Why spiders seem to be everywhere right before Halloween
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An orb weaver spins its web in Mission Trails. Photo: Courtesy of reader Christina T.
Spiders are getting in the spooky season spirit across San Diego, setting up sticky webs to ensnare sidewalk passersby right before Halloween.
The big picture: But the arachnids don't actually care about Halloween decorations. Those massive webs are part of their annual routine.
Reality check: Our spider neighbors, mostly orb weavers, are actually making webs all year. But in the spring, when they're babies, the webs are smaller and harder to see.
- "Silk is metabolically expensive, so if you're a little bitty spider, you don't want to make a big web," Rich Vetter with UC Riverside's Entomology Department told Axios. (Entomology = study of insects).
Catch up quick: Orb weavers have a yearlong life cycle, Vetter said, and their web-weaving activities are some of their last.
- They first come out in the spring as "itty bitty tiny babies," Vetter said, and they grow really fast in the summer.
- In the fall, the females lay egg sacs after mating with males.
- Then everyone dies.
Fun fact: The orb weavers you see in webs are always females, Marshal Hedin, an SDSU biology professor, told Axios.
- "Males don't make webs because they don't care about eating; they just want to find females," he said.
Other creepers: Tarantulas are also on the move in the late summer and fall in desert areas and at Mission Trails, often looking for love as well.
- Vetter said males leave their burrows and go out in search of a mate, making them more visible.
- While poisonous, tarantulas will not bite unless you mess with them.
- "If a tarantula bites you, you deserved it," Vetter told Axios.
Worthy of your time: Brown widows and black widows can take up residence in a storage shed or garage. They will bite only when pressed against flesh.
- So be careful before you put on things like gloves, boots, baseball mitts and roller skates, Vetter said.
Yes, but: While getting stuck in a sticky web might feel like a Halloween trick, Hedin said orb weavers' creations catch a lot of insects.
- So try not to knock them down, he said.
- It takes about an hour for the spider to build a big one, and they'll likely rebuild right away if you do walk through their creation.
- Instead, Hedin invites you to ponder: "How does the spider know how to do every single step and why doesn't it get caught in its own web?" he said.
- Even Hedin doesn't know for sure.