Introducing Cambridgea foliata

Now that I’ve divided my facebook friend into arachnophobes, arachnophiles and arachno-mehs, I should probably get to posting things about spiders. Or at least things about the species that I’m working with at the moment. So consider this a crash course on the primary Auckland Cambridgea species: Cambridgea foliata

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C. foliata male

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C. foliata female

 

 

 

lads and ladies

A couple specimens (sorry that they’re covered in ethanol and therefore very shiny). Male on the left with large jaws and genital bulb on his pedipalp. Female on the right without.

For wee NZ these are relatively large spiders (body length can be almost a couple centimetres). Males tend to have longer chelicerae (jaws) than females and have bulb-like structures on their pedipalps. If you have a microscope, you can see that these bulbs actually look more like this:

palp

NB: This is a Cambridgea palp but I can’t remember if it’s C. foliata specifically because I’m in a cafe avoiding eye contact with punters rather than at my desk doing the same thing. Anyway, these structures are highly complex secondary genitalia because, as I’ve been gleefully telling people who didn’t want to know, spiders don’t have penises.

Males still produce ejaculate out of their down there’s but rather than transferring directly to the female epigyne (external genital opening), they place it in their pedipalps and, from there, “deposit” it in the female.

Imma leave this here for y'all

Imma leave this here for y’all

Despite how widespread these spiders are, particularly in the Waitakere ranges, they’re relatively unknown because they’re nocturnal and hide in retreats during the day. Retreats can be tunnels drilled in live or dead wood by other invertebrates, tunnels in banks or even folded over nikau palms.

The thing people are probably more familiar with are their webs. New Zealand sheet-web spiders will spend weeks generating a giant mass of silk consisting of a main sheet guyed from below and a nightmare of knock-down threads above the web. Most (but not all) Cambridgea build these webs and C. foliata make the largest (up to a square metre in area).

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Just one of the many webs you will see if you ever go into Waitakere. Mainsheet and knock-down threads should be apparent.

 

 

At nightfall, the resident emerges from his or her retreat and will sit either at the entrance of the retreat or in its hub (centre). Flying insects from moths to huhu beetles blindly crash into the knock down threads and fall into the web. The disturbance of the insect attracts the spider who grabs it through the silk and gets down to the business of feeding.

If you go out at night between November and February you may be fortunate enough to see multiple spiders on a web. In the summer, males depart their lovingly constructed webs in search of females. When they find one, they take up residence with her and will even live in her retreat during the day (this sort of cohabitation is rare in spiders). I’ve already written/depicted what happens when a male enters a female’s when another male has already taken up residence.

So hopefully that’s enough of an introduction to the weird little world of spider life in Auckland. Happy now, Meg?

 

 

 

 

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One thought on “Introducing Cambridgea foliata

  1. Pingback: the process of a scientific illustration | drawing escape

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