April 17, 2014
Photo by Phyllis Sun
By Emily Hartop This week, I am pleased to better acquaint you with BioSCAN's Co-Principal Investigator, and Associate Curator & Director of the Marine Biodiversity Center, Dr. Regina Wetzer. Regina was a natural fit for the BioSCAN project. She is a marine biologist with a passion for taxonomy and biodiversity. She is also an accomplished ambassador — she works closely with both professors and students at USC and has colleagues across disciplines and around the globe. She understands deeply how collaborations allow researchers to accomplish bigger, greater goals than what they could achieve individually. As Co-Principal Investigator of this project, she supervises much of the day-to-day activity of the BioSCAN lab — including advising our many USC students on their BioSCAN-related research projects. She also manages the lab with impeccable organization and style, and plays a key role in putting on events like last weekend's soirée for our BioSCAN site hosts. Regina grew up here in Southern California — in fact, her grandfather used to push her stroller through the Exposition Park Rose Gardens next door to the Natural History Museum. She earned degrees at both Loyola Marymount (B.S. Biological Sciences) and Long Beach State (M.S. Biological Sciences/Invertebrate Zoology) before taking a job with a marine supply company. There, she worked for Rim Fay, Southern California's answer to Dr. Ricketts from Cannery Row. Eventually, fate led her back to the Natural History Museum here in Los Angeles. As a curatorial assistant, Regina found herself smitten — with crustaceans. After moving to the San Diego Natural History Museum for a time, she traveled across the country to get her doctorate working on crustaceans at the University of South Carolina. Regina's work in recent years has been on the taxonomy of crustaceans, focusing on the isopod family Sphaeromatidae. She has been working on this group's phylogeny and mate-guarding behaviors since 2002 — with work around the world including East Africa and the Great Barrier Reef. It is a testament to her dedication that twelve years after this project began, Regina is still working hard to answer the questions originally posed when she started her work on this particular phylogeny.
Photo by Dean Pentcheff
Regina's work has taken her to South America, the South Pacific, Australia, and even Mongolia (photos above and below — and, yes, landlocked countries have crustaceans, too!), but she speaks most fondly of her extensive travels in Baja. Part of her affinity for the peninsula comes from her fascination with organisms that are adapted to life in extremely harsh conditions, including desert flora and fauna. The fantastic landscapes of the San Felipe and Vizcaino deserts of Baja, with their boojum trees, ocotillo, and giant cardon, intrigue and delight Regina. These are magical lands for all who visit them, and Regina is lucky enough to have visited them many times.
Photo by Dean Pentcheff
In addition to her prolific body of scientific work, Regina is a fantastic and passionate cook, an avid gardener of cacti and succulents, and a devoted fan of gypsy music (she grew up with a father who plays accordion!). Her favorite vacation destination is her beloved Baja "Boojumland" (although she's in Tibet as we post this!). She's an amazing leader, an excellent scientist, and a fascinating human being — we're incredibly lucky to have her on the BioSCAN management team!
April 10, 2014
By Emily Hartop This week, we bring you a visual treat from BioSCAN's Principal Investigator, Curator of Entomology, and Photographer Extraordinaire, Dr. Brian Brown.
Photo by Dr. Brian Brown
By Emily Hartop This week, we bring you a visual treat from BioSCAN's Principal Investigator, Curator of Entomology, and Photographer Extraordinaire, Dr. Brian Brown. His beautiful photo (above) of Eristalinus taeniops was taken in the NHM's Nature Garden, home to BioSCAN Site #1. This species is commonly known as the Stripe-Eyed Flower Fly, from the family Syrphidae, commonly called Flower or Hover Flies from their habit of hovering hummingbird-style over flowers in search of nectar. Although syrphid flies are quite common in the BioSCAN traps, this particular species has not yet been captured by our project. Dr. Jim Hogue, also an entomologist and photographer as well as a BioSCAN site host, speculated that this fly is simply too strong a flier to be easily corralled into death by Malaise trap. The entomological equivalent of "The Ugly Ducking", the larvae of the stunning Stripe-Eyed Flower Flies are filth-dwelling Rat-Tailed Maggots. The "rat tail" is actually a telescopic breathing tube that allows larvae to mature in stagnant, and often polluted, water (and other moist substrates lacking in oxygen). The tube allows them to "snorkel" at the surface to breathe. Also on the list of this fly's unsavory larval habitats, rare cases of human intestinal myiasis — where larvae develop inside the human gut — have been documented for this group. The breathing tubes of the maggots, in this case, would be located in close proximity to their host's anus to allow them to breathe. Despite their distasteful beginnings, the Stripe-Eyed Flower Flies certainly turn out to be magnificent adults. Not only are they amazing honeybee mimics, but their striped eyes are absolutely hypnotizing. This pigmentation may serve an optical purpose, but more research must be done on this group before conclusions are to be made.
Photo Copyright by Dr. Jim Hogue (used with permission)
If you haven't seen the Stripe-Eyed Flower Fly buzzing around your yard, keep looking! The first California record for the species was in 2006 from Orange County. Three years later only a single specimen was found when Dr. Brown and Dr. Hogue worked on local Flower Flies for the booklet "Flower Flies of Los Angeles County". That single specimen was from Dr. Hogue's Eagle Rock backyard, which is now a BioSCAN site! Above, you can see another beautiful photograph of this species, this one taken by Dr. Hogue. Originally, Eristalinus taeniops was from southern Europe, Africa and the Middle East. Introduced species can sometimes create issues for native flora and fauna, but it doesn't appear that Eristalinus taeniops is creating any problems. We're glad, because it sure is a stunning addition to our Flower Fly fauna!
April 7, 2014
Have you ever seen this bird?
California Towhee visits the Natural History Museum. Image courtesy of Kimball Garrett
Okay, so unless you are a birder type, you may look at this picture and think, "How the heck do I know? It just looks like a dull, brown bird to me." This is almost exactly what I thought when I saw the picture in my inbox recently. However, after reading the e-mail it was sent in, I realized this is a bird I see, and hear, in Griffith park all the time. You see, this bird can be much easier to identify when it is alive—scratching around in the leaf litter in front of your eyeballs, and chirping away close to your earholes.
First rule of bird nerd club, you gotta look at more than just color and pattern!
Kimball, teaches this and an array of other tricks and tips during the many birding trips he leads for the Museum, Audubon chapters, and other groups.
Another thing Kimball has been doing at the Museum is taking data on the birds of the Nature Gardens by conducting weekly "area search" surveys, counting all birds on the garden grounds. These surveys rely on his acute ability to identify birds quickly by sight and sound. He can accurately identify what, to you and I, looks like a black flying speck from 50 feet, or sounds like a small chirrup in the cacophony or urban sounds.
It was on one of Kimball's recent surveys that he took the image above of a California Towhee, Melozone crissalis, in the Nature Gardens' "urban wilderness." Unfortunately, since male and female California Towhees are identical visually and this one wasn't singing (only the males of this species sing) we'll never never know if this one was a boy or girl!
Here's Kimball to tell us a bit more about the significance of the sighting:
"Although this is a common and familiar bird in natural brushy habitats and in suburban residential yards and parks, it is largely absent from the most urbanized portions of the L.A. Basin. As a ground-foraging species it is especially susceptible to predation by feral cats (etc.), collisions with automobiles, and other urban mortality factors. This towhee was high on my list of “target species” that the Nature Gardens might attract. Even though one sighting of a single individual doesn’t mean much yet, it is a start and we might someday get a population of towhees in the park. The two previous sightings of California Towhee in Exposition Park (30 Aug 1982, and spring 1996) were of single birds that did not stick around, and those pre-date the establishment of any usable habitat for the species in the park."
Wow, so this is the first time a California Towhee has been documented in the park in over 17 years! The question is, will this towhee stick around? Unfortunately, as far as we know, the bird hasn't been seen since Kimball took the picture. He saw it fly off into the brush, and like that, it disappeared. Maybe, this individual towhee was just passing through, but I like to think that he (okay it could have been a girl, like I said above) was checking out our accommodations. Maybe he'll tell all his buddies about the garden, or if we're lucky he'll bring back a girlfriend and have babies, just like some Bushtits, Psaltriparus minimus, are doing.
Apparently, bushtits are quite partial to Hershey's Kisses! Come and visit the Nature Gardens so you can check out the nest for yourself, and of course keep your eyes open for the towhees!
April 3, 2014
Photos by Kelsey Bailey
BioSCAN Buzz is excited to bring you the first in a new series of blog features: "The Faces of BioSCAN". We will be interspersing these posts, illuminating the amazing folks we have working behind the scenes, with continued coverage of exciting news from the project. This week, we begin our series by featuring the woman behind the amazing insect photographs you see on the blog: Kelsey Bailey.
Photo by Phyllis Sun
Kelsey is a senior political science student at USC, minoring in photography and social change. After graduation, Kelsey aspires to find a job that will utilize her diverse talents and allow for travel. She has the ambitious goal of becoming a photographer for National Geographic; from what we've seen she's well on her way to achieving success of that caliber! Kelsey's interest in photography encompasses all elements of the craft, from the technical to the artistic. Her art history and photography classes have left her intrigued and inspired about the "many different dialogues about time, legacy, representation, technology, mortality" that photography opens up. She is constantly challenging herself by working on both the technical specimen photography for BioSCAN and fine art, conceptual photography. She finds her job particularly exciting when the two intersect, which we like to think happens with our beautiful insect specimens. In her work with BioSCAN, Kelsey expressed her excitement that she gets to reveal a microscopic world through her photography: "To the naked eye, insects appear to be indistinguishable black specks in a petri dish, using a camera and a microscope I get to expose them as remarkably diverse creatures with intricate structures and vivid colors. Photography is an effective way to convey this biodiversity to the public as well as inviting people to take a peek at a microscopic world." Kelsey also spoke of the challenges of shooting insects: "They’re ridiculously small and sometimes difficult to physically handle. It’s been somewhat of a struggle to develop a process for photographing them, but it gets easier over time." Kelsey's process involves photographing the insects under a microscope with a camera connected to a computer. At high magnification, she must take a series of photographs at different focal lengths, and then "stack" them using special software. This allows her to create composite photos that have the entire depth of the insect in focus. Kelsey is well versed in dealing with the many challenges of insect photography. She photographs specimens both dried and in ethanol; each provide very different obstacles. Reflections and refractions are constant hurdles one must face when photographing through a liquid, or photographing insects, which often have reflective surfaces. Her favorite insect to photograph? So far, Kelsey's favorite photography session was with the asilid, or Robber Fly, which is the top left image in the collage above. Kelsey loved that the Robber Fly was "such a theatrical little monster!" Outside of BioSCAN, Kelsey loves music, politics, other art forms, the great outdoors, pouring cream into her coffee, making things with her hands, and beer tasting. Just recently, Kelsey ran the LA Marathon which she considered a "quite monumental" personal accomplishment (we agree!). We can't wait to see what Kelsey does next, and we're so happy we can share her talents with all of you!
March 25, 2014
Photo credit: Kelsey Bailey
Disclaimer: To our knowledge fig wasps are not really from outer space, they just look like miniature aliens. To understand the tiny wasps in the family Agaonidae, you must first understand their inverted-flower “spaceships of reproduction”: figs. A fig, although it masquerades as a simple fruit, is actually an inside-out inflorescence (cluster of flowers). This inflorescence, once pollinated, becomes an infructescence (cluster of fruits) that contains the fig tree’s seeds. Pollinating this “calzone of the flower world” is no easy task: enter the fig wasp. These flat-headed wonders of fig pollination measure out at a slender two millimeters in length, and have an obligate mutualism with fig trees —meaning the wasps and trees cannot live without the other. The ultimate example of a “pollination syndrome”, where a flower’s shape, size, coloration and other traits have evolved to facilitate pollination by a particular taxon, a fig can only be pollinated by this single family of miniature wasps. Despite their highly specialized co-evolution, the pollination of a fig tree by its wasp friends is not a cakewalk. Pollination is done exclusively by female wasps. These lovely ladies leave the figs of their youth to seek out new figs in which to lay their eggs. They hone in on the scent of a new tree, which is often species-specific (one species of wasp paired with one species of tree), and once they have it located, they must enter the fig to reach the flowers on the inside. This is a task of perseverance: the fig has only one small opening, called an ostiole, where the wasp can make her entrance. This small tunnel to the inner paradise of the inflorescence is lined with highly-modified leaves, called bracts. The narrow tunnel and its lining make entering the fig a tight, tortuous squeeze. Female fig wasps have a flattened shape to facilitate squeezing through this opening. They also have special teeth on the bottoms of their heads and on their legs to help them wiggle through. Often, these hard working women lose their wings and antennae in their struggle to gain entrance to the inner sanctuary of the fig. Once inside, however, their plush floral surroundings are the perfect site for egg deposition. As the wasp moves about laying eggs into the ovules of the flowers, she deposits pollen that she picked up in the fig of her birth. Any ovule that does not receive an egg, but does receive pollen, becomes a seed for the fig tree’s reproduction. The eggs mature inside the ovules of the fig’s inner flowers, creating galls. Once the larval wasps hatch, they feed off of the inner tissue of the flower until they are ready to emerge. Males and females emerge simultaneously, and mate inside the fig. Males are wingless and have two functions: mate and chew through the fig to create an escape for females. They die shortly thereafter. The females use the tunnels made by their mates to escape and go find a fig “spaceship” of their own. We know you are now wondering; am I eating fig wasps when I eat figs? The answer is: possibly, but they would be a different type of fig wasp than this alien-looking flat headed type. This particular genus of fig wasp, Pleistodontes, is a genus native to Australia that came over with ornamental fig trees. Because these wasps pollinate ornamental figs, they won't be found in commercial varieties in the store. Other fig wasps may be in commercial varieties, but different varieties are produced differently. There are fig trees that have been bred to produce figs without pollination, in which case wasps would not have an association with those breeds. There are also both monoecious and dioecious types of fig trees. In monoecious varieties, you will end up with figs that contain both seeds and wasps, whereas in dioecious varieties the male trees produce figs with mostly wasps (due to short styles that allow females to lay eggs in the ovules easily) and female trees produce mostly seeds (due to long styles that prevent egg implantation but allow pollination). If a fig comes from a male plant and is full of galls, you would certainly notice it. In female plants that have been pollinated (but not laid in) there may have been one, or several, female wasps that entered but never left. Luckily, figs produce enzymes that can break down any adult wasps that perish inside the developing infructescence. That “crunch” when you chew a fig? Rest assured those are seeds, which are considered a desirable trait in figs. When the fig was first being grown in California, we did not have the fig wasp here and our figs did not have those wonderfully crunchy seeds. It took a few years, but scientists finally figured out the problem — and we've been happily munching on crunchy figs ever since, all thanks to the introduced fig wasp.
August 12, 2016
August 9, 2016
March 21, 2014
Ask me where my favorite spot to explore urban nature is in Los Angeles, and I'll almost always say the river. This is particularly true during, and after, our seasonal rain storms. We're used to extreme heat episodes, wildlfires, and the odd earthquake* or two. But, by and large, us Angelenos are unaffected and unimpressed by the elements. Going down to the river after a good rain, you get a rare chance to see, hear, and feel the raw power of nature.
*Anyone else wake up abruptly last Monday morning after the 4.4 trembler, wondering how much water you could salvage from your toilet's holding tank?
River patrol after the El Nino rains in January 2010
During our most recent rain storms (February 28-March 2) I, along with a number of other people, ventured down to the river to watch all that water flowing through the concrete channel.
View of the river and the Fletcher avenue bridge March 1, 2014
Unfortunately, the above pictures just don't do it justice. They don't let you feel the power of that much water flowing past you. Maybe this photo collage, created by Damian Robledo, can do a better job?
Damian works right next to the river in Elysian Valley (aka Frogtown), and was able to duck outside his office at RAC Design Build, to document the dramatic change.
As you can see, the river filled the channel almost to the very top. Which, according to The River Project, means a flow rate of about "183,000 cubic feet of water per second," or in terms easier to understand that's, "40 million garden hoses going full blast," or, "14 times the flow of New York's Hudson River!" Whoa, that is one heck of a lot of water flowing through the heart of Los Angeles and on out to the Pacific Ocean. While watching this spectacle, I couldn't help but wonder about the animals that live in the river. What happens to them when 14 Hudson rivers are forced between the river's banks?
Obviously, some creatures, like the white egret pictured above (long-necked bird hanging out in the middle of the frame), can just fly out of the river and hole up until the storm is over. Other fauna native to California, have evolved different strategies to deal with our sudden influxes of water. According to Dr. Greg Pauly, our curator of Herpetology, amphibians are much better than we are at sensing changes in barometric pressure. When they sense cues that a storm is coming (i.e. a drop in barometric pressure), frogs and toads will hop out of the watercourse and find a place to shelter, like under a nice big bush, or down an abandoned ground squirrel burrow. Some amphibians even thrive after massive disturbances like winter floods. Greg told me that after the Mount Saint Helens eruption, Western Toad, Bufo boreas, populations exploded.
But, what about the water-bound creatures, do they fare as well? In the case of this introduced carp species, Cyprinus carpio, not so well:
I found this fish while exploring the river on March 2nd, during an ethnobotany tour put on by River Wild. Although, we were focusing on urban foraging of edible plants, none of us could help taking time to marvel at this massive fish. As you can see, it was was lying there dead, with much of its insides spilling out, including the roe (all those orange bits are fish eggs)! Apparently, carp roe are sold as a caviar substitute, but I just wasn't willing to try them early on a Sunday morning. Yes, a part of me worried that they could be contaminated with toxins present in stormwater*, but mostly it was because I grew up vegetarian in England and accidentally ate taramasalata at a friend's birthday party. Incidentally, taramasalata, is a Greek or Turkish dip made from vinegar, olive oil, lemon juice, and taramas (aka preserved roe). As you can imagine, this has permanently affected my taste for carp caviar!
*In 2008 FoLAR (Friends of the L.A. River) commissioned a fish study to determine species presence and toxicity levels. They sent five L.A. river carp to a lab to be tested for mercury and polychlorinated biphenyls (PCBs) levels. All the fish tissue tested came back with mercury and PCB levels below those designated by the Office of Environmental Health Hazard Assessment's for fish contaminants.
But, how did this impressive creature die, and how did it end up in a dry side channel of the river? I think, one of two things happened. Either, the carp was battered around and killed by debris during the flood, and was then deposited in the side channel as the water receded. Or maybe, the water receded so quickly that the fish was stranded and then, unfortunately suffocated. Either way, post-mortem, it seems that another animal came along to have a snack, apparently wild creatures are into carp caviar too! Then, for some reason (maybe we disturbed them), the epicurious scavenger fled the scene of the crime and left this mighty fish to decompose on the river bank.
March 20, 2014
Photo Credit: Kelsey Bailey
Shrouded in dusky, voluminous wings, a male strepsipteran catches the pheromone trail of a potential mate. With only hours to live, his first and only priority is to reproduce; his boysenberry-like eyes gleam as he heads upwind. As his hideously twisted hind wings plow through the air, lifting him into the sky, he reflects on his life. Born inside his mother's body cavity, this strepsipteran spent his early days with his siblings, consuming his mother from the inside out...
Without eyes, wings, or legs, his dear mother had made her home in the abdomen of a wasp. She had found this host when she was but a small, mobile larva, and burrowed into its abdomen. There she had matured, cloaking herself with host tissue grown specially for her protection. As a young maiden, she exposed her upper body between the plates of the wasp's abdomen, leaving a trail of pheromones for her Prince Charming to follow. When our male strepsipteran's father made his appearance, he pierced his mate just below her head in a romantic act lasting mere seconds. Nothing says "love" more than hypodermic insemination: this is where baby strepsipterans come from.
And so our hero was born, and he and his siblings nibbled away at their mother until she was but a shell, and he was old enough to leave the safe confines of her body. He ventured out in search of a new live host, and latched onto a wasp host of his own. Once in his new host's abdominal cavity, he grew up and pupated, his pupal case peeking out between his host's abdominal plates. When he was ready, he wiggled out from both his pupal case and his host simultaneously. He stretched his wings and set off to find a mate; which is where we first met him. Flying upwind, following pheromones, he catches sight of his darling's head protruding from her host. Swiftly, he flies down to her and, like his father before him, pierces her just below her head. He departs as swiftly as he appeared, his job done. Soon, his Love will be consumed by her own brood and his own little larvae will escape their original host by crawling out of the brood chamber opening in her protruding head. He will never meet them; his fleeting moment of passion with their mother was his last act before death. Fin. Addendum Although their life cycle remains the most intriguing thing about strepsipterans, that is not where the absurdities end. This order is an enigma to taxonomists. Originally, they were thought to be closely related to beetles (due in part to their extremely reduced and modified front wings), but recent genetic work indicates they may be closer to flies, or even a relative to the larger group that includes flies and butterflies/moths. Additionally, strepsipterans do not have the compound eyes you find in a majority of insects. Instead, they have clustered (but separate) eyelets that each produce an image of their own. These eyelets are what give the strepsipteran eyes their unique "boysenberry-like" appearance. The BioSCAN team has recently found representatives of the order Strepsiptera (the "Twisted Wing Parasites") from samples in both Silverlake and Mid-Wilshire neighborhoods. Adult males are extremely rare, and we were excited to share this order's exciting and unique life story with you. For pictures and videos of these amazing creatures, please see a recent article from Wired Science showcasing their amazing biology: http://www.wired.com/wiredscience/2014/03/parasitic-junk-trunk
February 7, 2014
Guest Blog by our very own Dr. Greg Pauly:
For local wildlife, living in the big city can be rough. Encounters with people and their dogs, cats, and cars all present threats not experienced by critters living outside of urban areas. Plus, these city dwellers still have to contend with many of the usual threats like predators and weather extremes. Here are two photos celebrating the scrappiness it takes to be a city dwelling reptile, and also celebrating the incredible opportunities to observe urban nature in action.
"David A." sent this photo to theeastsiderla.com of an adult San Diego Gopher Snake, Pituophis catenifer, schooling a juvenile Red-tailed Hawk, Buteo jamaicensis, near Elysian Park.
There are so many cool things going on in this photo. Cool factoid 1: Elysian Park! Smack dab in the middle of Los Angeles, just minutes from downtown, are two big native vertebrates in a life or death struggle.
Cool factoid 2: The where. This photo was taken in the middle of Scott Avenue in Echo Park. Scott Avenue runs through Elysian Park, which this gopher snake likely called home. David stated that the hawk "...just came down with the snake in the street."
The likely scenario is that this juvenile hawk spotted the snake and thought it would be a tasty meal. However, while tasty, a snake of this size is not necessarily an easy meal for a young hawk. A big snake means a big defense. Any misplaced grab by the hawk, in which the talons are far back on the snake means that the snake gets multiple loops around the bird to constrict it. This appears to be what is happening here with the gopher snake constricting the hawk's abdomen and apparently pinning back one talon. The defense was enough to impair flight and the pair ended up in the middle of the street. David observed the pair for five minutes, during which time the snake slowly freed itself, and both eventually departed the area.
Cool factoid 3: The when. The photo was taken Friday, Dec 27. That's right, winter. Or at least what the calendar tells us is winter. With our unseasonably warm weather, the temp that day was 82 in Echo Park after multiple days of warm weather and mild evenings. So while the calendar says it is winter, that doesn't mean our local reptiles are not active.
Cool factoid 4: Added bonus coolness—Look closely at the snake's neck. It is dramatically flattening its neck. This is a common, stereotyped defensive display used by gopher snakes and other snakes to look bigger.
Cool factoid 5: there's more! Here's another recent attempted predation event on a reptile, this time by a California Striped Racer, Masticophis (Coluber) lateralis, on a Southern Alligator Lizard, Elgaria multicarinata.
This photo was taken by hiker Rainer Standke on January 22 at Hollywood Reservoir. He gave the photo to Gerry Hans, President of Friends of Griffith Park, who submitted it to the Museum's Reptiles and Amphibians of Southern Calfifornia (RASCals) project. Striped Racers are huge lizard predators and certainly eat a good number of alligator lizards. But it is hard to eat an alligator lizard when the lizard is clamping your jaws shut! We don't know the outcome of this interaction. Maybe the lizard lived, or maybe the snake made a comeback and ended up with a big meal. Again, this is a "wintertime" observation, in which the snake was warm enough to be actively hunting and assured enough of warm temperatures over the next few days to think that it could digest a large lizard meal.
And as with the hawk-gopher snake interaction, this observation was made right here in urbanized areas of Los Angeles.
If you make your own local reptile or amphibian observations, please share them with us by participating in the RASCals project either by visiting the project page or emailing your photo and date and location observed to firstname.lastname@example.org.
January 27, 2014
Pseudolynchia canariensis. Photo: Kelsey Bailey.
This week, the BIOSCAN team brings you… a squashed fly from Gardena?! This may be what it looks like but we are excited to share with you our first specimen from the fly family Hippoboscidae, commonly referred to as louse flies. This particular species, Pseudolynchia canariensis, is a parasite on pigeons and doves, a bird louse fly. The BioSCAN team was thrilled to see this specimen appear in one of the site samples, not only because these flies are relatively rare, but because many flies in this family are flightless, and some are without wings at all. Obviously, wingless species are unlikely to be caught in a Malaise trap designed for flying insects, so we were lucky to catch this flying species. The unusual appearance of this fly tells us a lot about its life history. The flattened body (yes, it’s supposed to be that way, it hasn’t been squashed) allows the fly to slip between the feathers on its host, while keeping a low profile. Anyone that has been hiking locally may have dealt with ticks on their own body or that of a companion animal — ticks use that same flattened body shape to make themselves harder to remove. A flattened body shape (scientists refer to this as being dorso-ventrally flattened) helps prevent a parasite, in this case a fly, from being dislodged while it utilizes its food source — host blood. Feeding on the blood of another animal can be tricky business. Our BioSCAN scientists speculated that this fact (coupled with fly "old age") may have contributed to this specimen's tattered wings; perhaps the host tried to dislodge the feeding parasite and damaged it. One look at the view from below and it becomes clear that the sclerotized proboscis (fancy entomology words for "tough mouthpart") is undoubtedly painful; we don’t blame the bird for trying to get rid of it! Unfortunately for the pigeons, getting rid of these flies is not as easy as simply brushing them off. If you notice, the flies have long, curved claws on their feet. The last segments of insect legs are called the tarsi, and those claws are called tarsal claws. On most insects, these claws are small innocuous hooks — used for clinging to normal substrates. In these parasitic hippoboscids, however, these claws are enlarged with a pronounced curve to allow the fly to cling to its host — ouch! So where did these flies come from? Originally, this species was found in the Old World tropics and subtropics, but today they have spread virtually worldwide on domestic pigeons and doves. Despite this wide range, we rarely see them — they spend most of their time flying around attached to their avian hosts. So rest assured, for as ominous as this bloodsucking fly may seem, they are solely interested in bird blood, not yours.
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.