Quiz Answers: Spiders!

Pictured: The eyes of a brown recluse spider

Spiders have been big news in San Diego this year. We continue to receive more calls for spiders than usual - indicating a population surge for spiders. Perhaps it is the weather, or maybe more people have been putting out bird seed. Whatever the reason, it is not necessarily a bad thing! The overwhelming majority of household spiders are good for the ecological balance of your yard. Because of the bad press of a scary minority of spiders, it seems the whole group has a bad aura. Here are the answers for yesterday's quiz:

1. The number of spider species that have been identified world wide is (d) 37,000. This is of course an approximate number. But taking that number into consideration, it should become immediately apparent why we are not always able to identify spider samples. What we can do is rule out the most dangerous of local spiders. Which brings us to:

2. The number of spiders in San Diego County which deliver poisonous bites: (a) two. According to the County of San Diego's Pest Management website, "The only poisonous spiders in San Diego County are the Black Widow and the Desert Recluse." From the same source, the Desert Recluse is not the same as the Brown Recluse - and it is found mainly in the Sonoran and Mojave deserts, the foothills of the lower Joaquin Valley and areas close to the Mexican border. Check their excellent site here for more information on these two local spiders with attitude.

3. The largest spiders in the world can be found in (c) South America. In fact,  South American Tarantulas are about the size of a dinner plate - around 12 inches in diameter, with 1-inch fangs. For a video on these "killing machines" see the video here. The good news? Their sting is usually  no worse than a bee sting. There are no reported cases on human death by tarantula!

4. The most  reliable distinction between a brown recluse and a wolf spider is (d) the number of eyes. While it is true that the brown recluse has a dark, violin-shaped marking behind the head (on its cephalothorax), many brown spiders, including varieties of Wolf spider, have markings that could be interpreted as looking like a violin. While the 6 eye pattern of the brown recluse is easy to see with magnification, we do not recommend looking closely at the eyes of a live spider! Some spitting spiders do have a similar eye pattern, but do not have a violin. See the photo above for the distinctive eye pattern of the brown recluse. For more on how to identify the brown recluse, visit the website here. To view a map of where brown recluse spiders are found, see here. Note: The city of San Diego is NOT identified as a brown recluse zone on the map.

5. The largest family of spiders is (a) Jumping spiders (Salticidae), followed by Sheet Weavers (Linyphiidae) and Orb-weaving spiders (Araneidae). Using a well-developed hydraulic system which extends their limbs by altering the pressure of body fluid, jumping spiders can jump 20-60 times their body length as they pursue prey. They typically have eight eyes in two or three rows. Tarantulas are the largest of spiders, but not the largest family of spiders.

6. The best way to avoid spider bites is to (b) wear shoes outdoors. Keeping exterior house doors closed is also a good idea, but unless you are able to close even the smallest breaches under doors and around windows spiders are likely to find their way inside. 

7. The correct FALSE answer is (b) - all arachnids are spiders. In fact, all spiders are arachnids - but not all arachnids are spiders. One case in point is the Daddy-longleg, which is an arachnid but not a spider.

8. This is a trick question. Remember, this is the Hallowe'en edition of the quiz! Depending on what species of spider you were, and how tall you stand proportionally, you might be able to jump (a)85 feet, (b) 130 feet, (c) 260 feet (best answer) or (d) 350 feet. Remember, there are around 37,000 varieties of spiders in the world, with various abilities. Now that you know a little more about spiders, we hope you will not  jump when you see one! For more information in a short video about spiders, click here.