Mythbusting: gas-sniffing spiders are NOT invading our cars
Today the BBC reported on the giant recall from Mazda because of a "spider invasion" that is requiring a software update on over 40,000 cars. This is not a new story, but it's taking off today. I was particularly intrigued by the following statement on that website: "...The yellow sac spider is attracted to the smell of petrol".
Ok, now I've heard it all. Don't get me wrong - I'm not surprised that spiders are finding their way into various parts of cars: spiders get everywhere! But can spiders really sniff gasoline? I did a quick literature search, and although some spiders are attracted to certain 'cuticular hydrocarbons' (i.e., hydrocarbons found within the exoskeleton of arthropods), I have yet to find a scientific paper that suggests they are attracted to gasoline used in our vehicles. In my professional opinion: Spiders are not gas-sniffers!
Here's what I think is going on: in one car manufacturing plant, there were many sac spiders around, and a few (a lot?) of these arachnids found their way into various parts of some of the cars being put together in that plant. The documents from Mazda actually support this. There appears to be a single plant (in Michigan) where the most recent events occurred, and to quote those documents: "spiders may weave a web in the evaporative canister vent hose, blocking it and causing the fuel tank to have an excessive amount of negative pressure".
Did you read that...? they "MAY" weave a web in the evaporative canister. I have not found any documents to suggest they are specifically attracted to that part of the car. Perhaps it is just a nice habitat (?): dark, and maybe the correct shape and size.
Don't get me wrong: I'm not suggesting Mazda was wrong in putting this recall into place. Undoubtedly, it sounds like there's a problem that needs addressing, and that problem may be associated with the webs/silk from sac spiders. However, somewhere along the line, it was suggested that the spiders are actually smelling petrol, and before you know it's a SPIDER INVASION caused by terrifying gas-sniffing arachnids. It seems that this may have been started by an automotive journalist, reported here in 2011. In that piece, Mitsuhiro Kunisawa reports "this spider's distinguishing characteristic is that it likes the smell of gasoline...". I will do my best to contact that journalist and ask about the evidence for this: I just don't buy it.
The 'sac spiders' implicated in this story are very, very common, especially in human-buildings. I've written about these before, and it should be no surprise that Cheiracanthum are hanging around a plant that is manufacturing cars. Heck, they hang around our kitchens when we are manufacturing food! They tend to hide around crown moulding, and other nooks and crannies within our houses. But please, folks, they aren't crawling up tail-pipes, or seeking nooks and crannies of the seat-cushions of your Mazda, waiting to jump out and bite. Please drive with that peace of mind. (Zoom Zoom).