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Coloration in collared lizards

Friday, July 16th, 2010

Last week, I blogged about the huge variety of wildlife present in Joshua Tree National Park during the hot summer months.  Among my favorite animals in the park are the collared lizards, Crotaphytus bicinctores.  Collareds are aggressive, carnivorous lizards and are extremely flashy this time of of year.  They mate in late May-early July, and because of that, they have some fantastic colors.

male great basin collared lizard, joshua tree national Park california

Male Great Basin Collared Lizard, July 2010

The rich yellows and oranges on the legs, blue under the neck and black in the pelvic and pectoral areas are all characteristic of this species, and in my opinion, what makes it so beautiful.  The lizard above is a very accommodating male we found on the 49 Palms Oasis trail.  The females, however, are much less vibrant.

female great basin collared lizard, joshua tree national park california

Female Great Basin Collared Lizard, July 2010

Despite her more drab appearance, I still like the subtle hues present, especially the orange markings on the lateral sides of her body.  After the breeding season, these orange markings will fade, leaving the females a brownish color.  What do they mean?  While its long been known that animals change color, plumage, etc during their breeding season, a 2004 study published in the journal Herpetologica suggests that in female collared lizards, the orange markings signal to males that she is sexually receptive.  On average, orange female collared lizards were courted 5 times more frequently by males than non-orange females.

Its always important to remember that things that may just appear pretty (or sometimes, even ugly) to us very often have a function in nature.

Mothra!

Monday, October 19th, 2009

Despite my childhood fears, I’m confident that Mothra will never try to take over the world.  Mothra first appeared in the novel The Luminous Fairies and Mothra (Takehiko Fukunaga), but she has since appeared in several films.  A fictional Lepidopteran, Mothra has characteristics of both moths and butterflies, and while I cannot find any references as to how large she would have been, you can see her next to Godzilla at the right, suggesting she was quite large.

So, how can I be confident a moth this large could really never occur?  Moths and butterflies are arthropods and arthropods have a unique method of growth.  Because they have a rigid exoskeleton, they essentially are wearing a suit of armor that will not grow with them.  You and I have an endoskeleton that grows with us.  For arthropods, growth occurs in several steps:

  1. First the existing exoskeleton is shed, or molted
  2. The animal plumps itself up with water, causing it to swell
  3. A new exoskeleton is secreted around the swollen animal; within a few hours (or days) this new skeleton will harden
  4. The swelling goes down, and the animal now has an exoskeleton it can grow into.

During the period between steps 2 and 3 above, the animal is not only helpless, laying as a ‘blob’, but it also has nothing to support its weight.  Its likely that a bug the size of Mothra would have been crushed and killed under her own weight.

So, how big can arthropods get?  The largest terrestrial arthropods are probably the Giant Weta (Deinacrida spp.), found in New Zealand; the largest one documented was ~70g!  However, because water is more buoyant (and supportive) than air, aquatic arthropods can get much larger.   The Japanese Spider Crab (Macrocheira kaempferi) can reach a width of up to 13 feet, and a mass of 20kg (44 lb)!  I had a chance to photograph this crab last week at the Aquarium of the Pacific in Long Beach.

japanese spider crabJapanese Spider Crab (Macrocheira kaempferi) Aquarium of the Pacific, October 2009

Despite the fact there was a lot of glare on the glass, I rather like this photo.  Somehow I can’t help but think these crabs are planning a Mothra-like reve….

A visit to the aquarium

Saturday, October 17th, 2009

Yesterday my office mate and I visited the Aquarium of the Pacific in Long Beach to scope out potential field trip activities for our Zoology students.  I was able to take along my camera and photograph some of the unique life they have there.  This type of shooting carries with it several difficulties, including low light (I shot at ISO 1000 or great the entire time) and curved glass on displays (autofocus has a hard time with this, I found out).  However, its also really fun to shoot here because of the huge diversity you get to photograph in a very short time.

Angel FishCopperband Butterflyfish, Aquarium of the Pacific, Long Beach, CA, October 2009

Sea JellySea Jelly, Aquarium of the Pacific, Long Beach, CA, October 2009

I also had the opportunity to play with some really fun abstract images at the aquarium as well; something I don’t get a chance to do very often.  This image is an intimate shot of a sea anenome:

Sea Anenome AbstractSea anenome abstract, Aquarium of the Pacific, Long Beach, CA, October 2009

Over the next few days, I’ll share some more images from this really unique and fun location.  We’ll be visiting again next month, so the lessons about shooting under these conditions can be applied again as well.

Sphinx moths

Tuesday, September 22nd, 2009

A friend of mine in Laramie Wyoming reported snow yesterday; here in southern California we’re baking in nearly 100 degree temperatures, but that means that insects are still out, and I can still photograph them!  One of my favorite insects is the sphinx moth.  Sphinx moths are a family of moths (Sphingidae) comprising about 1,200 species; the white-lined sphinx moth (Hyles lineata) is very common here in southern California.

White-lined sphinx moth, 2009

I caught this individual flying around in my garage one evening (they’re nocturnal).  After catching it, I did what any good biologist would do: I put it in the fridge.  Why?  Because I wanted to do what any good photographer would do: take pictures of it.

After letting it cool down, I placed the moth on some vegetation in my front yard.  Using my 300/4 lens with a 1.4x teleconverter, I was able to fill most of the frame with the moth at the minimum focusing distance.  I used a flash with -1 2/3 stops compensation to act as a fill flash.

Moths–like all insects–are ectotherms, meaning they are “cold-blooded”.  In other words, they have to derive their body heat from somewhere other than metabolic sources.  You and I are endotherms–we produce our own body heat via our metabolism.  So, as this guy warmed up from being in the fridge it started to move around more and more.  But, it still needed more heat to be able to fly.  That’s when things got interesting.

Ectotherms have to derive their body heat from external sources (usually the environment–this is why you see lizards and snakes sunbathing), but sphinx moths display something called ‘periodic endothermy’–they flap their wings at a very rapid pace to build enough body heat to be able to fly:

White-lined sphinx moth beating wings in a display of ‘periodic endothermy’, 2009

Beating the wings in this manner generates a large amount of heat, which can then be used for flight.  This moth displayed this behavior for about 3 minutes, then took off.  It was a great interaction, a good physiology lesson, and I got some great pictures out of it!

Seeking the creatures of the night

Monday, August 10th, 2009

If you’ve done much photography/camping/hiking/being outside at all, you’ve surely heard all of the nocturnal critters starting their nightly rounds shortly after the sun goes down.  Have you ever wondered who is out there?  Seeing them isn’t all that hard, but photographing them can be a little challenging, and often downright hilarious!

Last night, a friend and I went to the University of California’s Motte-Rimrock Reserve, near where we live.  The Motte is prime habitat for Stephen’s kangaroo rats, Dipodomys stephensi.  However, life for kangaroo rats is hard: they have to contend with rattlesnakes, owls (both great-horned and barn) as well as photographers with big cameras trying to take their picture!

Our method was pretty simple.  We scattered a little bird seed near the rats’ burrows and waited for them to find it once the sun went down.  It didn’t take long; within about 20 minutes after dark, “k-rats” were bombing the bird seed from the safety of their burrow.  Seated about 20 feet away, my friend and I waited with a bright flashlight and our cameras.  

Once a rat was comfortable with our presence, one of us would spotlight it, and the other one used the light to autofocus on the rat, and fired:

Stephen’s kangaroo rat, 2009

Its not too bad of a system to take turns doing this, and doesn’t take a lot of extra equipment.  I shot my frames at f/8, ~1/60 of a second–it doesn’t really matter though because the flash will freeze the action.  

After you get bored with the k-rats, its nice to look for other critters.  While owls were flying around, they weren’t being conducive to being photographed.  But, like I said, there are other creatures who seek k-rats.  Locally we have a fairly large population of red diamond rattlesnakes (Crotalus ruber).  

We found this fellow curled up alongside the dirt road, about 20 feet from us.  It was clearly waiting for a meal:

Red diamond rattlesnake, 2008

The snake was very compliant, and gave us about 15 minutes to photograph it before it had had enough, and slithered back into the bushes.

After appreciating the creatures of the night, we headed home, allowing them to resume their nightly routine.  Its always nice to experience new wildlife, it is important to make your impact as little as possible.  No photograph is worth endangering an animal.

So, get out there and look at your favorite wilderness area in a whole new “light”!

 

Santa Rosa Plateau, part 3

Saturday, August 8th, 2009

A vernal pool is a seasonal pool that fills up during the winter rains, and dries out slowly over spring and summer, not refilling until the following winter.  In California, Riverside County has 14 vernal pools; 13 are protected within the Santa Rosa Plateau Ecological Reserve.  When I think of this place, I think of its crown jewel–the vernal pools.

The third, and final, image I have in the Plateau’s annual art show this year is of the vernal pools:

Vernal Pools, Santa Rosa Plateau Ecological Reserve, 2009

Fairy shrimp, frogs, toads, snakes, and migrating waterfowl are just a small group of animals that call the pools home, but also rely on them to breed.

The show begins tonight, and runs through September 20.

Biology exposure

Wednesday, July 29th, 2009

A few months ago, my friend Nikki over at Golden West College in Huntington Beach contacted me about using one of my images on the cover of their introductory biology lab manual.  The manual is finally done, and I couldn’t be any happier with the result:

Front_cover_new

I was very happy to have an image appear on this lab manual, but I’m also very happy with Nikki’s choice of photos.  I’ve been living in southern California for almost 7 years and the Brown Pelican has been one of my favorite birds since I moved out here.  To watch them fly is to watch pure grace.  The way they skim the water, just inches from its glassy surface is–to me–poetry.  As a photographer, I’ve spent many mornings standing on the bridge at Bolsa Chica Wetlands with Pelicans fishing all around me.  Its sometimes very satisfying to put my camera down, enjoying the moment.  The Pelican you see on the cover of the lab manual was photographed at La Jolla Caves in La Jolla, CA–a location well-known to bird photographers.

We’re lucky to see these magnificent birds at all.  In the early 1970s, pesticides like DDT severely threatened the future of these birds.  Fortunately, conservation measures were able to bring them back from the brink of disaster.