Tag Archive | New Zealand

Matachia!

Mar31

One of the coolest spiders I saw in NZ was quite small, and fairly inconspicuous. Matachia is NZ endemic genus of desid spiders which have a characteristic web architecture and retreat. There are several species of Matachia in NZ. Bryce McQuillan helped us find these in Christchurch, along the Avon River (just about here), in low branches above the bank.

 

Here you can see a Matachia poking out of her retreat, which is in the emergence hole caused by an insect (often the emergence holes of a twig-boring moth, Morovia subfasciata). The webs have radial lines for movement, and zig-zag calamistrated cribellate capture threads. Calamistrated silk is not gluey, 


The cutest aspect of Matachia behaviour we saw was that upon returning to their retreat, the spiders invariably enter it butt-first!

 

The Matachia we saw in Christchurch emerged onto their capture webs quite readily in response to vibrations from an electric toothbrush. Here arachnologist Erin Powell coaxes out a spider, while Bryce photographs it.

 

Some Matachia webs we saw also had these odd platform-like constructions just near the retreat. I am not sure if the resident spider makes these, or perhaps it is done by a courting male?

 

 

A backlit Matachia

I did manage to see a courting male, and the web did have this platform-like construction on it. An interesting thing to note about these males (and males of other calamistrum-bearing species) is that the calamistrum (which brushes out the lacy capture threads from the cribellum) is lost in the adult stage, meaning these males can no longer hunt as adults…

 

In this image, you can see not only an adult female in her retreat, but also a tiny juvenile, with greenish abdominal markings. In Matachia, the juveniles remain with their mothers until they are 4-5 molts past hatching, which is a remarkably long time!

Dolomedes underwater!

Mar10

Dolomedes dondalei in a tiny creek at our last night’s campsite in New Zealand.

 

Wow, it has been a long long time since my last post!

Well, too much to catch up on right now, but the news is that Catherine and I just got back from a trip to New Zealand’s South Island. I know Catherine is planning on doing a series of blog posts on our adventures there (we were there for the International Congress of Arachnology), but these pictures have been burning a hole in my hard drive and I just wanted to share them.

OK, after a lovely 8 days touring around the South Island, we came to our last night in NZ. We wanted to be in striking distance of some good katipo habitat, yet be able to get back to Christchurch the next day for our departing flight. We therefore decided to camp on the south side of the Banks Peninsula, so we could visit Birdling’s Flat to see some katipo. We settled down at the Little River Campground, a really lovely property with wooded sections and a cool little stream running through it (there are big eels in the stream!)

After our excursion to find katipo, we decided to look around the campsite. Our headlamps soon revealed glowing eyes adjacent to the stream, which we had learned in NZ signified fishing spiders in the genus Dolomedes (a big Dolomedes is way more likely than a big wolf spider in NZ). Just across the stream on a rock I spotted this big big Dolomedes, which Bryce McQuillan kindly ID’ed as Dolomedes dondalei (named for the Canadian arachnologist Charles D. Dondale).

After taking a single frame of the large spider in hunting position above the water, she got sick of me, and did what Dolomedes often do when they feel threatened: escape under the water!

Her concealment was not nearly good enough though, as she only popped just under the water’s surface, and she was still super easy to see! There she is, hairs covered in a film of air, clinging to a rock.

Here my shot gets photobombed by a fly attracted to my headlamp, just above the surface where the Dolomedes lurks.

 

I was able to coax her back onto the rock briefly for this shot showing her lovely dorsal surface. Note how even just out of the water she does not appear wet at all, as her hairs are hydrophobic.

 

She quickly went back down, in a slightly different position. Here we are looking down on the rear of her abdomen.

A bit of coaxing, and we can see her from the right side in a more open situation. To shoot this, I had half of my diffuser actually under the water, so I was not dealing with reflection from the surface.

So after this session with the big female, we left her alone, and looked along the edge of the stream for more Dolomedes.

For this shot of a juvenile, I tried to use the pop-up flash to see if I could get the eyeshine. You can see it, but it is not the same as in real time moving your headlamp and seeing the surprisingly bright reflected light.

Another juvenile in hunting position in woody debris above the stream.

Finally, a juvenile chilling high above the stream on some vegetation.

By the time I had shot this last frame, it was past midnight, and having driven a long ways from the Otago Peninsula the day before, and hiked all over the beach on our katipo tour, we decided to call it a night…But what a treat, seeing so many wonderful Dolomedes!!!! It was super impressive to encounter so many (we will post more from all around the island). They really seem to be the dominant large cursorial spider in a great many NZ habitats.