If you want to catch butterflies, you might be better off going to a rich neighborhood.
A new research paper suggests wealthier homes in cities have a greater variety of insects, spiders and other arthropods in them than poorer ones.
The reason can be summed up in one word: landscaping.
The phenomenon is referred to as the "luxury effect," and it has been found to be true for birds, plants and lizards, and even bats, noted a study published Tuesday in the open access journal Biology Letters.
Researchers from the California Academy of Sciences and North Carolina State University surveyed 50 homes in Raleigh, North Carolina, and found three factors that all correlated with a greater range of arthropods — the name given to invertebrate animals with exoskeletons. This includes everything from insects and spiders to centipedes and crabs.
Wealthier homes in cities are more likely to have gardens and more space for plants. This has a kind of cascading effect — the greater range of vegetation attracts a greater variety of arthropods.
"In contrast to the recognized pattern of increased biodiversity in wealthier neighbourhoods," the authors wrote, "there is a general perception that homes in poorer neighbourhoods harbour more indoor arthropods. The ecology of the indoor biome is relatively unexplored, yet recent work has revealed that it harbours more biodiversity than previously recognized."
Of course, the study examined the interiors of homes in one city, and conditions might be different in other cities with different characteristics — for example a city with lots of forest, open space, or parks, near lower-income housing. It also looked at freestanding homes, so the findings can't be applied to a block of luxury apartment buildings in Manhattan, for example.
But the study points out that wealthier homes are more likely to have lush gardens with a variety of plants that will, in turn, attract a greater variety of insects and wildlife. Maintaining gardens and plants is dependent on money and decision-making, the study noted. Even a home without a garden in such a neighborhood stands a higher chance of housing critters.
"Our unexpected, and perhaps counterintuitive finding of higher indoor arthropod diversity in wealthier neighbourhoods highlights how much we have yet to learn about indoor ecology," the authors wrote.