The BioSCAN Project, a citizen-science insect research project launched by the Los Angeles County Natural History Museum in 2013, has been turning up some fascinating captured insects. Museum staff have deployed insect traps at 30 locations across the L.A. region, from Burbank to Gardena, and each week's collection of trapped insects has brought new discoveries.
The traps have collected insect species well-known from the Los Angeles area and insect species wholly new to science, as well as some well-known insects that have nonetheless mystified insect researchers for some time.
We've picked five of what we thought were the among most interesting BioSCAN finds, starting with the bright green critter shown above: A male metallic sweat bee in the genus Agapostemon.
Agapostemon: Metallic Green or Sweat Bees
Agapostemon are called "sweat bees" because they're in the family Halictidae, most of whose members are attracted to sweat. Agapostemon aren't, particularly. They're also called "metallic green bees" by some, for what would seem obvious reasons. Females are uniformly metallic-colored, while the males bear that black- and yellow-striped abdomen that so many of their kin possess.
The genus Agapostemon is widespread across the Western Hemisphere, ranging from southern Canada to Argentina. Several species are known from California, though BioSCAN researchers haven't announced yet whether the above-shown male belongs to one of those species, or something new.
You're likely to see metallic sweat bees on blooming plants in the daisy family, especially in areas where there's deep, friable soil for the bees to dig their preferred long tubular burrows.
Strepsiptera: Cannibalism and Mind Control
It's not easy being a female strepsipteran. You hatch inside the body of your mother, then work with your siblings to consume her. Once she's eaten you emerge from both her and the living body of her host -- usually a wasp, looking like something between a maggot and an aphid. You crawl through the wasp's nest until you find a nursery full of wasp larvae. You choose a larva and burrow in, dissolving a hole with enzymes. There you'll stay for the rest of your life with only a bit of your body ever exposed to the world through a gap in your host's exoskeleton.
That bit of you isn't just poking out to get fresh air: it's there so that free-flying adult males of your species attracted by the pheromones you release can inject sperm into the back of your head, thus starting the grisly cycle anew.
The adult male strepsipteran in the photo above is one of a few caught in BioSCAN traps in Silver Lake and Mid-Wilshire. Male Strepsiptera have it a bit easier than their sisters: they go through the same mom-devouring early youth, then emerge to find new wasp hosts. Once they've fed and grown sufficiently, they emerge just to the surface of the wasp's abdomen, pupate, then grow wings, emerge, and fly off to find females before they die in five hours or so.
But being a wasp chosen as a host by strepsipterans is definitely the worst of all. Not only do the strepsipterans violate your bodily integrity, they also keep you alive and control your brain, compelling you to fly off and meet other infected wasps so that male strepsipterans on the wing can find mates more readily, Then they make you take them back to the nest so that those doomed females can release their young -- up to 7,000 per female -- into your nursery.
About 600 species belong to order Strepsiptera, some of those species specializing in other insect hosts such as bees, ants, or cockroaches. Taxonomists aren't quite sure what part of the insect family tree the order hangs on: though the Strepsiptera were once considered to be closely related to beetles, then to flies, it now seems they have no really close relatives in other insect orders.
Cuckoo Wasps: Like a Bird
Cuckoo wasps have been collected from all 30 of the BioSCAN sites: the one in this photo was collected in Victoria Park in Mid-City. They're so-named for their reproductive habits: like the bird version of the cuckoo, cuckoo wasps engage in "brood parasitism": they lay their eggs in the nests of other wasps or bees, leaving the task of raising the next generation to the involuntary foster parents.
These often gorgeous wasps stroll right into the nest of those other wasps to lay their eggs. If they're caught in the act, the especially thick armor in their exoskeletons protects them from the furious stings of the would-be foster mama wasp.
Cuckoo wasps are a huge group of insects, with more than 3,000 species known to science. They tend to specialize in parasitizing the broods of solitary wasps and bees, which live alone rather than in large colonies like honeybees.
And as semi-arid coastal Southern California is rich in solitary bee and wasp diversity, it's no surprise that it's easy to find cuckoo wasps in Los Angeles.
Though its egg-laying habits have brought it its birdy name, the cuckoo wasp shares a more obvious characteristic with another California bird: the Steller's jay. That bright blue color isn't the result of a blue pigment, but rather comes from the way the wasp's translucent exoskeleton refracts light -- just as a Steller's jay's feathers appear blue without having an actual blue tint.
Such so-called "structural color," also found in other insects and birds, fish, and even plants, can remain bright long after pigments would have decomposed. According to BioSCAN's Lisa Gonzalez, some of the insects in the NHM's collections still shine bright and colorful after being dead for more than a century.
Robber Flies: A New Species Discovered
One of BioSCAN's biggest discoveries was so far is one you might almost call an "inside job": a robber fly collected from a trap in NHM Entomology Department Curator Brian Brown's backyard. Brown preserved the fly in alcohol and handed it off to fellow entomologist Torsten Dikow of Chicago's Field Museum, who identified it as a new species of Leptopteromyia, a genus of robber fly previously thought restricted to a range running from south Texas to Central America.
Robber flies are so-called because of their method of feeding. They generally wait in ambush, then catch passing insects in flight. Once the fly has its prey in "hand" it stabs its pending meal with its proboscis, injecting both neurotoxins (to paralyze the prey) and enzymes that dissolve proteins. Those enzymes turn the hapless prey's insides to a slurry that the robber fly then sucks out.
Dikow is now working to describe the new Leptopteromyia species, about which little is known. The related Leptopteromyia americana is known to eat the common garden pest whiteflies, a fact sure to bring a smile to the faces of many gardeners who deal with the flies that eat many plants. If the Los Angeles Leptopteromyia has similar feeding preferences, it may be that L.A. gardeners have had a pest control ally they didn't even know was there, up until now.
Blow-Dried Coif: Bees by the River
Another pretty face in our final photo, this one featured in closeup to display the lovingly blow-dried coif-- no fooling -- bestowed post-mortem by NHM's Lisa Gonzalez. Its a miner bee, in the genus Andrena, a species collected in huge numbers at BioSCAN sites near the Los Angeles River.
Andrena are solitary bees that construct nest burrows in loose or sandy soil. They lay one egg in each burrow, along with a ball of pollen and nectar to feed the developing larva. After the larvae pupate, they emerge as adults from the burrows and mate.
Those emergences are generally timed to coincide with bloom of local shrubs, so that female miner bees have plenty of pollen and nectar to pack away for their developing larvae. In Los Angeles, Andrena seems very fond of willows, which shed copious loads of pollen in spring -- as many allergy sufferers will know to their chagrin.
But Andrena aren't picky: any flowering plant that offers pollen or nectar will do, which means that miner bees are one of the solitary bees helping boost yields in orchards and vegetable gardens.
There are more than 1,300 species of Andrena, making it one of the largest bee genera in the world. Females have a distinguishing characteristic shown clearly in the photo above: patches of "hair" between the antennae and compound eyes called "facial fovea." But only the luckiest of bees get help combing and blowdrying their faces before they have their close-ups taken.