Insects and Ethics

All animals are equal, but some animals are more equal than others

– George Orwell, Animal Farm

Posted by: Jessica Devitt @Colette_Keeha

I genuinely like insects…okay let’s be truthful, I love insects, or more correctly arthropods, I don’t discriminate. I think that their gormless little faces, with vacant-looking eyes, are utterly charming. I think that they are incredibly industrious, intelligent, remarkable little creatures, and they always have my attention. I know that I am guilty of anthropomorphising them and I know that it this might be irksome, so my apologies in advance.

This love naturally ended up becoming a life-long passion to work with insects in any capacity; if I had my way completely I would be raising endangered insects and writing about them, that would be the life!  However, the majority of work related to insects is around the damage that they can do to agriculture, native environments, the economy, freshwater systems…and the list could go on.  So excluding, controlling or eradicating (usually) invasive insects as a part of biosecurity, and invasive species management, is often where a lot of us entomologists earn our living.  Don’t get me wrong though, I understand and appreciate the need to keep invasive insects at bay, I love insects, but my love is not blind.

So in my day-to-day student life, there are times when I have to kill my insects, like when I had to freeze the remains of my entire Hadda beetle colony; they are invasive so could not be released…that was a sad day. These instances of insect homicide got me thinking recently about insects and the ethics of killing them and/or using them in research. I have several questions like, do they feel pain? Or a ‘version’ of pain? And is our current use of insects in research without the need for ethics approval morally okay?

Spider meme

Might need a bigger gun. (Meme Binge, 2014)

The use of animals for research in New Zealand is controlled under the Animal Welfare Act 1999.  Under the Animal Welfare Act (1999) it is an offence to ‘manipulate’ an animal, meaning to subject an animal to something that interferes with the animal’s normal behavioural, anatomical or physiological integrity, without being an approved code of ethical conduct holder (National Animal Ethics Committee, 2012).  If the code holder is say a research institution, and you are employed by that research institution, then you are in general terms covered by their code (ANZCCART, 2017a).  I put the word ‘animal’ in quotes here because the definition of an animal under the Animal Welfare Act it (1999) is a living animal that is a vertebrate, some invertebrates are included, such as crayfish, and squid but this definition of ‘animal’ does not apply to insects and most invertebrates, such as spiders.  Several insect species are however covered under the Wildlife Act (1956) in New Zealand due to the fact that they are endangered species, such as the giant wētā (Deinacrida spp.)

giant weta2

Giant wētā. (Moffet, 1991).

In terms of consciousness it is generally agreed that vertebrates are sentient as in they have the ability to subjectively feel and perceive experiences, they are conscious, and self-aware, hence they also have the capacity to suffer (Bekoff, 2013).  However, some of the methods used to justify animal consciousness or sentience, such as behavioural responses and neurobiology, are poorly fitted to answering the same question with regard to insects (Merker, 2016).  In saying this Klein and Barron (2016) argue that insect brains are functionally comparable to the vertebrate midbrain (an evolutionary ancient part of the brain in vertebrates), and that subjective experience, as a component of consciousness, is a construct of evolution, hence it is plausible that those animals that came before vertebrates, the invertebrates, would also have the capability of subjective experience (Klein & Barron, 2016).


The insect brain. (n.d.)


Milton the roach. (Daisy_Dazzy, n.d.)

The premise of using the human experience, our behaviour and neurobiological responses to pain as an analogue for how animals feel pain is inherently biased (Klein & Barron, 2016), but what other methods could we use?  Nociception is often cited as an analogue to show pain in vertebrates as compared to the human experience of pain (Adamo, 2016). Nociceptors, are specialised sensory receptors that detect harmful stimuli and signal the brain to react in a way that will minimise harm to the body, however ‘pain’ in itself is subjective (Fein, 2012).  Humans, other vertebrates and insects have nociceptors, and insects do react by altering their behaviour to harmful stimulus, although whether they are in distress from the stimulus is impossible to tell.  In saying this Adamo (2016) points out that the behavioural reaction of insects to harmful stimuli coupled with avoidance to harm are some of the same parameters used to justify distress in vertebrates, so why then is this not more considered by ethics committees and researchers?

when entomologists attack

Disturbing scene. (Kim, n.d.)

If the free use of insects in research was to suddenly become a bigger ethical issue, where the researcher had to apply for ethics approval, this would no doubt create a multitude of barriers in research.  Insects are often used as analogues for other animals, insect farming for human consumption is quickly becoming more acceptable, and people in my line of work, where insects are killed en masse, could be stonewalled.  Naturally I have mixed thoughts about this.  On the one hand, I personally do not always feel comfortable with how I have seen insects treated in research situations, nor am I comfortable with my use of them at times during my career, however I realise that I inherently would choose to destroy an insect over say a puppy if I had to pick one. Further to this, I have avoided the dreaded ethics application process (I have heard it can be difficult), which has meant that I have been able to do a range of experiments with minimal bureaucracy.

In saying all this, I still feel that perhaps as researchers we have had free rein over this for too long now, and that some form of middle ground needs to be established.  The three R’s could be a good place to start, where Replacement (use an alternative), Reduction (use less insects), and Refinement (minimise suffering), are ethical considerations taken when using insects in research.  Further, I also think that housing insects in environments where they can live out their bug lives as freely as possible, along with being disposed of humanely are important.

Now kiss3

Bug Life. (Banane, n.d.)

jessJessica Devitt is a PhD student at the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland and Plant and Food Research. She is researching the respiratory responses of the golden-haired bark beetle to advance fumigation techniques. She is supervised by Jacqueline Beggs from the University of Auckland, Adriana Najar-Rodriguez and Matthew Hall from Plant and Food Research.


Adamo, S. A. (2016). Do insects feel pain? A question at the intersection of animal behaviour, philosophy and robotics.  Animal Behaviour, 118, 75-79.

Animal Welfare Act. 1999. Retrieved April 28, 2017 from

Banane. (n.d.). Bug Life.  Retrieved from

Bekoff, M. (2013). A Universal Declaration on Animal Sentience: No Pretending.  Retrieved from

Daisy_Dazzy. (n.d.).  Milton the roach.  Retrieved from

Fein, A. (2012). Nociceptors and the perception of pain. University of Connecticut Health Center, 4, 61-67. Retrieved from

International Union for Conservation of Nature (IUCN). (2008). 100 of the World’s Worst Invasive Alien Species.  Retrieved from

Kim, N. (n.d.). Disturbing scene from When Entomologists Attack.  Retrieved from

Klein, C., & Barron, A. B. (2016). Insects have the capacity for subjective experience. Animal Sentience: An Interdisciplinary Journal on Animal Feeling, 1(9), 1.

Lynch, K. (n.d.) When is an animal not an ‘animal’? Research ethics draws the line. Retrieved from

Meme Binge. (2014). Might need a bigger gun.  Retrieved from

Merker, B. H. (2016). Insects join the consciousness fray. Animal Sentience: An Interdisciplinary Journal on Animal Feeling, 1(9), 4.

Moffet. M. (1991). The giant cricket.  Retrieved from

National Animal Ethics Committee. (2012). Ensuring regulatory compliance in the use of animals in science in New Zealand – the review process. (Occasional Paper No.9).  Wellington, New Zealand.  Retrieved from

Pimentel, D., Zuniga, R., & Morrison, D. (2005). Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecological economics, 52(3), 273-288.

The Australian and New Zealand Council for the Care of Animals in Research and Teaching (ANZCCART). (2017a). Animal ethics for the use of animals in research, testing or teaching.  Retrieved from

The insect brain. (n.d.). Retrived from

Wildlife Act. (1956). Retrieved April 28, 2017 from


Evolution of invasive traits

Posted by Melissa Kirk @ MGKirk_04
Invasive species are a major problem worldwide, causing numerous impacts on the environment, agriculture and human health. Whether an introduced species becomes invasive is dependent on many factors, but has been attributed to certain life history traits (or characteristics), including high competitive abilities, wide climate tolerances, fast development, wide host ranges and high dispersal abilities (Whitney & Gabler, 2008). Characteristics which enhance the invasiveness of a species can rapidly change and evolve during invasion but such changes are often associated with the lag phase, the stage before the invasive species forms large populations and becomes widespread (Crooks, 2005).


Fig.1. The ladybird, Harmonia axyridis. Image sourced from: Wiki commons- Harmonia axyridis. Image taken by Fritz-Geller-Grimm.

A recent example of rapid changes to an invasive species comes from the Harlequin ladybird, Harmonia axyridis. Within ten years of arriving in a new country, it had developed flight traits that increased its ability to disperse allowing the ladybird to become widespread in Belgium. The study found that ladybirds from the first population to establish had reduced flight speed, compared to those sampled from the expanding edge populations (Lombaert et al. 2014).

Figure two Lythrum salicaria. Image source from Wikimedia commons Lythrum salicaria

Fig. 2. Lythrum salicaria. Image source from: Wiki commons-Lythrum salicaria. Image taken by Manfred Heyde.

Comparatively, the invasive plant Lythrum salicaria, has evolved earlier flowering times to adapt to the climatic conditions at the expanding front of the population. This adaption has allowed for the wide spread dispersal of the invasive plant from South to North America (Colautti & Barrett, 2013).

figure three Ceratitis capitata. Image sourced from Wikimedia commons- Ceratitis capitata.

Fig. 3: Ceratitis capitata. Image sourced from: Wiki commons- Ceratitis capitata. Image taken by Imrich.

Further, the Mediterranean fruit fly, Ceratitis capitata, has evolved enhanced reproductive output and longevity in its newly invaded range compared to populations from older ranges. These adaptive traits allowed for rapid population growth and spread (Diamantidis, Carey & Papadopoulos, 2008).

Rapid evolution of invasive species shows that risk assessment, predictive models, control and eradication strategies can be difficult to design and implement. These examples highlight the need for ongoing research on the life history traits of invaders, even once they have established and begun spreading.

1173650_304225506394902_1331297686799750324_nMelissa Kirk is a MSc candidate in the School of Biological Sciences, University of Auckland and is supervised by Darren Ward (Landcare Research/University of Auckland) and Eckehard Brockerhoff (Scion).

Colautti, R. I., & Barrett, S. C. (2013). Rapid adaptation to climate facilitates range expansion of an invasive plant. Science, 342(6156), 364-366.

Crooks, J. A. (2005). Lag times and exotic species: the ecology and management of biological invasions in slow-motion. Écoscience, 12(3), 316-329.

Diamantidis, A. D., Carey, J. R., & Papadopoulos, N. T. (2008). Life‐history evolution of an invasive tephritid. Journal of applied entomology, 132(9‐10), 695-705.

Lombaert, E., Estoup, A., Facon, B., Joubard, B., Grégoire, J. C., Jannin, A., … & Guillemaud, T. (2014). Rapid increase in dispersal during range expansion in the invasive ladybird Harmonia axyridis. Journal of evolutionary biology, 27(3), 508-517.

Whitney, K. D., & Gabler, C. A. (2008). Rapid evolution in introduced species,‘invasive traits’ and recipient communities: challenges for predicting invasive potential. Diversity and Distributions, 14(4), 569-580.

Taken for granted – Auckland’s tree crisis

Posted by Cate Macinnis-Ng @LoraxCate

Another week, another decades-old tree is on the chopping block. This time a Norfolk pine in Ellerslie is being removed to make way for a car port. Residents believe the tree is unsafe. It’s all too common that people are worried about the perceived dangers of trees but there are plenty of benefits that are often forgotten in the rush the remove a ‘nuisance’ or ‘dangerous’ tree.

Ellery McNaughton already lamented the loss of trees at her urban study sites in February. So what good are trees?

1) Trees capture and store carbon. Through the process of photosynthesis, trees take up CO2 from the atmosphere and store carbon in their roots, stem, branches and leaves. The bigger the tree, the more carbon it stores as approximately 50% of biomass is carbon so that huge Norfolk pine is likely to store tonnes of carbon in wood and it will take decades for that carbon to be recaptured but a replacement tree.

wood pile2

Let’s stop reducing trees to this

2) Trees reduce air temperature. Trees cool things down in two ways. First, they obviously provide shade. Second, they lose water through their leaves through the process of transpiration. As water is lost from the surface of the leaf, evaporative cooling takes place. Trees are helpful in reducing the urban heat island effect, counterbalancing the warming effects of sealed roads, driveways and roofs.

3) Trees modulate the water cycle. Water taken up from the soil by roots travels up the trunk and then exits the leaves, returning to the atmosphere as transpiration. This process slowly removes water from the soil so when it rains, water can soak into the soil instead of becoming runoff and causing floods. Trees also act as a giant umbrella, catching water in their leaves. We call this interception and because tree canopies are complex, they can store huge amounts of water on the surfaces of leaves and branches. In a closed kauri forest, up to 44% of incoming rainfall across the year is captured in this way and returns to the atmosphere as evaporation when the sun comes out. This is hugely helpful in preventing floods!

4) Trees bind the soil, preventing erosion. This is particularly important in steep terrain where fast-moving water is more likely to cause slips, especially during heavy rain events.


This schedulded tree in Mission Bay had 40% of it’s crown unlawfully removed by a neighbour.



5) Trees enhance biodiversity. Trees provide food and homes for birds, invertebrates, reptiles and other plants.

6) Trees provide colour. Without trees, out landscapes become dull and grey. Trees provide greens of leaves but also reds, yellows, whites and oranges when they flower and fruit.

We know that trees improve property values because leafy areas are seen as being more affluent. While asthetics are important, there are clearly so many other good reasons to love trees. Surely it’s time to value are trees for the wonderful services they provide!

The million trees programme is a great way to rebuild forest but we also need to preserve what we already have with better tree protection.




Dr Cate Macinnis-Ng is a Senior Lecturer and Rutherford Discovery Fellow, School of Biological Sciences, University of Auckland.  She is a plant ecophysiologist and ecohydrologist working on plant-climate interactions.

Save the bees!

Posted by Jamie Stavert @jamiestavert

It seems that everyone loves honeybees and everyone wants to save them. Of course they do. Honeybees give us honey, they pollinate our crops, kids like them, and they’re great for science outreach. But despite their endearing, cuddlesome nature, I have issues with honeybees. Firstly, they’re exotic to New Zealand, some would even say invasive, and they’re probably having negative impacts on our native biodiversity. Secondly, I think they’re crying wolf (at least in New Zealand).

The general public have a terrible misconception about bees; when people think about bees they inherently think of honeybees. That’s it. One bee. Let’s save it, or we’ll all die. In New Zealand, the deluded media continues to wheeze and waffle about honeybees in peril, yet hive numbers have increased from 300,000 in 2000 to 685,000 in 2016. That’s a whopping 120% increase! Meanwhile, native bees continue to go unnoticed and unrecognised.

hive numbers in NZ

Change in the number of registered honeybee hives in New Zealand from 2000-2016. The red dashed line is when Varroa was first detected in New Zealand.

Unfortunately, few people know that there are over 20,000 bee species in the world and most of them don’t live in a colony with a queen. Rather, they live solitary lives and nest in the ground or in plant material. Globally, native bees, in combination with other wild insects, contribute more to crop pollination than honeybees. But unlike honeybees which are managed by humans, native bees are strongly affected by the bad things that humans do (e.g., agriculture, urbanisation, pesticides, climate change and invasive species). In addition, evidence is mounting that honeybees have negative impacts on wild insects, largely through competition.

Leioproctus of Coriander

An endemic New Zealand bee (genus Leioproctus)

I’m not saying that we should forget about honeybees altogether and let Varroa have its way with them. They’re important pollinators of many crops and make manuka honey that cashed up baby boomers pay $1,000/kg for to treat their pinot noir induced acid reflux. But it seems dumb to rely on a single species to do all the pollination. It’s akin to “putting all your eggs in one basket”. Resilience comes in the form of biodiversity. When we have lots of biodiversity we have many species that are equally capable of doing the job. For example, if we have 10 pollinator species that are equally good at pollinating a crop and for some reason five species go extinct, we still have five species left. However, if we have one species and it goes extinct, that’s it, game over.

So how can we save the bees? Our native bees? Essentially they need natural habitat, which provides floral and nesting resources. In New Zealand, native bees are active from September to February and require flowers (preferably natives!) throughout that period. They also require sites for nesting; small holes (2-3 mm) in timber/plant material for cavity nesting species and areas of warm, well drained bare earth for ground nesting species.

Leioproctus in hole

A ground nesting Leioproctus bee emerging from its nest hole

These solutions are feasible on a small scale (i.e., in urban gardens), but the real problem is at a much larger scale, where agricultural intensification threatens to wipe out native bee populations. Therefore, to “save the bees” perhaps we need to move beyond the capitalist dream of monocultures, mono-pollinators and massive profits, and instead vie for diverse production systems that truly value biodiversity.

For an up-to-date assessment on the global status, trends and threats to pollinators and pollination check out: the assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) on pollinators, pollination and food production.

IMG_0293Jamie Stavert is a PhD candidate at the Centre for Biodiversity &
Biosecurity, School of Biological Sciences, University of Auckland. He is interested in how functional traits influence ecosystem function and species’ responses to environmental change in pollination systems.
 He is supervised by Jacqueline BeggsAnne GaskettDavid Pattemore and Nacho Bartomeus.

International Day of Forests

By Melanie Zacharias @Mel_Zacharias

In our urbanised society people still have a deep relation to forests. A forest is a place to recover from noisy city live, a place to do sports without the smell of a sweaty gym or just an environment to find oneself. Unfortunately, most people do not know about the complex ecosystem services, forests provide worldwide. Carbon storage, water regulation and supply to timber production are only a few of them! Furthermore, even single city trees are proven to have economic and health benefits like filtering fine particles and reducing stress. Nevertheless, the trees of our world are threatened by deforestation, invasive species, soil degradation and of course climate change. We all like our high standard of living; with fancy cars, travelling around the world and exotic food but sometimes we should remember that our own consumer behaviour affects the conditions of forests.


The Food and Agriculture Organization of the United Nations (FAO) is an intergovernmental organization with 194 member countries to achieve food security for all. The United Nations General Assembly of the FAO proclaimed the 21th of March as the International Day of Forests (IDF) in 2012 to underline the importance of all types of forests and their threats. The versatile services of the forest ecosystems in ecology AND economy lead to the theme of 2017: Forests & Energy, chosen by the Collaborative Partnership on Forests. Whereas saving forests from logging is not only environmental protection, the timber energy sector is an important employer in both, developing and industrialized countries. With the growing demand for wood as aresource for renewable energy, sustainable forest management is at least as important as 300 years ago, when Hans Carl von Carlowitz first described the concept of sustainability in his book Sylvicultura oeconomica (1713).


If you want to give something back to the forests, join in and plant a tree 🙂 For example on Motutapu Island. There are many activities involving forests and trees around the International Day of Forests or just get out to your favourite local forest for the day and share a picture.

#IntlForestDay or #LoveForests

IMG_2462Melanie Zacharias is an intern in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland supervised by Cate Macinnis-Ng. She recently completed a MSc in forestry at the University of Technology Dresden, Germany.


Presence or absence: predicting the probability of population survival

Posted by Lloyd Stringer @lloydstringer2

With it being St Patrick’s day, I thought it appropriate to give you a little overview of one aspect of my research, population growth modelling, with a Paddy’s day theme.

Factoid- Student’s t-test was developed by William Sealy Gosset (publishing under the pseudonym Student) while working as a chemist at Guinness brewery.

Every year about this time, NZ experiences a mass migration of barrels of Guinness that require population management. Luckily, NZ has a biosecurity team of 4.7M people to help deal with this population outbreak (perhaps this isn’t what contributors to the Biosecurity 2025 document had in mind).

Guinness tanker

Developing a population growth model, is a key aspect to developing a management strategy. This isn’t readily available for some modelling targets, but luckily the biology of Guinness is well documented and experienced, so few assumptions are required.

While it does appear in hotels throughout the country for much of the year, it isn’t until we see the migration, that the shear overload causes additional pubs to sprout taps to dispense this nutritious bounty. During non-outbreak periods, population replacement approximately matches mortality. However, we’ve discovered that on March 17, during a peak outbreak time, population density displays exponential growth. It is a wonder that we don’t see masses of migrating Guinness pints moving about the landscape, but we find that nature has a unique way of dealing with the bounty.

lots of guinness poured

During times of plenty, particularly Paddy’s day, natural Guinness niches (pubs) produce music that is heard over a large area, and this brings in Guinness’ natural predator… Homo sapiens. The probability of H. sapiens being attracted to Guinness as a function of distance has been tested for quiet niches. During the Paddy’s day celebration, the number of individuals arriving at niches is 37 times greater than average. It is assumed that this increase in attraction range is due to the sound produced by the various Irish bands and clinking of glasses. Having this larger area of attraction increases the probability of Guinness being consumed, thus the probability of survival is reduced.

Psurvival-music = (1-Pconsumption)×Nconsumers_music/ha

With Nconsumers_music a function of the number of consumers expected to be attracted per ha with the increase in the attractive range of the niche with music over a quiet niche. We find that population growth changes from a predicted λ = 0.04 (without music) to λ = -0.002 (with music). If we start with an initial population of 1000 pints of Guinness, then we are likely to have 16 h before a musical pub runs dry.

drinking guinness

Of course, there will be variation around some of these estimates, especially climatic conditions. Canterbury for example has warm dry conditions predicted. This favours a rapid decline of the population (an additional 5%), further with Paddy’s day occurring on a Friday allowing for a sleep-in the following day, it is expected that the Guinness survival rate (warm and dry + sleep-in) will be 10% lower than λ = -0.002 estimated above to λ = -0.025, so population will be expected to only last ~3h.

By understanding a little about the potential growth rates of a population we can estimate the probability of survival of a population. It appears that for this year at least Guinness population will be managed naturally by the sleep-in, however, if pubs wish to increase the mortality rate the Guinness, increasing the ambient temperature of the pub will reduce Guinness survival rates.

Please note, many data were harmed during the writing of this piece.

Lloyd Stringer is a PhD student at the School of Biological Sciences at the University of Auckland, and scientist in the Biosecurity Group and Plant & Food Research, Lincoln. He is studying the effects of population management tools on insect Allee thresholds. He is supervised by Max Suckling, Jacqueline Beggs, and John Kean


I should be writing..

Posted by Alice Baranyovits @ABaranyovits

This post is slightly different from my usual efforts, mostly because I’m in the last (although it seems never ending) stages of writing up my thesis and it’s all my brain can think about at the moment.  As I haven’t successfully handed in my thesis yet I’m not sure if I am qualified to give advice but here goes anyway.

  1. Start writing early – this is the one that everyone tells you to do and they’re right. I remember very clearly at the start of my PhD thinking that I was definitely going to do this and I would be done with the writing at least a few months before my final deadline, giving me plenty of time for the final  edits and formatting etc. This has not happened. Whilst I had done my literature review and first chapter fairly early on, I wish I had done more.  So keep writing throughout, your future self will thank you.
  2. Find a method that works well for you – I use the Pomodoro technique; you can find out more about it here. I’ve also found that for me, when I’m just writing I work best at home (its quiet, I can sit out on the deck and there are plenty of snacks close at hand – see point 7). But I know many people that prefer writing at cafes or in the office – just find what works for you.
  3. Make sure you take proper breaks, even if it’s just for a few hours outside for a walk (getting out into nature also has many mental-health benefits), but preferably for at least a whole day now and again. I wish I had done more of this over the last few months because the occasions when I have had some time away from the thesis I am always much more productive when I get back to it. Just try and ignore the ‘I should be writing’ thoughts.


    Going for a walk outside can help reduce your writing induced stress

  4. Accept that some days aren’t going to be as productive as others & everything takes longer than you expect.
  5. Don’t worry to much about getting everything word prefect in you’re first draft.
  6. Take it one task at a time – there have been a few times in the last couple of weeks where I have been pretty overwhelmed with everything I have left to do (obviously if you have followed point number one you won’t have this problem). This is where I have found taking a break (go outside for that walk) and just planning what I need to get done that day or over the next couple of days and focussing on that, to be really helpful. Having smaller deadlines can help too.
  7. Snacks – never underestimate the importance of good snacks. Or tea.
  8. Stop procrastating & get back to work!

There is plenty of useful information out there from people who have actually successfully finished their thesis’, there are a few links below & feel free to leave some tips in the comments.

Anyhoo, I better get back to it – wish me luck.

Alice BABaranyovits is a PhD student at the School of Biological Sciences, University of Auckland. She is researching kererū (NZ pigeon; Hemiphaga novaeseelandiae) in urban areas. She is supervised by Jacqueline Beggs, Mick Clout, Todd Dennis & George Perry.

Getting out and about

Posted by Anna Probert @afprobert

From effects of artificial light on wildlife to sexual selection and weaponry of spiders and stress responses of seabirds, there is some really neat research being produced by students within our wider lab group.

In my opinion, one of the best things about being a PhD student is engaging with scientists conducting interesting research outside of my own field, and in some cases, having the opportunity to tag along and help them in the field. I had this pleasure last month, when I went down to Pureora Forest Park, where PhD student Kat Collier is researching the New Zealand lesser short-tailed bat Mystacina tuberculata


The opportunity to get up close and personal with a native New Zealand mammal is zen-kat-radiosomething that not many people, let alone many other scientists, often have the opportunity of doing. And whilst I had an enjoyable time out in the forest (which makes a nice change from the open scrub ecosystems I work in for my ant research), I also came back with some new skills and understanding of different ecological methods, such as radio-tracking and harp and mist netting for bats.


Going out into the field with other researchers is a great way to provide what is often much needed field assistance and support, as well as broaden your own personal skill set, which you may not have the opportunity to do within the limits of your own research. It’s also a great way to realise what you don’t like.

Overall, I think it helps to make you a more rounded ecologist and is a great excuse to get out the office and have a break from your own research.


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.

Tribute to the fallen: urban trees

Posted by Ellery McNaughton @EJ_McNaughton

Every month for the past 15 months I have stood on the streets at my study sites and conducted 10-minute bird counts. Somewhere along the line, I inadvertently began counting trees. Every site has at least one tree that birds seem to favour perching in over others, a sort of bird-version of the cushy chairs that granddads can always be found in. I often find myself focussing on these trees during my bird counts (while also not forgetting the other, less favoured bird-versions of church pews and university-seminar chairs). It makes it particularly noticeable when I turn up for the next month’s count, and that tree is gone.


Of my 27 sites, 14 of them have had at least one tree cut down in the past year. Some were natives. Some were over 10 metres tall. Sometimes they were replaced with other trees. Sometimes they were replaced with houses. Mostly they weren’t replaced with anything.

Urban trees are at risk. In places like central Auckland, where the majority of urban tree cover is on private land, it is important to have policies in place that can be used to protect and maintain the urban forest. Unfortunately, governmental policy reforms meant that in 2015 blanket urban tree protection was removed in Auckland, leaving an inadequate individual-based tree protection policy behind. With the exception of registered ‘notable’ trees and those in certain ecological areas, homeowners have free rein with regards to chopping down trees on their property.

Yes, a man’s home is his castle. The problem is, we live in a community of castles. Trees provide communal benefits. They increase health, mental wellbeing and air quality. They create additional opportunities for connection with nature by providing habitat to urban wildlife. People need to start looking past the boundaries of their property and their present time. When decades of growth can be cut down in minutes, the least one can do is consider the bigger picture. If nothing else, at least consider that it is jolly difficult to conduct a bird count over the noise of a chainsaw.

Ellery (2)Ellery McNaughton is a PhD student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. Her project investigates the effects of a city-wide changeover in streetlight technology on urban bird behaviour and ecosystem function. She is supervised by Margaret Stanley, Jacqueline Beggs, Kevin Gaston(University of Exeter, UK) and Darryl Jones (Griffith University, Australia).

Kauri and drought – What’s their survival strategy?

Posted by Julia Kaplick @julekap

New Zealand’s future climate is likely to be warmer and dryer and the frequency and duration of drought events is predicted to increase. Drought-induced tree mortality is increasing world-wide, with several instances also reported in New Zealand. So far we know very little about the drought vulnerability of New Zealand forest trees, but due to our research on kauri we are beginning to understand more and more about the drought survival strategy of this forest giant.



The roots are integral for trees to extract water from the soil and a good root network is crucial for drought survival. During times of water stress many trees, including kauri, invest in root growth. This allows them to keep up their normal transpiration levels for a little longer. So far it is assumed that kauri roots are very shallow, but sap flow measurements during the 2013 drought suggest otherwise. The upper soil layer during that time was extremely dry, but the trees still used water which suggests that kauri roots must reach a lot deeper than we previously thought allowing access to deeper water stores.


Kauri roots

Drought avoidance or toleration?

In general, every tree species falls somewhere on the spectrum between drought avoidance and drought toleration. Drought tolerating trees keep up transpiration as long as possible. Drought avoiding species on the other hand start closing their stomata to reduce water loss, when the soil moisture goes down. Both strategies have their downsides. Drought tolerators risk the formation of little air bubbles (xylem embolism) in their conducting tissue. This can lead to hydraulic failure if a drought lasts too long. Drought avoiders protect their hydraulic integrity but risk starvation, because the closure of the stomata also means a reduction of carbon intake. Kauri are clearly drought avoiders. Even under ideal growing conditions kauri are conservative water users, closing their stomata early in the day. They are known to be very susceptible to xylem embolism and protect their hydraulic integrity in that way.


Kauri cone in a bed of leaf litter

Leaf shedding

During the 2013 drought the kauri in our study plot lost a substantial amount of leaves and twigs. The reduction of leaf area is an effective way to reduce the water-losing surface and consequently the reduction of transpiration and the need for water uptake.


Base of a kauri stem

Water storage

All components of a tree (roots, stem, branches, leaves) can serve as water storage compartments. This is a drought survival strategy that succulents have perfected. Kauri make use of stored water on daily basis. Water is withdrawn from the stem and branches in the morning when the water starts to transpire from the leaves. During the afternoon and night these stores are refilled again. The massive stem volume paired with deep sapwood seem to make a great water store. During prolonged drought conditions kauri should be able to use the water reserves to their advantage. This is something we are investigation right now, stay tuned.


Julia Kaplick is a PhD student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. She is researching the response of native trees to seasonal variation in climatic conditions using measurements of sap flow, water relations and carbon allocation. Julia is supervised by Cate Macinnis-Ng (University of Auckland) and Mike Clearwater (Waikato University). Julia is supported by funding from the Marsden Fund.