Dr Bryan Lessard has spent hours on his hands and knees crawling around Canberra’s kitchens looking for bugs.
An entomologist with the CSIRO’s Australian National Insect Collection, Dr Lessard is working on a project to find out which species we’re sharing our homes with.
It’s the first time entomologists have taken a specific look at household critters in what is called a study of the indoor biome.
What they’ve found is the average Canberra house is home to about 100 species of insects, spiders and other bugs.
“There are about 62,000 insect species living in Australia and some of those are bound to get into our homes,” Dr Lessard told ABC Radio Canberra.
“It turns out the insect biodiversity in our homes is really quite broad.
“Of course houses that back onto a nature reserve are likely to have more bugs inside the house than inner-city apartments.
“And weevils and pantry moths, for example, can hitch a ride on our grocery shopping.”
Some of the most common household critters include gall midges, carpet beetles, booklice and dark-winged fungus gnats.
“We asked our study participants not to worry too much about cleaning or vacuuming before we got there,” Dr Lessard said.
“We wanted the houses to be exactly as they usually are.”
Dr Lessard said the majority of household bugs were found in hard-to-reach places.
“A lot of insects were found behind fireplaces in a living room or in kitchens where a lot of crumbs fall between the gaps,” he said.
“Many of the species we found are so small, most of them are the size of a pin head.
“You don’t even know you are living with them until you put them under the microscope.
“Then you can realise what you thought was a fleck of dust is actually a little spider mite.”
Working with researchers at the Californian Academy of Science, Dr Lessard and his team compared samples from houses on Magnetic Island in Queensland as well as in Canberra.
“Canberra represents the bush environment and Magnetic Island the tropical environment,” he said.
As part of a pilot study conducted by the same team, researchers in North Carolina found a strong link between household biodiversity and the wealth of a neighbourhood.
“We hypothesise it’s because there’s a greater range of plants and flowers in the backyards in wealthy suburbs that attract the insect species into the house,” Dr Lessard said.
Don’t freak out
And if you’re getting itchy just thinking about the number of bugs living in the crevices around your kitchen, Dr Lessard said you need not worry.
“You shouldn’t freak out too much because most of these species are benign and they won’t hurt you in any way.
“Some of the species we’re finding will help to get rid of pests as well.
“Huntsman spiders or daddy long-legs are getting rid of the mosquitoes or other blow flies that find their way into your house — they’re even cleaning the house for us in a way.
“If you try to nuke your house with a pesticide and get rid of all the bugs from head to toe, they will naturally migrate back in.”