A Pomace Fly Invasion

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 


(Posted by: Brian Brown)


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L.A.'s Frogs, Toads, and Salamanders Can't Wait for El Niño

January 5, 2016

Imagine you are a local amphibian. Maybe you are a Pacific treefrog (Pseudacris regilla), the most widespread native frog in Southern California. Or maybe you are a garden slender salamander (Batrachoseps major), a species commonly found in front and backyard gardens across much of the L.A. Basin (hence, its name).

 

Male Pacific treefrog calling to attract a mate, afer a rainstorm. 

These last few years of drought have been really tough on you. For amphibians, a large amount of oxygen uptake and water exchange is done through the skin, but the skin must be kept moist for proper functioning. This presents a major problem in a prolonged drought. Because of the lack of rain, most amphibians have not been able to leave their hiding spots. As a result, you and your amphibian brethren have had to largely stay below ground where it is cooler and more humid. Only the occasional rainstorm has provided appropriate conditions for you to come to the surface and seek out food, a potential mate, or new habitats to explore (all very exciting things for amphibian you). But most of the time, you have just been resting and waiting for better conditions.

 

Fortunately, this situation might just be changing. El Niño forecasts suggest higher than normal rainfall. As hopeful and excited as humans are that the El Niño rains might alleviate our drought, amphibians must have a thousand-fold more excitement (assuming they’ve read the forecast). With rains, frogs will emerge and congregate at breeding sites, and salamanders will come to the surface searching for insect prey and potential mates.

 

The few recent rains that have fallen in Southern California have provided a small glimpse into what may come. Submissions of Pacific treefrogs and garden slender salamanders to the Reptiles and Amphibians of Southern California (RASCals) citizen science project have already started to increase. With more rains, here is what you should be looking for in your backyard, neighborhood natural area, or elsewhere across Southern California.

A Pacific treefrog recently photographed by Cedric Lee and submitted to the RASCals citizen science project.

The Pacific treefrog is a pretty famous frog. Of the 6,600 species of frogs in the world, this is the only frog that actually says “ribbit.” Because it is loud and common in the L.A. area, it has been dubbed into movies and TV shows, with the result being that people worldwide think that all frogs say “ribbit” when in fact, only this one does. This small green or brown frog has a dark mask that runs through its eyes. It can be found in a huge variety of wetland sites from backyard ponds to our bigger lakes and rivers. The easiest way to found one is to listen for their calls in the evenings after rainstorms.

A garden slender salamander photographed by Stevie Kennedy-Gold and submitted to the RASCals citizen science project.

The garden slender salamander is much more cryptic than the treefrog. Look for it in the same places you might look for an earthworm. Often it is found beneath pots, rocks, or stepping stones in backyard gardens. With a quick glance, you might think you are seeing an earthworm, but four small legs and a head with two biggish eyes will make the identification obvious.

If you do see a salamander or treefrog, take a photo or record the frog’s call and submit that to the RASCals project via iNaturalist, by e-mailing the photo and the location to nature@nhm.org, or by tagging on social media #NatureinLA. 

 


(Posted by: Greg Pauly)


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Have You Seen "Canary-winged Parakeets" in Los Angeles?

December 29, 2015

Yellow-chevroned Parakeets feeding on dates in a date palm. Photo by Kimball Garrett.

Hearing a group of screeching Yellow-chevroned Parakeets (Brotogeris chiriri) flying over the NHMLA café patio at lunchtime is hardly unusual.  This native of South America thrives in much of the Los Angeles region, including Exposition Park where they especially favor the seeds of the floss-silk trees that are widely planted in the area.  But on Tuesday, October 27, a group of us, including myself (Ornithology Collections Manager Kimball Garrett) and Herpetology Curator Greg Pauly, noticed that two of the birds in a small flock overhead were distinctly different, showing large white patches on the inner half of the wings.  These were White-winged Parakeets (Brotogeris versicolurus) — close relatives of the Yellow-chevroned.  In fact the two were formerly treated as a single, variable species called the “Canary-winged Parakeet”, with Yellow-chevroneds hailing from central Amazonia and White-wingeds from the southern Amazon basin.

Two White-winged Parakeets were foraging alongside Yellow-chevroned Parakeets in the floss-silk trees next to the NHMLA Car Park on December 15, 2015. On the left, notice the white feathering behind the yellow wing patch – this white is conspicuous in flight as a large white triangular patch. On the right, notice the grayish color between the eye and the bill (this area is bright green in the Yellow-chevroned Parakeet). Photos by Kimball Garrett.

White-winged Parakeets were established in small numbers in the Los Angeles area — especially around San Pedro and the Palos Verdes Peninsula — in the 1970s, and small numbers continued to be reported into the 1990s.  But Yellow-chevroned Parakeet numbers began to boom in the Los Angeles Region in the 1980s (probably reflecting a changing source of imported birds), and for the past 30 years it has been the widespread and common member of this species pair in this area. We don’t know if the decline in White-wingeds was related to the establishment and proliferation of Yellow-chevroneds.

Specimens from the NHMLA collection show the differences between White-winged parakeets (above) and Yellow-chevroned Parakeets (below). Photo by Kimball Garrett.
 
Recent sightings of White-winged Parakeets in Exposition Park (I saw another flock of 6 on September 18) suggest that small populations still survive in the area, or perhaps that there have been recent instances of birds escaping or being released.  In any case, having these two closely-related but normally allopatric (non-overlapping ranges) species together in Southern California creates an interesting ecological experiment that will surely receive ongoing study. Your sightings of both species — uploaded to iNaturalist or eBird  (alternatively you can e-mail us your observations nature@nhm.org, or tag them #natureinLA on social media)— will help us track their ever-changing fates.

Yellow-chevroned Parakeet feeding at a seed pod of one of the floss-silk trees on the NHMLA grounds. Photo by Kimball Garrett.
 
Yelow-chevroned Parakeets can be seen most of the year in Exposition Park — look especially in the large floss-silk trees on the north side of the car park (see photo above).  Another great place to find them is Echo Park, with noisy flocks seemingly always present around the north side of the lake. Other prime sites include the Huntington Gardens in San Marino, Legg Lake in South El Monte, and the Rosedale Angelus Cemetery west of downtown Los Angeles. A map of sightings from the eBird citizen science project shows their occurrence here in much more detail — just zoom in on the Los Angeles area until individual sightings appear on the map. 

(Posted by: Kimball Garrett)


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Citizen Scientists Discover New Slug in Los Angeles

December 17, 2015

Arion hortensis/distinctus (Image courtesy of silversea_starsong)

In November, three citizen scientists reported observations to our @NHMLA SLIME project of a handsome looking slug, known as the garden arion, in three different neighborhoods of Los Angeles. No one had ever recorded these slugs in L.A. before!
The garden arion is a smallish slug, measuring between 40- 50 millimeters – a little less than half the length of a ballpoint pen. It has a blue/black body, a bumpy mantle (a cape-like fleshy covering near the head), and an amazingly yellow/orange underside (a.k.a. foot). From this foot it makes yellow slime!


Garden arion slugs include two species found in California, Arion hortensis and Arion distinctus. Both are originally from Europe and have been found as invasive species throughout much of North America, where they are associated with human-planted areas like gardens, parks, and farms. In California, these slugs have been common in greenhouses and nurseries in San Francisco and Oakland as early as the 1940s, and recently have been confirmed as established in Riverside and Santa Barbara counties. Without vigilant citizen scientists, there would be no record of the garden arion from Los Angeles County. Thankfully there ARE vigilant and observant citizen scientists contributing to the SLIME project.


To thoroughly establish the extent of this species in Los Angeles County, we need more help from you! We would like to know the geographic extent of the garden arion throughout Los Angeles AND we would like specimens to add to our collection as vouchers, or representatives of the populations living here.


This is where you can help: if you go slug hunting please take pictures of the garden arion, should you find it, and send us your pictures. You can add them directly to SLIME on iNaturalist, or you can e-mail us your photos to nature@nhm.org. If social media is more your thing, you can tag them #natureinLA.  Keep track of exactly when, where, and who found the slugs, and  any other details about where you found it (under wood pile, on sprinkler, etc.) would be extremely helpful. For example, is this slug found in the open after it rains or does it prefer to stay under flowerpots or rocks?


Likewise, if you find this slug and want to bring it to the Museum, our ticketing staff will be happy to receive it. Just put your garden arion slug in a plastic container with a piece of damp paper towel and something to eat (lettuce is a favorite). Include a label with your name and the location details of where you found your slug. You’ll be a big part of documenting the presence and range of an introduced and potentially invasive species, one of the primary goals of our urban biodiversity research!


Special thanks to iNaturalist SLIME contributors cedric_lee, silversea_starsong, and mckernink. 

 

 

(Posted by: Jann Vendetti)

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Backyard Bobcats of L.A.

December 7, 2015

“Miguel, I found a dead bobcat!” It was 8:30 in the morning when I received a call from my friend Jessie Jennewein. Jessie and I work together at the Natural History Museum and share a passion for urban carnivores, such as pumas and bobcats.  So you can imagine that this news got our day off to a bad start.

Bobcat repeatedly spotted using the same backyard near Griffith Park for over a year. Photo Credit: Susan Swan

Although Jessie’s news was sad, it didn’t surprise me.  I’ve lived on the edge of Griffith Park for many years and have studied bobcats and other carnivores from the park.  In this line of work I’ve seen a lot. I’ve set up camera traps and used radio-tracking to learn where bobcats live in the park and neighborhoods near my house. I’ve kept a roadkill bobcat in my freezer for a UCLA Ph.D. student. Once, I helped try to recapture a bobcat that was sick with mange due to exposure from rat poison. I expected Jessie to tell me she found it near my apartment on a street just outside of Griffith Park.  However, the bobcat was actually found closer to Elysian Park. Elysian Park (0.94 square miles) was considered too disconnected from known bobcat populations, and too small for a typical territorial bobcat, which requires 3 square miles of space if it is male and 1.5 if it is a female.

Camera trap video (motion triggered camera) captured of a bobcat marking its territory in a remote portion of Griffith Park.  Video Credit: Griffith Park Connectivity Study

The unexpected location of the dead bobcat initially made me worried about the status of this urban-sensitive species and how to study an elusive species in an urban landscape filled with private property.  However, the opportunities to study them with citizen science left me hopeful about their future.

It all happened as Jessie was on her way home from my P-22 (the famous Griffith Park puma) themed party the night before (yes, I love P-22 that much!). As Jessie was about to get on the 2 freeway near Elysian Park, she noticed a dead bobcat on the side of the road. The next day, the specimen was brought to our NHMLA Mammalogy Collections Manager Jim Dines, who also recognized the significance of the locality.  Jim and I had recently been discussing how our camera traps in the Atwater section of the L.A. River hadn’t captured any images of bobcats. Our study site wasn’t too far from where Jessie made her discovery. 

Jim Dines speaking to Jessie Jennewein about the significance of the location where Jessie discovered the deceased bobcat near Elysian Park.

Before one can truly understand the significance of a dead bobcat on the side of the Glendale Freeway, it is important to have a little background about local bobcat research and ecology. Unlike other urban carnivore species with more flexible diets and social structures (e.g., coyotes and raccoons), bobcats are solitary and have a strictly carnivorous diet. However, they are able to eat a wide variety of small prey.

Research by the National Park Service shows that local bobcats prefer to eat small natural prey such as rabbits (first choice), gophers, ground squirrels, and woodrats. Griffith Park camera traps have also captured bobcats consuming Eastern fox squirrels and mice. Many of these small prey species live in backyards, presenting new opportunities and new challenges to urban bobcats.

Bobcat carrying the remains of an Eastern fox squirrel in the Hollywood Hills. Bobcats are important predators that help regulate small mammal populations. Photo Credit: Griffith Park Connectivity Study

Like most urban mammals, bobcats avoid humans by being more nocturnal.  Researchers in both the Santa Monica Mountains and Orange County have documented bobcats and other urban carnivores coming out much later in areas with more human activity.  Their small stature and brown spotted coloration also allows them to hide in thick backyard vegetation during the evening and the day and usually out of sight from home owners.  The National Park Service has even documented female bobcats using suburban backyards as den sites, perhaps to protect kittens from coyotes that are more abundant in park interiors.  Their small-size and stealthy behavior allow them to stay out of sight and out of mind of the media who tend to portray local carnivores as dangers to humans and pets.  The National Park Service has studied over 300 bobcats in the L.A. area and none have ever been documented killing pets.

Regardless of their stealth, urban bobcats are still vulnerable in areas with poor habitat connectivity. The bobcat Jessie found was likely attempting to cross a matrix of freeway lanes to reach the L.A. River or perhaps some backyard hunting grounds in the neighborhood across the street.  Even if they can safely cross a highway or street, bobcats face many other dangers, such as rat poison exposure which makes them more vulnerable to contracting and dying from mange.

Biologists have learned a great deal about the ecology and urban dangers facing bobcats in the Santa Monica Mountains, Orange County, and Riverside including areas as urban as Irvine and the Hollywood Hills.  However, their range and population health further into L.A.’s urban core has remained a mystery.  Will occasional roadkill fatalities, like the bobcat Jessie found, remain our only proof of their persistence in more urban areas dominated by concrete and private property or will we use these unfortunate clues as a call to action?

After a local community activist shared Jessie’s story with a local newspaper, local residents began sharing bobcat sightings with the same newspaper and the NHMLA citizen science team.  A bobcat was reported in the Los Feliz neighborhood and three reports came from the Silver Lake neighborhood, including an ear-tagged individual sighted a few months later in a small greenspace between Silver Lake and Elysian Park-very close to where Jesse found the dead bobcat a few months earlier.  The ear-tag was very exciting because unique ear tag colors allow researchers to more easily identify individuals!

Bobcat B-253 in Franklin Hills backyard near Griffith Park. Researchers were able to identify the individual as B-253, originally tagged in Griffith Park, by using the unique numbers and color combinations of the ear tags. Photo Credit: Shirley Mims

Upon seeing the ear-tag, I contacted Laurel Serieys, former UCLA Ph.D. who studied Santa Monica mountains bobcats and is now a post doc studying urban caracals in Cape Town, South Africa.  Unfortunately, we couldn’t read the ID number or tell the true color on the ear-tags, so Laurel was only able to confirm that it was a bobcat that she either tagged in Griffith Park near the L.A. Zoo or it was a bobcat that she or NPS tagged in the Santa Monica Mountains west of the 101 freeway. Either way, it had an amazing journey.

I was relieved to learn that the dead bobcat wasn’t the last bobcat of the Elysian Valley. Intrigued by the wide ranging behavior of these bobcats, I decided to place a camera trap in Elysian Park. It took a few months due to widespread human activity but eventually I captured camera trap footage of an untagged bobcat! The experience probably created more questions than answers about Elysian Park and Silver Lake bobcats, but the main lesson was clear!  Neither I nor anyone else can practically search for bobcats in L.A.’s urban core without citizen science.  There is too much private property to cover without the help of local residents.

First photographic evidence of a bobcat in Elysian Park. Video Credit: Miguel Ordeñana

Fortunately another local biologist by the name of Erin Boydston feels the same way.  Erin is a Research Ecologist with the USGS who focuses most of her research on urban bobcats.  Following an iNaturalist training led by myself and Richard Smart, Erin set up a citizen science project based on iNaturalist called “Backyard Bobcats” that requests participants to submit georeferenced photos of bobcats from their backyards.  Unlike other backyard carnivores, bobcats have unique spot patterns that allow researchers to identify individual bobcats even without ear-tags. Therefore, it is possible to not only document their presence but also their population density. As citizen scientists from L.A.’s urban core, such as Silver Lake and Elysian Park residents, continue sharing bobcat data from their backyards, Erin’s search will continue to expand deeper into more urban neighborhoods.

One of many bobcat photographs shared with Miguel by fellow Griffith Park neighborhood residents. Photo Credit: Susan Swan

Once Erin’s project gathers steam, population patterns may become more apparent, such as which bobcat individuals from rural areas also use backyards. Perhaps the habitat value of previously overlooked urban parks, such as the Silver Lake reservoir or small fragments in more underserved areas like Elysian Park or Highland Park, will be identified.  Additionally, crucial habitat connections and corridors like the L.A. River and Arroyo Seco may be increasing the habitat value of these small parks by linking them together, creating a single, larger, and more functional ecosystem.  Are bobcats using urban areas due to a lack of resources and space in local open spaces or are these bobcats thriving in certain backyard habitat?  The public can help scientists like Erin map the health (e.g., photos of mangy bobcats) and distribution of bobcats throughout rural and urban areas by submitting their photos to Backyard Bobcats and the L.A. Nature Map.

Jessie’s discovery, while sad, did lead to the gathering of more data and increased awareness of urban bobcats in Los Angeles. My hope is that more people will send their bobcat photos to Erin’s project. It is only through data collected and submitted by Citizen Scientists that we will understand the role these charismatic wild cats have in our shared ecosystem and help us ensure that they have a long future in the City of Angels.

How to participate: Send backyard bobcat photos with date, time, and location information to the Backyard Bobcats and L.A. Nature Map using one of three methods:


  1. Email: nature@nhm.org

  2. Social Media: Tag photos with #NatureinLA

  3. iNaturalist: Submit photos directly to the Backyard Bobcats project or L.A. Nature Map via iNaturalist

 

(Posted by: Miguel Ordeñana)

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Oothe-whata?

December 1, 2015

"What is that?” That was the question I asked my supervisor, Lila Higgins, back in the fall of 2012 when she brought in a strange looking object attached to a stick. “This is an ootheca, an egg case” she replied.

Ootheca seen on a Lion's Tail plant (Leonotis leonurus) Nov 3, 2015 in the Nature Gardens at NHMLA. Photo credit: Richard Smart

The ootheca was attached to a stick that Lila had brought inside to our office. Lila saw the stick lying on the ground in our Nature Gardens. Originally, she was going to place the stick into a nearby garden bed, but as she looked closer she noticed the ootheca. She recognized the shape of the ootheca to be that of a mantid egg case. Lila decided she would help the mantid babies by bringing them indoors, so they could develop without interference from predators or people.

I was very curious on how long it would take for the mantids to hatch out, and I wondered just how many and how large the young mantids would be when they emerged.

Days of checking the ootheca, turned into weeks, which turned into months. Then finally, in March of 2013, I heard Lila happily exclaim, “The ootheca hatched!” I ran over and was fascinated to see miniature mantids on her desk. They looked like the much larger mantids I was used to seeing, but teeny tiny. They were unbelievably cute. Lila even wrote her own blog post about it.

Baby mantid seen March 29, 2013. Photo credit: Lila Higgins

That experience made quite an impression on me, and it came to mind recently when I saw an ootheca attached to a Lion’s Tail plant in the Nature Gardens at NHMLA. My colleague, Richard Hayden, also recently posted an ootheca to Instagram, and that got me thinking that others were likely seeing these in L.A. and perhaps they didn’t know what they were.

Backside of an ootheca seen on a Catalina Perfume plant (Ribes viburnifolium) November 18, 2015 in the Nature Gardens at NHMLA. Photo credit: Richard Hayden

An ootheca can blend in very well with the plant they are attached to, so many people may not see them. Or people may think they are a sign of a sick or injured plant, and may remove the branches they are attached to, not realizing they were removing baby mantids from their gardens. Mantids are considered to be a beneficial insect since they will eat many garden pests such as grasshoppers, caterpillars, and aphids – you want mantids in your yard. The egg case actually starts as a frothy mass, but hardens to form a tough capsule that protects the growing young inside. Depending upon the mantid species, there can be anywhere from dozens to hundreds of mantids inside the ootheca, so by picking up sticks with an ootheca attached to them can help out a lot of mantids. 

Ootheca on wire fence, Nov 23, 2013 in the Nature Gardens at NHMLA. Photo credit: Lila Higgins

Are you seeing oothecae in your part of L.A.? If so, I encourage you to let them be. The egg case will protect them from rain and temperature changes. If you see an ootheca attached to a broken stick laying on the ground then kindly place the stick in an area where they are less likely to be damaged by people. You can also take photo of the egg cases, and tag us using #NatureinLA so we can add your #ootheca photos to our L.A. Nature Map!

 

 

(Posted by: Richard Smart)


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Red Fox Sighted in San Pedro: From Fox Farms to Coyote Food

November 10, 2015

On a recent visit to San Pedro, the Natural History Museum’s Kimball Garrett crossed paths with a nonnative red fox (Vulpes vulpes) near the 22nd Street Landing . Although unusual now, red fox sightings were commonplace in many parts of coastal Southern California just a few decades ago.

Photo courtesy of Kimball Garrett

 

If red foxes aren’t native, how did they get to Southern California in the first place? Not surprisingly, their introduction was anthropogenic, the result of human activities. From 1905 to 1919, red foxes from the eastern US were imported into Orange County specifically for the sport of fox hunting. Simultaneously, the farming of imported foxes for the fur industry was becoming widespread throughout California. More than 100 fox farms existed across the state by the 1940s. Escapees and deliberate releases from both enterprises quickly became comfortable in their new environs, reproducing and expanding their population and distribution. Museum specimen records show that by the 1970s red foxes had become established widely throughout the region, with salvaged road kill specimens collected from North Hollywood, Glendale, the Palos Verdes Peninsula, and nearby beach cities.

Red foxes, like many introduced species that become successfully established, are generalists that easily adapt to new environments. They are capable of surviving—even thriving—in diverse habitats and on widely variable diets. More often than not, however, the success of an introduced species is to the detriment of native wildlife.

The population of red foxes boomed in Southern California in the 1980s and 90s, inflicting ecological devastation along the way. Red foxes actively preyed upon native species, many of which were already in trouble due to habitat loss. This included ground-nesting shorebirds and songbirds, lizards, snakes, rabbits, and native mice. At Orange County’s Seal Beach Naval Weapons Reserve and Bolsa Chica Wetlands, as well as the Ballona Wetlands in Los Angeles County, populations of endangered bird species such as the light-footed clapper rail, the least tern and Belding’s Savannah sparrow, were brought to the verge of extinction. Red foxes were also likely responsible for causing the local extinction of the Pacific pocket mouse from habitats like the El Segundo Dunes.

Efforts by the US Fish and Wildlife Service to eliminate the nonnative red fox were met with harsh criticism by animal rights activists, despite the looming threat to the endangered native fauna. Lawsuits ensued and much time and money was lost defending the effort to eradicate the nonnative predators. In the end, a lower profile program that targeted red foxes in specific areas resulted in a rebound of the native bird colonies in the late 1990s.

In addition to their hunting prowess, red foxes easily spread and thrived in Southern California due to their ability to adapt to just about any environment. While urban infrastructure is an impediment to species like the mountain lion, to the red fox it presents opportunity. Research published in 1999 by Jeff Lewis and Rick Golightly, of Humboldt State University, documented how red foxes in Southern California use flood control channels, freeway underpasses, railroad and highway corridors, and powerline right-of-ways to move around and expand into new territories.  They are also comfortable making their dens in culverts, at golf courses and parks, or even alongside busy freeways.

In light of their extraordinary adaptability, why have red fox sightings remained uncommon? One possibility is that coyotes actively suppress and kill red foxes. As coyotes have expanded into urban areas, they are taking over the same niche formerly occupied by the red foxes. It very well might be that the native coyote is succeeding where frustrated wildlife managers couldn’t: eliminating the introduced red fox.

 


(Posted by: Jim Dines)

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L.A. Bats Fight On!

October 5, 2015

Happy (American) football season everybody! Yes, some scientists enjoy playing and watching sports in addition to searching for wild animals and staring at tiny things under a microscope. This is true for me. Growing up in a Nicaraguan family, playing and watching sports was a big part of my life. Nicaraguans are known to be baseball fanatics, but my mother and I, both being USC alumni, are also serious Trojan football fans.  I’ve been watching the Trojans play at the L.A. Coliseum since I was a young boy and now I take my little brothers to games. But, even when a game is playing out below, I can't completely turn my scientist-self off–particularly when there are bats involved. Let me tell you about the bats that Fight On!

Mexican free-tailed bat (aka Brazilian free-tailed bat) from NHMLA's mammalogy collection. 

It was this season's home opener against Arkansas State. I attended the game with my mom, stepdad, cousin, and two little brothers. I stopped by my office before the game to pick up my bat echolocation (the ultrasonic calls that bats use to communicate, hunt, and find their way around in the dark) detector because I was going to scout out an area for a bat program the following day. I put the detector in my pocket (iPhone ultrasonic microphone attachment) and rushed over to meet my family. We enjoyed the blowout game like any other fans do–cheering, high-fiving strangers, and eating delicious junk food.  

Enjoying the USC football game with my brothers and cousin, just before I saw the bats!

It didn’t seem like the night could get any better until my 13 year old brother, Aaron, spotted something flying overhead and yelled, “Miguel bats!” I looked up, spotted one and exclaimed, “Good eye Aaron!” I stared for a while in awe and then I saw another, and then another. At first, I was content just watching the bats fly around, dipping and turning across the night sky. But then I remembered I had a bat detector in my pocket. Nerd alert!

Using the echometer to scan for bat echolocations.

I quickly fumbled for the detector, attached it to my iPhone, and began recording using the free Echometer app. Luckily, the detector was picking up their echolocations. Over the next 20 minutes I recorded over 100 sonograms (graphs representing sounds) many of which I hoped would help me identify the bats later. I couldn't wait to get back to a computer to figure out what species were enjoying the game just like my family and I were.  But what were they doing here?

As I was trying to capture the bats' echolocations, I noticed they were hunting! As they flew in and out of the arcs of light, I saw them pick off moth after moth. At this point I was standing at the edge of our section, reaching out so my phone's microphone had a better chance of recording the bat sounds. I was worried because I might have been blocking someone’s view of the game. But quickly I recalled we were on the way to a landslide victory, and then I heard a lot of other people talking about the bats. It seems the bats were putting on a show for other fans too, not just for my family.

The game ended on a high note with the Trojans beating the Red Wolves 55 to 6.  

When I got back in the office and analyzed the sonagrams, I found out the bats I had detected were Mexican free-tailed bats, (Tadarida brasiliensis). Fifty-two of the 105 recorded sounds, belonged to these bats. The species are known for their spectacular nightly emergence from beneath Austin’s Congress bridge as they leave to consume millions of insects (a lot of them being pestiforous moths) in a single evening.  They are also known for their ability to adapt to urban areas by roosting in human structures.  This species was detected in Exposition Park for the first time in 2013 by our bat detector in the NHMLA Nature Gardens.  It was very gratifying to find out what species were flying overhead but it made me hungry for more answers.

Millions of Mexican free-tailed bats emerging from the Congress bridge, which has now become a tourist attraction (photo by Austin Convention and Visitors Bureau).

Are the bats roosting in dark corners and crevices of the coliseum during the day?  Are there more than one species feeding at the coliseum?  Do migrant bats use the coliseum structures like the Vaux swifts of downtown L.A. do on a seasonal basis?  Who knows, but it is notable how one single eye-opening experience can inspire so much wonder in unexpected places.  These moments remind us how many urban wildlife events are hiding in plain sight and as a result remain scientific mysteries. Perhaps, this story not only reminds us that wildlife spectacles sometimes occur unnoticed at commonly visited gathering spots (stadiums, amusement parks) but that there are other amazing wildlife moments we can observe once we simply begin looking. 

 


(Posted by: Miguel Ordeñana)

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Introducing Your Los Angeles Snails!

September 25, 2015

There is a new citizen science project in town and we need your help to document the snails and slugs that call Los Angeles home. SLIME (Snails and Slugs Living in Metropolitan Environments) kicked off earlier this year, and we are already making some interesting discoveries about life in L.A.'s slow lane. 

White Italian snails on a sprinkler at the White Point Nature Center, San Pedro, Los Angeles County. Notice the variation in color and pattern. Photo by Austin Hendy.

There are about a dozen common land snails in Los Angeles County. If you’ve hiked within the Palos Verdes peninsula, or up to the Baldwin Hills Scenic overlook you’ve probably seen two of the most common snails in urban Southern California. Like most Angelenos, they thrive in a Mediterranean climate and, in fact, ARE from a Mediterranean climate. The white Italian snail (Theba pisana) and milk snail (Otala lactea), hail from Southern Europe and reproduce abundantly in our neighborhoods, their adopted home. They are often found clustered on the same plant stem, sprinkler, sign, or fence, and in numbers from the dozens to hundreds.

Despite this presence, and close proximity to people in Los Angeles parks and along hiking trails, they are often confused for each other or misidentified as other species. Here's why. 

 

Both are highly variable in color and in pattern. The next time you seen a bunch of them, take a close look. In white Italian snails, shell color can range from white to tan with varying degrees of banding, zigzags, and stripes of variable thickness. 

Likewise, the milk snail’s shell can range from almost totally white to heavily banded with brown and tan stripes, which can be solid or stippled. And, to add to the confusion of the casual snail-watcher, these species sometimes overlap in habitat, as in the gardens of the White Point Nature Center in San Pedro.

Milk snail on a twig at the White Point Nature Center, San Pedro, Los Angeles County. 

So how do you tell the difference?

 

The white Italian snail (Theba pisana) is the smaller of the two species and at maturity is about the size of a dime. As an adult, its umbilicus, or the center of the underside of the shell, is partially covered by the lip of the shell.

 

The milk snail (Otala lactea) is the larger of the two species and about the size of a quarter at maturity. As an adult its umbilicus and part of the underside of the shell is glossy and brown in color. 

Easily distinguing a milk snail (left) from a white Italian snail (right) by examining the underside, or umbilical view of the shell.

 

Such confusion is not limited to sizable snails you’d find hiking, but makes distinguishing two tiny Los Angeles snails tricky as well. If you look under rocks, among leaf litter, or in the soil of potted plants, you might find two more snail doppelgangers: the orchid snail (Zonitoides arboreus) and the glass snail (Oxychilus sp.). They share the same two-toned gray-colored bodies, and flattened amber-colored shell, but can be distinguished by size and subtle differences in the shell.  

Glass snail (top) and orchid snail, tiny snails with subtle differences. 

When in doubt, which is most of the time even for seasoned snail observers, the best way to photograph a snail for identification is to take images of the shell from three different angles; the top (apical view), the side (apertural view), and the bottom (umbilical view).

The 3-view approach to photographing milk snails apical (top), apertural (middle), and umbilical (bottom) views.

So next time you find a snail (or slug for that matter) take pictures and send them into the SLIME project. You can submit them directly to iNaturalist, e-mail them to slime@nhm.org, or tag them #natureinLA on social media. Either way, you will be able to put your new-found snail identification skills to the test, and I might get to help with the tricky taxonomy of terrestrial molluscs.

 


(Posted by: Jann Vendetti)

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Slimy Friends Or...?

September 30, 2016

Meet the Insects of L.A. City Hall

September 20, 2015

Being a resident of the most filmed city in the world, there are some buildings that I have as much familiarity with from portrayals on the silver screen as I do from my daily commute home.  One such building is our iconic City Hall, completed in the 1920s in a fashion one architect described as an architectural hybrid “Modern American” style.  Built from concrete taken from sand from all 58 Californian counties and mixed with water from all 21 Missions, this classy behemoth has been featured in dozens of films and TV shows (my personal favorite cameo is Carpenter’s 1980s classic, “Escape from L.A.”).

Photos above by Estella Hernandez. All photos below by Kelsey Bailey.

Standing at 450 feet, L.A.’s City Hall is a structural symbol of the growth and prosperity of its time, but to an urban biologist, the grounds surrounding it have a different potential; the opportunity for discovery of our wonderful wildlife. It was with this curious spirit that the NHMLA BioSCAN team partnered with LA City Councilmember Paul Koretz. We erected several insect traps on the grounds, in the trees, and on the south roof to see what types of bugs call City Hall their home.  From just one summer month, we have so far identified several hundred species from over 90 families!

Some of the insects collected are very common backyard residents that most would recognize (Argentine ants, green lacewings, European honey bees), but the vast majority are surprising dwellers at the core of the city!  Below are just a select few of the thousands of insects we found from our brief survey.

Ants, bees, and wasps (all in the insect order Hymenoptera) are the largest group found in these traps in terms of diversity, but also the smallest in terms of size.  Thousands of microscopic wasps only a few millimeters in size were collected, as well as 6 different species of bee. Low ant diversity was expected: the traps we used mainly to collect flying, not crawling, insects. Above, micro-wasps associated with figs in the families Pteromalidae and Agaonidae. Below, metallic sweat bee (genus Agapostemon). 

Flies to tantalize your eyes! This astonishingly diverse group of insects in the order

Diptera do everything from pollinating flowers to decomposing, to preying on other insects.

Measuring at almost 1 inch in length, predatory robber flies were some of the largest insects we collected (below).

Some flies like to make love on the wing, as was evidenced by the two pollen-feeding “window” flies collected in our trap in copula (below). 

The third most common group we collected from City Hall include a wide variety of insects such as aphids, hoppers, assassin bugs and stink bugs, to name a few. Although some are pests on plants, many have beautifully colored markings and ornate stained-glassed patterned wings, such as this lace bug and the smoketree sharpshooter (below).


(Posted by: Lisa Gonzalez)

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