Lab life during lockdown

Lab life has, of necessity, been curtailed throughout the world but it has provided an opportunity for researchers to spend time trawling the literature for data to use in meta-analyses. Our lab is no different and so in this edition of lab life we aim to give an overview about what some of our members have been working on.

Michaela Parascandalo has continued the data mining of reproduction data to enable the group to ask: do larger individuals produce disproportionately more gametes / offspring than smaller individuals in taxa other than fish? So far, we have more than 1000 species across 10 phyla and more than 100,000 data points.

One tricky element of this data collection has been converting the different body size measurements to mass. For example, a paper may present data on head width in wasps, hind tibia length in grasshoppers, or carapace lengths in crabs but Michaela needs to convert this to a measure of mass. To do this she has had to create a repository of morphometric allometries for a number of different species, another great resource for other meta analyses that the lab group might do in which body mass needs to be calculated.

A separate study is also underway that is looking at not only the number of offspring but the size of those offspring in relation to maternal size. So, Melanie Lovass, with help from Michaela, has been compiling data to enable Hayley Cameron and our (now virtual) visitor Darren Johnson from California State University to ask the question: do bigger mothers produce bigger and/or more offspring and are there any differences between warm-blooded and cold-blooded animals?

PhD student, Emily Richardson is particularly interested in organisms that have complex life histories or, in other words, go through metamorphosis to become adults. Emily is gathering data on growth rates in amphibians, fish and marine invertebrates to test the theory that growth rate is maximised relative to mortality rate at the time of metamorphosis, which would mean that fitness is increased.

George Jarvis and Sam Ginther are also doing meta-analyses that relate to their PhD projects. George, like Emily, is interested in organisms with complex life histories but he is looking at large scale evolutionary change in metabolic rate. For his meta-analysis he is compiling metabolic data from marine invertebrates and looking at how metabolic rates vary between species with different developmental modes. With this work, he hopes to better understand the evolution of metabolic rate in complex life cycles.

Sam is interested in the cost of reproduction. He is collecting data on metabolic rates in reproductive and non-reproductive adults as well as their offspring.  This will help him understand how the energy used for reproduction affects the production of offspring in species with dramatically different life histories.

Louise Noergaard has just started a post doc in the CGB and is busy working on a collaborative project between Dustin Marshall and Beth McGraw from Penn State University. Louise is looking at the relationship between wing length and body mass in mosquitoes and assessing how these measures of size relate to lifetime reproductive output. This information can then be put into a model that will consider how these measures of size and reproductive output affect existing predictions of mosquito spread.

Several members of the group are interested in organisms with complex lifestyles. The marine tubeworm Spirorbidae shown here is an example. Larvae are released from the adult brood chamber via a split in the chamber wall (a), the larvae are non-feeding, free swimming (b), when they find a suitable surface the larvae settle and start to metamorphose (c/d) and once metamorphosis is complete newly settled juveniles start to feed.

Research fellow position: ecologist specialising in life history theory

Update: this position has now been filled.

  • Level A, research-only academic
  • $66,706 to $90,532 pa + 9.5% superannuation
  • Full-time, starting late 2018
  • Two-year, fixed-term
  • Monash University Clayton campus

The Centre for Geometric Biology is currently seeking to recruit an experienced ecologist who specialises in life history theory. This position will be with Professor Dustin Marshall and based within the School of Biological Sciences at Clayton Campus.

As the successful candidate, you will be expected to use existing datasets to investigate evolutionary patterns both within and across species, but more importantly demonstrate a strong conceptual understanding of relevant life history theory and have a demonstrated track record in producing high quality publications. 

Key selection criteria

  1. The appointee will have a doctoral qualification in life history theory or evolutionary ecology
  2. Demonstrated analytical and manuscript preparation skills; including an excellent track record of refereed research publications in high impact journals
  3. Demonstrated experience in asking questions about life history theory using cutting-edge quantitative approaches
  4. Ability to solve complex problems by using discretion, innovation and the exercise of diagnostic skills and/or expertise
  5. Well-developed planning and organisational skills, with the ability to prioritise multiple tasks and set and meet deadlines
  6. Excellent written communication and verbal communication skills with proven ability to produce clear, succinct reports and documents
  7. A demonstrated awareness of the principles of confidentiality, privacy and information handling
  8. A demonstrated capacity to work in a collegiate manner with other staff in the workplace
  9. Demonstrated computer literacy and proficiency in the production of high level work using software such as Microsoft Office applications and specified University software programs, with the capability and willingness to learn new packages as appropriate

Enquiries to Professor Dustin Marshall on +61 3 9902 4449

For more information, or to apply, refer to the Monash University website

Student session: Applying for a postdoc

Not all PhD students want to pursue a career in academia; some definitely do, while others feel that they would like to further their academic training through doing a postdoctoral fellowship before moving into industry or other fields.

But how do you go about getting a postdoc? 

Professors Dustin Marshall and Craig White will be speaking about their experiences as academics looking for postdocs, and we invite students and interested early career researchers to join us armed with questions about how to go about getting a postdoc, what to expect from a postdoc and ‘conversations you should have’ when starting a postdoc.

When: 2 pm, Thursday 23 August 2018

Where: Sanson Room (22 G01/02) Rainforest Walk, Monash University Clayton

Focus on PhD research

May has been a busy month for the postgraduate students within the Centre for Geometric Biology. Not least with Amanda Pettersen graduating just before flying out to Sweden to begin a postdoc position.

Alex Gangur, who arrived from the UK in February of this year is immersed in pilot studies to help him design an experiment that will be central to his PhD research.  

Alex is interested in how natural selection will play out in areas that differ in productivity. He is planning a large, long term laboratory experiment where he will manipulate food densities of a marine, harpacticoid copepod (Tisbe sp.) to provide environments that are able to support different numbers of copepod, that is, have different carrying capacities. Alex will then be able to track numerous life history characteristics, such as size, reproductive effort, age at reproduction etc, in the copepods over multiple generations.  

In order to be sure that his proposed food densities create environments where population growth is limited by food and not some other factor, Alex is testing his experimental food densities in a pilot study. If populations stop increasing as food is increased then the population size is limited by something other than food and Alex will need to use a lower food concentration.

To further fine-tune his experimental protocols, Alex wants to know if he can use chemostats to grow up his copepod populations rather than glass bottles.  

The chemostats work by bubbling air up through the bottom of the chamber which, while an advantage in keeping waste build-up to a minimum, can have a downside as airflow can kill copepods if it gets in under the carapace.  Alex will monitor the growth of a population split between a glass bottle and a chemostat to see if they are the same and, if they are, he can go ahead and use the chemostat. 

Lukas Schuster is approximately half way through his PhD candidature. He is currently running two experiments using one of the lab’s favourite animals; the colonial bryozoan Bugula neritina. Lukas is interested in how metabolic rate (a measure of energy use) co-varies with measures of survival, growth and reproductive rate. By directly linking metabolic rate to measures of fitness Lukas can measure how selection acts on metabolic rate.

In his first experiment for this field season Lukas is deploying newly settled Bugula on panels that are either hung horizontally – a benign environment for Bugula – or vertically; a harsher environment due to increased exposure to UV and sediments. 

We know that the harsher environment tends to reduce growth rates, reproductive output and survival in this species, but what we don’t know is if, or how, selection on metabolic rates differs between these two environments.  Every 2 weeks Lukas collects his panels from the two environments and brings them back to the lab where he measures colony size, growth rate, survival, and reproductive output (number of ovicells) as well as metabolic rate for each of approximately 400 individual colonies. 

Lukas has another 1,000 colonies in the field that he is monitoring fortnightly for a separate experiment. In this one, Lukas has taken a field populations of Bugula and measured metabolic rate for every individual colony. He then selected colonies with low, high or intermediate metabolic rates so that he has effectively created new populations that have different mean metabolic rates. At the same time, he is manipulating densities so that he will be able to tell if it is population density or metabolic rate that is having an effect on the growth rate, survival and reproductive output of the Bugula colonies.

Hayley Cameron is in her final year of her PhD and is following up on earlier experiments. Hayley is also using Bugula neritina as a model species to test some fundamental theoretical ideas. Hayley is interested in the outcomes of maternal investment. She is spawning Bugula in the lab and then choosing big, small or intermediate larvae to settle and create populations of siblings that differ in mean size. Hayley wants to know if it is better to produce a few, larger, offspring, or more, smaller, offspring when they have to compete with their siblings (which many marine invertebrates do).

Hayley has returned her populations of different sizes to the field and every week measures size, number of ovicells and survival for each of her 300 individuals. She has been doing this for 9 weeks so far, but will continue to track each individual’s performance across their entire life span (probably a matter of months). In addition Hayley is spawning her colonies in the lab when they are reproductive because she wants to know what size offspring they make.  Will the bigger offspring do better, even when in competition with their siblings and, in turn, make bigger offspring themselves? Watch this space.

Staff news

Mike Cullen Research Fellow Award

Congratulations to Giulia Ghedini who was recently awarded the Mike Cullen Research Fellow Award. This prize was awarded to Giulia for her Ecology paper Does energy flux predict density-dependence? An empirical field test, which was the subject of a previous post.

Giulia’s work is important because it is the first demonstration of the energetic mechanisms that underpin density-dependence. Up until now reductions in body size in denser populations have been attributed to reduced food intake due to increased competition, but Giulia found that it was not so simple. In her study, she found that population density influences both the energy intake (food consumption) and expenditure (metabolism) of individuals. By reconstructing their energy budgets across population densities, she was able to demonstrate that smaller sizes result from the faster decline of energy intake relative to expenditure as density increases, such that scope for growth is reduced.

New interdisciplinary study 

Martino Malerba will be starting work in collaboration with the Faculty of Engineering to measure the metabolism and energy output of individual cells simultaneously.  This cross disciplinary study is funded by the faculties of Science, IT and Engineering and will bring together techniques developed in the two departments and which have never been combined before.

Martino’s algal cells undergoing high throughput phenotypic arrays.

Martino will be using his artificially evolved large and small algal cells described in previous posts to ask the fundamental biological question how much of the total energy (metabolism) of a cell is invested into locomotion, that is, energy output? To do this Martino and Callum Atkinson from the Department of Mechanical and Aerospace Engineering will first characterize total metabolic energy of individual cells, using the high throughput phenotypic array in the Centre for Geometric Biology.

Then, for the same cells, Martino and Callum will use the techniques developed in Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC) to analyse the power output associated with swimming performance of cells moving through the fluid.

Moving on

Amanda is now officially Dr Pettersen and will be moving to Sweden in a couple of months.  Amanda has been awarded a Postdoctoral scholarship from the Wenner-Gren foundation to undertake research for 1–2 years on maternal affects and climactic adaptation in wall lizards (Podarcis muralis) at Lund University with Tobias Uller. 

Amanda’s new study species, the wall lizard Podarcis muralis. Image credit Philippe Garcelon via Flickr.

While commonly distributed throughout Mediterranean Europe, wall lizards have more recently been introduced north of their natural range to England. Despite experiencing air and soil temperatures 6–10 °C cooler than their native range, introduced populations in England have rapidly adapted to their cooler climate, exhibiting faster embryo growth and developmental rates which allows offspring to complete development before winter. Through the use of experimental approaches, Amanda hopes to identify general mechanisms by which maternal effects facilitate rapid, counter-gradient adaptation.

Research fellow position: Adaptive Dynamics Modeller

Update: this position has now been filled.

  • Level A, research-only academic
  • $64,450 to $87,471 pa + 9.5% superannuation
  • Full-time, starting late 2017
  • Two-year, fixed-term
  • Monash University Clayton campus

The Centre for Geometric Biology is currently seeking to recruit an experienced theoretical biologist experienced in adaptive dynamics modelling.

As the postdoctoral researcher, you will use adaptive dynamics modelling approaches to explore the drivers and consequences of body size evolution. Working with other researchers in the Centre for Geometric Biology, you will parameterise models based on empirical findings and provide advice of key tests of model predictions.

You will further be expected to maintain consistently high research output in the form of quality publications, supervision of students, development and submission of grant proposals to external funding agencies, contribute more generally to communicating the research activities of the group, and participation in appropriate career development activities.

Key selection criteria

  1. A degree in a relevant area, utilising adaptive dynamics approaches, from a recognised university with subsequent relevant work experience, or an equivalent combination of experience and training.
  2. Demonstrated experience in developing theoretical models in fundamental ecology or empirical research using cutting-edge quantitative approaches.
  3. Demonstrated ability to undertake outstanding research; with a high quality research publication record in recognised journals.
  4. Ability to solve problems by using discretion, innovation and the exercise of high level diagnostic skills within areas of functional responsibility or professional expertise.
  5. Excellent written communication and verbal communication skills with proven ability to effectively analyse information and produce clear, succinct reports and documents which requires interaction with others.
  6. Demonstrated planning and organisational skills, with the ability to prioritise multiple tasks and set and meet deadlines.
  7. Demonstrated awareness of the principles of confidentiality, privacy and information handling.
  8. Demonstrated ability to effectively work independently and in a multidisciplinary team to make a contribution to research and scholarship.
  9. Experience of, or willingness to work on, marine systems.
  10. A demonstrated understanding of questions in fundamental ecology and/or evolution.

For more information, or to apply, refer to the Monash University website

Research fellow position: Life History Empiricist

  • Level A, research-only academic
  • $64,450 to $87,471 pa + 9.5% superannuation
  • Full-time, starting late 2017
  • Two-year, fixed-term
  • Monash University Clayton campus

The Centre for Geometric Biology is currently seeking to recruit an experienced zooplankton biologist.

You will further be expected to maintain consistently high research output in the form of quality publications, supervision of students, development and submission of grant proposals to external funding agencies, contribute more generally to communicating the research activities of the group, and participation in appropriate career development activities.

 

Key selection criteria

  1. A PhD on zooplankton or a relevant area, from a recognised university with subsequent relevant work experience, or an equivalent combination of experience and training.
  2. Demonstrated experience in developing theoretical models in fundamental ecology or empirical research using cutting-edge quantitative approaches.
  3. Demonstrated ability to undertake outstanding research; with a high quality research publication record in recognised journals.
  4. Ability to solve problems by using discretion, innovation and the exercise of high level diagnostic skills within areas of functional responsibility or professional expertise.
  5. Excellent written communication and verbal communication skills with proven ability to effectively analyse information and produce clear, succinct reports and documents which requires interaction with others.
  6. Demonstrated planning and organisational skills, with the ability to prioritise multiple tasks and set and meet deadlines.
  7. Demonstrated awareness of the principles of confidentiality, privacy and information handling.
  8. Demonstrated ability to effectively work independently and in a multidisciplinary team to make a contribution to research and scholarship.
  9. Experience of, or willingness to work on, marine systems.
  10. A demonstrated understanding of questions in fundamental ecology and/or evolution.

Enquiries to Professor Dustin Marshall on +61 3 9902 4449

For more information, or to apply, refer to the Monash University website

Evolution 2017 conference

Centre members Dustin Marshall, Keyne Monro, Amanda Pettersen and Hayley Cameron are currently attending the Evolution 2017 conference in Portland, Oregon.  This is a joint meeting of the American Naturalist Society, the Society for the Study of Evolution and the Society of Systematic Biologists with over 1,800 delegates expected.

PhD student Amanda Petterson will speak about how competition mediates selection on metabolic rates in the field. Metabolic rates reflect the ‘pace of life’ in every organism and provide a measure of an organism’s capacity for essential maintenance, growth and reproduction – all of which interact to affect fitness. Despite the importance of metabolic rate in shaping processes from the individual to community level, empirical studies have mainly been confined to the laboratory, with very few estimates of selection on metabolic rate under realistic field conditions. Amanda’s research combines laboratory measures of metabolic rate throughout development with field measures of fitness (reproductive output) across three levels of competition (intra-specific, inter-specific, and no competition) for a marine bryozoan. Amanda and supervisors Craig White and Dustin Marshall have found that the strength and direction of selection on metabolic rate depends on both the stage of development, and environment to which individuals are exposed.  Amanda will present data to demonstrate the complex nature of context-dependent selection that likely generated these patterns, and the potential evolutionary and ecological consequences of variation in metabolic rates.

Fellow PhD candidate Hayley Cameron will be presenting her latest research into the underlying causes of unequal maternal provisioning of offspring, which is often attributed to ‘bet hedging’. Hayley’s PhD project (supervised by Dustin Marshall and Keyne Monro) has found that broods that varied more in size had higher mean performance than less variable broods. Hayley will present the surprising results from this experiment along with the possibility that when siblings compete for the same resources, and offspring size affects access to these resources, the production of more variable broods can provide greater fitness returns given the same maternal investment; a process unanticipated by the current theory.

We wish Amanda and Hayley the best of luck with their presentations.

A day in the life

Today postdocs Martino Malerba and Giulia Ghedini spent the day investigating if the size of algal cells will affect the grazing rates and total amount ingested for the filter feeding bryozoan Bugula neritina.

To do this they used large and small cells that had been generated through artificial selection of the microalga Dunaliella tertiolecta  and added either equal volumes or cell numbers of each size class to vials containing Bugula. These vials were kept on a roller system to ensure that algal cells didn’t sink and become unavailable for feeding.

Giulia took samples every half an hour for two hours from each of the 60 vials, with the help of volunteer Blake Chan, who then had to run the samples over to Martino who was waiting in a separate building.

Once Martino had the samples he was able to put them through a high-tech flow cytometer and get accurate measurements of the number of algal cells for more than 300 samples.

From the data the team will be able to work out whether the Bugula have consumed more cells of a certain size and whether this equates to a greater overall amount of algal biomass consumed.

This work forms part of a larger program that is investigating whether (and in what way) evolution in size of one species can effect another species.

If you would like more information about this research please contact Martino or Giulia.

In the balance: competition and facilitation affected by resource availability

Congratulations to Karin Svanfeldt who recently submitted her PhD and has published some of her research in The Journal of Animal Ecology, with her supervisors, Keyne Monro and Dustin Marshall.

Karin was interested in the balance between the negative effects of increased population density, (when interactions are dominated by competition for resources), versus the positive effects of increased densities which can arise from facilitation. In examples of the latter, increased densities can provide benefits by making the habitat more suitable for other individuals or through increasing the availability of basic resources. Karin particularly wanted to test how manipulating resources affected density-dependent performance in the field.

There have been few field studies that have directly manipulated environmental conditions to test these types of ideas and so Karin and her colleagues designed an experiment where they could influence both food availability and flow rates and measure the performance of an encrusting colonial bryozoan, Watersipora subtorquata.

Watersipora subtorquata, commonly known as the ‘red rust’ bryozoan.
Watersipora growing on artificial substrates.

Watersipora is sessile (non-moving) and filters resources such as food and oxygen from the surrounding water. Reducing flow rates will therefore impact resource availability. Karin was able to manipulate food availability by creating slow releasing food blocks (‘Reef Feed’ mixed with dental plaster) and flow, by boxing in the artificial substrates that were home to different densities of Watersipora colonies. Performance was measured by recording changes in size of Watersipora colonies over 13 weeks as well as the colony survival and the proportion of the colonies that had senesced.

Karin’s PhD research found evidence that resource availability altered the balance between facilitation and competition in the system they were studying. When resources were abundant, facilitation dominated and when resources were scarce, competition dominated. This work adds to existing evidence that both competition and facilitation can be important and explores how the balance between the two affects interactions within and between populations.