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Thursday, March 29, 2012

North Campus DIY

This week I've been working with Jared Nielsen, one of the Museum's Exhibit Technicians, who also happens to be a DIY (Do it Yourself) enthusiast. With his help we've managed to build and install two nest boxes and launch our first garden surveillance balloon!

Jared installing a nest box in the Shadow Garden

The other nest box in the Home Garden

The nest boxes we chose are made of PVC and designed to be particularly appealing to certain cavity nesting birds such as Western Bluebirds, Sialia mexicana.  These birds have been spotted in Exposition Park by Kimball Garrett, the Museum's resident ornithologist, and we hope they'll stick around to use our new nesting sites. The boxes are also designed to be minimally appealing to other species of birds that we don't wish to encourage, such as introduced European Starlings, Sturnus vulgaris, and House Sparrows, Passer domesticus.

We ordered the boxes from the Gilbertson Nestbox Company and Jared brought all the materials necessary to assemble and install them in the North Campus. The cost for all materials including the nest box is approximately $30 each. Instructions for installation and how to properly monitor birds that move in are available on the Gilbertson website.

I'll keep you posted, and let you know as soon as any birds move in. Of course Sam Easterson, our resident video naturalist is also waiting in the wings. As soon as a nest is built, he will install a video camera and we'll hopefully be able to capture images of eggs being laid and nestlings hatching!

As if that wasn't exciting enough, today we launched our first garden surveillance balloon.

Affixing the surveillance camera to the balloon

Our garden surveillance balloon is a project Jared discovered through the Public Laboratory for Open Technology and Science. Their Grassroots Mapping project provides instructions on how to build your own balloon mapping kit, or you can purchase a kit for $85 from their website!

Jared opted for the DIY approach and sourced all of his own materials, including the 2 meter wide weather balloon and a rental helium tank! Following the Grassroots Mapping instructions, Jared rigged the balloon to carry a camera and tethered it to a 1000 foot long string which he held onto as we walked it around the site. The camera was also adapted to continually take pictures every second until our 16 megabyte memory card was full (about 2 hours). Over the next few days Jared will take all the images and stich them together using a free online software that will create an aerial map of the North Campus gardens. Not only will this map look really cool, it will also help us to keep track of all of the plants in the gardens and see how it changes over time. Yes, we are going to do this again, maybe even every few months!

We needed a lot of help from staff to make sure the balloon
didn't float away as we were filling it with helium!
(Jesse Daniel, Jared, Briana Burrows, and Karen Ewald)

Karen celebrates a successful launch

Our first aerial view of the North Campus.
Can you spot us in the bottom right corner?

Friday, March 23, 2012

New Snail Record for North Campus and Los Angeles County

We've discovered a snail never before found in L.A.! A few weeks ago, I was wandering through the North Campus and  happened upon a tiny gastropod snailing along the Living Wall! Most snails don't catch my attention as they are usually of the common garden variety, aka Brown Garden snails, Helix aspersa. This particular specimen caught my eye, because unlike the Brown Garden snail, this snail was much smaller and flatter (the shell is only 6.9 mm wide). I grabbed the snail, placed it in a vial and took it to our snail expert, Lindsey Groves.

Brown Garden snail, Helix aspersa

Southern Flatcoil snails photographed in Cathedral City
(Image courtesy of Patrick LaFollette, Museum Research Associate) 

Lindsey is the Museum's Malacology Collections Manager and when I showed him the snail, he got pretty excited. Although some people may find this strange, I did not. In fact, I was excited too. What I did find strange was that Lindsey already had another specimen of the exact same species sitting under his microscope at that very moment!

Malacology Collections Manager, Lindsey Groves

It turns out that the snail I found is a Southern Flatcoil snail, Polygyra cereolus. According to Lindsey, this species of snail ranges from southern Florida to South Carolina and across much of the Gulf coastal states to Texas, as well as several areas of northeast Mexico. Over the past few of decades, it has become common in other locations such as Wisconsin, Hawaii, and even a number of countries in the Middle East including Qatar, Saudi Arabia, and the United Arab Emirates! These range extensions are attributable to accidental introductions through importation of sod and/or ornamental landscape plants.

The specimen that Lindsey was examining under his microscope was recently collected in the Laguna Hills area of Orange County. He is currently working on documentation of this new county record and will also document the snail found on the North Campus, which is now preserved in the Museum's Malacology collection. The snail has also been discovered a bit further afield in Cathedral City, Riverside County.

Top view of Southern Flatcoil snail.

Another in a long list of introduced terrestrial mollusc species in our area, 20 to be exact, it is reported that the Southern Flatcoil snail feeds on clover and alfalfa. As such, they have in some instances been reported as agricultural pests, but will likely feed on many other types of vegetation found in parks and gardens. In Florida, they have been observed assembling in large numbers on sides of buildings and walls without apparent regard to sun exposure, which is very unlike many snails. In one building at the University of North Florida, an aggregation of thousands of individuals were found coating the building surface! According to one of Lindsey's colleagues in Florida, "they are like a weed."

Side view of snail. Apparently the characteristic apertural 'tooth'
for this genus must have broken off when it was collected.

Friday, March 16, 2012

Breaking and Entering: Squirrel Moves into Opossum Den

We have another new sighting for the North Campus. A California ground squirrel has been spotted using the opossum den located underneath one of our Museum sheds. So far it seems that both the opossums and the squirrels are sharing the space!

Sam Easterson's camera trap captures the first image!

This is what Jim Dines, our Mammalogy Collections Manager, has to say about them:

The California ground squirrel, as its name suggests, is common throughout California as well as the rest of the western U.S. Scientists know this rodent as Otospermophilus beecheyi (formerly known as Spermophilus beecheyi). They are diurnal (active during the daylight) and, like other ground squirrels, live in burrows that they excavate or take over from other animals. Our ground squirrel has apparently moved into a den built by an opossum.

Ground squirrels eat seeds, nuts, and a variety of other plant material, as well as insects and handouts left by humans. Since they also invade gardens and cultivated areas, California ground squirrels are commonly regarded as pests. Their extensive burrow systems can be very destructive. They are also a host to fleas that can carry plague, so pose a health risk to humans and their pets. Rattlesnakes are one of the main natural predators of California ground squirrels and the squirrels have developed an interesting defense mechanism: the ground squirrels will eat the shed skins of rattlesnakes and then lick themselves and their young, thus covering themselves with rattlesnake scent and confusing a potential rattlesnake predator into thinking it is merely smelling another rattlesnake. Pretty sneaky, eh?
The California ground squirrel has a fairly bushy tail so is sometimes mistaken for the Eastern fox squirrel (a tree squirrel), but has different colored fur and retreats underground instead of up into a tree.

Watch Sam accidentally startle the squirrel into the den!

Friday, March 9, 2012

Thorny Devils in the Garden

I was recently out and about in the garden and found some fascinating insects, Keelbacked Treehoppers, Antianthe expansa. They were on some of our celery plants and are, according to Vanessa Vobis Master Gardener and Museum Gallery Interpreter, "a very annoying pest on our tomatoes."

Adult Keelbacked Treehopper on celery
(Approximately ¼ inch or 7 mm long)

When I found the Keelbacked Treehoppers, all but one were in the nymphal (immature) stage. As nymphs, these insects do not have wings (this is true for all insectsjust look at caterpillars, grubs, and maggots), and are bound to the area in which they were deposited as eggs by their mother. The nymphs are often attended by ants, which feed on their sugary excreta and provide a level of defense against the treehopper's predators. Though it should be noted that this is not always the case, there were no ants in attendance around the treehoppers I found, so this isn't a reliable mode of identification.   

When I found the treehoppers in our Edible Garden, they were feeding on one of the celery plants. They feed on the juices (phloem sap to be exact) inside the plant by inserting their tiny straw-like mouthparts and sucking up the liquid. Although many sources say that these insects cause little, if any, damage to the plants they are on, this is not always the case! When populations of these insects are high enough they can cause serious stunting and sometimes lead to the loss of plants. Many gardeners in our area complain of these pests on their tomatoes. It is not clear if the decline in plant health is due to excessive feeding by these insects or by secondary infections spread to the plant during feeding. 

Immature Keelbacked Treehopper
photo courtesy of Vanessa Vobis

From a naturalist's perspective these insects are some of the more weird and wonderful. Adult treehoppers (family Membracidae) can be recognized by the prominent enlargement of the pronotum (segment directly behind the head). This enlargement gives many treehoppers a humpbacked or thorny look, hence the other common name for these insects: thorn bugs. However, some tropical species go beyond the thorny devil look and opt instead for something a bit more insectuous! Case in point, the Cyphonia treehopper has a pronotum that mimics an aggressive ant species, which not only looks awesome, but is a great defensive mechanism against predators.      

Cyphonia treehopper with ant-like pronotum
image from Nicolas Gompel/Nature