Growing old with caterpillars

January 21, 2016 / aucklandecology / 1 Comment

Posted by Zane McGrath

For the remainder of these summer months I will be searching far and wide for the kawakawa plant. It isn’t the odour emitted by its heart shaped leaves or berries I am attracted to, but the caterpillars hosted by the plant, which I will attempt to adopt and take back to their new home, the luxurious lab at Landcare Research. Although in highlighting the beauty of ecological research, and just to make things more confusing (see earlier posts by Sam and Carolina on ecological complexity), it is not the plant or the caterpillars that will be the main focus of my Masters research, but parasitoid wasps which emerge from the caterpillars.

The kawakawa plant (top) and kawakawa caterpillar (bottom)

Parasitoid wasps spend part of their life cycle within a host, such as a caterpillar, and basically eat their way out when ready to pupate, eventually killing the host. Fascinating or down right freaky (have a look for yourself in this video), parasitoid wasps have the ability to act as natural enemies for controlling agricultural pests. For my Masters research I will be focusing on whether Meteorus pulchricornis, a species accidentally introduced into New Zealand, is competing with native species for caterpillar hosts.

The culprit, Meteorus pulchricornis (Photo: iNaturalist.org) (top) and its cocoon hanging from a kawakawa plant, which is unique to the species (bottom)

In order to understand this, the caterpillars I collect will be reared until they reach their fate. If I’m lucky, but the caterpillar isn’t, a parasitoid wasp will emerge.

This is where I must hone my husbandry skills. The caterpillars can grow considerably over the period of a month or so before pupating. They will be fed their favourite meal, a kawakawa leaf that is replaced every five to seven days. However, as a parent would say, the growing up process isn’t always a pretty sight. Their homes can become inundated in frass (caterpillar poo), and need I say the larger the caterpillar grows, the larger the frass… but hey, it’s all part of being a parent.

Frass and a caterpillar

Zane McGrath is an MSc student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. He is supervised by Darren Ward and Graham Walker (Plant and Food Research, Auckland) examining parasitism by exotic species in native environments.

Bush mad in the city

October 22, 2015 / aucklandecology / 1 Comment

Posted by Samantha Lincoln @slin247

Over the course of this year I have been undertaking intense field work across some of Auckland Councils public parks. Urban ecology is inherently strange; emerging sweat-soaked from a long day’s work, and carrying a small colony of beetles in your hair onto a main road whilst startling local dog walkers and being serenaded by Auckland Zoo’s primates. While not as idyllic as disappearing to the mountains for a week, urban ecology is incredibly important when most of our human population is urban. Connecting with nature is undeniably important for our wellbeing.

Auckland has hundreds of public parks of all sizes, both without and without maintained walking tracks as I have discovered. They are refuges for native species in the middle of our manicured city, but how well do we really look after these spaces? During my field work my volunteers and I have found a range of debris: backyard clippings spreading weeds, Victorian inkwells, a year’s supply of newspapers courtesy of a lazy paperboy, shelters built by those with nowhere else to turn (a growing issue in Auckland) and a pile of books featuring a bunny not often seen during pest control.

Live capture of a rat during a capture-recapture study

As Auckland city grows, more pressure is being placed on these biodiversity refuges and how we value and care for them becomes more important as was noted last month. Will we value and nurture these green spaces, or will they fail under the pressure? Will we continue to use them as personal rubbish dumps, or will we take interest in the other species that use these spaces? I will be a science advocate – we can all lend our voices. To me nothing beats the feeling of following a fantail nest from first cheeps to first awkward flight, as I make my daily visit to the rat trap at the tree’s base.

Sam Lincoln is an MSc student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is trying to disentangle interactions between domestic cats and rats in urban environments. She is supervised by Margaret Stanley, John Innes and Al Glen.

Giving two hoots about city birds

August 17, 2015August 17, 2015 / aucklandecology / 1 Comment

Posted by Sam Heggie-Gracie @SamHegGra

It’s not easy being a city slicker; vainly calling over car noise, isolated from my friends in a small patch of forest, narrowly avoiding a cat (I’m allergic; also, see Sam’s post). And that’s just me. Urban birds must navigate these conditions too, and for them, it can mean the difference between life and death. By measuring a number of these pressures, I hope to elucidate which abiotic and biotic drivers mould the avian assemblages of Auckland city for my MSc.

Urban ecology studies are a relatively new area of research, as people around the world are increasingly drawn out of a bucolic lifestyle and into the jobs and excitement that cities can provide. The sprawling city of Auckland spans out from the concrete jungle of the CBD, through a gradient of increasingly green urban and suburban areas and onto rural outskirts. Our bird friends are found throughout, so I will be assessing the difference in bird abundances and composition across this environmental gradient. Additionally, I will be looking into what drives bird composition within urban habitat fragments. By assessing housing density, fragment size, noise pollution and a myriad of other urban characteristics, I hope to determine which of these are most important for providing a suitable home for our birds.

Tui Art by Cally Whitham https://www.behance.net/gallery/native-endemic/5061863

Previously, the words ‘all bird observations will occur between 5 and 9 am’, had filled me with much apprehension, but after overcoming the dread of waking at such an ungodly hour, I have become most earnestly committed to the birds of Auckland city and relish getting up to listen to the beatific morning chorus. Hoot hoot!

Sam Heggie-Gracie is an MSc student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. He is investigating the drivers of bird composition in cities. He is supervised by Margaret Stanley and Cheryl Krull (AUT).

There was once an old lady who swallowed a fly…

July 3, 2015 / aucklandecology / 4 Comments

Posted by Sam Lincoln

Biological systems are incredibly complex (see ecological networks blog). Introducing a spider to eat a fly may not help; New Zealand found that out the hard way with rabbits and ferrets. When one food source is running low, most predators prey-switch, and in New Zealand that often means moving onto our native birds. We regularly control rats both in our homes and local parks with little knowledge of the indirect impacts wrought upon biological systems. My Masters project aims to take a first look at how domestic cats respond to the removal of rats in local parks – are they eating more of our birds?

In Auckland Council’s local parks, a mix of native and introduced birds share their space with predators such as rats and domestic cats. There has been much recent debate about the impact of cats in New Zealand; while scientists agree that cats have negative impacts on our native species, the SPCA often has a far more cat-friendly view citing rodent control by domestic cats as potentially helping birds. Even politicians are involved in the cat debate, with Conservation Minister Maggie Barry in one corner fighting for kiwi versus Prime Minister John Key representing Moonbeam. My pilot study of 11 cameras set for two nights captured 14 individual cats in two local parks (as well as a few possums and an MSc student).

Photos from cat camera pilot study, clockwise from top left: two cats, MSc student Sam Lincoln and a possum. Cats were photographed visiting both parks during the day and night.

By assessing the changes to cat behaviour after removing rats from half of the sites, I will get a first look into what really goes on between cats, rats and birds – is rat control bad for birds due to increased predation by cats, or are rats the main culprits in an urban environment? What would happen if cats were to go? Should we instead be moving toward a predator free New Zealand where our birds can exist without either of these mammalian invaders?

Marvel takes a risk with Ant-Man whilst I assess the risk of ants

June 25, 2015June 25, 2015 / aucklandecology / 2 Comments

Posted by Anna Probert @AFProbert

Ant-Man. The official superhero of 2015 and my PhD

I have a feeling that my beloved study group are going to be gaining quite a bit of interest this year. I would love to say that it is a result of some ground-breaking research I have conducted, but alas. The true reason why I think 2015 is The Year of the Ant, is the impending release (that’s 16^th July) of Marvel Studio’s Ant-Man. For those of you that are perhaps not on my level of Marvel fandom, Ant-Man is based on the comic of the same name, where the protagonist has the ability to shrink down to the size of an insect and has superhuman strength and agility. Although in my spare time I’m still trying to discover Pym Particles, my full time role involves being a PhD student here at the UoA and looking at assessing invasive species risk to native ecosystems, using ants as a model.

Unfortunately for our native environment, when it comes to exotic species arriving and establishing in New Zealand, we often let them slide by if they don’t have a perceived potential social or economic impact. As a result, we end up with exotic plant and animal species that become naturalised in the environment. How do they affect the environments in which they naturalise? Well in most circumstances, we don’t really know.

Out in the Hunua baiting for ants. Photo credit Luke McPake

Here in New Zealand we have 29 established exotic ant species (compared to only 11 native species) and very little understanding of how they are influencing the environments in which they live. The Argentine Ant is the species most people would have heard of, as it is a well-known invader worldwide, causing various negative impacts on the environments in which it invades. But what of the other 28 established exotic species we have in New Zealand? What are they doing?

I don’t have the answers… yet, but for my PhD I’m specifically going to be looking at the ways exotic ants influence the invertebrate community structure within different ecosystems, as well as investigating their role in altering ecosystem function. This will involve conducting different manipulative field trials over the upcoming spring/summer seasons – and I’m always on the lookout for field assistants, so let me know if you want to spend a day in nature out with me and the ants.

P.S. Marvel Studios, I am indeed open to sponsorship.

Anna Probert is a PhD student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is using ants as a model to assess the risk posed by exotic invertebrates to native ecosystems. She is supervised by Margaret Stanley, Jacqueline Beggs, and Darren Ward.

What we talk about when we talk about ecological networks

June 11, 2015June 12, 2015 / aucklandecology / 3 Comments

Posted by Carolina Lara @carislaris

I was recently asked by an engineer friend of mine what my PhD project was about. In my (failed) attempt to put it into simple words, I ended up giving him a large discourse on the topic. A couple of days passed and he got back to me to say “… I always thought biological systems were simpler”. I am new to this world of ecological networks, but simplicity is not a word that can be used to describe them. More specifically for animal-plant mutualistic networks, a set of animals interacts mutualistically with a set of plants that are connected to another set of animals that interact with another set of plants. Animals disperse a plant´s genes and get food as a reward, as in the case of pollination and seed dispersal ecosystem services.

Kereru (Hemiphaga novaeseelandiae), New Zealand’s native pigeon, feeding on Nikau Palm (Rhopalostylis sapida) fruit

The dynamics of these networks and how they are built have profound implications on the coexistence of species and moreover, they can give us insights about how resilient they are to human disturbances, such as habitat fragmentation. It has now been recognised that conservation efforts should not only be directed to species alone, but should also be extended to the interactions and networks they form. Loss of interactions would translate into loss of ecological functions and this could happen even before actual species extinctions, a concept known as extinction debt of ecological interactions. Daniel Janzen, a pioneer scientist in tropical ecology, stated more than 40 years ago that “what escapes the eye, however, is a much more insidious kind of extinction: the extinction of ecological interactions”. So, we really are talking about complexity when we talk about networks. And I’m glad I changed my friend´s perception of just how complex biological systems are.

Carolina Lara M. is a PhD Candidate within the Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. Her research interests focus on seed dispersal networks within fragmented landscapes. She is supervised by Margaret Stanley, Jason Tylianakis, Karine David, and Anna Santure.

What’s the point of urban ecology?

April 23, 2015April 23, 2015 / aucklandecology / 7 Comments

Posted by Margaret Stanley @mc_stanley1

What’s the point of urban ecology? This is a question I get asked a lot. Many ecologists believe ‘real ecological research’ occurs outside of city boundaries, preferably the further the better from a city. While the focus of ecologists and conservationists is often on biodiversity outcomes within protected areas or in rural areas, the perceptions and values of city-dwellers disproportionately (in terms of numbers of votes!) influence decision-making around management of biodiversity outside cities. Therefore, the often limited experiences city-dwellers have with nature, such as seeing a tūi in their backyard, can greatly affect biodiversity outcomes. However, we also know that there is an increasing disconnect between people and nature as we become more urbanised. How many city-dwellers have visited a regional or national park in the last year? Reconnecting people with nature in the city not only benefits their mental and physical wellbeing, but can also have positive effects on how they value biodiversity and take action on conservation issues. The 2008 Erfurt Declaration also recognises the intrinsic value of urban ecosystems. Globally, urban areas can be hotspots for biodiversity – cities are often built in very fertile areas, and can be centres of evolution and adaptation.

Josie Galbraith’s project on the effects of backyard bird feeding on bird communities. Washing lines for hanging birds bags and deck furniture for banding and microchipping birds are a blessing for the urban researcher!

There are a range of exciting and interesting research questions to be asked about biodiversity in cities. While some drivers of change are unique to cities, most are just modified versions of what’s happening outside cities (e.g. habitat loss) or are agents of change originating from cities (e.g. pollution, invasive species). My lab group are tackling questions, such as whether people feeding birds in their backyards can restructure urban bird communities, how light pollution might influence ecosystem function (eg. pollination) and how robust connectivity is for bird-dispersed plants within fragmented urban landscapes.

Two of the most frustrating things about urban ecology are: firstly, you can’t escape people (more social scientists please!); and secondly, there are no large, homogenous landscapes in which to put untold replicates. Experiments are critical for untangling drivers and interactions, but conducting experiments in urban landscapes can be very challenging: the high levels of variability over short distances, negotiating access to sites from many landowners/householders, and the high risk of vandalism to equipment. Even the main health and safety fieldwork issues are unusual: domestic dogs and dubious people, rather than getting lost in the bush or being injured far from a hospital. But if it all comes together, the results can be great. Watch this space within the next week or two for PhD student Josie Galbraith’s PNAS paper, where we report on our 18-month bird feeding experiment in suburban Auckland.

Road ecology research often requires the use of an orange flashing light on your car! Esther Dale (L) and Dr Cheryl Krull (R) during Cheryl’s postdoc research on rodent behaviour around roads.

There’s also an unfortunate but realistic reason why urban ecology is attractive to ecologists. Science is getting more expensive, funding is declining, offshore islands and national parks are expensive to get students to. Urban ecology is a much better option in terms of science output/$ of funding. And then there’s the unexpected bonus of doing fieldwork in the city – the ability to order pizza for the cold, hungry field crew…

Pizza delivery to Josie Galbraith’s field sites

Dr Margaret Stanley is a Senior Lecturer in Ecology, School of Biological Sciences, University of Auckland and is the programme director of the Masters in Biosecurity and Conservation. Her interests in terrestrial community ecology are diverse (particularly in terms of taxa), but can be grouped into three main research strands: urban ecology; invasion ecology; and plant-animal interactions. The most interesting and challenging projects are where these three strands overlap!

Ecology to genomes and back: Using integrative genomics to gain insights into community assembly dynamics

March 30, 2015April 22, 2015 / aucklandecology / Leave a comment

Centre for Biodiversity and Biosecurity seminar – all welcome.

Posted by Jacqueline Beggs

Tuesday, 14th April, 12.30pm
Tāmaki Campus, University of Auckland
Building 733-234

Speaker: Dr Manpreet Dhami, Stanford University, USA

Manpreet Dhami received her Ph.D. in 2012 from the University of Auckland studying the multi-trophic interactions between scale insects, their symbionts and honeydew consumers. She was supervised by Jacqueline Beggs and Mike Taylor. Manpreet discovered and characterized a novel bacterial symbiont associated with endemic New Zealand scale insects (Dhami et al. 2012), and elucidated the cophylogenetic patterns between bacteria and their scale insect hosts (Dhami et al. 2013a). She also documented the diverse fungal community associated with honeydew (Dhami et al. 2013b) and showed that honeydew from each scale insect species had a distinctive amino acid and carbohydrate signature (Dhami et al. 2011).

Currently she works as a postdoctoral research fellow at Stanford University in Tad Fukami’s lab, where she is developing an ecological genomics approach to assess the mechanisms underlying microbial community assembly.

Talk outline

Next generation sequencing has revolutionised access to genomics to address key ecological questions such as genetic mechanisms of fitness. I present two case studies that integrate genomics and classic ecological approaches.
Case study 1: Sap-feeding scale insects thrive on a nutritionally poor diet of phloem, possibly enabled by the presence of novel obligate symbionts. Such symbionts, however, cannot be cultured in-situ, hindering further study of their function. We sequenced the genome of one symbiont, establishing its nutritional role in the ecological success of this insect.
Case study 2: Floral nectar hosts a complex community of microbes, such as the dominant Floricolous yeast, Metschnikowia reukaufii. We characterised cell and colony morphology, growth rates and sequenced the whole genome for 23 strains of M. reukaufii. This yeast’s high intraspecific phenotypic variation was correlated with genotypic diversity, potentially contributing to its success as a nectar specialist.