Spider and Beetle

2021 March 7

On July 19, 2019, we spotted this spider on the house siding next to our front door. She had caught a nice big beetle.


When I came in a bit closer to get a better picture, the spider got spooked and dashed off to her hidey-hole, next to her egg sac (that brown, papery-looking object off to her left). You can also see the egg sac in the upper left corner of the first picture.


Since she had been scared off already, I went ahead and got some pictures of the beetle, too.



So, the spider appears to be a Common House Spider, Parasteatoda tepidariorum, which I have photographed hanging around the front door before. The beetle is new, though – it looks like the Golden-Haired Flower Beetle, Lepturobosca chrysocoma. The larvae eat rotting wood, and we often see the adults (along with several related beetle species) on flowers, feeding on nectar and pollen.

When I came back the next day to see how things were going, the spider had re-hung the beetle closer to her retreat and egg case.


This time, she was actually feeding on it, although a casual glance makes it look more like she is kissing it.


Beetles are pretty heavily armored, and I expect there are a limited number of vulnerable spots where a spider can get through to inject their digestive juices. And it looks like one of those spots is through the mouth.

While she already has one egg sac, I expect she was working on making more, which was why she was still hunting for things like this beetle. By the time fall comes around, I usually see these spiders with two or three egg sacs. It looks like she lays one, then fattens up for a while before laying the second and maybe a third. The eggs don’t appear to have a particular season for hatching, so you can find common house spiders at all life stages pretty much throughout the year. They just find sheltered spots to get through the winter. They particularly like garages, basements, and outbuildings. According to BugGuide, they can actually live over a year, and have been seen with up to four egg sacs before running out of eggs.

2 Responses
  1. March 10, 2021

    It’s amazing she was able to bring this brute down. Kind of like a Cro-Magnon bagging an elephant.

    Does she mate once and then produce multiple egg sacs or is it one mating per sac?

  2. March 10, 2021

    Yes, the availability of webbing and venom gives spiders a massive advantage in these tussles.

    As for the mating frequency, that’s a good question. And for a change, I can actually find an answer.

    According to this article, they only mate once, and then keep laying eggs off of the stored sperm for as long as they hold out

    It rather looks like these spiders have become a standard model organism in the laboratory, kind of like fruit flies. And in fact, since they like to eat fruit flies, a genetics lab could easily have both fruit flies and spiders.

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