Exotic Insect Invaders – can taxonomic collections help us learn from the past?

By Kaavya Benjamin @kaavyabenjamin95

Globalisation has ensured the prompt arrival of our Amazon purchases, direct flights to Hawaii and ability to share the best of what NZ has to offer with the world. However, the increase in global trade and transport has also intensified the establishment and spread of exotic insect species. These are insect species who invade areas they aren’t native. A recent study also showed that these hitchhiking invaders aren’t planning on stopping any time soon.

Exotic insect invaders can do a lot of harm to native ecosystems. For example, in NZ Vespula wasp invaders have been known to reduce honeydew by 70% and compete with the endangered Kaka. Argentine ants are one of the most problematic invaders of the insect world. Like Genghis Khan’s hordes, the abundance and aggressive nature of this species cause major problems for native birds, lizards and insects. These issues have driven numerous studies to understand the negative impacts of these invaders on native ecosystems. However, very little is known about the dynamics of their spread once established

Image 1 Kaka and wasp image

More than 1,400 exotic insect species have established in NZ, that we know of. Of these over 500 are herbivores who attack numerous plant species. However, other than a few well-known examples, comparatively, there aren’t many instances of exotic insect herbivores spreading into native NZ ecosystems. This is thought to be due to the resistance of the native ecosystems to invaders because of phylogenetic differences between NZ and overseas plants.

However, the more alarming fact is that exotic insect species in NZ have not yet reached equilibrium, meaning their spread will likely continue in the future. A study in 2012 showed the vulnerability of habitats to invasion was dependent upon rates of spread of exotic species. Thus, taxonomic collections, which house specimens collected over a wide range of time and space, could help identify key drivers of population dynamics for the spread of exotic insects. This could point to management options to control/limit widespread invasion. Taxonomic collections can also come in handy when informing conservation managers where control efforts can best be targeted. I am using the New Zealand Arthropod Collection to assess the spread of herbivorous insects into native NZ ecosystems as a part of my Masters’ project. This could help DOC and MPI come up with better pest risk-assessments and provide information for invasive species research.  

Image 2 Collections image.jpg

Understanding the dynamics and patterns of past invaders could also result in better-informed predictions for future exotic invasions. While taxonomic collections are far from perfect, they are still a robust source of information which can aid conservation management.

Kaavya is a Masters student in the School of Biological Sciences, University of Auckland. Her project aims to assess spread, over time, of all exotic herbivorous insects into native New Zealand ecosystems. She is supervised by Darren Ward.

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Tuning in to smallness

Posted by Yen Yi Loo @looyenyi 

How do you survive by being small? The soundscape in a New Zealand bush is filled with splendour. But among the powerful song and majestic plumage, there is a niche for all things small and sweet. In Boundary Stream Mainland Island, a forest reserve in the Hawkes Bay region, a group of tiny birds constantly flick and flutter in the trees; Tomtits, Grey warblers, Silvereyes, Robins…and the smallest of them all is the Rifleman. They are so small that a wing flap of a butterfly could be mistaken as a Rifleman. Not only that. They are also very difficult to hear. Rumour has it that people after about 50 years of age can’t hear them. And because of that, many don’t notice them among the Tūī, Bellbirds, and Kākā. I spent the first week of my PhD fieldwork tuning in to the high pitch calls of the Rifleman, tilting my head this way and that, like an owl, to pick up subtle wisps of conversation between foraging pairs. After some practice, I could finally tease apart the calls between Rifleman, Grey warblers and Tomtits, by their small differences in pitch and length.

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Spotting a rifleman takes a little patience and a good sense of auditory localization,
and also ways to watch from different perspectives!
© Ines Moran

I am a first year PhD student looking at the vocal learning abilities of the Rifleman. Could they be learners? Well, we know that they are not songbirds, because they don’t sing to defend their territory or to attract mates – or do they…? But findings in the past decade have also plucked them from the suboscine group and placed them as a link between the passerines and the parrots. So here we are, trying to decipher their potential hidden skill of vocal learning. The more I spend time with them, the more I learn about their interesting behaviours. For instance, they constantly open and close their wings while hopping on branches and trunks of trees in an incredible speed of about 0.05 seconds for each ‘flick’, maybe to maintain balance due to their short of tail? And I saw a male hover for one second in the air!

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“Whoa, didn’t see that branch there!”
© Yen Yi Loo

I can relate to the Rifleman in many ways. For one, I am small, even for Asian standards. For another, I speak softly – well, because I wouldn’t want to disturb the birds! And most relatable of all, I can’t sit still. Although the Rifleman don’t migrate or have large territories, they are busy little birds constantly communicating and working on staying alive. It is difficult to follow them because they move so quickly. I, too, am constantly moving; I travel the world from one side to the other, chasing little birds and learning their behaviour and language. Truth be told, there is a lot to learn wherever we go. And it led me here to this beautiful land of unique bird life. Being surrounded by the soundscape of this forest and the wonderful team that I’m working with, I am glad this is where I will spend all the summers of my PhD doing fieldwork!

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The Cain Lab on the first week at Boundary Stream Mainland Island.
From left, Me: cold and numb from the NZ spring rain,
Daria Erastova: looking to expand her incredible bird list,
Sarah Withers: the pioneer of Rifleman research in the North Island,
Ines Moran: my PhD team mate – the best I could ask for,
and Kristal Cain herself!

YenYen Yi Loo is a PhD student in the School of Biological Sciences, University of Auckland. Her study aims to determine whether the rifleman (Acanthisitta chloris) are vocal learners by investigating the ontogeny and temporal changes in their vocal parameters, and its implication on the evolutionary origins of vocal learning in the avian phylogenetic tree. She is supervised by Kristal Cain and Margaret Stanley.

 

10 Reasons to Love ‘Bird of the Year’

…and why we should have ‘Critter of the Year”

Posted by @mc_stanley1

When you’re completely swamped and just trying to get through the day hour by hour, hoping to find Hermione Granger’s time-turner, how do you get through the massive stress of being overloaded*?

The answer for me this week has been NZ ‘Bird of The Year’.

Bird of the Year voting has filled Twitter with the most amazing positive energy and opportunities to smile.

Here’s why I think ‘Bird of the Year’ is awesome:

  1. It’s a stress-relieving reward: “If I just finish marking this assignment, I can have a sneaky peek at the hilarious memes” (healthier for mind & body than food rewards!)
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Two of the of many awesome memes – check out whio & weka memes too!

2. Breaks down stereotypes – it’s a brilliant opportunity to showcase that scientists are creative, and funny. Scientists such as Stephanie Galla and Josie Galbraith show us that science and art go hand-in-hand (I’m jealous).

 

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Art by Josie Galbraith, Auckland War Memorial Museum (Left) and Stephanie Galla, University of Canterbury (Right)

3. #Scicomm (science communication) is increasingly important in an age where there is a distrust in science among some groups. Ecologists throughout NZ are developing their fledgling #scicomm wings this week and communicating the incredible reasons why these birds are important. While some are old hands at this.

Here’s a couple:

Josie Galbraith on the numbers of Kakī left in the wild: “There are probably more cats on your street than that, more cocopops in your bowl, more lone socks in your drawers.”

tinder

Stephanie Galla’s  genius scicomm – explaining the kakī captive breeding programme by putting kakī on Tinder.

4. What biodiversity in Aotearoa-New Zealand needs is for people to care. And people to care enough to do something about it. We need people other than us biodiversity nerds to care and that means engaging people other than our own peer groups. The Bird of Year has seen some high profile supporters, including the Prime Minister (Black Petrel – ‘the bogan bird’), raise the profile of their chosen species – reaching more New Zealanders we could ever do alone.

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While Bill Bailey and Stephen Fry are onboard, #TeamKakī tries desperately to attract Sam Neil @TwoPaddocks attention, while #TeamHihi are trying to win over Hilary Barry @Hilary_Barry. Come on Sam!

5. Talking to people about why they are voting for a particular species is fascinating and tells us something about nature connection. Some examples:

  • ‘I’m not voting for something I’ve never seen’
  • ‘That bird doesn’t need a profile, not voting for that’
  • ‘It’s won before, it [kakapo] should be deleted’
  • ‘It’s not even endangered’
  • ‘I like an underdog’
  • ‘A robin almost stood on my shoe – it was so cool’
  • ‘But it’s got a tiny head and beady red eyes’
  • ‘They shouldn’t lump all the shags together, no one can connect with a lumpy shag

6. Tea room battles: again with the people interaction – it’s fascinating watching the tearoom come alive with fiery debate about which bird should win (& why you shouldn’t jump ship just because your bird didn’t win last year).

7. Because kakī have to win:

No other native bird is more kiwi than the kakī.  They wear an all black jersey, and every day is Red Socks Day. Josie Galbraith

8. Because who doesn’t love a scandal?

scandal

This has opened up a whole thread on Australians and shags – great mid-marking silliness

9. Because it paves the way for Critter of the Year! Yes New Zealand! No one can possibly wait another year for the enjoyment Bird of the Year has brought us! We need to vote on the forgotten fauna – the freaky but awesome Peripatus, the Otaaaaaaaago skink, and the glorious Powelliphanta snail. Come on NZ Entomological Society! Forest & Bird! RNZ! #CritteroftheWeek

And finally…

10. Because of this:

sad birds

 

IMG_9315 (2)Dr Margaret Stanley is an Associate Professor 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, but can be grouped into three main research strands: urban ecology; invasion ecology; and plant-animal interactions.

* besides having an awesome husband who steps up to do far more than his share of kid duty 🙂