Where angels fear to tread

The male St Andrew’s cross spider (Argiope keyserlingii, slightly out of focus in the background behind the female) is taking his life in his pedipalps.

St Andrews cross spiders

A male St Andrew's cross spider (background) sizes up the female.

This one did all the classic things – stayed behind well back behind the female, plucked on his own thread-within-her-web to get her attention, and dared to draw near while she was occupied feeding. I didn’t see the actual mating. If he was lucky, he would have escaped intact, though this morning there is no sign of him.

According to Australian Geographic magazine 77, Jan-Mar 2005 (on the front cover of which there is a magnificent painting of a female and male), the ‘cross’ pattern on the female’s web reflects ultraviolet light strongly and attracts the flying things (flies, moths, butterflies, bugs, bees, cicadas, insects in general) that are the spider’s prey. To our eyes, it would also seem to attract predators (including spray- or broom-wielding humans) by being so obvious. Another possibility is deterring non-predators by saying what lives there.

There are a lot of the greenish egg sacs of these spiders about at the moment (January). The eggs sacs are apparently attacked by parasitic wasps and flies, and the adults by mantids and birds.

Don’t worry, spiders

I keep house

casually

Kobayashi Issa (1763-1827) (transl. Robert Hass)

Egg case St Andrews cross spider

Egg case (typically greenish) of a St Andrew's cross spider

Advertisements
This entry was posted in Animals on land, Spiders. Bookmark the permalink.

2 Responses to Where angels fear to tread

  1. Cath Clark says:

    Keep the spider stories coming, O’ woman of earth and sea. The St. Andrews grows to magnificent size in FNQ when left undiscovered by birds. Funny enough, the bird that most actively favoured them around our house on Magnetic Island was the tiny sunbird!

  2. Joy Window says:

    I guess your former house on Magnetic Island may no longer be there after Yasi. Nor may the spiders. I’m wondering whether those big ‘St Andrew’s cross’ spiders you saw were bird-eating spiders, a different species. They grow huge, and do catch and eat birds in their webs. The webs are really strong – I once walked into one accidentally at Mission Beach and was brought up short. Didn’t see the spider, but she would have been a relative of Shelob! Those sunbirds are delicate, colourful and gorgeous – the nearest thing we have to American hummingbirds.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s