Bisley, El Yunque (Caribbean) National Forest

Bisley, El Yunque (Caribbean) National Forest
Bisley #3 Stream

Thursday, November 30, 2006

Tarantulas: Amazing Spiders

Tarantulas are considered by many people as dangerous animals. They even have been used by the motion picture industry as instruments of terror in films, such as the science fiction horror film, Tarantula (1955). Even in the first agent 007 film, Dr. No (1962)where one scares the hells out of James Bond, and in, Indiana Jones: Raiders of the Lost Arc (1981), among many others. In Indiana Jones, they used close to 100 live tarantulas.
In spite of their menacing appearance, many tarantulas are actually docile toward humans, and only attack in self-defense when it raises its hind legs and shows its shiny black fangs (chelicerae), as shown on the photo of Phormictopus cancerides, above on the left.
Tarantulas are large hairy spiders with approximately 1,500 species in the world. There are some 30 species in the United States and 7 species in Puerto Rico.

The largest living arachnids are both the Goliath tarantula, Theraphosa blondi, and its sister, Theraphosa apophysis, both from South America. Pseudotherathosa apophysis is the biggest tarantula, with a leg span of about 13 inches (33 cm). These arachnids have a very long life span; some species can live over 30 years. Phormictopus cancerides, a tarantula from the Hispaniola, has been identified as the largest tarantula of the Antilles with 16-18 cm (both photos on the right).

Because of their weight, they can't spin webs, so each species either lives in underground burrows, on the ground, or in trees. Tarantulas eat insects, other arachnids, small amphibians and reptiles, bird chicks and mice.

In reality, tarantulas have simple eyes (photo on the right) and can only distinguish between light and darkness, and since they are nocturnal, they find their way by the use of sensitive hairs on their legs and bodies. In fact, they can sense your approach just by detecting the vibrations caused by your moving feet.

Somewhat at odds with their fearsome appearance, tarantulas as well as all spiders are fastidiously clean animals. Especially after eating, they will spend long periods of time rubbing their legs together and over their bodies in order to clean off any remains of the prey and other debris.

Although they have the ability to jump up to a few inches, they possess sticky hairs on each leg which allows them to climb almost anywhere. Depending on the species they can be found on the ground or in trees, where they line their burrows with silk.

All tarantulas drinks extra water before molting and does not eat for one week. Like typical spiders, tarantulas produce silk, but is variously used to line their lairs, create egg-sacks, and in the case of trap-door spiders, to form a hinge for the earthen door to their burrows.

In Puerto Rico, there are seven species, among them the terrestrial Cyrtopholis portoricae (photo on the left) and the arboreal Trichopelma corozae and Avicularia laeta. Despite their ferocious appearance, no one has ever died of a tarantula bite. Because of their weight, they can't spin webs; so depending on the species,they either live in underground burrows, on the ground, or in trees.

The Puerto Rican Pygmy, Cyrtopholis portoricae is the most common species of tarantula in Puerto Rico. Although it is called a "pygmy", they are medium-sized terrestrial tarantulas that live in burrows digged on the ground, where they can be found during the day. This species has a dark brown with light rosy stripes on each leg. Some people regard them as extremely aggressive, this is exagerated. They will defend themselves if provoked or if they feel threathened.

Another uncommon species is the arboreal, Trichopelma corozali an endemic species which
also has the ability to climb; during the day they dwell in burrows excavated on tree trunks or among the roots. As you can see on the photo on the left, these hideouts and the entrance are covered with silk. The second photo was taken on the trail to Mt. Britton at the El Yunque National Forest (formely known as the Caribbean National Forest) after the spider emerged from its burrow during the night. It can be easily identified by just looking at the abdomen with dark-grey or black hairs.

Avicularia laeta, or the Puerto Rican Tree Tarantula, is also an endemic species to the Greater Puerto Rican Region. Unlike other tarantulas, this species is adapted to an arboreal lifestyle, because they possess under the distal portion of the legs made of microscopic hooks; this allows
them to walk over branches and leaves. It builds silk nests in holes in tree-trunks or in the crevices of large boulders and at limestone cliffs. They can also build their nests in the central rosettes of some species of bromeliads, as you can observe on the photo on the right. This photo was taken at St. John, U.S.V.I; the first two were taken at the University of Puerto Rico, Humacao.

Pepsis vs Holothele

One the most remarkable natural events, is the relationship between the wasp, Pepsis ruficornis (first photo at the end) and the tarantula, Holothele sp. The female wasp actively looks for a tarantula; when one is found, she stings the tarantula, and then with her antennae determines if is the right species. The wasp next digs a hole where she will bury the spider and then lays one egg next to it. After it hatches, the larvae will be nourished by slowly eating the spider, keeping it alive by saving the vital organs for last. In the last two photos you can observe the wasp in pursuit and when it tries to sting the small tarantula. The outcome... the predator not always win.

Saturday, November 18, 2006

La Soufrière Volcano, St. Vincent - The Adventure of My Life

This adventure is not for the faint of heart. The trip to La Soufrière started with a drive from Kingstown, the capital of St. Vincent and the Grenadines, which is located on the southwestern part of the island. There is a drive (for us on the wrong side of the road, left side) through a rugged and narrow road to the east windward coastline, passing through the town of Georgetown and then turning westward (inland) again through Orange Hill (a banana plantation).

After weaving through an extremely narrow and unpaved side road, we reached an area at about 1,200 feet of elevation, where we left the car. From there, we started to climb on a very steep three-mile trail to the edge of the volcano, at about 4,050 feet approximately. Along the way we enjoyed the amazing flora and fauna of the surrounding tropical rainforest.
Toward the summit, a dwarf forest emerges, followed by scrub or alpine-like vegetation, which is the result among the many factors, of the strong winds which prevails at these altitudes. The last 30 to 45 minutes of hiking were done on a very steep slope with loose volcano ash which makes things strenuous, up to a rocky lava field in between.

The first photo was taken from the east side of the crater's edge. On the right side, you can observe the magma dome and a small fumarole which looks like fog. That day, the crater was covered by a thick layer of clouds. However, luckily a gust of wind cleared the crater for about 30 minutes and the sight was awesome. The second photo shows the magma dome.

This hike can be attempted also from the western (Leeward) side of the island where there is another trail near Chateaubelair. This one is longer than the eastern trail and takes about seven hours of strenuous hiking, instead of just four hour. Some people hike from east to west, so their descent is from the most demanding part of the trail.

However, instead of the four hours it takes to reach the summit, we did our hike in less than two hours; even while carrying backpacks with our camera gear and water; although some of the long-lenses were left behind.

We were informed that this volcano is ‘one of the most studied volcanoes in the world.’ There are seismograph stations that constantly monitor the volcano’s activities.

La Soufrière’s last eruption was in April 1979. Later, experts studied the succession of deposits on the volcano’s flanks, thus acquiring excellent records of its history. According to this record, La Soufrière’s activities started approximately at least half a million years ago, with periods of inactivity lasting thousands of years. It has been determined, that the present period of activity started about 1,300 AD. However, written records date only back some 284 years, when in 1718, an eruption which left a mile-wide, 1,500 feet deep crater was documented. A lake then formed inside the crater. You can see on the last photo what is left of the lake. The magma dome is growing, but predictions as to the next volcanic activity are yet to be made.

Endemic Birds of Puerto Rico

Spindalis portoricensis is endemic to Puerto Rico and commonly found almost throughout the Island on forests, plantations and even on urban and suburban areas. There is a marked sexual dimorphism with the male’s brighter coloration, than the female’s dull olive-green colored plumage. This species feeds on fruits and berries of a wide variety of plants, including Ixora (Cruz de Malta), Cecropia and others, and sometimes on insects.

Since males are territorial, sometimes people will find their car windows and side mirrors “dirty”. This is because the male confuses his own reflection with that of a rival bird and will “attack to defend its territory”.
Based on their differences in calls and in the plumages, scientists have separated this genus into four species: Spindalis portoricensis (Puerto Rican Spindalis), Spindalis nigricephala (Jamaican Spindalis), Spindalis dominicensis (Hispaniolan Spindalis), and Spindalis zena (the Western Spindalis) found in Bahamas, Cuba, Grand Cayman, and Cozumel Island off Mexico.

On a recent trip to the Bahoruco National Park, located at the south-western part of the Dominican Republic, Hispaniola, I had the opportunity to take photographs of a male Hispaniolan Striped-headed Tanager, Spindalis dominicensis. For comparison purposes, I have included photos of a male Spindalis portoricensis (top) and a male Spindalis dominicensis (right). The first species is endemic to Puerto Rico, while the second is endemic to the Hispaniola. Notice the differences in colorations in the plumage, look especially around the back of the neck area and on the striations of the wings.

Friday, November 17, 2006

Sunrise at Piñones State Park

Have you seen this larvae and wondered which is the species?

This is the larva of the moth, Pseudosphynx tetrio. The larvae bright coloration says everything, since it feeds voraciously on Allamanda cathartica, Himanthus, Plumieria rubra, P. alba and from others members of the Apocynaceae and Bombaceae families. These tree species produce a toxic, white sap to avoid predation from most other insect species. However, as a co-evolutionary mechanism, this moth has developed a way to be immune to the trees’ toxic sap.

This species is commonly found from southern Brazil north through Central America, Mexico, and the West Indies to south Florida, southern Mississippi, Texas, and southern Arizona.

Its pupal stage occurs either under the leaf litter or in subterranean chambers from where the adult emerges. There is sexual dimorphism among the adults, with the female larger than the male.

Coquí de Richmond

This amphibian is Eleutherodactylus richmondi (Coquí de Richmond), a species considered as threatened. This species's number are diminishing rapidly and supposedly “vanished” from the El Yunque National Forest (formerly Caribbean National Forest). On January 2006, our group found a small population in that same forest.

On Sunday, October 12, 2006 we returned to the area and to our delight, we found that this population was still there and that by the quantity of singing males this population had probably increased in numbers.

Ironically, this population is currently found in an area where the “locals” (who care about “their” environment) dump their solid and toxic wastes inside a National Forest. The photo of the “vocalizing” male was taken while I was kneeling on top of a decaying dog that was dumped on the site. The photo on the right shows part of the area. Enjoy!