January 10, 2017
Over the last few weeks I have been bombarded with praying mantis sightings, stories, and text messages. It is the season for LARGE mantids, and I wanted to share a few with you.
Found in our Nature Gardens on a 'Cynthia Giddy' aloe flower, this female mantis looks as though she is about to drop an egg case at any moment. Finding a mantis egg case, also known as an ootheca, in your backyard is a good sign. Mantids are great predators and help to keep pest insects in check.
Across the city in Koreatown, this mantis was actually caught in the act of laying her ootheca! Over time the mass will harden and the upto 100 eggs will develop. In the spring the eggs will hatch and 100s of teeny tiny mantids will emerge. They better move fast though. If no other food is present, baby mantids often make a meal of their weaker brothers or sisters!
Just in time for Halloween, this last mantis is actually DEAD. It is also one of the few gray colored mantids (tan/brown or green mantids are more commonly seen). Although it is doing a good impression of a ghost, this mantis if real, unfortunately real dead. We can only hope that it was able to mate and pass on its genetic material before its demise.
January 10, 2017
The Museum's Nature Gardens continue to be the gift that keeps on giving by providing precious habitat to wildlife living in the urban core of LA. Last November, we not only had our second alligator lizard sighting, but we also uncovered a rarely seen flower fly from our Malaise trap that collects insects as part of the BioSCAN project. This project has examined over 2,000 flower fly specimens representing 35 species in LA so far, but this rare fly from the garden, Myolepta cornelia, is the only one we have seen so far!
Before you dismiss this finding as “just another fly,” take a minute to ponder the many talents of these mini-marvels. Faster than a hummingbird, clocking in at 250 wing beats per second (!!!), flower flies spend their day revelling in the garden’s floral buffet. They can fly backwards as easily as they do forwards, or can be spotted hovering perfectly still in mid air, like little meditating, levitating yogis. Just like the beloved bee, they pollinate the flowers they feed upon. In fact, as hymenopteran (the bee, wasp, and ant group) mimics many are mistaken for a wasp or a bee, a trait that offers protection from potential predators.
Their ecological importance does not end there. As wee little fly babies (the maggot or larval stage, in other words), they act as beneficial predators or decomposers, depending on the species. The activity of the larva of our rare special fly M. cornelia is still a mystery to entomologists! We know that many of their close relatives feed on rotting wood in the larval stage and have a preference for oak woodlands, so it is possible that M. cornelia is helping to break down dead wood in the Nature Gardens.
Special thanks to Jim Hogue and Martin Hauser for their identification skills and syrphid fly insight!
Brown, Brian, James N Hogue and F. Christian Thompson. "Flower Flies of Los Angeles County". Natural History Museum of Los Angeles County. 2011.
Reemer, Menno, Martin Hauser and Martin C. D. Speight. "The genus Myolepta Newman in the West-Palaearctic region (Diptera, Syrphidae)." Studia dipterologica 11 (2004) Heft 2: 553-580.
January 3, 2017
It is a sparkling New Year! But have you sat down and thought long and hard about a New Year's resolution yet? We know that they can be overwhelming, and some people think they're cliche, but we are here to help. The only catch is, it might be a bit unconventional...
NHMLA's recommended New Year's resolution:
I will dedicate my waking hours to looking for snails and slugs in Southern California.
Here's how to get started:
1) Go outside (after it rains can be particularly fruitful).
2) Look for snails and slugs. Damp spots are best--under bushes, among wood pieces in wood piles, between and under rocks or bricks, on tree bark, on plants, among leaves, along wet sidewalks, and popping out of mushrooms! Remember if you flip a log or rock, put it back the way you found it (it is likely an animal's home).
3) Take pictures of any snail and slugs you find. Snails and slugs move slowly, so it is fairly easy to take multiple shots that are in focus. Also, try to take pictures from different angles, particularly for snails. Getting images of the top and sides of the shell can be helpful. If it is a snail-less shell, they can often still be identified. Try to get an image of the shell opening. Don't forget to take note of where you are and the day/time.
4) Send us your pictures. You can submit them directly to iNaturalist (using the free smartphone app, or on your home computer), e-mail them to email@example.com, or tag them #natureinLA on social media.
We are interested in any and all snail/slugs you might find. But because you are not going to do anything by halves with your New Year's resolution, keep on the look out for these five species. If any of these were found in Southern California (and submitted to the SLIME project) they would be new records for the region. They are all native to far off places but may be closer than we think...
Common names: Zachrysia provisoria-Cuban brown snail, Meghimatium bilineatum-Chinese slug, Parmarion martensi-yellow-shelled semi-slug, Boettgerilla pallens-worm slug, and Veronicella cubensis-Cuban leatherleaf slug.
December 28, 2016
The museum's Nature Garden is a great place to see birds. Not necessarily one-in-a-lifetime type birds, but enough of a variety that beginners and photographers can find lots to appreciate. Here are some photographs I took on 20 December, 2016 to show that, at a time when much of the country is covered in snow or miserably shivering because of the cold, we here in Los Angeles have an almost unbelievable opportunity to observe colorful wildlife in the center of the city.
December 13, 2016
Baby opossum season is thankfully coming to a close, but only for a short while! We get quite a few calls here in the Live Animal Programs office when these bumbling troublemakers are out looking for a new place to call home.
Photo by Jill Franklin
A few years back, a young opossum made its home in the engine block of a Museum pool vehicle that hadn’t been used for a while. You can see with the leaves he dragged in, it was a perfectly cozy den. Luckily for him we didn’t start the engine and he was an easy eviction. More recently, a friend of an NHMLA Staffer wrote in a panic questioning how to get an opossum out of her house. It had pulled off a window screen and attempted to make itself at home.
Photo by Leslie Gordon
But we’re lucky. According to one rehabber I know, she gets calls several times a day early February/March and July/August. Of course, the young marsupials aren’t really looking for trouble, but they absolutely find it in our yards, homes, sheds, garages, engine blocks… you name it.
When they emerge from mom’s pouch and start riding on mom’s back, or tagging along behind her is the time when they start getting into trouble. If the mom did not become roadkill, and her scampering young were not grabbed up by a dog or cat, (the former scenarios comprise most of the rehabbers’ calls to rescue babies) they eventually start to look for a place to call their own. And they can call anything a home--under your garage, porch---almost anywhere.
We get our fair share of calls, but the reason it gets especially crazy for rehabbers is because opossums are virtual baby factories. Unlike many mammals, the baby season can happen multiple times a year, and at around 13 babies a litter, that’s a lot of babies! And they are in a hurry, too. They gestate for just 12 days, and when they are born (the size of honeybees), they have just a few minutes to race to one of 13 teats in mom’s pouch. They latch on and nurse for about 100 days, but toward the end of that period, they get large and start riding on mom’s back garbage-man-style. And at just about 3 to 4 months of age they are ready to go on their own! It is shocking to most people to see how small they are when they are technically ready to go. But remember--for an animal that lives maybe 3 years tops, every month is rather like 3 years of ours. And those first few months out of the pouch are clearly a real obstacle course for them.
So what to do if you run into one of these little kiddos when the next season comes around?
#1 Please don’t attract them by feeding. We strongly discourage feeding most any wild animals, especially nonnatives like opossums.
#2. If they are discovered in your trash cans, typically either gaping their giant mouths or playing dead, simply tip the can so they can get out, or put in a ”ladder” so they can escape. This can be a branch, an actual ladder, a crate, almost anything. Often they fall in and get stuck there. Remember, the playing dead routine is very effective. They go stiff, emit an odor and even allow flies to land on their open eyes! If you are unsure, walk away and ensure privacy/escape for at least 2 hours. If it is still there, you may have a dead opossum. If not, your ladder probably helped it get to freedom.
#3. If they are in your home, you can typically treat them like an equivalent-sized cat. If simply shooing them out with a broom didn’t work and they are very small, throwing a towel over them usually works. Wear heavy gloves if you are worried. If they are larger, your presence is usually enough. But leave a clear, unobstructed exit back out of your home and you'll make outdoors seem more appealing. Just make sure a curious dog or neighbor isn’t blocking the path.
The best advice is to be patient. They’re slow, but they really don’t want to tangle with humans.
City of Los Angeles Animals Services – Wildlife 323-225-9453
Coast and Canyon Wildlife Rehabilitation 310-480-1760
County of Los Angeles Animal Control – Wildlife 562-728-4882
Pasadena Humane Society & SPCA – Wildlife 626-792-7151
December 6, 2016
These monstrous looking pinchers are the mouthparts of a dragonfly larva imaged with a Scanning Electron Microscope (SEM). Amazingly, this image wasn’t taken of the animal itself, but rather of its abandoned exoskeleton (called an exuvium) that the larval and freshwater-living dragonfly (or naiad) leaves behind when it becomes a winged dragonfly. This dragonfly and the ones below are from the family Aeshnidae.
Below is the whole exuvium in glorious detail. You can find these shed exoskeletons on rocks and vegetation at the border of freshwater ponds, steams, and lakes. I found this one amond the reeds in NHMLA's Nature Garden pond.
Image taken, with thanks, by Kelsey Bailey on a Keyence VHX-5000 digital microscope.
November 29, 2016
At the border of the Hollywood Hills and Los Feliz neighborhoods is an enchanting, tree-shaded half-mile trail of Griffith Park that meanders along a trickling stream dotted with ponds. This verdant paradox in the city of Los Angeles has an appropriately puzzling name: Ferndell Nature Museum. If you go there looking for “the Museum,” there isn’t one; the collection of plants and animals living there IS the Museum.
The history of this Griffith Park canyon and what became “Ferndell” or “Fern Dell” includes the natural spring that feeds the stream, a village site of the native Tongva/Gabrielino people, planting of much of the canyon’s greenery in the early 1910s, development of the trails and bridges by the Civilian Conservation Corps in the 1930s, disrepair in the 1980s, and refurbishment and restoration (in stages) up until today. This human history complements Ferndell’s unique biological composition: it hosts a diverse flora and fauna that, much like nature elsewhere in developed Los Angeles, is a mosaic of native and introduced species.
The ferns of Ferndell are plentiful and include Adiantum and Athyrium, some of which are California natives, but others are non-native. Button and snail ferns (Tectaria sp.), leatherleaf ferns (Rumohra sp.), and tree ferns (Cyathea cooperi) hail from Africa, South America, and Australia. Elephant-ear plants (Colocasia sp. from East, South, and Southeast Asia) and Philodendron selloum (from South America) shade the trail and provide a tropical ambience. Native coast live oak (Quercus agrifolia), western sycamore (Platanus racemosa), and California bay (Umbellularia californica) round out a geographically disparate forest that also includes a huge Roxburgh fig tree (Ficus auriculata), climbing English ivy (Hedera helix), and California coastal redwoods (Sequoia sempervirens).
Under this diverse canopy are some of Ferndell’s most charismatic residents, the animals. In the ponds and along the trail are red-eared slider turtles (Trachemys scripta elegans), crayfish (Procambarus clarkii), mosquito fish (Gambusia affinis), large koi (Cyprinus carpio), goldfish (Carassius auratus), guppies (Poecilia reticulata), Corbicula fluminea (prosperity clam), and Oxychilus sp. snails. While many Angelenos are familiar with these residents of magical Ferndell, not one of the aforementioned animal species is native to Los Angeles or even to California!
The “prosperity clam,” Corbicula fluminea, for example, is native to Eastern-Southeastern Asia, Africa, and Australia. In California and elsewhere, this non-native mollusc is also invasive, whereby it easily colonizes and greatly alters freshwater environments changing them profoundly for native species. In Los Angeles County, Corbicula fluminea has been recorded from (among other sites) Lincoln Park Lake, Lake Balboa, Kenneth Hahn State Recreation Area, Frank Bonelli Regional Park, and the Los Angeles River. iNaturalist observations and our collections at the Natural History Museum of Los Angeles County are both essential for documenting the occurrence and spread of this species throughout Los Angeles County. As far as we know, our October 2016 discovery of Corbicula fluminea in Ferndell is the first from this location.
Ferndell also hosts diverse native animals including insects (dragonflies, water striders, bees, butterflies), birds (Cooper’s hawk, Nuttall’s woodpecker, California towhee, among many others), mammals (gray and fox squirrels, coyote, bobcat, mule deer, raccoon, rabbits, skunk), and reptiles and amphibians (western fence lizard, Pacific tree frog). Discovering the relationships between native and non-native species, especially in the urban environment of Los Angeles, is one of the goals of NHMLA’s Urban Nature Research Center.
If you haven’t explored Ferndell, I’d recommend it. The trail is a unique and surprising pocket of Los Angeles that is easily accessible, a good entry point for the rest of Griffith Park, and fun for kids. The unusual “Museum” of Ferndell’s flora and fauna almost guarantees to “wow” first time (and repeat) visitors with what is a microcosm of the city’s biodiversity: a complex mix of species that are established and new, native and foreign.
November 3, 2016
Earlier this month, I received an e-mail from a friend of mine asking if I wanted to adopt “a tame squirrel.” I paused and re-read her sentence, and then saw a photo of an extremely cute baby squirrel.
Through several e-mail exchanges I learned that my friend’s coworker saw the baby squirrel in a park near her home, and was surprised at how unafraid it was of people (it came right up to her and let her touch it). Worried that this squirrel was a lost or abandoned pet, she picked up the squirrel, placed it in a box, and took it to her office. Everyone in her office was amazed that the squirrel was not afraid of people, and that it would let them touch it. That’s when I received the e-mail about the squirrel. My first thought was, “Oh no! Why was that squirrel picked up?” I did some chastising since I told them that the baby squirrel may not have been lost or abandoned, and that since it was a baby that could explain why it wasn’t afraid of people. I knew that the person who picked up the squirrel thought she was helping, but taking an animal away from its home is not recommended. My friend asked if they should release the squirrel at a nearby golf course, and I quickly said, “No!” Animals in a successful habitat know where food and water can be found, they know where they can take shelter to avoid predators and the weather, and have enough space to avoid high rates of competition. If this squirrel was placed in that golf course it would not have been familiar with its surroundings, would not know where food, water, or shelter could be found, and it is not likely that the squirrels living in that golf course would have accepted it. Also, if animals are successful in establishing themselves in new areas, they can have a negative effect on the animals already there (example 1, example 2, example 3).
I spoke with Leslie Gordon, who is one of the Managers in NHMLA’s Live Animal Program, and she had some great insight about "helping" wild animals: It is not just unwise, it is illegal to keep a wild animal without a permit. Squirrels especially make terrible pets. Even those dedicated to raising them (with permits) note they are flighty, inconsistent, difficult, and …well…”squirrelly”. Fear is a healthy thing for animals- friendliness is not. Wild squirrels (or any animal) can carry a plethora of zoonoses (diseases or parasites that can spread to humans). Squirrels, in particular, can also carry the plague. So when you see one that seems “unafraid”, that doesn’t necessarily mean it wants to be pals- It may be very ill. A lack of fear can also mean it has been habituated to humans by feeding. If you have ever heard the term “a fed (blank) is a dead (blank)” that is what it refers to. Squirrels become habituated to humans and unafraid of them. When this happens they become food aggressive and begin to chase any human they find. It begins a loop of aggression (squirrels especially seem to find it satisfying when we run away screaming) that ends up with a squirrel being trapped by the City due to complaints and killed, or worse a kid getting bit. This is why rehabbers go to great lengths to avoid the animal seeing them or associating them with food, so it can be released again and keep its fear of humans. Don’t feed squirrels (or any wild animal)! If you see an animal who is unafraid it is not wrong to leave it alone, especially if it seems otherwise safe, and simply report it to City animal control. They do bring animals to rehabbers when they can. If it seems in danger of being killed or injured, and you feel you can keep yourself safe from disease or bites, it is okay to bring it to a rehabber or shelter yourself. I encouraged my friend and her coworker to call a wildlife rehabilitation center, and they found one in Malibu that specializes in squirrel rescues, Coast & Canyon Wildlife Rehabilitation. The rehabilitation center was able to accept the squirrel, and through the care of their trained wildlife rehabilitators they believe it will be able to be reintroduced successfully into the wild. If you see a wild animal that you think needs help, it is recommended that you contact a wildlife rehabilitation center and/or animal control, rather than to try and help the animal on your own. Below is a list of places you may contact. California Wildlife Center 818-591-9453 City of Los Angeles Animals Services – Wildlife 323-225-9453 Coast and Canyon Wildlife Rehabilitation 310-480-1760 County of Los Angeles Animal Control – Wildlife 562-728-4882 International Bird Research & Rescue Center 310-514-2573 Pasadena Humane Society & SPCA – Wildlife 626-792-7151 South Bay Wildlife Rehab 310-378-9921 Squirrelmender Wildlife Rehab 805-338-0481 Wetlands and Wildlife Care Center 714-374-5587
October 27, 2016
Green lacewing larva disguised as a tiny lint ball, walking up our den wall. Photo by: Martin Schlageter
The other night, as I was walking through the house turning out lights and locking up, I saw a weird, tiny ball of debris—the kind of thing you see in the corner of a house that has multiple pets and an idle vacuum cleaner—making its way up the wall. I called for my husband and said, “What in the world is going on? Does that dust bunny have legs?”
For the next 20 minutes we watched it slowly traverse our wall and tried to capture photographs of it on our small point-and-shoot, hoping to get a closer look on the computer (blurry photo above). The next day my husband submitted a couple of photos of it to iNaturalist and received a prompt answer: green lacewing larva.
Lacewings are beneficial insects in the garden. Their larvae are voracious predators called aphid lions, as aphids are a preferred meal. They also eat a number of other soft-bodied insects, like mealybugs and immature whiteflies, that are considered garden pests. I am always gratified to find their distinctive eggs—individually laid on a minuscule silken stalk—on plants in my garden. It's not unusual to find adult lacewings at night near a porch light, to which they are attracted.
Their larvae look like little alligators, with ferocious sickle-shaped mandibles that are used to capture prey. What my husband and I didn't know was that the larvae also use debris, including the corpses of their victims, to camouflage themselves from both predators and prey. Amazingly, that behavior dates back to the early-to-mid Cretaceous period, about 130 million years ago.
Green lacewing larva eating whitefly nymphs. Photo by: Jack Dykinga, courtesy of U.S. Department of Agriculture
Earlier this year, an international team of researchers published a study in which they examined 35 insects, including lacewing relatives, preserved in amber from Myanmar, Lebanon, and France. The researchers were astonished to find the broad range of camouflage already used by insects in the Cretaceous.
"It is very surprising how early in evolution such complex insect behavior developed: The larvae had to search actively for suitable 'camouflage material,' pick it up, and cloak themselves with it," said Dr. Bo Wang, who led the research team, in the study's press release. Dr. Jes Rust, a paleobiologist at the University of Bonn, which participated in the study, explained that camouflage, with its distinct advantages, was 'invented' multiple times in different insect species during evolution.
My husband gently captured the wondrous little ball of lint and took it outside, where we hope it will continue its valued work in our garden.
June 13, 2017
April 19, 2017
October 18, 2016
What comes to mind when you imagine the call of P-22, L.A.'s famous urban mountain lion (Puma concolor)? Do you imagine a roar or violent hiss? If so, you are not alone because that is what people most often see and hear in the movies.
Photo by Miguel Ordeñana
However, a recent video of P-22 vocalizing (first ever!) paints a different picture. The video supports recent cutting edge research suggesting that puma communication is more complex than we once thought. As we prepare to celebrate our beloved Griffith Park denizen on P-22 Day, the rare footage reminds us how much we still have to learn about mountain lions, including L.A.’s most famous mountain lion.
First and only footage of P-22 making a vocalization. (Turn your volume up or else you'll miss it!)
Whenever a mountain lion is featured in a movie, the special effects crew usually use the roar of a big cat (animals in the Panthera genus--i.e. lions, tigers, jaguars, and panthers) or they use the call of an agitated mountain lion, which isn’t surprising, because its main objective is to entertain rather than accurately portray puma behavior. Using the roar of a big cat is inaccurate because only big cats, with their specialized larynx and flexible hyoid bone, can roar but can’t purr. [Exception: Snow leopards (Panthera uncia) are big cats that can’t roar but can purr]. All other cats, including mountain lions, purr but can’t roar. The larynx of a small cat is ossified (hardened) and has special folds that allow it to produce the purring sound when it is inhaling and exhaling. Although mountain lions can make agitated calls, they more frequently use other methods of communication. In fact, the most common mountain lion communications don’t involve sound at all!
**Fun fact: Cheetahs and mountain lions belong to the puma lineage and are not closely related to other large cats but instead are considered oversized small cats. **
Mountain lions, like many other cats rely on stealth for survival. Remaining out of sight and out of mind is important not only to hide from potential threats like competitors, but also because mountain lions--- like most cats, including your pampered pet cat---are ambush predators. Instead of chasing down prey from long distances, ambush predators are expert stalkers and conserve their energy and minimize injury risk by waiting for the victim to get close enough to improve the probability of a successful kill. Mountain lions are equipped with night vision as well as retractable claws that are concealed in padded paws. Additionally they are instructed by their experienced mothers on how to sneak up on prey and roam around unnoticed in the cover of darkness, while remaining still during the day.
Mountain lions are generally difficult to study because they are not only nocturnal but also occur at low densities due to their being solitary and territorial. Mountain lions are especially territorial in the fragmented landscape of Los Angeles because there is very little suitable habitat to go around, so direct communication can be very risky. Indirect communications between pumas come in the form of olfactory and visual cues such as urine or fecal deposits, scratch marks on trees, or a combination (Allen et al. 2015). Adult males, especially dominant males usually delineate territory boundaries, display dominance, or express sexual status using scrapes. Scrapes are produced primarily by males when the puma digs into the ground with its back feet (only), just like P-22 in the video below.
This is the only footage of P-22 digging a scrape to mark his territory.
Prior to the invention of camera traps, scientists were only able to study puma communication based on indirect cues, knowing that they regularly miss a totally different form of communication, vocalization. Even expert trackers almost never observe the cats vocalizations, limiting puma vocal communication research to captive pumas.
Fortunately, relatively recent advancements in camera trap technology such as high definition (HD) camera trap video has allowed biologists to study mountain lion communication in the wild, including vocal communication. Max Allen and UC Santa Cruz researchers executed a new study (Allen et al., In Press) using camera trap video technology to record the different types and functions of mountain lion vocalization. Allen and his colleagues identified five calls that fell under two categories: “attention attracting” and “contact and alarm calls.” “Attention attracting” calls are primarily used by females to let to males know they are ready to mate or by kittens calling to receive food from their mothers.
Kittens nursing and calling to receive more food in Northern California. Video Credit: Max Allen
“Contact and alarm calls,” are typically used to communicate with nearby mountain lions. Similar to male-dominated scrapes, males and females differentiate in the vocalizations they primarily use. For instance females predominantly caterwaul, which alert males in the area that they are available to mate.
Female caterwauling to attract a male in Northern California. Video Credit: Max Allen
But if vocalizations are motivated by territoriality and mating, why would P-22, an isolated mountain lion occupying the smallest and most urban territory ever recorded for a mountain lion, make a vocalization?
The first clue to the mystery is his long track record of exhibiting natural behavior identical to that of his more rural counterparts. He has actively avoided people and pets and seems to shy away from heavily trafficked areas. He also has been documented exhibiting territorial behavior such as boundary patrol of his territory and scent marking. The type of call he has been recorded using mostly resembles a chirp/whistle, which is a short, high-pitched call that is categorized as a contact call. The high pitch allows the sound to travel well through woodland habitat. Any interpretation of his behavior is, however, somewhat subjective. Allen and his colleagues feel they are only scratching the surface of puma communication research and that there are many more than five vocalizations that they have identified.
P-22’s regular territorial and natural behavior suggests that he hasn’t given up hope that a female will someday enter his territory and/or he hasn’t put his guard down in case another male encroaches on his turf. What it tells me is that his retention of natural puma behavior such as patience as an ambush predator, territoriality, and lack of habituation to humans may be keys for survival in an isolated and urban environment. The fact that P-22 hasn’t given up on encountering another puma someday means he hasn’t given up on connectivity. Perhaps Angelenos and conservationists can use this as motivation to tackle the formidable barriers to improving habitat connectivity, thus ensuring a future for L.A. area mountain lions.
Allen, M., Y. Wang, and C. Wilmers. In Press. Exploring the adaptive significance of five types of puma (Puma concolor) vocalizations. Canadian Field-Naturalist.
Allen, M.L., H.U. Wittmer, P. Houghtaling, J. Smith, L.M. Elbroch, and C.C. Wilmers. 2015. The role of scent marking in mate selection by female pumas (Puma concolor). PLoS One 10: e0139087.
Elbroch, M. and Rinehart, K. 2011. Peterson Reference Guides to Behavior of North American Mammals. Houghton Mifflin Harcourt Publishing Company, New York, New York. pp. 72.
Hunter, L., and Barrett, P. 2015. Wild cats of the world. Bloomsbury Natural History, an imprint of Bloomsbury Publishing Plc. London; New York. pp. 9.