A little gift on the doorstep

When you have cats, you have to get used to odd and sometimes gross gifts on the doorstep, but this morning's little surprise didn't come from the cats.

Wētā dropping with embedded seeds.  The New Zealand 10c coin is 20.5 mm diameter

Wētā are large flightless Orthopterans (crickets), and this is wētā poop.  The dropping is about 5 mm diameter, so this is a big insect.  Note the embedded seeds; they've passed right through the wētā's gut. Probably it was a Wellington tree wētā (Hemideina crassidens), which are common in the garden.  These seeds are quite large, and I suspect they're Coprosma robusta.

Coprosma robusta in fruit, Tunnel Gully, Wellington.

I could wash them out and put them under the microscope to confirm their identity, but instead, I've just planted the poop to see what comes up.  I'll report back when I get a result.

A close-up of the seeds.

Duthie et al. (2006) reported wētā dispersal of seeds in New Zealand.  Mostly the seeds dispersed were smaller than these.  The underside of this dropping had several more showing, so I'm expecting up to 8 or even 10 seedlings.

Reference.

Duthie, C., Gibbs, G., Burns, K.C., 2006. Seed dispersal by weta. Science 311: 1575.

45 years on—10th April 1968.

Forty-five years ago I was a first year student at Victoria University of Wellington, studying Botany, Zoology, and Chemistry.  On April 10th, I woke up early, before seven, to the howling of the wind and the house creaking and shaking.  It was a very strong single-story house – Dad designed it with earthquakes in mind and the builder claimed it was “overbuilt” – so it didn’t creak often.  I don’t recall if I was worried, but I was certainly surprised by the strength of the wind, the constant roar of noise, and the shaking.  In the hallway outside my bedroom I met Dad on his way back from the bathroom.  He told me the inter-island ferry Wahine was aground on Barrett’s reef, but that everyone was safe.  The wind is said to have peaked that day at 275 km/h.  NIWA has published a catalogue of weather extremes, damage, injury, and loss of life that day.  Our house in Linden was at a similar altitude and exposure to Kelburn, where they recorded just under 200 km/h.

At breakfast we debated about going in to work (Dad) and university (me).  It was probably after breakfast that the power went off, ruling out our usual transport, the electric trains.  Then a neighbor called to say her husband had tried to drive into town and had turned back because it was too windy on the motorway.  We decided to sit tight.

I guess it was mid-morning when the roof blew off the house next door but one.  For some reason, Dad and I were in the laundry watching the storm from there, so we saw the iron sheets lift off one by one and fly tumbling through the air towards us.  Dad had the presence of mind to get me out of the room and close the door; however no iron hit the house, but it did demolish our fence where some sheets embedded end-on 5mm into the wood.  Dad and I dashed across the intervening section to help our neighbors evacuate the house.  I foolishly sprinted through the swirling iron; he sensibly ducked around the back out of its flight path. 

Minor damage at home, 10 April 1968

At some stage during the morning our 5m Norfolk pine (Araucaria excelsa: Dad used to call it the Alka-Seltzer) tipped over at about 30˚ off the vertical.  We watched a tree across the road thrash itself out of the ground and then roll end-over-end down the street like a giant tumbleweed, never to be seen again.

Some time in the early afternoon everything went calm.  We thought it was the eye of the storm, and expected the wind to pick up again from the north, but it was all over.  I don’t recall hearing more about the Wahine until the TV news that night.  My memories of that are all mixed up with what I’ve heard since.  Fifty-four people died in that storm, 51 on the Wahine.  The display at Wellington's Museum of City & Sea captures it all; it still makes me tear up.

Students who did turn up for lectures had an exciting morning, they told me later.  Prof Gordon had valiantly tried to give the Botany I lecture, but abandoned it when slates from the roof of the Hunter Building started crashing through the lecture room windows.

Smashed pine trees, Colonial Knob, Wellington, 1968

 The following weekend was Easter, and I went tramping in the Tararuas with two friends.  Another friend couldn’t come because his cross country running club had volunteered to search the south coast for bodies.  On Cone Saddle we encountered a whole beech forest tipped over.  We ended up having to climb among the fallen trees to get through, sometimes walking along logs that were 5m above the ground. 

At home, we fixed the fence and pulled the Norfolk pine upright again.  For me, the day had been pretty benign really, but I still think about it every time 10 April comes around.  For many people, I guess life took a sudden and unexpected turn that day.  People survive a lot worse—Christchurch earthquakes, the Sept. 11 attacks in New York, let alone the blitz, Dresden, or Hiroshima—but these things all leave their mark.

Improvised macro lens for a point & shoot camera.

Flower of an unnamed native buttercup, photographed with my old Spotmatic. The flower is probably about 15 mm diameter.

Years ago (about 1970) I was given an Asahi Pentax Spotmatic 35mm camera with a 50mm macro lens.  I used that camera for field and family photography for about 30 years.  It was tough and I never had it serviced, and sometimes the photos were great.  In the last 12 years I've had three different digital cameras, all cheap(ish) point-and-shoot models.  While they get pretty close, they don't match the best performance of the Spotmatic for plant close-ups, although they have some real advantages.  On the whole I'm pretty happy with the latest one, a Sony Cybershot 14.1 megapixel camera.  It's small and light and has a macro function that does a reasonable job with all but the smallest flowers.
 
Digital cameras are evolving rapidly and so I seem to need a replacement every few years. Fortunately they're also getting cheaper as they get better.  I'm reluctant to shell out a lot of money for a digital SLR, knowing in a few years it'll be obsolete, or at least surpassed by newer models.  However, I would like to get closer to small flowers, so I've been playing with cheap alternatives.

The latest is a $10 home-made macro lens.  It's inspired by the idea of the Ōlloclip lenses for iPhone (I've just bought a set of these and they're pretty good and very portable).  You can get reasonable results by simply holding a botanist's field lens in front of the camera lens, but I was lucky enough to have a cheap jeweler's loop that fits quite snugly over the lens of my camera.  Unfortunately though, it's a bit tricky to hold it aligned in place while you take the photo.  I wanted something a bit more stable.

I hit on the idea of using cheap plastic plumbing attachments to hold the lenses together.  Here's the camera with the parts of the new system.  The loop fits snugly in one end, and the other end fits snugly over the camera lens when it's extended.  You have to zoom a bit to fill the field of view.

My point & shoot camera with components of the clip-on macro lens: a $2.50 plastic pipe attachment and a $10 jeweler's loop.

And here's my camera with its new macro lens fitted.  I still have to hold it while I take the photo, but the pipe fits snugly so I don't have to position it as well.  I could superglue a threaded plastic ring onto the camera, then screw the pipe attachment into it (it's threaded on both ends), but I don't want to do that to my camera, at least until it's out of warranty (in a few weeks).  If I did that, I could put the camera on a tripod for greater stability and better focusing, so I might do it quite soon.

The macro lens clip-on in place.

The real test is in the results.  Here are three shots for comparison: using the standard camera as close as it can get (left), then using the new clip-on lens with the zoom half-extended (centre) and fully extended (although not quite focused, right).  Printed at 300 dpi, the 1 cm wide key in the right hand picture would be about 33 cm across:

The new system has quite a good working distance and is easy to use.  There is a little distortion of parallel lines (see above), and there might be other effects like chromatic aberration that I haven't looked for.  But at $12.50, it's a bargain.  I'm playing with other improvised systems too, and might report on them later.

I used it in the field this week too:

Veronica scutellata, Foxton Beach.  In the original photo, the flower was 1240 pixels across; in life it's about 6mm.

Veronica catenata, Himitangi Beach.  In the original photo, the flower was 800 pixels across; in life it's about 4 mm.

To finish, here's what the Ōlloclip macro lens can do with an iPhone 4S:

Veronica serpyllifolia capsule.  It's 4 mm across, and spans about 600 pixels in the original.

It focuses at 13mm, so I guess I need some kind of adjustable stand to hold the phone at that distance from the subject.  I've started building one.

Wednesday wildflower: Banksia integrifolia

Many of our most widespread New Zealand invasive plants came here as weeds, maybe as seed impurities, or in soil or agricultural products.  A majority came from Europe, where the new people came from and where climates and land use practices are similar.  Others were deliberately brought, like gorse and barberry as hedging plants.  But as people started to realise the risks of allowing invasive plants into the country, our controls have tightened, and now it's pretty hard to deliberately or accidentally get something across the border.

So where are the weeds of the future going to come from?  Many are already here, as garden plants.  Perhaps 20,000 species are cultivated as ornamentals or crops.  Many are tender and hard to grow, and it's unlikely these will escape.  But if the climate changes, some subtropical or dry-climate plants might be able to propagate and spread without human help, becoming new weeds.

An infestation of Hieracium lepidulum, near Arrowtown, Otago.

Weed naturalisation often takes a while.  There may be a period of decades when botanists find the odd few plants, but it's not certain whether full naturalisation is taking place.  But then, in some, there's a sudden increase and they quickly become common and widespread.  Hieracium spp. did this.  Maybe the slow start is caused by low genetic diversity, lack of pollinators or dispersers, or maybe there's a change in land use (irrigation, fertilisation) that suddenly suits the invader.  In some, it's possible that the establishing population might evolve (allele frequencies change in the establishing population, due to natural selection or perhaps genetic drift).

Banksia integrifolia is a weed that seems to be in this early establishment phase.  It wasn't included in the Flora of New Zealand volume that deals with naturalised "dicotyledons" (Webb et al. 1988).  I remember collecting a wild specimen on Great Barrier Island in 1990.  Whether or not that was the first wild record, nowadays this small Australian tree has been picked up in quite a few localities.  I collected my second specimen a few years ago growing just outside the predator-proof fence of the Karori Wildlife Sanctuary (now Zealandia).  The authoritative plants database of Landcare Research is the best source for plant data because it's collection based (therefore verifiable) and it incorporates the expertise of the professional taxonomists there: they record specimens of Banksia integrifolia from Northland, South Auckland, Taranaki, Manawatu, Wellington, and Nelson.

It's possible Banksia integrifolia is a new woody weed in the making, which will take off shortly and become a problem.  However it is a fire-adapted species, needing fire to split the woody seed capsules and release the seeds in large numbers, and being a tree, it should be easy to eradicate before it flowers, unless there are large numbers.  This is a plant to be viewed with caution, so a number of Wellington botanists were concerned when Zealandia planted young trees inside the sanctuary because their compact inflorescences could provide out-of-season nectar for birds like tūī, hihi, and bellbirds.

Banksia integrifolia at Zealandia

I visited Zealandia today and took these photos.  The sanctuary and the forest are doing well, even in this dry summer, and the bird life was spectacular.  The Banksia have established well, ironically quite close to a display that warns about invasive plants.  They were in flower, which is timely because the only native bird-pollinated flowers I saw were on a single rātā, Metrosideros fulgens, and that seems out of season (normally flowers early Spring).  So, it's good for the nectar-feeding birds, but let's hope the local botanists who advised Zealandia against planting Banksia were wrong about its ability to establish.  Time will tell.

An inflorescence of Banksia integrifolia

Banksia is a member of the Protea family, Proteaceae.  Its flowers are pollinated when birds are attracted to feed on the nectar that flows from small nectaries alongside the base of the ovary.  The stamens are carried on the four petals, and these curl back after the stamens have deposited their pollen on the style.  Later, usually after the pollen has been removed, the stigma expands and becomes receptive, so the style and stigma first present the pollen to visiting birds, then receive pollen in later visits.

Two flowers of Knightia excelsa, rewarewa.  Note the bands of white pollen on the club-shaped tip of the style, and the anthers now tucked away on the coiled petals at the base of the flowers. The stigma will expand at the very tip of the style, later in the life of the flower.

The native tree Knightia excelsa (rewarewa) is also a member of the Proteaceae, and also has large clusters of flowers that function in a similar way, being pollinated by native birds like tūī.

Updates.

Leon Perrie commented: "That's amazing that Banksia integrifolia isn't in the 1988 Flora IV, given that adventive populations are now so established and widespread. The New Zealand Virtual Herbarium has over 130 specimens, most of them probably of wild plants. I think this species can definitely be put in the weedy category! I've seen it spreading prolifically in the Northland 'gumlands' (along with Hakea). Also a few spots around Palmerston North."

Mike Bayly from Melbourne tells me the plants there (subsp. integrifolia) probably don't need to have a fire to open their fruits; I guess warm dry weather is enough.  He's seen unburned plants with open fruits.

These two comments indicate I underestimated its current establishment and its potential to be an aggressive weed in my post.

Reference

Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. 1988.  Flora of New Zealand, Vol. 4.  Botany Division, DSIR, Christchurch.

The Big Dry of 2013

Wellington has been sunny and calm almost all year, with no rain in the last month.

As I write (13 March 2013), Wellington has just 20 days worth of stored water reserves.  We had a stunning Christmas Day, hot and still, with a temperature in the low 30s, and since then it's been mostly sunny, warm, and calm.  It's the best summer weather since we moved back here in 1994, although my childhood memories are of endless summers, swimming at the beach, and burnt dry lawns every year.  It's too soon to panic, because there's a chance it will rain this weekend.

The garden is coping pretty well.  I just have to water the plants in pots and things that are newly planted.

Veronica stricta suffering from drought.  This plant's roots are in a crack in a block wall, so it doesn't have access to a deep moist soil.

The hebes (Veronica spp.) are like coal mine canaries for drought in the garden.  They're the first to wilt and their normally glossy leaves lose their shine.  But give them a good soaking as soon as they start to wilt, and they'll bounce back pretty quickly.  The related speedwell hebes are similar.

A small speedwell hebe (probably a hybrid between Veronica lanceolata and V. hookeriana), originally from the Maungaharuru Range, now growing in a pot in Wellington, and suffering from the drought.

OK, it's time to water the driest plants in the garden, as frugally as I can.

More on ants and pollen

Phil Lester, the entomologist who kindly identified the ants I wrote about yesterday, has sent me some pictures of ants with Muehlenbeckia flowers, and given me permission to use them.  This is the same ant species, Monomorium antarcticum, on flowers of Muehlenbeckia complexa.

Southern ant, Monomorium antarcticum, on male Muehlenbeckia complexa (photo (c) P.J. Lester)

In the photo above there appears to be pollen caught in the hairs on the ant's head; he's walking away from a cluster of male flowers.  Here's an enlargement.

Here, another ant is on a female flower.

Southern ant, Monomorium antarcticum, on female Muehlenbeckia complexa (photo (c) P.J. Lester)

There doesn't appear to be pollen on this ant, and the flower is probably too old to pollinate; the ones above and below are more likely to have had receptive stigmas.

These photos were taken near Wellington Airport on the coast.  The plants had a major scale and mealybug infestation that was probably attracting the ants.

Ants on Parsonsia.

Southern ant with its head in a Parsonsia flower; its hairy abdomen is at the top of the picture, head (also hairy) at the bottom.

A couple of climbing plants are having a second crack at flowering right now.  Muehlenbeckia australis and Parsonsia heterophylla are both flowering again, even though the same individuals flowered heavily back in November.

Parsonsia heterophylla, Karori November 2012.

Muehlenbeckia australis, Karori, November 2012.

The Parsonsia flowers were covered in little black ants, which I didn't see in the November flowering.

It's hard enough to identify plants from photos and we don't like being asked, so I'm grateful to Professor Phil Lester for telling me this is probably Monomorium antarcticum, the southern ant. It's a common native species, or more likely a species complex.  My pictures don't show the mandibles and the segments of the antennae, which are needed for a formal identification.

Head to head, two ants probe the same flower.

It's tempting to make the assumption that these are pollinators.  There were large numbers of them, they were concentrating their attention on the flowers, probing deep into the centres of them.  But it's harder to test the idea.  You'd need to show they were carrying pollen on their bodies and transferring it effectively between flowers.  Phil Lester says he's seen Monomorium visiting flowers before, and with pollen on the hairy parts of their bodies, so they might transfer pollen between flowers, but less likely between vines.  Heine (1937) recorded several flies, including both Tachinids and Syrphids, a beetle, and several moths, but not ants, as flower visitors to Parsonsia heterophylla.  It seems likely to me that if ants are pollinators of Parsonsia they play only a minor role compared to other insects, and if they're stealing nectar they might even be counter-productive overall.

Reference.

Heine, E.M 1937.  Observations on the pollination of New Zealand flowering plants.  Transactions of the Royal Society of New Zealand 67: 133—148.