Do Spiders Eat Cockroaches?

Cockroaches are unwanted organisms in the house. Do you know that spiders can help you get rid of them? Here’s evidence that spiders do eat cockroaches.

Seeing things like a house spider preying on a cockroach excites me. I never saw such marvelous predation in my life until just this morning.

decapitated head of cockroach
Decapitated head of the cockroach shows its long antennae.

As I prepare early in the morning, around 4:30 am, and bringing my shoulder bag with me in my favorite writing area, I noticed something unusual at the side of the bag. There it was, a large spider clamping under its body a cockroach or what remained of it after some parts had been removed. Its body measures approximately 1.5 cm long and its legs extend 9 cm across. I noticed that the head of the hapless cockroach was decapitated from its body, indicating that the spider knows where to strike.

My camera is inside the bag, a standard habit I’ve developed through the years as I shoot pictures readily whenever an opportunity like this arises. I have to make sure that I retrieve my camera carefully so as not to disturb the spider, but quickly, because at any moment, I expect the spider will notice my intrusion to its privacy.

I took a few shots with flash at close up. Indeed, after five pictures and a video, the spider speedily jumped out from the bag into the table. It then dropped off the edge of the table onto the floor at a height of three feet, hid under the table for a while then scampered towards safety in the dark corners of our refrigerator – the cockroach still stuck on its abdomen. I can no longer poke at it and take a shot. It’s an adaptive response to ensure its survival. But I have no intention of swatting it at al.

A Documented Fact

So what does this observation imply? For the layman, this moment is just one of those things that “normally” happen in everyday life. But if you consider yourself an inquisitive person as how a good researcher should behave, this phenomenon means much more. It’s not just an awesome experience that you can forget after a while. It is actually a documented fact — that spiders prey on cockroaches.

Of what use is this observation? This simple observation and documentation spares a researcher trying to establish the fact that spiders do feed on cockroaches. This article, therefore, can be cited as a source that this type of spider do prey on cockroaches. You can see the spider or the cockroach separately but seldom will you find a spider feeding on a cockroach unless you catch a spider, keep it in a glass cage, wait for long hours and see if it will feed on cockroaches that you put inside the same container. Under captivity, the spider might not feed at all.

Ecological Implications

Now that you know that spiders do prey on cockroaches, and you consider cockroaches as pests more than you might consider spiders as pests, too, then this means that if you kill all the spiders, the cockroaches that they prey upon will increase in number. That’s a lot of cockroaches, and possibly lots of diseases. Cockroaches are carriers of 33 kinds of bacteria including E. coli and Salmonella, six parasitic worms, among others (Parada 2012).

Application

This knowledge that spiders (at least the species featured in this article) eat cockroaches can be used to control the number of cockroaches in your home. Catch a spider like the one you see here (a huntsman spider) and breed it to maturity. Then release in your house if it is infested with cockroaches or sell to people who need them. The population of cockroaches will surely be under control. There will be no need of harmful pesticides.

So which one would you like to have in your house – spiders or cockroaches?

Reference

Parada, J. (2012). The truth about cockroaches and health. Retrieved on April 11, 2014 from http://www.pestworld.org/news-and-views/pest-health-hub/posts/the-truth-about-cockroaches-and-health/