Spiders · Urban Ecology · Biodiversity

It’s Nephila season!

I’m in the thick of thesis writing at the moment so this blog has been a bit neglected, but it’s the time of year when all my spiders are out in force so I thought I’d write a little (more) about them.

Here is a juvenile from outside my building at the University of Sydney

(my hand is there because it’s easier to take a photo on my phone with something in the background!)

 

As my previous post mentioned they lay these beautiful yellow egg sacs towards the end of their lifespans from May- July. The females then die off (the males are already gone, they are only around at the beginning of the season) and the eggs remain dormant till around November.

Then at the end of the year the spiderlings will hatch out but stay within the egg sac for the first couple of molts (around 3 weeks). See this page for more info on why spiders molt. In November/December they emerge as tiny little spiders that look nothing like the adults (they have a lot of growing to do).

One of the egg sacs that hatched in the lab, 100’s of spiderlings!

They will live in a little group like this for a few weeks before venturing out to make their own webs.

By the time the new year comes around you’ll start noticing Nephila of all sizes, often in aggregations which include multiple developmental stages.

In January/February you will also start to see the little red males sitting in the females web. Even if the female is not mature yet, they will sit around and wait for her last few molts (once they stop molting they have reached maturity).

The numbers of Nephila fluctuate drastically from year to year. In the first year of my PhD (2012) I was inundated with large females everywhere I looked (including on campus at USYD) but in 2013 there was a heat wave in NSW and my counts went from over 200 spiders at one site to less than 4.

I have been monitoring the numbers and developmental stages of Nephila from around Sydney for three years now, and I hope that this data will shed some light on the factors affecting their fluctuating populations.

You can help me with this research by taking a photo of any Nephila you find and uploading it to my project on inaturalist (either on your computer or through the app). www.inaturalist.org/projects/golden-orb-weavers-nephila-plumipes-in-sydney

If you would like any more info or need some help with the inaturalist site just pop me an email at elizabeth.lowe@sydney.edu.au

 Happy spider hunting!

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