostrips is a command-line tool written in Python and R, that uses variant call format files as input and generates a heatmap view.

Continue reading “Issue 8.8”

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Conservation and management, Lab Methods, Methods papers

Imperfect Pathogen Detection: What to Do When Sampling and Diagnostic Tests Produce Inaccurate Results

Post Provided by Graziella DiRenzo

A salamander having its skin swabbed to test for Bsal infection.
A salamander having its skin swabbed to test for Bsal infection.

Imagine you’re at the doctor’s office. You’re waiting to hear back on a critical test result. With recent emerging infectious diseases in human populations, you are worried you may be infected after a sampling trip to a remote field site. The doctor walks in. You sit nervously, sensing a slight tremble in your left leg. The doctor confidently declares, “Well, your tests results came back negative.” In that moment, you let out a sigh of relief, the kind you feel throughout your body. Then, thoughts start flooding your mind. You wonder– what are the rates of false negatives associated with the test? How sensitive is the diagnostic test to low levels of infection? The doctor didn’t sample all of your blood, so how can they be sure I’m not infected? Is the doctor’s conclusion right?

 Now, let’s say I’m the doctor and my patient is an amphibian. I don’t have an office where the amphibian can come in and listen to me explain the diagnosis or the progression of disease − BUT I do regularly test amphibians in the wild for a fatal fungal pathogen, known as Batrachochytrium dendrobatidis (commonly known as Bd). Diseases like Bd are among the leading causes of the approximately one-third of amphibian species that are threatened, near threatened, or vulnerable to extinction. To test for Bd, and the recently emerged sister taxon Batrachochytrium salamandrivorans (hereafter referred to as: Bsal), disease ecologists rely on non-invasive skin swabs. Continue reading “Imperfect Pathogen Detection: What to Do When Sampling and Diagnostic Tests Produce Inaccurate Results”

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