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Disclaimer: Of course, I don’t know for sure if the spiders in my pictures for today are St. Andrew’s Cross spiders, but I am assuming they are the same as those in photographs I found on the WEB of spiders by that name in Australia and Tasmania. The big question is this: If these are St. Andrew’s Cross spiders, how did they get to San Diego from Down Under. I may have to wait a couple of years for my insect and spider authority gets a little older. My naturalist friend, Nicholas Fudge, is only nine-years-old, and he knows much more than I do about almost any bug; I’ll give him a couple more years before I expect him to be able to identify all the spiders and bugs in the world outside San Diego County.
THE ST. ANDREWS CROSS SPIDER is the poster creature for adaptation for survival. First it spins an orb web, usually on low shrubs. The cross-like web decoration has been the subject of debate; at first, it was thought to strengthen and stabilize the web. More recent ideas explain the design by saying it facilitates catching prey and avoiding predators. The ribbon-like silk reflects ultra-violet light strongly... such light is attractive to flying insects which fly into the web looking for food.
It might be expected that the silk decoration would attract predators like birds and wasps; but as a matter of fact, it seems that the variability of the shape of the cross decoration makes web recognition confusing to predators. Birds learn that diving through the sticky web leads to a lot of plumage cleaning, so any food reward is hardly worth the effort. When threatened, the spider may drop from the web, or it may begin shaking the web so violently that both spider and the web become a blur, confusing the attacker.
The St. Andrew’s Cross spider preys on flies, moths, butterflies, bugs and bees. When they fly into the web, they are immediately secured and wrapped in silk before being bitten. Mating, which occurs from summer to autumn, can be hazardous for small male St. Andrew’s Cross spiders. After a disastrous attempt to mate with an unreceptive female, the wounded male, missing a leg or two, will sometime hang around on the upper parts of the web. It’s hard not to bring anthropomorphic sentiment to the situation and feel sorry for the rejected suitor. A successful male constructs a mating thread within the web, onto which it attracts a receptive female by vibrating the thread. I got this information from an Australian Museum WEB site... Those down under folks know spiders, even San Diego spiders.
Disclaimer: Of course, I don’t know for sure if the spiders in my pictures for today are St. Andrew’s Cross spiders, but I am assuming they are the same as those in photographs I found on the WEB of spiders by that name in Australia and Tasmania. The big question is this: If these are St. Andrew’s Cross spiders, how did they get to San Diego from Down Under. I may have to wait a couple of years for my insect and spider authority gets a little older. My naturalist friend, Nicholas Fudge, is only nine-years-old, and he knows much more than I do about almost any bug; I’ll give him a couple more years before I expect him to be able to identify all the spiders and bugs in the world outside San Diego County.
THE ST. ANDREWS CROSS SPIDER is the poster creature for adaptation for survival. First it spins an orb web, usually on low shrubs. The cross-like web decoration has been the subject of debate; at first, it was thought to strengthen and stabilize the web. More recent ideas explain the design by saying it facilitates catching prey and avoiding predators. The ribbon-like silk reflects ultra-violet light strongly... such light is attractive to flying insects which fly into the web looking for food. 
It might be expected that the silk decoration would attract predators like birds and wasps; but as a matter of fact, it seems that the variability of the shape of the cross decoration makes web recognition confusing to predators. Birds learn that diving through the sticky web leads to a lot of plumage cleaning, so any food reward is hardly worth the effort. When threatened, the spider may drop from the web, or it may begin shaking the web so violently that both spider and the web become a blur, confusing the attacker. 
The St. Andrew’s Cross spider preys on flies, moths, butterflies, bugs and bees. When they fly into the web, they are immediately secured and wrapped in silk before being bitten. Mating, which occurs from summer to autumn, can be hazardous for small male St. Andrew’s Cross spiders. After a disastrous attempt to mate with an unreceptive female, the wounded male, missing a leg or two, will sometime hang around on the upper parts of the web. It’s hard not to bring anthropomorphic sentiment to the situation and feel sorry for the rejected suitor. A successful male constructs a mating thread within the web, onto which it attracts a receptive female by vibrating the thread. I got this information from an Australian Museum WEB site... Those down under folks know spiders, even San Diego spiders.
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