Archive for April, 2016


A few weeks ago our son, Giles discovered some new & interesting spiders living near his home. These looked like tiny droplets of mercury, some were minute, and all we could see was a small glimmer of light reflecting off them. Good old Google images came up with a name, Dew Drop Spiders, or to give them their full name Argyrodes antipodianus. These originate from Australia but are pretty well spread throughout NZ. They are described as ‘kleptoparasitic’ – parasites by theft, which is a new word for me. This tiny spider makes a web which is attached to a host spider’s web, & from this it can sense when small prey are entrapped, small enough that the host spider doesn’t notice. The Dew Drop Spider makes a sortie onto the web, grabs its dinner & hastily retreats back to its own web.

Dew Drop Spider

After having a good look at the Dew Drops we wandered around looking to see if we could find any more on the fences. I came across quite a large web, with what looked at first to be a bird dropping on it, but as I looked more closely I could see some sort of spider in the middle. As we watched this very odd shaped spider came out to bundle up a fly, then it took it back into the central line, adding to what I’d first thought was a bird dropping. Above the web, there were three brown blobs, which we took to be tree gum or something similar, later, via Google again we found that these were egg cases for the spider. Now some weeks later they are still unchanged.

Information I have gathered about this weird spider, it’s official name is Cyclosa trilobata, a native to NZ. It belongs to the Orb Spider  category, & it seems that it’s habit of crouching in the middle of it’s fly debris may be a form of camouflage. They vary a lot in colour, grey, black, red, browns & silvers, & the males perhaps have more silver markings. Some of their Australian cousins make the most stunning webs, but this one is pretty unremarkable.

Three Lobed Spider Egg Cases Three Lobed Spider

Advertisements

In March 2014 I wrote an article about the health of our waterways, & had entered a piece of fibre art into the Nelson Fibre Art exhibition called ‘Downstream.’ I’ve just been reading an article in the Listener about a scientist called Mike Joy who is taking a stand for the wellbeing of New Zealands fresh water resources, here is the link:    http://www.listener.co.nz/current-affairs/ecologic/river-stance/

Our Creek Millstream

I’m interested in the study of species found in the water that act as indicators of water health or otherwise. I’m going to do some research of my own & report back what I find out. At the moment I can’t even identify many species so shall have to get familiar with those creatures we may hope to find in our own creek & other waterways. I have noticed that there seem to be few koura or freshwater crayfish around at the moment & this is unusual as we often see dozens in one spot. We also continue to have large rafts of algae in the slower running places, which block the stream & exacerbate growth of duckweed etc which further blocks the flow, hard to tell if this is a result of upstream pollution or simply that one of the large willows fell down & there is more sunlight warming the water & feeding the algae.The link below is informative on the process of checking the invertebrates in a given water supply. (benthic means at the lowest level, eg. the bottom of a stream bed, including silt.

Now it’s April, I have had one foray into the creek with a net & bucket, but alas also with leaky gumboots, which dampened my enthusiasm. The leaky boots also hindered my attempts to find critters to identify since I am a total sook about cold water. I took a few photos, & identified a couple of things,(I have meantime lost the piece of paper with their names on,) so on the whole it was not a hugely successful outing. We have some intrepid friends visiting this weekend & shall have a more thorough go at finding  some creatures & identifying them. Hopefully I can add some more useful info after that.

Critters from creek march2016 005 (Copy)

http://cber.bio.waikato.ac.nz/images/Macroinvertebrates_and_water_quality.pdf