How well do we know our NZ insect fauna? Survey results

If you don’t feel like reading everything I have put my major findings in bold type and there is a set of conclusions and resources at the bottom of the post

So on Wednesday I gave a talk about a cool project I’ve been working on to produce a set of playing cards featuring 52 native insects. Emma and I have been chipping away at it for a little more than a year and recently confirmed the start of manufacture with Legends Playing Card Co. We also have a facebook page which you can like and stuff (hint hint).

To make small talk as an entomologist is a lot of fielding odd looks and deciding how specific to be for the benefit of all involved (“I’m a behavioural ecologist” vs “I watch praying mantises eat each other or, best case scenario, have sex”). There are also inevitable forks in the conversation at which point you have to decide whether you want to be the “well actually” person or let some well-meaning error pass. I’m not criticising. We don’t know what we don’t know and it is rarely important for people to remember the difference between grasshoppers and praying mantids unless you’re a male mantis.

Anyway, when I started up the playing card project with the aim to introduce a few more of our insects to folks, I was working entirely off anecdotal evidence that people mostly don’t know much about insects. This felt insufficient when presenting to a range of zoologists and ecologists as I did last Wednesday at our departmental meeting. Maybe I just feel uncomfortable presenting anything which doesn’t have graphs. With nary a thought of human participant ethics in research I opened up a Google Form with three questions.

  1. Name up to 10 NZ birds (Scientific names not required)
  2. Name up to 10 NZ insects (Scientific names not required)
  3. What is your background in zoology?

The first two were long form answers and the third was multiple choice with the options “none”, “studied biology in high school”, “studied zoology (generic) at a tertiary level”, “I have trained in or studied entomology” and “it’s a personal interest”. The aim was to set up a short quiz which would give me some handle of how knowledgeable people are about insects with the bird question providing (what I hoped would be) a clear comparison with a well-represented class of animals. The background question I hoped would give some indication about where folks were getting their information from.

I shared this survey on Facebook and Twitter where it received maybe 10 shares/retweets total. I received a total of 137 responses with a fairly good spread of backgrounds:

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It was a short and informal survey which answers a few simple questions and gives me a whole bunch of reckons. But before we get to the findings let’s talk about:

Methods: The problem with jargon

Going native

The wording I used in the survey was “NZ insects” and “NZ birds” and I was deliberately vague as I explained when people asked, “Do you mean native species?” The word “native” means something quite specific to ecologists which certainly overlaps with how most think of the term but not entirely. I didn’t want to knowingly asking different questions to different people nor did I want to make the question seem more complicated or run the risk of people not knowing what “endemic” meant. So I left it as “NZ” and let everyone answer the same vague question as they liked. Consequently, I accepted any insect (provided that it was indeed an insect) which has possibly been seen in New Zealand. Yes I was that broad.

Types, species and orders

Similarly, I didn’t specify that I wanted bird or insect “species”, “genera” or “types” because, again, those words mean either different things or nothing at all depending on who you ask. The result was that the birds and insects were described with vastly different degrees of specificity which, I think, reflects our general understanding of each group.  Pretty much every bird offered was specific at least to genus (for example, we have multiple species of Kiwi or Apteryx to give it its scientific name). By contrast, most insects listed encompassed a very large number of species. For instance, did you know that there are actually more than 70 species of “wētā” in New Zealand?1 A lot of answers were even broader than that (e.g. “beetles” or “ant”). While I counted all of these as correct individual entries, it does make direct comparison between the birds and insects a bit tricky2.

 

Results:

So. What did the survey show:

  1. Everyone knows what a bird is.
  2. In general, we can name ten “NZ birds” but struggle to name ten “NZ insects”. Even with the almost meaninglessly broad definition I took of “NZ insect”, on average participants could name 9.17 birds compared to 5.71 insects (t92 = 9.733, p < 2.2e-16). This test was conducted by subtracting the number of insects from the number of birds each participant offered.
  3. In fact, while everyone can list ten birds, only those who studied or trained in entomology specifically could name ten insects (Fig 1.). Yes indeed if you compare the difference between insect and birds offered by participants of different backgrounds, only entomologists could fill out both lists consistently. The big surprise here is that even university students/graduates who studied zoology of some variety fared, on average, not much better than those with only a high school level of biology or no background in biology at all (F128,4 = 8.8331, p < 0.0001). Test was conducted on the difference between the number of birds and insects offered.
  4. There are a range of native birds which readily spring to mind. With insects it’s wētā all over (Fig. 2 – click to enlarge). I took counts of the first animals listed (in the case of insects it was often the only animal listed). I ranked the animals based on how often they appeared first in people’s lists. A little surprising but 47% of entries began with Tūī which I put down almost entirely to the time of year and the fact that more of us have probably seen live Tūī. Kea and kiwi fared similarly although they fell far behind at 16 and 14% respectively. Far less surprising was that wētā came up first in 75% of entries with the next most common insects, giraffe weevil and huhu beetle only first 8% and 5% of the time respectively. What we can conclude about this and the results in general is a little more complicated but I have a couple reckons.

 

fig-actual

Fig. 1: Number of birds (white) and insects (grey) listed depending on background in biology

Fig. 2: Birds (left) and insects (right) most frequently listed first. [By the way I hate working with pie charts].

Discussion: 

So, nearly everyone knows ten native birds regardless of background. By contrast only those who actively study insects are likely to know ten native insects. This was mostly surprising as even a university degree in biology didn’t improve answers much. To me this suggests that promotion of our avian fauna is a) much more pervasive and b) a lot more varied in that a lot of species get a look in (supported by the greater distribution in first place positions in people’s lists).

In addition, I have a few reckons based on the responses:

  1. People tried to list native insects and birds without explicit prompting. When people ran short of obvious candidates, they pushed their own definition of “NZ” or the definition of the animal. A few ran short of birds and went for “sparrow” and “starling” which I still accepted for the same reason I accepted german wasp. When people ran short of insects which happened a lot more often, they either started listing exotic species or orders of insects e.g. beetle. Or, they started listing clearly native terrestrial invertebrates such as the katipo or the Peripatus velvet worm. One potential shortfall here is that I accepted loose definitions of NZ but I was pretty firm on definition of “insect”.
  2. Māori names are really helpful for two reasons
    1. One of the easiest ways to tell if something is probably native is “does it have a Māori name?” This is the most tentative of my conclusions and perhaps it’s better to call it a hypothesis. The top four insects listed first were the wētā, the giraffe weevil, the huhu beetle and the puriri moth. The giraffe weevil sticks out a little but I’m tempted to say that it received so many entries because a large number of my lab group (past and present) have worked with them and couldn’t help but find them charming. Meanwhile the bird answers were a cavalcade of ks. Whether it’s that a) the Māori names are easier to remember or b) Māori names are just a shorthand for “definitely native” or c):
    2. Māori names of fauna are frequently used for naming places. I had a couple discussions with people and we reckon that if I had included a “List 10 NZ plants”, plants would have done better than at insects but worse compared to birds. I think the reason for this is that names such as “rata” and “kahikitea” are really prevalent in our day-to-day so that even if you couldn’t identify a totara tree, you might know someone who lives on the street. Similar for birds.
totara

Other examples include names of hospital wards and parking levels

kereru

Just to prove my point

Conclusions

I don’t think it’s too much to say that we on average have greater familiarity with the diversity of our avian fauna compared to our insect fauna even if we haven’t directly interacted with all the birds we might know. I can’t pinpoint the reasons for this from these results alone but I would assume that it comes from promotion of bird species outside of academic institutions whereas information about insects is generally acquired through deliberate study.

This is not to say that we have to promote insects on equal footing as birds (there’s no scientific test for that). But I think there must be consequences of this relative lack of appreciation which feeds into how we value different forms of conservation at the ecosystem and species levels.

Emma and I hope that we can help to close this gap in our knowledge just a little bit with the insect cards and if you’re interested in other resources on our native insect fauna I highly recommend tuning into RadioNZ’s Critter of the Week and checking out some of the links below.

Thanks very much to everyone who took part in the survey – it’s been illuminating!

Resources:

Critter of the week – Each week Jesse Mulligan talks to DoC’s Nicola Toki about an underappreciated native species which are frequently invertebrates. Fridays @1:30 on RadioNZ National. Here’s an example.

NatureWatch – a site where people post photos of animals they’ve seen around the country. A lot of scientists lurk on that site ready to help identify the animals people find! A good way to find out where people tend to find certain types of insects.

Landcare research – Landcare research is a Crown Research Institute which deals a great deal with our terrestrial invertebrate fauna and they offer a few guides (start with “What is this bug”) to identifying species as well as fact sheets on a handful of our species.

 


1 Unless you listed multiple types of wētā or said “all the wētā species”, I just counted “wētā” as one.

2 You might argue that this definition “punishes” people who tried to list only native/endemic species and that, had they known that I was accepting generic insect answers, they could have listed 10 insect orders. This is probably fair and asking the question in that way was a gamble that people would read “NZ insect” and do their best to list natives (for why I think that this is exactly what happened, see my “reckons”). If I were to do this survey in a more formalised way I would certainly be more specific.

Observations. Night #2

My reaction when, after 2 hours of watching spiders do nothing, they start mating

(which isn’t actually what I wanted)
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My face when the other male got in on the action and thetwo males started fighting

(which is exactly what I want)
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And finally, how I felt when one male impaled the other on its fang and began to eat his dying foe

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First forays into μ-CT scanning

Now I’m just using this blog to validate the work I do each day…

And on this particular day I’ve been messing around with a CT scan of a spider jaw (chelicera). As I might’ve mentioned previously, during the summer, the male sheet-web spiders (who have massive jaws – far bigger than those of the females) go wandering in search of females/their webs.

Lads and ladies (Cambridgea foliata)

Lads and ladies (Cambridgea foliata)

When they find one, the male sits in the hub of the web and will stay there all night. If the male wanders into a web with another male already resident, they will fight. What determines the outcome is the differential in “resource holding potential”. RHP is combination of an individual’s body size, weapon size, physiological condition and previous experience. The individual with the higher RHP is more likely to win.

I’m looking at the evolution of exaggerated male weaponry and it has been suggested that extreme male weapons evolve to help males win these competitions i.e. contribute significantly to RHP. The idea is that a bigger weapon makes for a better fighter or that a large weapon makes a male look like a better fighter so other males are less likely to approach. Both processes would result in a male who is able to monopolise the female.

The problem is that weapon size is highly correlated with body size so it’s been very difficult to determine statistically whether larger weapons actually make any meaningful contribution over and above that of a larger body size. Try to imagine a giant bare-fisted boxer who had massive hands which were big relative to the boxer himself. Like, hands bigger than own face. One could argue that bigger hands/fist could help him to win a fight but how do you actually prove that? You would have to separate the effect of his hands from the effect of just being a big person. You can’t consider the two traits in isolation because that would require removing his hands which only shows that you need hands to box effectively and that a disembodied pair of hands is…just that.

maim_anakin

thing00

Jedis and Thing are the only exceptions

There are a couple ways that people have tried to circumvent this when studying animals. One is that people have used force transducers to get direct measurements of bite force or nipping force, depending on the type of weapon. Another avenue is doing finite element analysis on the structures. Some biologists already use finite element analysis to look at loading on things like leg bones in different species of moa and have used various traits to estimate bite strength from crocodile skulls. Recently someone has done this sort of analysis on spider fangs.

One of the first steps to doing such an analysis is doing a micro-CT scan (computed tomography) of the weapons and the musculature. I went along for my first CT training session a couple weeks ago. I was told to bring a sample to scan so I decided to take along part of a male Cambridgea foliata. Unfortunately I was an eejit who decided to dissect off the jaw to scan rather than taking the whole head. The result is that you can’t see the full length of the muscles controlling fang movement but the scan I got has given me the chance to play around with different bits of software and generally get a first look into the structure.

The end result is an 8 second video which I’m more proud of then I really should be. *tadaa* *spirit fingers*

 

 

Spontaneous generation feat. bisecting things is fun

So something happened today which would neither surprise nor impress someone who actually had any experience studying spiders. But this is my first year of it so I’m going to bring it up anyway.

So I had spiders in my house over the summer for observations and some of the females laid egg cases.

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Female C. foliata and spawn

These were roughly spherical orbs slightly less than 1cm in diameter which would be hung from the roof of their mesh cages. Sheet-webs in the wild will incorporate forest floor debris into the egg casing. In the case of my spiders their cages were a little Spartan so they had to make do with the left over legs of the insects I had fed them.

When the females died I removed the egg cases and kept them in little pottles (plastic jars), trying to keep them suspended if I could. Demonstrating an innate aptitude for husbandry, these various eggs were starved of oxygen i.e. lids on until I realised this was dumb; they were exposed to extreme desiccation i.e. left on the window sill during the summer; and then they endured several months of Auckland winter in a cold student flat.

Then I read somewhere that, in some cases, the female spider actually has to open the egg case for the young to escape.

Needless to say, when I brought a couple of the egg cases into the lab a full 6 months after they were laid, I was expecting, at best or at worst, to open up the sacs to find puckered, charcoal eggs. Either that or the bodies of hundreds of spiderlings squashed together until they were indistinguishable or utterly dismembered, mutilated in the Battle Royale which I had imposed on them with one engorged baby spider lying prone, ultimately unable to escape the silk prison.

battle royale

Amazingly, only two males were cannibalised

The outer casing of the sac is white with the feel of a tough napkin which I had to cut through with my dissection scissors. On the inside there was a cluster of eggs (each egg <1mm diameter) held together with an off-white cement. This cluster hung in the centre of the sac, suspended in fine, kinked threads which came in every direction from the inside surface of the outer sac.

A nice word for it would be that the eggs sat in a harness, a more amusing one would be that the egg sac is basically a spider zorb.

(The block of eggs broke)

I pulled some of the eggs away a cut them open but the magnification on the dissecting microscope wasn’t really up to the task of distinguishing the contents. The eggs themselves ranged between dark brown and pale orange and some did indeed look pretty much dried up and there wasn’t a whole lot of evidence of anything breaking out of the egg.

egg 1 bissected

 

But it was at this point while I was looking at a block of the cluster that had broken off that I saw little pale blobs moving around. I think that they might be mites.

You can see some little orange legs just above the top egg.

egg 1 friend

The suckers are <0.5mm and move around so I couldn’t really get a good focus on them. You can see the pale oval (it’s abdomen) with an orange head on the dark egg.

 

 

egg 1 single 2 marked

egg 1 friend marked As a hint

 

A similar surprise met me when I opened up the other one, albeit a more…plentiful one. This egg was almost completely full of what looked like fine grain sawdust but *surprise* the sawdust is little animals!

Who fancies some granola?

Egg e4

Yep. ALL of the little pale ovals are…arachnids of some description

If these things are mites then it looks like they have chewed up the eggs hence the mess.

What does this have to do with anything? Not a whole lot. I have the animals in a mesh cage in the lab at the moment and will try to rear them in the time honoured tradition of “let’s see what happens”.

I like an animal which can survive in spite of me.

(Here’s a quick sketch of them (the abdomen isn’t big enough). Makes me think mite).

[Late] ‘So what’s your PhD on?’; Waitomo trip 2 Wednesday 18th Dec – Friday 20th Dec 2013 and Happy [insert preferred holiday]

Although other PhD students had suggested otherwise, I reckon that the thesis proposal seminar can’t be more gruelling than running the social gauntlet called ‘December’. Christmas function after Christmas function after family get-together after beach road trip. It’s like we honestly believe that civilisation as we know it might end on December 31st and we literally have x number of days to see each other before we are all transformed into giant tiger prawns by the rising 2014 sun.

Now I accept that my PhD thesis topic is so blue-sky that you should be able to see out of the stratosphere. So when family/friends/acquaintances/my own doubts ask me ‘so what is your research going to contribute to society?’, my face does not look the way it does because I have, for the first time, been forced to confront the uselessness of my own field of study. At most, I’m just running through the list of comebacks I formulated from the last time that I was asked that question: five minutes prior1.

But before the university closed on the 20th, a few of us managed to get into the field near Waitomo for a bit of late night harvestmen and sheet-webs spider voyeurism. 

Booo field work

The activities for the period included:

  1. manual searching, the technical term for [from here on ‘tttf’] my holding containers are arms-length and trying to close them over giant spiders;
  2. pitfall trapping, tttf digging holes for plastic containers so that the top is flush with the ground with a lid elevated slightly above the ground so that insects/arthropods fall in overnight and can’t get out again;
  3. observations ranging from between 1.5 to 2 hours in length, tttf sitting in the dark with a red light and watching spiders do nothing.

The idea was that pitfall traps would help me to catch males which will wander around to find females in their webs. We were a little short on time so on the first day I identified a few sheet-webs and put the pitfall traps near the tree trunk. Asides from a few tiny beetles these didn’t fetch much which isn’t really that unexpected given that the containers were only out for two nights, I had no idea initially whether the webs actually even had spiders (although most of them did when I checked during the night), and males are apparently less active during December (of all months).

Manual searching (read: moderately frightened flailing) was a little more successful. The last time I’d been to Waitomo I’d collected the wrong species (Stiphidion facetum, not Cambridgea spp. duh.) but this time I think I actually found some Cambridgea spp. which is different from the species that I collected in the Waitakere’s which are now living under my house and are laying eggs yay. 

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The females collect up debris from the base of the enclosure and encase the egg case – I probably should’ve left more for them.

What was also interesting was that I found several bodies sans abdomen in the webs of a large-ish female (?). It looks like a couple males and a couple females of the same species. Maybe I’m being an idiot (always possible) but they don’t look like moults so while I don’t want to come to any conclusions until I’ve seen it happening, I wonder whether the ratbags are cannibalising each other. Common (un)knowledge(?) says that spiders do not ingest their prey whole sale which raises the question of how they would be ingesting the bloody abdomen but it may be that the chelicerae play some role in mushing (technical term) up the prey for external digestion.

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Oh the humanity

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I might have a better idea after the break as I have a large male in the freezer along with his weta prey. I’d caught him after an observation nomming on the weta in his web so it will be interesting to see how much of the weta is left in the container.

Another interesting thing I saw during that particular observation is that there is a certain species of smaller spider which might be parasitizing the sheet-web spider’s kill. I caught a couple of them in a container. They would be maybe a 20th of the size of the sheet-web spider and would very very carefully approach the prey item, perch on a point that wasn’t too close to the larger spider and… … I assume it was eating. Red light. More like lame light.

There are a couple different species which seem to hang out on the edges of these webs and I think it would be interesting to identify these guys – could possibly just do an observation on a web and try to collect the whole structure and all its occupants. As I said, I already collected two of one species by which I mean I now I have one because I kept them in one container and the larger ate the lesser. #Studyingcarnivores.

The university is closed at the moment so I’m looking forward to doing some keying up and getting a handle on how to measure chelicerae size and genital morphology. I’ll have to go back at some stage to do more observations and pitfall trapping but at the very least I think I have several specimens from several different species which will be helpful for constructing a molecular phylogeny.

Also caves are cool and we got to knock harvestmen off the ceiling with broken stalactites.

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Also voyeurism is hard as are cameras

1 One I would like the chance to use is ‘it’s not about what the study of spider genitals contributes to society. It’s about how long the study of spider genitals can keep deviants like me locked away in a basement laboratory’