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Monday, October 31, 2011

Happy Halloween: Bats!

To help celebrate Halloween here are some bats!

The Big Brown Bat, Eptesicus fuscus, is the most common bat in our area. They are easily seen at dusk flying around parks and water sources as they search for their insect food. We're putting up a  bat box in the North Campus in hopes that some of these bats will move in.

The Hoary Bat, Lasiurus cinereus, is another species often found in L.A. This specimen was collected at the Museum on the cafe patio a few years ago.

Last but not least here's the ghost-like Pallid Bat, Antrozous pallidus. Even though this species of bat is rarely found in the urban core, it is found in the desert regions surrounding Los Angeles. Unlike the Big Brown Bats these bats capture their food on the ground! They locate their prey by finding a perch and listening for insect footsteps (note the massive ears). When the right vibrations are heard they swoop down catch the unsuspecting insect and return to the perch to devour it!

Thanks to Jim Dines, the Museum's Mammology Collections Manager, for allowing me to photograph these awesome creatures!

Thursday, October 27, 2011

Dirty Work: Dead Birds, Skulls, and Macerating Flesh

Today a small group of volunteers showed up at the Museum to gut, skin, flense, and macerate birds (flensing is the process of stripping an animal of its skin).  It isn't because Halloween is next Monday; they actually do this every week.

Kimball Garrett, Ornithology Collections Manager, runs this unique volunteer program and supervises all gutting, skinning, and skeletonizing. Dead birds are acquired by the Museum through salvage on a regular basis and this group does the very dirty work of  turning the limp lifeless carcasses into scientifically useful specimens that will live in the Museum's collection.

This Loggerhead Shrike, Lanius ludovicianus, has just been gutted and had the carcass removed. Next it will be stuffed with cotton, mounted on a small wooden dowel, and labeled.  

These are leftover bits and pieces from the Loggerhead Shrike. Kimball and the volunteers call this snarge. The lab's centerpiece is the snarge bucket with the bits and pieces of the various birds prepared that day.  

Bacterial maceration jars!

Not all birds that come into the lab are made into study skins; some are kept for their skeletons. After the majority of the flesh has been removed by the volunteers, the remaining carcass is placed in a jar of water. Naturally occurring bacteria remove the leftover flesh and leave clean bones behind. This process takes a few weeks to a few months and gives the lab a very distinct aroma!

Harpy Eagle skull after bacterial maceration

Thanks to Kimball and his volunteers for letting me take pictures in the lab!

Monday, October 24, 2011

Today on the North Campus

I went out for a walk around the North Campus today and this is what I saw:

They are filling the pond to make sure there aren't any leaks and that the waterfall cascade is level.

Underneath the pedestrian footbridge is the best spot for mushrooms. I think this is a morel, Morchella esculenta. I am consulting with some mushroom experts to see if they can make a positive identification.

Apparently the Monarch caterpillar I found two weeks ago made its pupal case on a wall. I just love how green they are!

Thursday, October 20, 2011

Flesh Flies and CSI!

Since it's October I decided to focus the rest of this month's posts on Halloween inspired themes. Wracking my brains for topics, I realized something I saw last week in the basement would fit the bill nicely. Flesh flies!

Generally the Live Animal Program doesn't keep flesh flies but Shawna Joplin, Coordinator of Animal Care and Education, brought them in as a new food source for our spiders in the Spider Pavilion (open through November 6). The species we are keeping are grey flesh flies, Sarcaphaga bullata, which get shipped to us a pupa. After about a week and a half the adult flies emerge from the puparium and are ready for us to release into the pavilion.

Grey flesh fly pupae

Our adult flesh flies feeding on banana

Flesh fly emerging from its puparium

Contrary to their common name, adult flesh flies don't feed solely on flesh. In fact they just as often eat nectar and other sugary items such as rotting fruit. All flesh flies in the family Sarcophagidae are larviparous, which means they incubate eggs internally and then seemingly give birth to live young, or maggots. It is the place of "birth" that gives these flies their common namethey are deposited on any available dead flesh! In fact these flies are some of the first visitors to roadkill, discarded innards, and even murder victims. Putting these flies to work, forensic entomologists have painstakingly studied their lifecycle, so they can assist Crime Scene Investigators in determining time of death. Because they rapidly discover a body and their development times are predictable under particular environmental conditions, the time of death can be calculated by counting back the days from the life stage of the flies found living on the body.

Next time you feel like seeing these maggots in person, just do what some of our Adventures in Nature campers have doneput out a piece of store-bought liver and wait for the maggots to show up! WARNING: This is smelly, messy work! Lots of other species of flies, beetles, and other creatures are likely to show up too. Are you prepared?

Happy Early Halloween!

Thursday, October 13, 2011

North Campus Monarchs

Yesterday afternoon myself and number of other staff members braved the heat to continue our survey of North Campus insects. On the heels of last week's Gulf Fritillary discovery, I found the site's first Monarch butterfly caterpillar, Danaus plexippus!

Monarch butterfly caterpillar

As soon as I saw the caterpillar I knew it was a Monarch: There isn't another caterpillar in our area with such yellow, black, and white banding. Also, the caterpillar was found on a narrow-leaved milkweed plant, Asclepias fascicularis, which is one of the food plants of this well-known species.

Based on its size, this caterpillar is in the second to last caterpillar stage (4th instar). Over the coming weeks it will molt to the last and final stage (5th instar), and then turn into a chrysalis.  In time for its fall migration, the adult Monarch will emerge and make its way to an overwintering site somewhere along the coast.

In the coming years I hope to tag and track the adult Monarchs that emerge in the North Campus, so we can determine the exact location(s) of our Monarchs' overwintering site(s). Tagging Monarchs is an easy process that in no way hurts the butterflies. The adults are collected with a net and then carefully held while a small sticker (approximately 2% of the butterflies weight) is attached to the hind wing of the butterfly. The butterfly is then released and flies onto its overwintering site. When the Monarchs dies the following spring (after mating) the tags are hopefully retrieved and we can answer the question, where do our North Campus Monarchs overwinter?

Demonstrating how to handle a Monarch for tagging

Wednesday, October 5, 2011

First Caterpillar Record for North Campus!

The last few weeks I have been spoiled with bloggable stories, but this week I needed inspiration. I took a stroll out to the North Campus to see what I could find, and was excited to happen upon the first North Campus caterpillar.

The caterpillar I found was in the last and final "J stage" of its larval lifecycle, just about to pupate. 

Easily recognizable, Gulf Fritillary caterpillars are striped and spiny.

24 hours later the caterpillar had metamorphosed into the pupal stage, aka chrysalis.

If you look close, you can see the developing wings.

This pupa is a Gulf Fritillary butterfly, Agraulis vanillae, native to Mexico and the southeastern United States where its passion vine food plants are also native. However, this species is now very common to our region because of all the passion vines that have been planted in yards, parks, and also in the North Campus! The species of passion vine I found the caterpillar on was Passiflora 'Lavendar Lady' cultivar, which is a cross between P. amethystina and P. caerula.

Typical alien-looking flower of passion vine, 'Lavender Lady' cultivar.

If you want to encourage these butterflies in your own yard, try planting a few passion vines of your own. Here is a list of the other passion vines we plan on planting in the North Campus:

Passiflora edulis
Passiflora caerulea
Passiflora alatocaerulas