Hey People We've Got Baby Opossums

Remember back in December, when I said I'd let you all know if we had baby Virginia opossums, Didelphis virginiana? Well it's spring, and right on cue they're here! Sam Easterson's camera traps have caught the babies (we think there are three) on video over the last week, and although many people don't find opossum babies cute, there are a few of us here at the Museum that do. Check them out and make your own assessment.

Out for ride on Mom's back!

Here are some interesting facts about opossum babies.

• The opossum gestation period is only 11-13 days.
• When they are born, the babies are the size of a lima bean!
• Female opossums can give birth to more than 20 babies in one litter.
• After they are born the babies crawl up into the mother's marsupium (aka pouch—remember opossums are the only North American marsupials) and attach to one of her teats.
• There are only 13 teats in the marsupium, and its first come first serve. 
• Babies are carried in the marsupium for between two and three months
• When they are large enough, the babies venture out of the marsupium and are carried around on the mother's back when they are out of the den.
• The average lifespan for an opossum is only two to three years!

Check out this video Sam's camera trap caught. It puts me in mind of all those fight scenes I've seen where outlaws are fighting on top of moving train that is about to go into a tunnel. Admittedly the mother opossum moves quite a bit slower than a train and the baby is not as nimble as a knife-throwing outlaw, but hey, you get the picture!

Carting all those babies around must be pretty tiring!

Rotting Fruit and Puddle Parties: Check out the Butterfly Pavilion!

It is that time of year again! Sunday is the opening of our Butterfly Pavilion, and although we still have hundreds of free-flying butterflies there's a lot that has changed out there. We have replanted the entire space, adding many more nectar and host plants for adults and caterpillars. We have also added new food sources for some of the adult butterflies that aren't quite so partial to sipping nectar!

The Mourning Cloak butterfly, Nymphalis antiopa, is one of the California native butterflies we put in our pavilion. Although these butterflies are not common to our area, they can be found in areas where their host plants thrive. Caterpillars of this species feed on various willow (Salix species), cottonwood (Populus species), and ornamental elms (Ulnus species). Unlike many of the other species of butterflies in our pavilion, the Mourning Cloak butterfly prefers to feed on rotting fruit  rather than plant nectar. In an effort to appeal to the tastes of this epicurean butterfly, we've put out platters of rotting banana, mango, and plum.

Mourning Cloak butterfly sucking up

liquefied rotten fruit—tasty!

Shawna Joplin and Lydia Gotcher working

in the Butterfly Pavilion

We've also installed two mud puddles in the pavilion. These puddles will hopefully be places for butterflies to get the other nutrients they need beside sugar—nutrients like salt, amino acids, and nitrogen. In nature, male butterflies are often seen gathering on the edges of puddles. Sometimes large numbers of males gather at the same puddle, which entomologists have termed, puddle parties! Males more often exhibit this behavior because they need salts and other nutrients for their spermatophores. Spermatophores are small capsules containing sperm and nutrients that are passed from the male to the female during mating.

Puddle party pads! Look very closely in the yellow circle

and you can see a Buckeye, Junonia coenia, feeding.

One of the questions I get asked most frequently is how we get all the butterflies for our pavilion. The short answer is, we buy 'em. This makes the process sound easy and non-time consuming, it is anything but! Months ago, Shawna Joplin, the Museum's Coordinator of Animal Care and Education, started placing orders for butterfly pupae. She works with vendors all over the United States, to ensure that we will have the numbers and diversity we need to achieve a magical butterfly experience.

Last week we received our first pupae shipment. Each vendor sends us about one shipment a week, and each shipment can contain anywhere from 25 to 250 pupae! Every time we get a shipment, the Live Animal Program staff have to inspect each individual pupa and then prepare it for emergence. Some pupae get pinned and hung in our emergence case, whereas others can rest on the bottom of case. Twice a day this case is inspected and all healthy adult butterflies are removed and then released in the pavilion.

Emergence case with emerging sulphurs and monarchs

Pipevine Swallowtail, Battus philenor, pupa.

Look at those colors!

Come by and check out the Butterfly Pavilion! For ticketing information visit our website.

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?

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.

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!

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 insects—just 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



Killer Legs: Crab Spider Wins Prize with Eight!

On Sunday, February 26, Museum Educator Anna Holden, and myself took some families out to the North Campus to collect spiders! The spiders were collected so they can be identified and preserved as part of our ongoing L.A. Spider Survey. They will also be added to our ever-growing North Campus species list.

Briana Burrows and Anna Holden

(looks like they really like collecting spiders too)

All told, we collected 17 spiders (not bad for a newly planted habitat) many of which were very small and non-descript – think tiny brown specks almost indistinguishable from a piece of dirt (did I mention these children have amazing eyesight?). However, there was one spider that stood out from the crowd. She was large, and yellow, and had oh such lovely legs! Let me introduce you to the Whitebanded Crab Spider, Misumenoides formosipes (her species name is derived from the Latin formosus = beautiful and pes = foot or leg).

Female Whitebanded Crab Spider

This group of spiders is so named for their crab-like appearance and movement. They are adept at quickly moving sideways, backwards, and forwards. This quick movement is only infrequently observed by us humans, as they are "sit and wait" predators. This means they sit very still on a flower and wait for pollinators to visit, and then, quick as a flash, they'll attack and subdue their prey. Also of note, they can change color! Watch out chameleons, these eight-legged lovelies also have the ability to better blend in with their surroundings. Although it has to be said that they can't deviate greatly from their original color and the process takes a few days to complete.

The beautiful specimen we found on Sunday was a female. The sexes are very easy to distinguish as the males are a lot smaller and much less rotund. She was collected on the bright yellow, sunflower-like flowers of Encelia californica, commonly known as bush sunflower. Next time you are in the North Campus, check out the bush sunflowers planted atop the living wall. Who knew so much drama could be unfolding on each and every flower?

Crab spider versus European Honey Bee

(It was a tie, the honey bee flew away)

Thanks to Karen Ewald for taking the spider collecting picture.