September 20, 2016
Dioprosopa clavata. Photo by Brian Brown.
With the flowering of the buckwheats almost completely finished, the insect activity has temporarily dropped off in the Nature Gardens. I say temporarily because the coyotebush, Baccharis 'Centennial,' is almost ready to flower, and when it does the 1913 Garden becomes an insect photographer's paradise.
Green fig beetles (Cotinis mutabilis). Photo by Brian Brown.
Until that happy event, only a few days away, the action is now best seen in the Edible Garden. Not only are the Green Fig beetles (above) swarming all over flowers and fruits, other insects are also concentrating on the relatively large number of flowers available.
Anthomyiid fly. Photo by Brian Brown.
Some of them are what what we consider pests, like the larvae of the anthomyiid flies (adult pictured above), which are known as root maggots for their feeding on onions and other buried bulbs. Others we look at more benignly, like the flower flies, such as the Dioprosopa clavata (top), whose larvae feed on aphids. All of them, however, are part of our urban biodiversity, which makes the Nature Garden the best place in Los Angeles to photograph and see insects!
March 7, 2016
Phorid flies are 1 to 3 mm long insects that most people probably never see. They are busily at work in your backyard, decomposing, parasitizing, pollinating, and doing all the other things that small insects do. But people don’t care about them...how could they? They don’t even know they exist!
In the Urban Nature Research Center, I get comments all the time, or even looks from some of my colleagues that say “they are only flies”, or “there is more to the world than phorid flies”. Why, it is insinuated, can’t we just base conservation decisions on things people care about, like birds and mammals?
The problem with this idea is that birds and mammals are large, highly mobile creatures, like us. Although we tend to admire creatures that are most like us, in some ways they are the worst indicators for local conditions. After all, what tells you more about your backyard-a fly that never strays farther than one meter from the dead mushroom it was reared from, or the red tailed hawk that soars across half the basin in the afternoon? Small creatures give us information on a finer level than the large ones do.
Insects like phorid flies have faster generation times as well. That red tail may be five years old, but you know that fly hatched within the last year, and represents conditions that occurred this year only.
Finally, insects give us an incredible amount of knowledge because there are so many of them. In the book Insects of the L.A. Basin, Charles Hogue estimated that there were 2-to-3000 species of insects in Los Angeles. By studying phorid flies in detail, we know now that Charlie was way off. Here we can do the math: our study has found about 100 species of phorid flies in Los Angeles. Flies make up about 16% of the worlds insect biodiversity, and phorids make up about 1/40 fly species worldwide. We know that phorids are incredibly more diverse than one in 40, however, so let’s say one in 20 (.05). One hundred local species equals .05 of the 16% of insects that are Diptera, so 100 equals .05×16% of “x” (the total number of insect species). This calculates out to the staggering 12,500 species of insects in Los Angeles, most of which are probably not described! That means there are legions of tiny beetles, wasps, gall midges, and other unassuming creatures sharing our city, going about their business, maintaining the environment. It is our own private army of ecosystem service providers.
Oh, and by the way, phorid flies are incredibly cool.
All images by Kelsey Bailey.
January 12, 2016
The beautifully-striped African fig fly, Zaprionus indianus. Photo by Kelsey Bailey.
We always say that biodiversity is constantly changing in the Los Angeles area, but few groups of insects show this as blatantly as "pomace flies" do. This group, more formally known as Drosophilidae, includes the famous laboratory fly, Drosophila melanogaster, whose genetics have been the source of many of our advances in medicine and cell biology. Most of us know these flies because they "magically" appear when bananas become overripe on the kitchen counter, or they suddenly appear when a bottle of wine is opened. Their attraction to fermentation is also historical, with the first records of these flies in the literature noting that they are found in wine cellars. Growing up, we always called them "fruit flies", but that name is more properly reserved for another fly family, the Tephritidae, which includes the famous med fly. Thus, the common names "pomace flies", or "vinegar flies" are more appropriate and less confusing (once you know why).
Of course, like many other insects, the association of one species, in this case Drosophila melanogaster, with fermentation is just the tip of the iceberg in terms of life histories and diversity of species. Some drosophilids (the way we refer to members of a family like Drosophilidae is to call them "drosophilids") are associated with fungi, and can be seen in clouds over mushrooms on damp logs. Others are parasitoids, whose larvae attack and kill spittle bug larvae (a type of bug that produces a frothy mass to live in–they are often seen on Rosemary plants) . Still others attack plants, as leaf miners (literally living under the surface of the leaf and burrowing through the cells) or flower feeders, and one tropical group feeds on the embryos of frogs! According to my colleague, and world expert on the family, Dr. David Grimaldi of the American Museum of Natural History in New York, most pomace flies are not associated with fruits.
Last year (2015), we reported on two unusual drosophilids from the BioSCAN project: one was a species previously known only from a handful of specimens from Central America, the other previously known only from Australia. Because of this, Lisa Gonzalez (one of the collection managers working on the BioSCAN project) keeps a close watch on the drosophilids from our samples. When I asked her a couple of years ago to watch out for the newly recorded Asian species Drosophila suzukii (the spotted-winged pomace fly), she quickly returned with specimens.
More recently, last year, we received a bulletin from the Los Angeles County Agricultural Commissioners office about yet another newly recorded pomace fly, Zaprionis indianus, a beautiful orange colored fly with a couple of white stripes through its body. Although present in low numbers in the past, Z. indianus populations seem to have exploded in the last 6 months. The bulletin from Thursday, August 20, 2015, in part, read:
The African fig fly Zaprionus indianus was found in backyard figs in Downey. It is a generalist drosophilid that breeds on fallen fruit and fruit on the tree. It is known to infest fruits of 70+ species of plants. Can possibly become a problematic pest for our fig industry.
I brought this bulletin to Lisa's attention, and she relatively quickly found one from a Malaise trap sample from L.A. City Hall.
Z. indianus range as of 2010. Photo from Wikimedia Commons.
Fast forward to today, with our initiation of phase 2 of the project, and suddenly Lisa finds these flies in virtually every Malaise trap sample in our "ocean to desert" transect! It is incredible how quickly this fly has gone from first recognition to complete colonization of the Los Angeles area. Because we've been looking for pomace flies in hundreds of samples over the last few years, we are able to track and recognize this explosive range expansion.
It is sobering to think about how many other insects are being introduced, and rapidly spreading throughout the Los Angeles area, without anyone noticing. How large is the insect fauna of Los Angeles? Does the fact that this fauna is highly modified, with many native species negatively affected by urbanization, make it more susceptible to invasions like that of the African fig fly? How much turnover in species occurs among these tiny, and inconspicuous insects? Does the introduction of species like the African fig fly affect populations of other native or introduced pomace flies here? These are all questions that we hope to begin to address with our ongoing study
November 23, 2015
Photo by Kelsey Bailey.
Insects inspire wonder, curiosity, fear or disgust, but very few have caused the widespread panic, political controversy, and public outcry like the Mediterranean fruit fly. Shortly after appearing in California in the early 1980s, the saga of the Medfly erupted into a battle between the Agricultural Industry and the residents of the affected counties, with local politicians wedged firmly in between. As an entomologist from L.A., the aerial spraying of pesticide over the city to combat the Medfly that happened so long ago is still one of the topics I am most often asked about. It is firmly etched in many Angelenos’ memories, but most are unaware of what became of this notorious little fly.
The Mediterranean fruit fly, Ceratitis capitata. Photo credit: Kelsey Bailey
First let’s take a moment to gaze upon the beauty of this insect: the yellow tiger-stripes, black bands, iridescent eyes, and sweet little face belies the damage this insect can cause. Medflies lay their eggs inside of a wide variety of fruit (apples, avocados, citrus-- to name just a few), and it is estimated that the total value of crops that could harbor destructive Medfly larvae (the “maggot” stage of the fly) is more than 7.2 billion dollars. This considerable financial threat to California’s agricultural industry set in motion a massive attack to try to eradicate the invasive pest 30 years ago. Helicopters loaded with the pesticide Malathion flew over L.A. and Orange counties, triggering hysteria as people were asked to stay indoors and cover their cars to reduce paint damage. Despite the best efforts by the authorities to state the low risk of this pesticide, the public was not persuaded. There was a collective negative gut reaction as some described the scene as reminiscent of “Apocalypse Now.” (In true L.A. fashion, the aerial spraying over L.A. inspired the opening scene of Robert Altman’s 1993 film “Short Cuts”).
The story gets stranger. As public outcry intensified and the federal government intervened against Governor Jerry Brown’s decision to halt aerial spraying, a bioterrorist group that called themselves “the Breeders” claimed responsibility for releasing more Medflies into targeted areas. In a letter sent to major newspapers and Mayor Tom Bradley’s office, the group threatened to continue releasing flies unless the aerial spraying ended. To this day, no evidence has surfaced to confirm whether the releasing of Medflies by the Breeders was a hoax, but in light of the public relations fiasco and extreme opposition, it was clear another approach to a very serious problem had to be found. And it was.
Sterile male Medflies are identified with a red dye marker. Photo credit: Kelsey Bailey.
If you look again at the fly portraits above, it’s possible they may seem familiar. Chances are that many of you reading this have seen a Medfly in L.A. before. On the surface, that may sound troubling, but the Medflies most often encountered are little heroes that are unknowingly fighting the good fight against, well, themselves. An ingenious method called the Sterile Insect Technique, implemented in the mid 1990s, is used to irradiate male Medflies, damaging their testes and making them infertile. The sterile male medflies are then airdropped out of helicopters like miniature secret agents, hopefully hitting their targeted areas but sometimes turning up in very surprising places. One sterile male Medfly was collected from the top of the U.S. Bank tower at a height of 1, 018 feet! Fortunately, all of that action does not stop them from seeking out love amongst the fruit trees, and the females are happy to oblige with these available sterile bachelors. The result is an astounding success story that has reduced the medfly infestations in L.A. by 93%, protected our state’s agricultural assets, and minimized pesticide use over urban areas.
January 13, 2014
Our scientists found another species of ant-decapitating fly in Glendale, Pseudacteon amuletum!
Pseudacteon amuletum. Photo credit: Phyllis Sun
Here's an account of this tiny, yet impressive fly, by Lisa Gonzalez, one of our BioSCAN entomologists:
"For those of you who missed Lila’s exciting account of the moment Dr. Brian Brown first spotted an ant-decapitating fly in one of our BioSCAN samples as it was being sorted in front of our visitors in the Nature Lab, please enjoy this post. As Lila so eloquently described, ant decapitating flies are tiny but mighty little phorid flies that lay their eggs inside of the bodies of, you guessed it, ants. Many of these specialized flies have been the focus of our Entomology Department’s research as conducted in other, more tropical locales, so it may come as a surprise to hear that we have these incredible phorids right here in L.A. These parasitoids (a term we use to describe organisms that eventually consume and kill their host) will not just lay an egg in any ant they come across, but instead target a particular species.
Pseudacteon californiensis. Photo credit: Kelsey Bailey
For instance, Pseudacteon californiensis, the first ant decapitator to turn up in a BioSCAN sample, preferentially seeks out the native velvety tree ant, small ants with an orange thorax that nest beneath bark and in tree cavities. Some ant decapitating flies, like zombie hunters, “aim for the head,” but P. californiensis has been observed hovering over the abdomens of velvety tree ant workers where they appear to “lift” the abdominal segments to insert an egg into the host. The larvae must then travel towards the head, making their way through the occipital foramen (the very narrow opening containing the connective tissue between the thorax and head), to complete their development in the head capsule, which eventually is separated from the body by enzymes released by the developing maggot.
Our second Pseudacteon discovery from the same site in Glendale is P. amuletum, named from the Latin word for amulet due to its distinct horseshoe shaped oviscape that is reminiscent of a charm or pendant. One may also infer a deeper meaning of the name beyond shape but also of function: amulets can protect, and this species of Pseudacteon is important as a form of biological control against fire ants. A close relative of P. amuletum has been used to help control the spread of the imported fire ant Solenopsis invicta due in part for its rate of parasitism, but mainly because of how it affects the ant’s behavior. Solenopsis ants assume a very strange position when they detect Pseudacteon flies by lifting up their bodies and tucking their abdomens under and forward into a “C” shape with the same incredible skill of a Cirque de Soleil contortionist. It is believed that this helps protect the abdomen from egg invasion, but the trade-off is reduced foraging by the ant, which puts it at a disadvantage in relation to other more industrious, less preoccupied ant species. In this way, Pseudacteon contributes to a reduced fire ant population, which is greatly appreciated by those who know the alarming pain of a fire ant sting."
I don't know about any of you, but I can't wait to hear if we find a third species of ant decapitating fly. For breaking news on what they're finding in the other BioSCAN traps, check out their blog.
November 18, 2013
I just found out we have ant-decapitating flies here in Los Angeles! Dr. Brian Brown, the Museum's Curator of Entomology and one of the world's foremost experts on flies, made a chance discovery by looking right under the nose of an unsuspecting USC student.
It all started last Friday, while we were enjoying a nice stroll through the Nature Gardens. First, we checked out the Malaise trap that Brian and his staff set up as part of the BioSCAN project, which aims to survey the insect biodiversity here in Los Angeles. Then, we headed into the Nature Lab to see insects from this trap, and the 25 others that have been placed all over Los Angeles, being sorted.
As we got close to the demo table, Brian was suddenly transfixed. He'd seen something interesting on the screen that shows visitors the insects our scientists are sorting under the microscope. By some amazing coincidence, the USC student who was sorting a sample collected in Glendale, just happened to be looking at a phorid fly. Phorids, aka humpbacked flies, are the group of flies that Brian studies, and according to him, they are a mega-diverse family. How mega, you might ask? Apparently, there are estimated to be 40,000-50,000 species of phorid flies, and only 4,000 have been described by scientists so far. Wow!
But, it wasn't just any phorid fly. After taking a look through the microscope himself, Brian nonchalantly walks back over to me and said, "Yep, it's an ant decapitating fly."
Whoa, what? I had no idea we had ant-decapitating flies (ADFs) here in L.A.! How could he have neglected to mention this exciting fact during all of our insect musings? Sure he's regaled me with stories of ADFs from Costa Rica and Brazil, always with devilish decapitating detail. But, he never mentioned we have phorids in the genus Pseudacteon, also known as fire ant decapitating flies, here in L.A.
Fire ant decapitating flies do just as their name implies. When a female is ready to lay an egg, she locates an unsuspecting worker ant and injects her egg into the thorax. As the larva develops it migrates into the head capsule and molts a number of times. Through this entire process the ant behaves normally. However, just before pupation, the maggot begins to consume the tissue inside the ant's head, which causes the ant to act oddly, and soon after, to expire. The head falls off and the mouth parts are pushed out, so the oral cavity is clear. As the larva pupates, the adult fly emerges from the now-clear oral cavity of the ant. How's that for an alien ant birth?
Later that day, Brian wrote an e-mail to the homeowner where the trap was located in Glendale:
"Your backyard trap got something unusual- a phorid fly (the group of insects I study) of the genus Pseudacteon. The flies in this genus are all ant parasites, developing in the ant's head, and are referred to as 'ant-decapitating flies.' Usually, in suburban areas, the ant hosts of Pseudacteon are eliminated by the introduced Argentine ant, but you must have (or be close to) a healthy native ant fauna!"
This, as Dr. Luis Chiappe, Vice President of the Museum's Research and Collections Department, put it, "is the power of science!" The presence of this parasite, allowed Brian to infer the presence of the host. If we went out to Glendale today, we'd likely be able to find native fire ants somewhere close by! And I know you all dying to join me on that adventure.
August 9, 2013
Ever heard of a fly that is big enough to be mistaken for a small hummingbird? Don’t worry this is not some horror movie featuring an overly large arthropod (think The Fly, Them, or the upcoming Big Ass Spider movie) this is real-life nature! Also, this is rare nature for Los Angeles; these flies are very, very uncommon in our region.
Ever seen this exhibit?
Some of you may have heard of the Delhi Sands Flower-loving Fly, Rhaphiomidas terminatus abdominalis, a federally listed endangered species. In fact, this is the only fly on the U.S. Fish and Wildlife Service’s (USFWS) endangered species list for the continental U.S. (there are a bunch of listed flies from Hawaii). We even have a whole exhibit dedicated to these flies in a somewhat hidden stairwell (close to the ground floor elevators—have I ever mentioned how much I love our hidden exhibits?). However, the fly I’m talking about was thought to be extinct until recently!
The coastal dunes in southwestern L.A. used to be home to a population of the El Segundo Flower-loving Flies, Rhaphiomidas terminatus terminatus. It was thought that this subspecies was totally extinct, since there had been no sightings of the fly since 1965. However, research conducted in 2001, by George and Mattoni, found a small colony on the upper Malaga sand dune (on the Palos Verde peninsula). How could we have thought these flies were extinct for 36 years?
It is not an easy question to answer. Maybe the entomologists weren’t out there looking (funding for research isn’t always available), or maybe they were looking in the wrong place, or at the wrong time. The biology of these flies is pretty intriguing. Adult flower-loving flies emerge in the summer for a period of only about two weeks! The rest of their lives are spent underground as eggs and larvae. The only way to find larvae is to a dig a large pit, and sift through lots and lots of soil. As you can imagine, this isn’t always feasible, especially in sensitive dune habitats that support other rare species. No wonder these flies went unnoticed for so long.
If you are a visual person like I am, you can see how the range of the El Segundo Flower-loving Fly has changed over the last 100 years in our new Nature Lab. Check out our Life on the Edge interactive (directly underneath the taxidermied mountain lion). Here’s a teaser:
Guess what happens to the range of this fly when you press the "Today" button?
Now that scientists have confirmed this fly is not extinct, I would have thought that it too would be on the USFWS’s endangered species list, but it is not. I am not sure why, something to contemplate and look into deeper mmmm...
December 24, 2012
I've been scratching my head for a story to tell in this week's blog. At 6:20 last night it hit me! I've never related our Curator of Entomology, Brian Brown's, story of how he discovered a brand new species of fly, right here in Los Angeles! That's right folks, undiscovered fly species are here right under your noses — oh and don't forget that one that flew into your eyeball, maybe that was new to science too, I guess next time you should try to save it!All kidding aside, there are likely hundreds of new species scientists have never discovered before, right here in L.A.. Brian is famous here at the Museum for saying, "It's just as likely to find a new species to science in L.A., as it is in Costa Rica [where he does a lot of his research], 100%." All you have to do is look at the numbers. Scientists have described almost a million different species of insects. However, they estimate that there may be anywhere between 9 and 29 million yet to be described! And this is just the insects we're talking about people. A New York Times article that came out last year noted that, "A single spoonful of soil may contain 10,000 different species of bacteria, many of which are new to science."Back to Brian and his flies. Not everyone believed Brian when he told them he could find loads of interesting and new species here in L.A.. To prove that urban environments can be a frontier of discovery, he set up an experiment. In a Brentwood backyard, he set up a Malaise trap — a tent-like device that captures flying insects in a large jar of alcohol, a.k.a. "jar of death." One week later he visited the backyard again, collected the jar full of insects, took it back to the lab, and separated out all the phorid flies (that's the family of flies that Brian is a world specialist on).
Poolside Malaise Trap
"Jar of death"Sitting at his microscope, Brian pulled out a small (~2mm in length) yellow phorid fly that looked interesting. To identify these flies, you have to dissect them and take them through a special fly key, that asks the you to look for crazy characteristics like laterally flattened hind femoras. So Brian popped the head off the fly and stuck it under the microscope. He took the small fly through the entire key and it didn't match anything — this was a brand new species to science, it had never been described before, and it was the very FIRST fly he had looked at!
Brian's new fly speciesBrian pulled out a second fly from the sample and repeated the process. This specimen was similarly small, but brown instead. It also had a characteristic he recognized, the penultimate tarsal segment (a.k.a. second to last segment of an insect leg) was shorter than the last one. This is a characteristic common to a species only known from Europe. Brian took it through the key, and it was indeed the European species. Which, might I add, had never before been recorded in the U.S.!
European flies have a certain je ne sais quoi!Wait, wait there's more! Seriously, as Brian kept looking he found a third interesting fly in the sample. This fly was a male from the genus Chonocephalus. This fly is from both coasts of Africa, the Seychelles and Canary islands to be exact. This was the very FIRST time it had been discovered outside of that native range!
Chonocephalus, African phorid flySo, by looking at only three, seemingly inconsequential flies, Brian had made three scientific discoveries, which have since then been published in well-known journals. Imagine what a month of sampling might uncover, or a year, or what about three year's worth of sampling!This is exactly what the Museum has funded Brian and a group of other Museum scientists to do. Brian and his crew have dubbed the project BioSCAN (BIOdiveristy Science: City And Nature). Here's what the BioSCAN website has to say about the project:"This first-of-its-kind scientific investigation will discover and explore biodiversity in and around one of the world's largest cities: Los Angeles. In three years of sampling from the urban core right out through less-urban surrounding areas, we will focus on the insects, the most diverse group of animals on our planet. We will discover and document the diversity of insect species living with us in Los Angeles as well as test intriguing hypotheses about how natural areas around the city affect its biodiversity, and specifically, how light in the urban environment is affecting its inhabitants."Wow! I can't wait to hear what they find.
June 22, 2012
I've been away all week in Yellowstone for work and wasn't sure how I'd manage the blog this week. While there, I was stunned by the awesome wildlife I encountered, including bison, elk, black bears, pronghorns, mountain goats, bighorn sheep, and even a pack of six gray wolves!
Bison jams are a common occurrence in Yellowstone!For those in the know, these animals are called charismatic megafauna. They are beloved by most, and therefore it's easy to get people to care about them and the issues they face. In stark contrast, much of the fauna I work with, and a focus of both the North Campus and Nature Lab projects, are tiny, seemingly inconsequential, and many times a turn-off to visitors. For instance, it's hard to get people to care about insects that live in what looks like spit! This morning I went out to see what charismatic microfauna I could find in the North Campus.
A pill bug seemingly doing a break dance move!(It was actually caught in a spider's web.)
Aphids eating and ladybugs mating! (Note the soft focus on the ladybugs...I didn't want it to be too explicit.)
Immature Dusky Ladybug(Look at that body gear)
Spittlebug retreats on our rosemary plants.
Spittlebug that lives inside the frothy retreat.Have you seen these insects in your garden? They are a fairly common sight in L.A., and I most often find them on rosemary plants. Although these spittlebugs, a.k.a Froghoppers in the Cercopid family, can be considered pestsby some gardeners, they don't actually do much damage to the plants. I was actually very excited when spittlebugs showed up in the North Campus, as I get a huge kick out of showing them to kids and adults alike.Visitors are fascinated when I point out the white frothy homes on the plants and then gently remove an immature insect so they can see it up close. Through these moments of wonder and discovery, I hope I can inspire people to care, at least a little bit, about these creatures. They make our outdoor spaces more diverse, interesting, and also play a part in the intricate web of life that exists in each of our backyards.
January 20, 2012
There are over 150,000 species of flies in the world! Most visitors who come to the Museum can name only a few of these flies (house fly, horse fly, or mosquito for examples) and many hold the belief that we would be better off without flies in our world. On Wednesday, January 18, we found a fly that I am sure will help you realize that all flies can't be cast as "bad" characters — I introduce the humble aphid eating flower fly, Eupeodes volucris.
Female Eupeodes volucrisPhoto taken by Jerry FriedmanWhy do people like these flies and not others? This isn't an easy question to answer, but I'll have a go... First of all, these flies eat aphids and as any gardener will tell you, aphids are a serious garden pest. Secondly, they belong to a family of flies known as “flower flies” so called for their proclivity to visit flowers and suck down nectar. Thereby they play a role in pollination. Finally, if you look closely at these small flies you'll see why a lot of geeky people, like myself, think they are quite beautiful. Not only are they brightly colored and highly patterned, when their eyes catch the sunlight just right they have an iridescent sheen! Although I might add that E. volucris isn't as flashy as its close relative, the aptly named stripe-eyed flower fly, Eristalinus taeniops, also a native to the Los Angeles area.
Stripe-eyed flower flyPhoto courtesy of What's That Bug websiteHow does a fly eat an aphid? It is actually the larval stage of the fly, or maggot that chows down on aphids. Much like immature ladybugs they trawl through a sea of aphids on a plant and chomp any that get in their way! Though they don't have quite the same look as a ladybug!
Flower fly maggots eating oleander aphidsPhoto courtesy of What's That Bug websiteTo find out more our local flower flies, swing by the Museum gift shop to get a copy of our latest entomological publication, Flower Flies of Los Angeles County.
Thanks to Brian Brown and Jim Hogue for supplying fly information and identifying the fly specimen.