Evolutionary Biologist and Nature Photographer

Posts tagged “animals

I’ll have the ‘Cuisses de Grenouille’ please

The family Colubridae is the most diverse family of snakes with almost 2,000 species, though this group is non-monophyletic (that is, in evolutionary terms, the group does not contain all descendants of the most recent common ancestral species).  Thus, this family requires a great deal of work by taxonomists to sort out the natural groups and determine relationships among them.

Leptophis is a genus of colubrid snakes, commonly called parrot snakes.  Parrot snakes are long, slender, bright green snakes found in the tropical forests of Central and South America.

The parrot snake shown in the first two images below, Leptophis ahaetulla (Colubridae), had just found itself a hearty meal. Despite having obviously lost this battle, the frog did not give up the fight so easily, as it kicked and squirmed until the very end. If you look at the expanded body of the snake you can see just how large this frog was – the snake was more than 4 feet in total length.  Notice that the skin stretches as the snake swallows the frog – the blue coloration is the skin beneath the green scales.

(Click the images to see them in full size)

Parrot snake (Leptophis ahaetulla)

Parrot snake (Leptophis ahaetulla) eating a frog, La Selva Biological Station, Costa Rica

Parrot snake (Leptophis ahaetulla)

Parrot snake (Leptophis ahaetulla) eating a frog, La Selva Biological Station, Costa Rica

The next three photos are a second species of parrot snake, Leptophis depressirostris, barely distinguishable from the species shown above except for one scale between the eye and the nostril (just learned this interesting fact today from a friend, Ethan).

In the picture below, this parrot snake is demonstrating its incredible and intimidating defensive display.

Satiny Parrot Snake

Satiny Parrot Snake – Leptophis depressirostris (Colubridae), La Selva Biological Station, Costa Rica

Below you can see the body of a large tick, full of blood, attached under a scale on the snake’s neck.

Satiny Parrot Snake

Satiny Parrot Snake – Leptophis depressirostris (Colubridae), La Selva Biological Station, Costa Rica

Satiny Parrot Snake - Leptophis depressirostris (Colubridae)

Satiny Parrot Snake – Leptophis depressirostris (Colubridae), La Selva Biological Station, Costa Rica

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The green harvestman!

This species appears to be well camouflaged in its natural habitat – high elevation tropical wet forest with an abundance of mosses and ferns at Las Brisas Nature Reserve, Límon province, Costa Rica.  Luckily I snapped some photos of this species before preserving a few individuals in ethanol to examine later in the lab because, unfortunately, the gorgeous color faded quickly!  Upon closer inspection our research team discovered that the harvestman does not produce the green pigment, but rather, the pigment is produced by epizoic cyanobacteria that lives on the dorsal scute of the harvestman.  This is an extraordinary example of the evolution of symbiosis.  Although it is unclear whether this relationship is mutualistic (one would have to determine whether the cyanobacteria is actually benefiting), the green coloration does appear to provide camouflage for this harvestman within the very lush, green habitat in which it was observed.

Prionostemma sp. "verde" - The green harvestman

Prionostemma sp. “verde” – The green harvestman


Caterpillar of the Eastern Tiger Swallowtail

I’ve been so busy writing other stuff (proposals and manuscripts) that I haven’t had time to post many pictures lately. That also means I haven’t been out much to take new pictures.  So here are some photos from a couple weeks ago – a caterpillar that belongs to one of the species of swallowtail butterfly – probably the Eastern Tiger Swallowtail (I also posted a photo of the adult for this species below).

The “eyes” that you see are not actually eyes at all.  Instead this is a  type of cryptic coloration (specifically mimicry) that has evolved to look like eyes as a defense mechanism.

Eastern Swallowtail Caterpillar

Eastern Tiger Swallowtail Caterpillar found along a trail in western North Carolina

Eastern Swallowtail Caterpillar 2

Eastern Tiger Swallowtail Caterpillar

Eastern Swallowtail Caterpillar 3

Eastern Tiger Swallowtail Caterpillar. The eye spots seen above are a type of defense mechanism using cryptic coloration. The real eyes are two bluish-grey objects below.

Eastern Swallowtail Butterfly

Eastern Tiger Swallowtail

 


Peek-a-boo

I was out hiking the other day looking for harvestmen and spiders, but almost every large rock I turned yielded a salamander!  Here’s one of the little guys hiding in some leaves.

North Carolina Salamander

A salamander from western North Carolina

The above image is actually a stack of two photos to get the depth of field I wanted on the face of this salamander.


My, what big eyes you have!

During the arachnologist field trip to Toft Point in Wisconsin a couple weeks back, I was in the field collecting with opilionologist Jeff Shultz and arachnid photographer Joe Warfel.  Jeff collected Caddo pepperella, a rare species of harvestman.  Previously this species has only been collected in pitfall traps so this was the first time anyone has ever collected and photographed this species alive!  I thank Jeff and Joe for giving me a chance to photograph the specimen.

Caddo pepperella is a tiny litter dwelling harvestman that very few people will ever observe out in the wild!  The length of its body is less than ONE millimeter!!!  And its legs are not much longer than a couple millimeters.   But small as it is, relative to its body size, the eyes are huge!

Caddo pepperella (Caddidae), from Wisconsin

 

Caddo pepperella (Caddidae), from Wisconsin

Updated on 4/2/13 – species is Caddo pepperella, ID by J. Shultz.


The Harvestman with Horns

The ubiquitous species of harvestman Phalangium opilio was named by Carl Linnaeus in 1758.  P. opilio is now distributed all over North America, where it has been introduced from Europe (thankfully it is not a pest!).  The species range has also apparently spread into parts of Asia and Africa.  This species thrives in a number of different habitats, including natural habitats, such as forests, as well as anthropogenic habitats/structures, such as under bridges, in gardens or green spaces.

Males of P. opilio have large horns on their chelicerae (pointing outward, away from the anterior end).  These structures are used as weapons in male-male contests which most often results in the loser fleeing and the winner having a chance to mate with a nearby female.

Below are a few more photos from a field trip to Toft Point, WI during the 2012 meeting of the American Arachnological Society at UWGB.

Notes on image below: The cheliceral horns are the long pointed cones sticking off of the first pair of appendages (the chelicerae).  The chelicerae bend downward, each terminating in a movable, pincer-like claw that is not visible here.  Note that the male pedipalps are very long, unarmed, and appear as if they are an additional pair of legs (here the pedipalps are more gold in color, while the legs are black).  This male is also missing the second walking leg on the near side of the body.

Male Phalangium opilio Linnaeus 1758.

Image below: Same male, dors0lateral view.

Male Phalangium opilio Linnaeus 1758.

Image below: Female from a dorsal view.  The pedipalps are shorter and are held close to the body partially covering the smaller chelicerae of the female.

Female Phalangium opilio Linnaeus 1758 demonstrating the lack of cheliceral horns and smaller pedipalps.  Dorsal view.

Female Phalangium opilio Linnaeus 1758 demonstrating the lack of cheliceral horns and smaller pedipalps. Lateral view.

References:

Harvestmen: The Biology of Opiliones. 2007. R. Pinto-da-Rocha, G. Machado & G. Giribet (Eds.). Harvard University Press.

Willemart RH, Farine J-P, Peretti AV, Gnaspini P. 2006. Behavioral roles of the sexually dimorphic structures in the male harvestman, Phalangium opilio (Opiliones, Phalangiidae). Can. J. Zool. 84: 1763-1774.


Arachnologists Unite

At most academic meetings the arachnologists often get lumped into an entomology section.  Or they might find themselves mixed in with general invertebrates.  But not this time!  Two weeks ago, in Green Bay, Wisconsin, more than 100 arachnologists from all over the world met for the annual meeting of the American Arachnological Society hosted by University of Wisconsin at Green Bay.  The meeting took place over the course of four days and included all kinds of arachnid-based talks, posters, social events and an auction with all kinds of spider paraphernalia (books, t-shirts, toothbrushes, old photos, jewelry and more)!  It was a great opportunity for many enthusiastic arachnologists to share their exciting research regarding the charming little animals that strike fear into the hearts of most people!

After the official meeting concluded there was a field trip to visit Toft Point State Natural Area, on a peninsula along the western shore of Lake Michigan.  About 40 arachnologists jumped on a bus, headed up to Toft Point, and collected specimens in hopes of adding to the list of known arachnids from this site.  Here are a few spider photos from the field trip.

A small juvenile, female Dolomedes tenebrosus (Pisauridae).

This spider appears to have placed its egg sac into what’s left of this dead plant.

The always charismatic jumping spider, Phidippus sp. (Salticidae)