Americans share their houses with any of more than 500 different morphospecies of arthropods (insects and their relatives) – at least on a short-term basis, according to a team of entomologists led by North Carolina State University scientist Matt Bertone.
Proportional diversity of arthropod orders across all rooms in the study. Image credit: Bertone M.A. et al., doi: 10.7717/peerj.1582.
Dr Bertone and his colleagues from the California Academy of Sciences, the North Carolina Museum of Natural Sciences, North Carolina State University, and the Natural History Museum of Denmark, visited 50 houses in North Carolina in 2012.
“We randomly selected 50 homes/volunteers to visit from among participants who filled out an online questionnaire about the characteristics of their household and behavior of its residents,” Dr Bertone and co-authors wrote in their paper published online yesterday in the open-access journal PeerJ.
“All homes included in the study were within a 30 mile radius of Raleigh’s center. Each home was visited once between May and October 2012.”
Across all 50 homes, the entomologists identified no fewer than 579 different morphospecies of arthropods.
Individual homes had, on average, about 100 morphospecies. The most commonly collected groups of arthropods in the homes were flies, spiders, beetles, ants and book lice.
“We discovered high diversity, with a conservative estimate range of 32–211 morphospecies, and 24–128 distinct arthropod families per house,” the scientists said.
“While overall diversity was high, 12 frequently found families were identified in at least 80% of homes. Only four families were identified from 100% of houses sampled: cobweb spiders, carpet beetles, gall midge flies and ants.”
“Book lice and dark-winged fungus gnats were found in 98% and 96% of homes, respectively.”
“Nearly half of all families (five of 12) found in over 80% of homes were true flies; fungus gnats; mosquitoes; scuttle flies; non-biting midges; and gall midges.”
The vast majority of the arthropods Dr Bertone and co-authors found in homes were not pest species.
“They were either peaceful cohabitants or accidental visitors,” they said.
“Typical household pests were found in a minority of the homes, such as German cockroaches (6% of houses), subterranean termites (28% of houses), and fleas (10% of houses).”
“Bed bugs (Cimex lectularius) were not found during the study,” the scientists added.
“Larger cockroaches, such as smoky brown (Periplaneta fuliginosa) and American cockroaches (Periplaneta americana) were found in the majority of houses (74%).”
One of the findings that surprised the team was that only 5 of the 554 rooms they sampled did not contain any arthropod specimens.
“We think our homes are sterile environments, but they’re not. We share our space with many different species, most of which are benign. The fact that you don’t know they’re there only highlights how little we interact with them,” Dr Bertone said.
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Bertone M.A. et al. 2016. Arthropods of the great indoors: characterizing diversity inside urban and suburban homes. PeerJ 4: e1582; doi: 10.7717/peerj.1582
