Wednesday, June 20, 2012

Black Widows Are Back

Several guests have lamented the absence of black widow spiders on exhibit. For those who miss them, we have great news. The spiders are back, and bigger, shinier and better than ever.

For years, Pacific Science Center has exhibited these lovely but venomous arachnids. But although they are showy and colorful, there are several challenges to putting them on display.

Because they are naturally shy, Black widows like small, closed in spaces to build their web, settle down, and hide. To increase the chances of a spider being visible at any time, we split the enclosure into thirds and show three spiders. Clear dividers keep them from getting into each other’s area, which could result in one of them making a meal of another.

Black widow spider venom is also notoriously dangerous to humans. There are in fact few serious incidents involving black widow bites, but that is partly because the spiders go out of their way to avoid people. We wanted to help them out with that in every way we could! So in addition to being locked, their enclosure has an extra level of security, an inner lid with a small opening to let us feed and clean.

Like all spiders, the black widow is a carnivore. She catches prey in her web, immobilizes it with silk, delivers a paralyzing bite, and then continues to wrap it with more silk until it is entirely enclosed. She then suspends the food from a strand of web and climbs down to feed.

Black widow silk is extremely strong, and their webs are irregular. This makes cleaning up the cage a real challenge. The bodies of prey get stuck in silk and trying to pull them out disturbs the web and brings out an understandably upset, and nastily venomous, spider.

Adult black widows can live for up to a year. A few months ago, we had a rare situation where all three chambers of the cage were vacant – perfect opportunity to take it apart, remove all the old cricket parts, clean out the silk and start over. But while we had three perfectly presentable spiders, something held us back.

And then came “Big Bertha”. This spider was received by a grocery store, in a shipment of produce. She is the biggest, most splendid specimen we had ever seen, and seemed made to go front and center in the display. She seems to know how fantastic she is, and has built her web right out in the open. Please come take a look.

So we tend to let the cage go, and periodically clean the whole thing.

While on the topic of black widows, there are a few very common beliefs about them that are not entirely, or even mostly true. Black widows are famous for eating their mates. In fact, this is uncommon under normal circumstances. Many male black widows not only survive mating, but live near the female and eat some of the prey captured in her web. Nor is the bite of the black widow usually fatal to humans. But DO NOT test this, as a bite is said to be extremely painful and can kill under some circumstances. Only the adult female’s bite is a threat to people, but males and young are venomous to their prey.

1 comment:

  1. Well written piece, I will try to stop by soon and check them out!