Recently, I had the opportunity to hear Dame Dr. Jane Goodall speak about her Roots & Shoots program at Kristin School. Her intense passion for science began when, as a little girl, she saved money and bought as many second-hand books as she could. One book, ‘Tarzan of the Apes’, which she still treasures, caught her attention. She fell in love with Tarzan, but what did Tarzan do? He fell in love with the wrong Jane. Heartbreak aside, Tarzan inspired her to grow up, live in Africa among wild animals, and write books about them. Seventy-five years later, Jane has realized her dreams and more. For 50 years, she has revolutionized the field of primatology and redefined species conservation to include the needs of local societies and environments.
Dr. Goodall, clutching her ever-popular handful of soft toys, began her talk by declaring that every person can make a difference, especially the youth. Announcing that young people are some of the most compassionate and creative solutionaries our world has seen. She founded Roots & Shoots, in 1991, to empower and encourage young people to pursue their passion, rally their peers and become the compassionate leaders our world needs to ensure a better future for animals, people, and environment (A.P.E.). Roots & Shoots started with 12 students in Tanzania and has grown to 150,000 groups helping develop skills for young people worldwide. The organizations’ mission is to promote respect and compassion for all organisms, further understanding of all cultures and beliefs, and to inspire everyone to act to make the world a better place.
Various Roots & Shoots projects are currently undertaken by Kiwi students, from kindergarteners planting gardens to attract bees and butterflies; to educating local communities near Mount Pirongia about endangered bats; and even the famous the ‘BAN THE BAG’ campaign. Students from the De La Salle College gave a presentation about implementing their ‘Our Stream, Our Taonga’ restoration project on a small stream that runs through their campus and flows into Otaki Creek. The land around the stream was open fields, saturated with weeds. Rain runoffs from the area, leaf litter and rubbish used to flow into the stream resulting in an unpleasant smell and an unhealthy waterway. The students understood that people had destroyed this ecosystem and they had to do something or else it would never change. A small group of students in 2015 took charge of the clean-up and started small. They pulled out debris from the stream, including tires, branches, and even a bicycle. Next, they cleared weeds from the creek banks and planted native trees to stop soil runoff, increasing oxygen levels, restoring carbon into the ecosystem and attracting birds and insects. Since 2015, 100 students and staff have maintained this project and planted approximately 3,500 native trees. The students continue to monitor, pH, and water clarity along with birds, fish, and invertebrate, who have all returned in numbers to the stream.
Dr. Goodall stated there
has been a disconnect between our brains and the human heart and “only when
head and heart work in harmony can we attain our true human potential.” The
Roots & Shoots program is hugely beneficial and an excellent way of
involving students to think about imparting positive impacts in their world, and
encouraging them to work within their local communities to achieve a global
New Zealand is a weird place for biodiversity. An
estimated 20,000 invertebrate species live in New Zealand and at least 50% are
undescribed. When discussed, perhaps most often mentioned is the ‘high degree
of endemism’. This is the proportion of species found only in NZ and nowhere
else in the world. Overall, about 90% of insect species in NZ are endemic.
What is far less appreciated is the number of new
species still to be discovered and described. I am often asked ‘Are there still
new species to be found in NZ?’ Yes, there are, and many hundreds of them.
Recently, twenty-four new species of Mecodema, a genus of large-bodied ground beetles, have been described (Seldon & Buckley 2019), with one species even from Clevedon in the northern Wairoa! This genus is highly diverse with species spread throughout mainland New Zealand, and on many offshore islands. Many species are found in relatively restricted geographic areas and their presence indicates past geological events which have shaped New Zealand; including, isolation from the mainland, diversification and adaption in alpine zones; and volcanic activity.
Just this week, a new species of parasitoid wasp, Sierola houdiniae, was described (see Magnacca 2019) from a single specimen, reared from the larvae of a caterpillar, Houdinia flexilissima, better known as “Fred the Thread”. The caterpillar is found in Waikato bogs and peatlands in the living stems of Sporadanthus ferrugineus, a large endemic New Zealand rush, and is considered a species of high conservation status.
Discovering such hidden diversity is an important part
of understanding how the world works, but also gives a sense of wonder about the
diversity of the weird and wonderful little critters around us.
is an entomologist in the New Zealand Arthropod Collection at Landcare
Research, and a senior lecturer at the School of Biological Sciences,
University of Auckland.
Seldon & Buckley. 2019. The genus Mecodema Blanchard 1853 (Coleoptera:
Carabidae: Broscini) from the North Island, New Zealand. Zootaxa. doi.org/10.11646/zootaxa.4598.1.1
Magnacca. 2019. Two new species of Sierola Cameron (Hymenoptera:
Bethylidae) from New Zealand and Australia. New Zealand Entomologist. doi.org/10.1080/00779962.2019.1602899
This word cloud gives you an impression of the topics that went through my head during a University seminar on “Sustainability, science, society, water, food production and consumption”. The speakers covered a wide range of interesting topics and ideas. But there was one thing missing: a pragmatic approach on a scale that is larger than the local guerrilla gardening initiative, but still practical enough to not be forgotten as some idealist’s dream. After the fourth talk, I was still waiting for this one term “organic agriculture”.
There is a lot of scientific evidence for and against organic farming. I won’t give you a literature review here, as I think it’s up to everyone to inform themselves. Although some controversy about organic farming, I was surprised to not hear it mentioned in the discussion of “sustainable food production and consumption”. Do Kiwis still doubt the credibility of organic certification? Are most thinking “In New Zealand, everything used to be organic and that’s why we don’t need this organics fuss”? Or are organics still considered elite products for health freaks and people with pockets deeper than PhD students?
“Organic Agriculture is a production system that
sustains the health of soils,
ecosystems and people. It relies on ecological processes, biodiversity
and cycles adapted to local conditions, rather than the use of inputs with adverse
effects. Organic Agriculture combines tradition, innovation and science to benefit the shared environment and
promote fair relationships and a good quality of life for all involved.”
(c) Julia Schmack
far-fetched, doesn’t it?
Well, it’s not. It’s important to have goals and to work hard to reach them. Although you may not reach organic utopia, it’s certainly better than not having tried at all. Perfectionism often keeps us from trying to make change. We are bound to make mistakes when we try to improve conventional systems, and will likely be disproportionately criticised for not being perfect. This is too often the case when it comes to organic farming. There are logical benefits for biodiversity and animal welfare on organic farms compared to conventional farms. However, scattered cases of fraud cause people to mistrust the entire movement and, unfortunately, revert to the comfort of the status-quo.
I worked at the Research Institute for Organic Farming in Frankfurt for three years. There are things in organic agriculture I disagree with, such as the transport of organics over thousands of kilometres. It would be a lot more sustainable to eat local and seasonal, that much is obvious. I also disagree with the working conditions on some organic farms that rely on the hard work of volunteers. But I also understand that surviving as an alternative system in an economy that is ruled by stock markets is not easy. I don’t like that, in any kind of agriculture, baby cows get taken away from their mothers so that we can pump their milk into plastic bottles only to be let ferment in the communal fridge.
Despite these critiques, after visiting some 60 organic and conventional farms and meeting the farmers, there is one thing that I can say for certain: if I were a cow, pig, or chicken, and I could choose between the two farming systems, I know which farm I would choose. 100% the organic farm! The same goes if I were an earthworm, bird or plant. If I were a weed, the organic farmer wouldn’t be allowed to spray me with nasty chemicals. They would have to use less invasive and often more time intensive methods. But this is what you get when you pay that extra dollar.
(c) Julia Schmack
There is a lot of confusion around certification systems, which leaves many thinking “I don’t trust all these certifications. The ‘free range chicken’ that gets an hour of daylight and is still called ‘free range’”. It’s all too easy to throw your hands in the air and claim “well, who really knows” than to inform yourself. But on the website of the Ministry of Primary Industries you can read up on organics in NZ.
It’s up to you what you want to support with your money, but I think these small decisions make a big difference. In New Zealand, organics are still a somewhat elite and often expensive product, but it doesn’t have to stay like that. Remember that supply and demand means that a higher demand from the organic sector results in its growth. In Europe, the high demand for organics resulted in more affordable organics along the entire value chain. New Zealand is already very successful in exporting high-end organic products, but we need more sustainable foods in our schools, kindergartens, universities, hospitals, and defence forces.
What about a little experiment at University of Auckland. On the UoA Sustainability Website it states that “The University of Auckland is committed to pursuing sustainability via research, teaching and learning, operating practices, partnerships and capacity building”. UoA also recently came out first in the international sustainability rankings for universities showing commitment to sustainability. Sweet, here’s my idea for an operating practice to increase sustainability at UoA:
the conventional milk (a brand that so many people complain about) for an
organic alternative, and provide plant-based options.
Taking a bunch of money from big corporations and investing it into farmers with a sustainable vision of agriculture, is a simple and practical step. It not only makes a big difference for the farmer themselves, who now has an entire institution backing him, but it also makes a statement: we want our food to be produced sustainably and we invest in those with the best outcomes for all levels of sustainability, economy, ecology and society!
Let’s do it! Let’s make a change by investing in good (but not perfect) ideas!
Julia Schmack is a PhD student at the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is researching the ecology and control of social wasps, supervised by Jacqueline Beggs and Darren Ward (Landcare Research). Her PhD is funded by the Biological Heritage National Science Challenge. twitter: @julia_schmack
It’s not quite as catchy as the original (Love is all around), and
probably just as awkward as the Love Actually Billy Mack version (Christmas is all around),
but it does make my point that tipping points are all around us, often without
The world around us is made up of lots and lots of systems
and many of these are classed as ‘complex’. Complex systems can have tipping
points, where unexpected behaviour and sudden large changes can result from
seemingly small actions due to interactions between parts of the system. This
is often difficult to anticipate as studying parts of the system separately
doesn’t tell us how the system is going to behave as a whole (concept of emergence).
In my previous blog (The point
of collapse), I gave the example of an environmental tipping point
involving our freshwater ecosystems in New Zealand tipping suddenly into a
degraded unhealthy state from gradual changes to the surrounding land. However,
as complex systems can include anything from ecosystems, politics, economy and
cities, to the human body and the individual cells that compose it, tipping
points (both positive and negative) can also be found in these systems.
Viral disease epidemics also show tipping points
as they reach a critical mass
of people infected making it difficult to contain (are we heading this way for measles
globally due to a drop in number of people vaccinated?)
Companies want their product sales to cross a
tipping point in terms of popularity (social
media can play a big role in this)
If you are interested in social tipping points I’d recommend
reading Malcolm Gladwell’s book The Tipping Point or
checking out one of the many summaries out there like this.
So what examples of tipping points have you seen around you? What could you do to encourage positive tipping points or halt negative ones? Do you feel like singing out about them? I feel it in my fingers, I feel it in my toes, tipping points are all around me, and so the feeling grows… Maybe, just maybe, it’ll catch on!
Ellen Hume is a University of Auckland PhD student funded by Te
Pūnaha Matatini Centre of
Research Excellence. Her project is looking at tipping points in complex
systems to enable better risk-based decision making, with supervision from Cate
Macinnis-Ng and Shaun
Birds’ melodious songs, bats’ echolocations, insect’s crackling lisps and shuffles are sounds heard in nature that have fascinated humans for many centuries. Bioacoustics, the science of natural sounds produced by living organisms, is a relatively new field of science that has become central to the study of linguistics, animal behaviour, animal ecology and animal conservation.
Prior to any technological tools in the field of bioacoustics, scientists described animal sounds using various medium such as music notes, intricate words, or onomatopoeia with letter combinations that attempted to reproduce particular sounds. In order to accurately identify sounds in nature, scientists needed detailed behavioural notes associated to phonetic references. One may imagine how difficult it would have been to walk in a forest and try to detect an animal sound described as Grea-deal for example. For the curious minds, Grea–deal was a phonetic sound that referred to Alder Flycatchers from Massachusetts.
Beethoven’s pastoral Symphony No. 6 in F major ends with instrumental European birdsongs from the nightingale (flute), the quail (oboe), and the cuckoo (clarinets) (here respectively denoted with the German translation Nachtigall, Wachtel and Kukuk). Image from muswrite.blogspot.com
Like with many advances in science, new technologies often play an essential role in making new discoveries. In the mid 20s century, a technological revolution changed how scientists studied animal sounds. In 1950s with the invention of recorders and sound visualization tools, a new era in the field of bioacoustics began. Thanks to these devices, scientists could record and visualize sounds of wild species. A new window in the inner lives of animals opened up to scientists. For the first time, scientists could record and measure complex vocalizations and repertoires, vocal differences between individuals, sound variation throughout seasons or even vocalizations produced during specific breeding stages in wild animals. With these technologies, new horizons opened up in linguistics, animal behaviour, animal ecology and conservation. For example, new sound libraries, like the Macaulay Library, have built up impressive collections of animal sounds from the wild. Playback experiments, in which animal sounds are played back to live animals, became a common technique for wildlife biologists and allowed researchers to answer new questions about animal behaviour. Later, automated recorders, devices left in nature for long periods of time, allowed researchers to record the sounds of habitats known as soundscapes, which in return provided important information about the health of ecosystems.
Spectrograms help scientists visualize sounds, while recording devices help scientists record wildlife, and sound recordings ultimately become part of libraries of animal sounds on Earth, like the Macaulay Library. (Left) spectrogram with multiframe output made with SeeWave R package (image from http://www.rug.mnhn.fr/seewave/). (Right) map of the world with the number of wild species showing missing recorded sounds in the Macaulay Library, as of November 2018 (image from http://www.macaulaylibrary.org).
Recently, the Cain lab – at the University of Auckland where I am conducting a PhD in bioacoustics- started to use some of the latest technologies available in the field of bioacoustics, to advance our knowledge on the evolution of vocal learning in birds. Research in the Cain Lab investigates the vocal learning abilities of rifleman (a small passerine) in a remote reserve, Boundary Stream Mainland Island, New Zealand. Researchers at the Cain Lab use relatively novel bioacoustics technologies, such as automated recording devices, computer programming and machine learning, to record and analyse bird vocalizations.
Recording equipment deployed by researchers at the Cain Lab at the University of Auckland, are used to record the rifleman birds of a North Island forest, in Boundary Stream Mainland Island, New Zealand.(Left) a female rifleman; (middle) passive bioacoustic audio recorder (BAR) from The Frontier Labs; (right) a researcher, Ines G. Moran, from the Cain Lab, recording a rifleman in the tree canopy, with a handheld microphone, a recorder and a tripod. (Photo credit for left and middle photo: I.G. Moran; right photo: Y.Y. Loo)
The development of new technology in the field of wildlife bioacoustics has changed the way we study the vocal world of wild animals. New technologies in bioacoustics are rapidly advancing, and with them new questions are emerging. Animal vocalizations has fascinated humans for many centuries and will keep doing so for many more centuries. As frogs would say: ribbit ribbit!
Recommended resources for the detection and analysis of animal sounds.
Several R packages, in particular warbleR, SeeWave, bioacoustics, and monitor, and software are available to analyse, detect and classify sound. Here are few examples of great R packages and software:
warbleR : warbleR is R package that combines analytic tools used to measure and detect acoustic signals. Authors: Marcelo Araya-Salas & Grace Smith-Vidaurre (email@example.com)
Seewave Seewave offers a wide array of tools to analyze animal sounds with R signals. Acoustic template detection and monitoring database interface. Authors: Jerome Sueur et al. (firstname.lastname@example.org)
monitoR monitoR uses acoustic template to detect sounds. Authors: Sasha D. Hafner (email@example.com)
bioacousticsbioacoustics contains tools to transform, detect and classify animal sounds. Authors: Jean Marchal et al. (firstname.lastname@example.org)
Sound autodetection software
Kaleidoscope Kaleidoscope uses sound recognizers to detect animal sounds. This software saves a lot of time when processing numerous and long audio files.
Interactive sound analysis software
Raven– Cornell Lab of Ornithology Raven is a user-friendly platform that allows visualizing of sounds and annotation of animal vocalizations.
Ines G. Moran is a Ph.D. candidate in the Cain Lab at the University of Auckland, New Zealand. Her research investigates the evolution of vocal learning in birds, as well as dialects and vocal behaviours of kinship groups in the titpounamu/ rifleman (Acanthisitta chloris), New Zealand.
New Zealand is committed to preserving
its uniquely rich biological heritage with Predator-Free New Zealand (PFNZ). This
audacious programme is focused on ridding the country of the three most
biologically and economically harmful mammalian taxa by the year 2050 (Innes, Kelly, Overton, & Gillies, 2010). Pests targeted for
eradication include rodents (Rattus
rattus, R. norvegicus, R. exulans), mustelids (Mustela furo, M. ermine, M. nivalis) and the common brushtail
possum (Trichosurus vulpecula). These
mammals predate upon native biota and threaten to undermine New Zealand’s most
lucrative industries, including tourism and the primary industries. There is
unilateral support for PFNZ, but how close are we to actually achieving this
goal on New Zealand’s offshore islands?
If we exclude large islands that are source to substantial
pest populations, including Stewart Island (Rakiura)
and Great Barrier Island (Aotea), and
islands that cannot support mammalian life for extended periods (islands < 5
hectares, ha), 85 offshore islands (islands ≤ 50 kilometres from the mainland) currently host PFNZ
mammal pests. Insofar, 87 offshore islands have been eradicated of mammals since
New Zealand began systematic removals in 1980 (Figure 1). This means that over
half (50.5%) of the islands with a historical pest presence have been
Figure 1: PFNZ mammal eradications that have occurred on New Zealand offshore islands from 1980 through present.
If we investigate the total amount of island area eradicated
in this dataset, we paint a slightly different picture; 84,300 ha of island
area currently host mammal pests, and 24,200 ha have been eradicated. This
means that only 22.3% of island area historically hosting mammals have been
eradicated. Note, this dataset includes only cases of confirmed pest presence (islands
with an unknown status were excluded) and excludes incursions as being
considered confirmation of pest presence. Moreover, these numbers do not coincide
with other eradication estimates that use different geographical boundaries or
different pest species (e.g.(Towns, West, & Broome, 2013).
Admittedly, there is much work left to accomplish. This does not mean that PFNZ is impossible, though, only that it will be an uphill battle. In order to keep with the designated timeline, multiple government agencies and private groups have come together seeking creation of new (or “future”) control technologies that can address issues of ethical and technical concern. Transformative genetic control tools (including virus-vectored immunocontraception, RNA interference, and transgenic ‘Trojan’ approaches), and novel takes on current-day technology (including automated self-resetting traps, remote monitoring, and highly attractive lures) are being designed to target specific species in a manner that is cost-effective, environmentally benign, and exceeds the public conception of humaneness (Campbell et al., 2015). Such tools will be essential to the success of PFNZ. If they can be implemented in a timely manner, New Zealand will be well on its way to being the first nationwide endemic sanctuary.
Zach Carter is a PhD student at the University of Auckland in the School of Biological Sciences. He works with Dr. James Russell prioritising eradications of mammal pest species throughout New Zealand.
Campbell, K. J.,
Beek, J., Eason, C. T., Glen, A. S., Godwin, J., Gould, F., . . . Ponder, J. B.
(2015). The next generation of rodent eradications: innovative technologies and
tools to improve species specificity and increase their feasibility on islands.
Biological Conservation, 185, 47-58.
Campbell, K. J., Beek, J., Eason, C. T., Glen, A. S., Godwin, J., Gould, F., . . . Ponder, J. B. (2015). The next generation of rodent eradications: innovative technologies and tools to improve species specificity and increase their feasibility on islands. Biological Conservation, 185, 47-58.
Innes, J., Kelly, D., Overton, J. M., & Gillies, C. (2010).
Predation and other factors currently limiting New Zealand forest birds. New Zealand Journal of Ecology, 34(1),
Towns, D. R., West, C., & Broome, K. (2013). Purposes, outcomes
and challenges of eradicating invasive mammals from New Zealand islands: an
historical perspective. Wildlife
Research, 40(2), 94. 10.1071/wr12064
I recently participated
in a community conservation forum, when a community engagement colleague coined
the acronym ‘HIMBY’. I was exasperated by what I perceived as the community not
being able to see the ‘big picture’ of evidence-based strategy around pest
management and restoration.
“It’s the opposite of NIMBY
[Not In My BackYard]” she said. “It HAS
to be In My BackYard – HIMBY”. And she’s dead right.
This particular scenario is increasingly raising its head as community groups
voraciously compete for conservation funding and action.
Of course we desperately need highly activated communities to be engaged in conservation and restoration. We can enhance biodiversity over a larger area with limited resources when community groups and volunteers give their time and energy for free. It’s also important to have place-based conservation – this allows a sense of ownership and community buy-in that allows sustainability of people and groups over time. Ecologists have long since recognised that ecological science alone won’t solve conservation problems, and social science and community partnership is a critical cog in the conservation wheel.
also need to remind our communities about the risks of ‘HIMBY’ and community-based
conservation. One of the major risks of a national emphasis on community-based conservation
is that funding could be diverted away from areas that don’t have people – then
we could end up in a situation where much of our conservation
action is not taking place on land that is representative of
different ecosystem types/biodiversity. In fact, we know that community
conservation is biased towards coastal forest ecosystems, where
people are concentrated.
At a local
level, where funding and resources are prioritised and allocated within regions
or cities, ‘HIMBY’ is alive and well. Community groups within cities/regions
are understandably vying for resources. However, prioritisation of pest
management must incorporate more than community activation. Firstly, it must be
cost-effective and have preventative outcomes, rather than the ambulance at the
bottom of the cliff. We should prioritise prevention. The Treasure
Islands programme which funds pathway biosecurity to prevent
pest invasion on Hauraki Gulf Islands both 1) protects assets with
previous large investment in removing pests (e.g. Rangitoto-Motutapu Islands) and
2) prevents new invasions, thereby saving money in the long term. We know how
cost-effective it is in medicine to vaccinate rather than belatedly treat the
Given the impacts of Aotearoa-New Zealand’s invasion debt, we have to continue to ‘treat the disease’ and reduce pests and restore habitat. But the ‘where’ should be decided strategically. Yes, the degree to which a community is activated is a key factor in prioritisation along with other cultural and societal factors, but ecological factors (beyond our backyards), such as level of pest infestation, the value of the conservation assets within sites, and habitat connectivity, should be key factors in deciding where conservation actions should take place to achieve the best outcomes for biodiversity across the city or region.
we’re primed as humans to be highly attached to ‘our backyard’ and want the
best outcomes for it, we need to see the wood for the trees. This is why
larger-scale conservation visions, such as the North-West Wildlink and
Cape to City
are becoming increasingly important. If we can all buy into the larger landscape
scale conservation vision, then we will be willing to see that the priorities
for action/$$ spent might not be in our backyard, but over the fence, in
someone else’s backyard. We’ll also understand that by taking action in the
neighbour’s backyard, we will benefit from the biodiversity spilling over into
look up from our backyards and take on the larger vision.
Dedicated to the champion work of conservation staff within agencies engaging with communities, and also to those champion activators within our communities, rallying people to conservation action!
Dr Margaret Stanley is an Associate Professor in Ecology, School of Biological Sciences, University of Auckland. Most of her research is applied ecology, working to improve outcomes for biodiversity.
Dispersal is an integral part of population dynamics. Through
simply moving from one habitat patch to another, the dispersal of an individual
has consequences not only for its own fitness, but also for population persistence
Understanding the causes and consequences of dispersal is
vital for population management and predicting population response to changes
in the environment. This is particularly important in conservation and
re-introduction efforts, biological control and management of alien species. Furthermore,
the factors that determine the extent to which dispersers are selective and
capable when searching for a new habitat is of interest.
A newly arrived population of a potentially invasive species
is usually small, and dispersal could play an important role in its establishment
success. Species with a high dispersal rate could end up spread out too thinly,
resulting in the inability to find suitable mates, the loss of predator
dilution or to defend against predators. These and/or other component Allee
effects could scale up to a demographic
Allee effect and ultimately lead to the demise of the population.
Reasons for dispersal
The reasons for dispersal are multiple and could include factors
such as finding suitable host patches, finding potential mates, avoiding
inbreeding with kin, avoiding intra- and interspecific competition, and escaping
low or declining host patch quality.
Cues used during dispersal
The bee Chelostoma rapunculi makes use of a combination of visual and olfactory cues to find its host plant
When searching for a new habitat patch, insect dispersers make use of several cues, including visual (shape, size, colour) and/or olfactory cues (communication chemicals such as host-plant volatiles and pheromones). For example, the bee Chelostoma rapunculi makes use of a combination of visual and olfactory cues to find its host plant. Similarly, the Asian Longhorned Beetle, Anoplophora glabripennis uses both olfactory and visual cues to locate its host plant Acer negundo.
For certain insect species the chemical cues from colonised
host plants are important in host location; in this case both cues released by conspecifics
already colonizing the plant (pheromones) and plant cues induced by herbivore
feeding (feeding-induced plant volatiles), or by oviposition, can influence the
apparency of the host patch. This gives rise to a clumped distribution or
aggregation of the insect species on selected host patches.
Using chemical cues from colonized plants can be both
beneficial and detrimental. Particularly, it signals the availability and
quality of food and the presence of conspecifics, thereby negating the Allee
effect through dilution of predation risk, overcoming host defences and
ensuring potential mates. Ultimately it reduces search costs, and other costs
related to exercising vigilance during foraging and mate-finding. For example, the
flea beetle, Phyllotreta cruciferae, makes use of a combination of male-produced
pheromone and feeding-induced host volatiles to form aggregations under field
On the negative side, the volatiles from an herbivore-infested plant represent a food source with competitors and elevated risk of influx of predators and parasitoids. For example, feeding-induced volatile emissions from Nicotiana attenuata plants increased predation by a generalist predator, Geocoris pallens, on the eggs of the flea beetle Epitrix hirtipennis.
My interest in the topic of dispersal is its role in the initial
establishment and population growth of small, recently arrived populations of
alien species – especially during eradication efforts when small populations
are subjected to management actions such as host removal. During this process
habitat is broken up into fragmented host patches, often with reduced numbers
of individuals scattered over several patches surrounded by unsuitable matrix. Should
these individuals roll the dice and aggregate?, and thereby form a population
large enough to overcome Allee effects. If they remain scattered (no dispersion
or inefficient dispersion), will they eventually die out?
Neolema ogloblini adult on stem of Tradescantia fluminensis. Photo: Murray Dawson.
My studies use the leafbeetle Neolema ogloblini, a biocontrol agent for Tradescantia fluminensis in New Zealand, as proxy for an invasive insect pest species. By studying the dispersal choices of recently released adults of N. ogloblini, I was able to determine that the beetle species utilizes cues from colonized host patches. The beetles responded to the presence of actively-feeding adults, but not to non-feeding adults, suggesting their response is motivated by feeding-induced volatiles and/or pheromones that are only released while feeding.
Experiments to determine how efficient the beetles are at
finding patches of their host plant as influenced by the degree of isolation of
a potential host patch and the matrix surrounding it, is to be completed this
Results of my studies will ultimately give guidance on what eradication approaches are promising for particular invasive species.
Hester Williams is a PhD candidate in the School of Biological Sciences, University of Auckland and is stationed with the Landcare Research Biocontrol team in Lincoln, Canterbury. She is interested in invasion processes of both insect and plant species. Hester is supervised by Darren Ward (Landcare Research/University of Auckland) and Eckehard Brockerhoff (Scion), with Sandy Liebhold (USDA) as advisor. Her studies are supported by a joint Ministry for Primary Industries – University of Auckland scholarship. The project is an integral part of an MBIE program “A Toolkit for the Urban Battlefield” led by Scion.
About to bite into that luscious, juicy taste of summer, a tree-ripened nectarine? Be thankful you do not live anywhere with fruit fly. This group of insects are infamous for the damage they do to a wide range of fruit and vegetables.
Apricot (left) and pear (right) are two of the many fruits affected by fruit fly. Images used by permission Plant Health Australia
As well as summerfruit, they attack citrus, apples, pears, berries, grapes, olives, persimmons, tomatoes, capsicum, eggplant, and avocado. We are not talking a bit of cosmetic damage to the skin – fruit can end up as a soft, mushy, inedible mess. Fruit fly females lay eggs into fruit and the developing maggots munch away, causing the fruit to rot and drop to the ground.
The extent of damage can be devastating. The island of Nauru ended up home to four species of pest fruit fly. By 1998, about 95% of mango were infested and island-grown fresh fruit and vegetables were so scarce locals had to rely on more expensive imported produce. Fortunately, an intensive lure and poison programme eradicated three of the four species and mango and breadfruit were back on the menu.
Australia is not so lucky. They have two highly damaging fruit fly species, the Queensland fruit fly and Mediterranean fruit fly. Commercial growers spend hundreds of millions of dollars on various control measures and quarantine measures are in place to try to stop the spread into uninfested areas. With varying degrees of success.
A single Queensland fruit fly (Bactrocera tryoni) was recently detected in Devonport, New Zealand. A full scale response has been triggered as it is regarded as a serious pest [Image: James Niland, Wikimedia commons ].
It is no surprise then that detection of two different species of fruit fly in New Zealand in a week makes headline news and our dollar falls. Finding a second Queensland fruit fly near to the first is concerning. We certainly do not want them to establish. However, I think we should also celebrate. The detections are really New Zealand’s biosecurity system operating at its best. We have in place a world class fruit fly detection system; a nationwide surveillance network of 7737 traps baited with fruit fly specific lures that are checked seasonally.
Including the three latest finds, this network has detected 13 incursions of economically important fruit flies since 1989. More importantly, early detection and effective control means fruit flies have not established in New Zealand. With such high stakes, it is critical that we keep going with research to improve surveillance, eradication and control tools. Recent PhD work at University of Auckland by Dr Lloyd Stringer is a good example; he developed a population model that helps to identify the most successful management and eradication options for Queensland fruit fly.
We cannot afford to take our foot off the pedal. Fruit fly will keep pushing at our border since there are around 80 pest species found in many countries we trade with and travel to. Furthermore, some regions have given up trying to achieve area wide fruit fly control, leading to higher density of these pests. That makes it easier for an individual fly to slip past all the measures we have in place to keep them out. So hats off to all the folk involved in keeping fruit fly at bay. That includes you – letting biosecurity officers onto your property to check for infestation, making sure you do not move fruit or veges from “controlled areas”, and encouraging everyone to never bring undeclared produce into New Zealand.
Who’s afraid of the dark? Society in general it would seem. Some people have good reason to be, living in places where humans are not top of the food chain, and darkness provides cover for those that are. Yet even in places where predation is not a risk to contend with, darkness gets a bad rap. The Dark Side, the Dark Lord with his Dark Mark, dark magic, somehow we have conflated darkness with evil. Perhaps this is because in the dichotomy of light and dark, light outshines darkness in the PR department. Light is the stuff angels wear to look suitably holy. Light signifies safe places for lion kings to rule their lion kingdoms. Light is the symbol of enlightenment and civilisation, an indicator of human innovation, technology and progress. And in the immutable logic of opposing pairs, if light = good, then darkness must therefore = bad. It’s algebra, or something.
Choose light or choose dark. Choose the hero or the villain. Somehow they’re always the same choice
However, darkness really is our friend, preserving our sleep patterns and physiological processes, keeping our biological clock running in an orderly manner. It’s an unappreciated and often abusive friendship on our part. Natural darkness is being eroded away as we increasingly choose to hang out with the cool new kid, light. Natural limiters of daily activity are for lesser species, and if we want to work late into the night, nothing can stop us (even if the numerous health problems should). Some people love light so much that when their streetlights are changed to have less light spill, they buy outdoor lights to make up for the lack of illumination. That’s not just enabling a later bedtime; it is actively avoiding the presence of darkness. Why are we afraid of the dark?
Dumbledore promoting light pollution
While urban dwellers generally don’t have to deal with predation, in the dark we often feel at risk from other humans. Walking home at night becomes an exercise of fearful imagination, where every shadowy bush, alley or doorway becomes a hiding place for others up to no good. Light banishes the shadows and leaves no place for imagination to run riot; security lights are so named for a reason – they make us feel secure. This is in spite of the fact that light doesn’t appear to reliably banish the presence of the criminal element. Of course, even if light doesn’t actually make us safe, it is important for people to feel safe in their cities. And until we as a society stop viewing darkness as a villain to be conquered, light is a necessary evil.
Ellery McNaughton is a PhD student in the Centre of Biodiversity and Biosecurity, School of