L.A.’s Friendly Neighborhood Spider Woman (and the Spiders from Mars?)

January 26, 2016

I have an incurable case of arachnophilia. Ever since early childhood, even before reading “Charlotte’s Web,” my mother constantly scolded me to stop picking up spiders (good advice if you don’t know what kind it is) and to just observe them instead. Where others scream, “Kill it with fire!” I said, “Let’s feed her crickets.” To me they are delicate long-legged ballerinas, caring mothers, industrious homebuilders, and astonishingly clever predators.  Alas, arachnophilia is very rare. Fear of spiders, on the other hand, is so prevalent, it made every “top ten” list of phobias I could find, and one study showed that arachnophobia even affects many entomologists (6 legs good, 8 legs bad?)!

 

 

The author unabashedly, unapologetically in love with an orb-weaving spider from the Natural History Museum’s Spider Pavilion.  Photo credit: Cat Urban.

 

So, as you can imagine, us spider-admirers have a huge challenge. To begin to change the conversation away from, “every spider is evil and deadly” (FALSE) to, “the vast majority are harmless, beneficial predators" (TRUE), we must first provide lots of evidence, and that is exactly what Jan Kempf, the NHMLA Entomology Department’s own Incredible Spider Woman, has been doing for the past 15 years. Along with the help of Citizen Scientists who have turned in spiders from their yards, gardens and parks as part of the Los Angeles Spider Survey, Jan has single handedly looked at over 5, 500 spider specimens from L.A. and surrounding counties so far.  In Los Angeles alone, 232 species of spiders have been identified from this survey, showing that even in a highly developed urban environment, spiders are highly adaptable creatures.  I recently had the great pleasure of joining Jan on a spider hunt in the backyards of our BioSCAN Super Citizen Scientists. In a matter of minutes, Jan’s expert eye could find around a dozen spiders hiding under rocks, hanging out in bushes, and living in nooks and crannies of patio furniture, just waiting for a tasty insect treat to wander by for lunch. Spiders are all around us!

 

 

Jan Kempf, spider collector extraordinaire. Photo credit: Lisa Gonzalez. 

A dish full of spiders collected from one of our BioSCAN sites. Photo credit: Kelsey Bailey.

 

Think about that for a moment: If spiders are ubiquitous in our yards, patios, and parks, then how do we survive each day surrounded by these “deadly” beasties? Humans do just fine because the vast majority of spiders are harmless. Out of the 232 species Jan has identified from the survey, only two that live in the city, the black widow and brown widow, can potentially cause medical harm to humans in the rare cases that bites actually occur.  There have only been two confirmed cases in Southern California of a bite from a brown widow and in both cases the reaction was fairly mild. Both species of widow spiders are very nonaggressive and typically drop to the ground, curl up, and play dead when threatened. The black widow spider has been increasingly hard to find in urban environments in the past few years (if you see one, please let us know!) since the discovery of the brown widow in L.A. ten years ago. In fact, the first record of a brown widow specimen was turned in by grade school students as part of the L.A. Spider Survey!

Black widows have a red hourglass shape and a smooth egg case. Photo credit: Steve Ryan.

 

Brown widows are displacing the once common black widow. They have an orange hourglass shape, banded legs, and a spiky egg case. Photo credit: James Hogue.

 

Both brown and black widows are very easy to recognize by the presence of the hourglass shape on the bottom of their abdomens. As mentioned earlier, they are shy creatures that usually “play dead” when threatened, but it is still important to be careful around them, especially when placing your hands or feet in small crevices or shoes left outside. The very few confirmed bites that have occurred are usually when the spider has been cornered in a tight spot. Once you recognize these two iconic spiders, you can rest easy with the knowledge that all of the other spiders in L.A. you see have venom that is only capable of hurting a wee little cricket or fly, not a human.  I hope that helps those with arachnophobia to feel empowered, and maybe even helps you to stop and appreciate the struggle of the spider, just trying to survive in the big, bustling city.

 

I would be remiss in discussing spiders in L.A. without mentioning one of the most feared of them all: the brown recluse (Loxosceles reclusa). Due to an unfortunate misperception perpetuated by the media over a decade ago, many people are under the false impression that the brown recluse lives in California. Despite the evidence that is provided by spider surveys and many other scientific studies (see links below), people still hold tight to the misconceptions of brown recluses living in L.A. and spider bites being very common. As I mentioned before, Jan has looked at over 5,500 specimens from the L.A. Spider Survey, and not one was a brown recluse. Additionally, the University of CA at Riverside conducted a similar survey that supports the conclusion that there are no established populations of brown recluses in California.

 

A final note in honor of David Bowie

 

Bowie Altar. Photo Credit: Ray Duran

Just as there are no brown recluses in California, NASA has yet to find spiders on Mars, but that did not stop arachnologists from honoring David Bowie by naming a spider species, Heteropoda davidbowie, in 2009.  At a recent tribute I attended the weekend after his death, a beautiful altar was created by the participants, complete with a jar of preserved spiders doused in glittery stardust. Is it possible that Bowie was evoking a visual comparison between a spider skillfully plucking at her web, and Ziggy’s long skinny fingers playing his guitar? I adore his use of spiders as a glamorous visual metaphor, rather than harbingers of doom. Thank you for that image, and for everything, David Bowie.

 

 

References

 

UCR Spider Research Site

http://spiders.ucr.edu/

 

““Spider Bite” Lesions Are Usually Diagnosed As Skin And Soft-Tissue Infections.” Dr. Jeffrey Ross Suchard, MD

http://entomologytoday.org/2013/09/15/arachnophobic-entomologists-when-two-more-legs-make-a-big-difference/

 


(Posted by: Lisa Gonzalez)

2 Comments


Related

Second Ant-decapitating Fly Found in Glendale

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.


(Posted by: Lisa Gonzalez)


Related

Bee Sex in the Nature Gardens

June 19, 2013

In July 2011, our Curator of Entomology, Dr. Brian Brown, brought in some old redwood he had lying around his yard. He wasn't just trying to pawn off some lumber he didn't need anymore, we wanted it to make some bee hotels.  Jerome Brown, one of our amazing exhibit technicians, fabricated two hotels and Phil Bouchard personally drilled the over 200 quarter inch holes (about an inch deep). Thanks guys!

Bee hotel in its new home by our hummingbird feeders.

This spring we finally saw the first bees using the hotels! I was so excited, I jumped up and down, Brian did not, he just smiled. We watched as bees checked out the little holes and then I saw two fall to the ground. "Oh look they're fighting," I exclaimed. "No," Brian responded, "they're using the hotel like they should be. They're having sex!"

Well, it's all about the birds and the bees after all.

Here’s a photo Brian took of a bee using the hotel:

But why go to all the bother? The short answer is to provide a place for solitary bees to make their nests. The female bee Brian photographed is in the genus Megachile (pronounced mega-ki-lee), and she is about to start constructing a nest for her egg to develop in. Before any egg laying can happen she’ll excavate the nest and line it with chewed up leaves or plant resin (hence the name which is Greek for mega-big, cheil-lip, as in big powerful mouthparts for chewing up leaves and such). She’ll then lay an egg, or maybe a few, in individual chambers and supply them with a ball of pollen mixed with nectar to chow down on after they hatch. After eating all the pollen, they’ll go through a brief pupal stage and then chew their way out of the nest as an adult.

If you are reading this and thinking, why on Earth would I want to attract bees to my yard, here’s some food for thought. First off, don’t worry these bees are not aggressive stingers. Since they are solitary and don’t hang out in big colonies like honey bees, they don’t have the same urge to sting and protect their sisters back in the hive. Also, their venom is very mild. I mean you really have to work to get stung by one of these bees, like taking one and squishing it in your hand—and who would be dumb enough to do that? The sting pain index guy, Justin Schmidt, that’s who! *Nerdy entomological sigh*. He describes the sting of these bees as “lightly brushing a thorn,” and rated the sting as a zero, compare that to the two rating of the European honey bee! Other reasons to break out the drill and start constructing your own bee hotel: You’ll be able to boast about how you are increasing biodiversity in Los Angeles. You’ll have more native pollinators in your yard, and your neighbors' yards too, aren’t you a good person? Oh yeah, and it is super fun to lay bets on which hotel room is going to get used next! Of course you don’t have to lay down money, you wouldn’t necessarily want to teach your kids how to gamble, not till they’re 21 at least.

Now go out and build a bee hotel, then post a picture to NHMLA’s FaceBook, Instagram, or Twitter feed!


(Posted by: Lila Higgins)

1 Comment


Related