Backyard Biodiversity

entomology curator

Entomology Curator Brian Brown sets up a Malaise trap in a backyard in Monrovia, Los Angeles County. The trap has yielded new and rare insect species.

Natural History Museum of Los Angeles County

Even for Brown, this was a stunning range expansion. “Finding a fly previously known only from the coast of Africa in a Los Angeles backyard shows how little we really know about the distribution of life around the world.”

His advocacy of “backyard diversity” isn’t new. Brown first became interested in it during the Museum’s Spider Survey, which began in 2001 and invited Angelenos to bring arachnids to his department for an informal citywide inventory.

The survey found that the local eight-legged fauna had as much in common with Europe as with the surrounding wild lands. It encountered new species, new distribution records, and even the first examples of the now common (but then undetected) South African brown widow spider.

“The reaction to it was almost overwhelming at times,” Brown says. “We got over 1,000 families participating, bringing in close to 5,000 spiders. So I knew there was a lot of interest in wild life, even in an urban area like Los Angeles.”

As natural habitats increasingly become replaced by suburban development, the insect and other animal life found in gardens and other altered landscapes are increasingly the only wildlife people encounter. But if they look closely, this fauna isn’t an impoverished one. Introduced insects mix readily with native species able to thrive in the new, relatively water-rich and lush backyard habitats.

“I have seen tropical butterflies laying eggs on passionflower vine in the heart of downtown L.A.” cites Brown. “For me, it’s as typical an L.A. experience as seeing flocks of feral parrots fly over. They enrich the quality of our lives by living in our backyards.”

When Brown talks about backyards, he means two things: the area in and around our homes, and the area in and around Los Angeles. To that end, the Entomology Department recently received two small grants from the Santa Monica Mountains National Recreational Area to conduct terrestrial invertebrate inventories.

One grant will incorporate Malaise trap collections of hover flies, brightly colored wasp and bee-mimicking flies that are important pollinators. The other supports data mining inside the Museum—essentially a hunt for specimen labels from the Santa Monica Mountains that have been collected over decades.

“They know a lot about the mammals and the plants that are there, and they’ve got really finely grained vegetation surveys,” Brown says. “But they know almost nothing about the insects. We’re just trying to find out what’s there. You can’t manage natural areas if you don’t know what’s present.”

In the meantime, Dr. Dikow will describe the new robber fly and Brown will continue to explore biodiversity in backyards, both figurative and literal. “It is truly amazing,” Brown says, “how poorly known, but biologically rich, the fauna of Los Angeles can be.”

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