"... he that breaks a thing to find out what it is

has left the path of wisdom."

    Gandalf the Gray to Saruman the White, in The Lord of the Rings: The Fellowship of the Ring

    John Ronald Reuel Tolkien (1892-1973)

Greater Hispaniolan tarantula, Phormictopus cancerides, female. Near Cabral, south-western Dominican Republic, Hispaniola.

PHYLUM ARTHROPODA: ARTHROPODS

    This is by far the largest taxonomic aggregation of animals, perhaps comprising more than three quarters of all extant organisms. Every single terrestrial and aquatic habitat on Earth has been colonized by arthropods of one kind or another.

    These organisms probably arose from a worm-like form, back in the early Cambrian Period. Their closest living relatives are the onychophorans, which were discussed in the previous section.

    The term "arthropod" derives from the Greek composite word meaning "that which has jointed legs" and, indeed, this is one of the main characteristics of the whole phylum. The locomotive appendages, as well as mouth parts, wings, antennae, and ovipositors of members of this group are jointed to the body, and are most often divided into movable sections themselves. This is a resulting need of their other trait: all arthropods possess a chitinous or calcareous exoskeleton that must be shed by a process of ecdysis (molting) as the animal grows. Since the exoskeleton is rigid, the appendages need to be jointed in order the be able to be moved.

    While being encased in a rigid armor would seem to be excessively confining from the point of view of softer bodied organisms with an internal skeleton (like us), indeed arthropods are immensely successful animals. Those that are aquatic breathe through gills, and often reproduce externally, by releasing eggs and sperm into open water. Terrestrial species breathe through tracheae that open to the exterior through tiny spiracles along their bodies. These forms reproduce internally, either with males passing their sperm to to females through spermatophores, as is the case with many arachnids and chilopods, of  by direct contact of their respective genitalia, as happens with most millipedes and insects.

    A number of groups within this phylum, notably some crustaceans, centipedes, and insects carefully and fiercely protect their eggs and young. This behavior, quite uncharacteristic among invertebrates in general, ensures that a greater number of offspring will reach reproductive age, in their own turn.

    Although arthropods are so different from us humans that we could almost seem to belong in different planets, and in spite of the fact that so many people look on them with scorn, revulsion, and fear, life on Earth as we now it today would be impossible without them. We feed on many of them (lobster, crabs, even some insects) and they feed on us (mosquitoes, horseflies, and ticks). They eat our crops (land crabs, locusts, and caterpillars) but they also pollinate our crops (butterflies, bees, and flies). They bite and sting us (centipedes, spiders, fire ants, and scorpions) but those same also hold back hordes of disease-carrying others (cockroaches, assassin bugs, and sand flies). They may have diets that are repulsive to us (maggots, dung beetles, and pillbugs) but it is their diets which keep our environment free of rotting corpses and pestilence. They destroy our furniture (termites and wood borers) but those same annually recycle billions of kilograms of dead wood, keeping forests healthy. They eat our clothes (cloth moth caterpillars) but also give us materials to clothe ourselves with (silk-moth caterpillars).

    In the end, the same bee that stings us will give us honey.

    And even aside from the direct and mediate, willing and unwilling relationships that we may sustain with them, arthropods are sublime creatures worth pondering, plain and simple. The industrious societies of ants and termites; the impossibly complex color patterns of many butterflies and moths; the hordes of land hermit crabs in their yearly pilgrimage down to sea to spawn; the delicate fastidiousness with which a tarantula grooms its fangs after its last meal; the agility of a centipede as it climbs up a branch; the blurring speed of a mantid shrimp pouncing on its next victim; the parsimonious undulations of a millipede's legs as it walks; the studied movements of a jumping spider looking for the easiest route to the next perch; the jewel-like iridescence of a hawk wasp; the mechanical walk of a scorpion; the helicopter-like hovering of a dragonfly; the symmetry of a dew-covered spider's web; the eerily human-like stare of a praying mantis as it swivels its head to look at you right in the eye...

    God made arthropods to make our life on this planet even possible.

Eight-Legged Wonders

CLASS ARACHNIDA: ARACHNIDS

    Most arachnids (spiders, opilionids, scorpions, sun spiders, whip scorpions, etc.) prey on the abundant insects with which they share West Indian grasslands, swamps, and forests. Named after the Greek weaver goddess Arachne, (in allusion to the webs of many spiders), some members of the class, however, are incapable of producing silk.

    Not all are predatory, either. A vast number of species of mites (a group that include ticks) are parasites of other animals or feed on dead organic matter. But the largest spiders, whip spiders, and scorpions can prey on small vertebrates. As a group, arachnids are the main terrestrial arthropod predators in the Antilles, although some mites are aquatic, being able to breathe through their thin bodily walls.

    Arachnids have two body sections, a cephalothorax and an abdomen, a trait they share with their distant relatives, horseshoe crabs and the extinct eurypterids. They have four pairs of legs, and also two pedipalps, one on each side of the mouth. Pedipalps are unspecialized and leg-like in most spiders and solfugids (albeit used as intromitent sexual organs by males of many species). Alternatively, they are modified into grasping pincers in scorpions and pseudoscorpions, or into what resemble sickles bristling with fierce spines used for grabbing prey in a deadly embrace, as in whip scorpions and whip spiders. Finally, instead of the complex mandibles of most miriapods, crustaceans, and insects, arachnids possess simpler structures called "chelicerae". These are appendages tipped with sharp fangs used to pierce and inject venom into the bodies of their prey. In fact, arachnids cannot eat solid food but, rather, enzymes found in their venom and saliva soften the insides of their victims. They then proceed to suck in the liquefied tissues of their prey. I such way, a spider will feed on its meal until only an empty husk of the latter is left behind. This is a thorough, if slow, process. A large tarantula, for example, will chew on a cockroach or even a mouse for hours, sucking in their liquefied flesh until only a tiny ball of indigestible chitin or hair remains.

    On the other hand, the chelicerae of parasitic arachnids are modified into piercing needles with which they feed on already liquid nourishment, as is the case with the blood-sucking ticks.

    Many, if not most, of the larger arachninds provide some form of parental care for their offspring. This might even entail actual feeding performed by the adults as well as active protection against predators.

Greater Hispaniolan tarantula, Phormictopus cancerides, female and spiderlings. Pico Diego de Ocampo Nature Reserve, north-central Dominican Republic, Hispaniola.

Order Acarina: Mites

    These are the most abundant and varied of all arachnids. However, most are tiny (less than one millimeter in length), and even microscopic. Ticks comprise an exception to this rule, since some can be relatively large. Ticks are parasitic and feed on the bodily fluids of their hosts as they pertinaciously hang on to them with legs and sharp mouthparts. Many feed on the blood of terrestrial vertebrates, though some invertebrates are not free of their attacks. Several species of ticks are important vectors of diverse pathogens, like those that cause lime disease.

    Some velvet mites are also among the giants of their order, and are predators of small invertebrates in leaf litter or under rocks.

Many mites are parasites of vertebrates. Such are the ticks, (order Parasitiformes), and they do not only feed off dogs and cats.

This geckolet, Sphaerodactylus roosevelti, has a tiny tick (species undetermined) attached behind its eye,

while an even tinier mite (a pterygosomatid, probably Geckobia sp.) is inside its ear.

Guanica State Forest, south-western Puerto Rico.

Ticks, possibly Amblyomma antillarum, on the neck of a greater Puerto Rican boa, Epicrates inornatus. Cambalache State Forest, northern Puerto Rico.

(Photograph courtesy of Mr. Alfredo Colon Archilla).

A tick, possibly Amblyomma antillarum, clings to a toad. Windsor, central Jamaica.

Mite (species undetermined) feeding on an eneopterine cricket. Cambalache State Forest, northern Puerto Rico.
(Photograph courtesy of Mr. Alfredo Colon Archilla).

Red velvet mite, (order Acariformes), probably Trombidium sp. This comparatively huge species is often found under rocks in xeric areas.

Guanica State Forest, south-western Puerto Rico.

Order Opiliones: Opilionids

    Opilionids (the "daddy-longlegs" of English-speaking countries) are not true spiders, in spite of the strong resemblance between the two groups. Their bodies almost look like small spheres with none of that discernible partition between the cephalothorax and the abdomen that is so obvious in spiders. Opilionids are atypical arachnids in that instead of being exclusively predatory can be scavengers or feed on plants and fungi. However, some are indeed predators of smaller invertebrates. They thrive in the humid tropical microhabitats under rocks and debris.

    In spite of the small size of their bodies their legs are extremely long (hence their common name) and serve the function of antennae as well as locomotion.

Opilionids, species undetermined. Guilarte State Forest, west-central Puerto Rico.

Opilionid, Vonones sp. Carite State Forest, east-central Puerto Rico.

Cosmetid opilionid, species undetermined. El Yunque National Forest, north-eastern Puerto Rico.

Cosmetid opilionid, species undetermined. El Yunque National Forest, north-eastern Puerto Rico.

Courtting pair of opilionids, Yunquenus portoricanus. El Yunque National Forest, north-eastern, Puerto Rico.

Opilionid, species undetermined. Guana Island, British Virgin Islands.

Opilionid, species undetermined. Mount Scenery, Saba, Lesser Antilles.

Opilionids, species undetermined. Cambalache State Forest, north-western Puerto Rico.

Order Scorpiones: Scorpions

    The approximately 1050 living species of scorpions belong to one of the most ancient terrestrial metazoan groups on Earth. As it is known today, their lineage dates back to the Silurian Period, 400 million of years ago, when some marine species ventured onto land and developed the capacity to breath gaseous oxygen. Several dozen species inhabit the Antilles. All scorpions have their pedipalps modified into pincers with which they seize and tear apart their prey.

    Scorpions are related to the largest arthropods known: eurypterids. These were fearsome predators - some reaching two meters in length - that actively hunted for their prey in the oceans of the Silurian and Ordovician periods. Even some extinct terrestrial scorpions might have measured about a meter in length, perhaps being the most massive land invertebrates that ever existed.

    All scorpions have the same basic bodily plan. To the frontal section, or prosoma, are attached all locomotive appendages, as well as the chelicerae and pedipalps. On the underside of the prosoma, a pair of specialized sensory organs, the feather-like pectens, serve to detect vibrations in their surroundings. Then follows the opisthosoma, itself divided into a mesosoma and a metasoma (this last is the scorpion's "tail"). The last segment of the metasoma is modified into a telson or stinger, containing two toxin-producing glands opening each into a duct through which the venom flows at will, as the animals attacks its prey or defends itself. The sting of West Indian species can be painful, but none are known to be fatal to humans.

Buthid scorpion, Centruroides guanensis, female. Santa Cruz del Norte, north-eastern Cuba.

(Photograph courtesy of Mr. David Ortiz Martinez).

Buthid scorpion, Centruroides barbudensis, female. Saline, Saint Bartholomew.

(Photograph courtesy of Mr. Karl Questel).

Buthid scorpions, species undetermined. The Quill National Park, southern Saint Eustatius, Lesser Antilles.

Buthid scorpions, Centruroides gracilis, male and female with scorplings. Havana, north-western Cuba.
(First photograph courtesy of Dr. Rolando Teruel Ochoa. Second photograph courtesy of Mr. Joseph Burgess).

Buthid scorpion, Centruroides platnicki, male. Monte Cristi, north-western Dominican Republic, Hispaniola.

Buthid scorpion, Centruroides robertoi, female. Santiago de Cuba, south-eastern Cuba.
(Photograph courtesy of Dr. Rolando Teruel Ochoa).

Buthid scorpion, Rhopalurus princeps, female. Enriquillo National Park, south-western Dominican Republic, Hispaniola.

Buthid scorpion, Rhopalurus garridoi, female. Guantanamo Naval Base, Guantanamo, south-eastern Cuba.

(Photograph courtesy of Mr. Joseph Burgess).

Buthid scorpion, Rhopalurus bonetti, male. Cabo Rojo, south-western Dominican Republic, Hispaniola.
Some species of the genus, like this one, emit a rattling sound when they are disturbed by vibrating the pectes on their undersides.

Buthid scorpion, Rhopalurus junceus, female. Granma, south-eastern Cuba.
(Photograph courtesy of Dr. Rolando Teruel Ochoa).

    Scorpions are unusual among invertebrates in exhibiting a rather elaborate degree of parental care for their offspring ("scorplings"). These last are given birth, instead of hatching from eggs, and the females will carry them on their back for some time until they are able to fend for themselves.

Order Solifuga: Sun Spiders

    Subjects of several ridiculous legends and superstitions, (including some narrated among soldiers I spent time with in Iraq), these creatures are actually quite harmless.

Solfugids are a poorly studied order of arachnids. Their closest relatives seem to be pseudoscorpions, and they inhabit much of the drier regions on Earth. Most are small, and the largest are only about 10 centimeters in length. Most species in the Caribbean belong to the family Ammotrechellidae, and are found mainly in xeric forests of both the Greater and Lesser Antilles. They share with scorpions and opilionids a segmented abdomen. But perhaps their most extraordinary trait is their massive and proportionally powerful jaws that resemble a double set of beaks. Although sun spiders seem to lack an envenomating apparatus, their jaws dispatch their prey with ease.

    The name of their order means "that which runs away from the Sun", owing to their nocturnal habits and their tendency to hide from even artificial ligh sources.

Sun spider, Ammotrechella sp., female. Saline, Saint Bartholomew, Lesser Antilles.

(Photograph courtesy of Mr. Karl Questel).

Puerto Rican solifuge, Ammotrechella pallida. Guanica State Forest, south-western Puerto Rico.

The peculiar jaws of solifuges are one of their unique traits.
Puerto Rican solifuge, Ammotrechella pallida. Guanica State Forest, south-western Puerto Rico.

Order Amblipygi: Whip Spiders

    There are two related orders of "whip scorpions". The "whips" of amblipigids are actually an elongated first pair of legs, held and used in the same fashion as an insect's antennae. Amblipigids - the tailless whipscorpions or (better named) "whip spiders", are denizens of the spaces under rocks, fallen logs, rock crevices, and caverns. Like most macroarachnids, they are predators of insects and other small invertebrates, which they capture with their spiny pedipalps and crush them with their short but sharp chelicerae in order to injest their liquified tissues. Amblipigids are mostly harmless to humans and possess no venom glands, although the pedipalps of the largest species can pinch and draw some blood from a careless human hand.

    As is the case with the true scorpions, these arachnids have segmented abdomens, but in their case this body section is wide and flattened. Although their pedipalps festooned with spines give whip spiders a horrid appearance to many humans, they are elegant creatures in their movements, as they nimbly walk while touching everything within their reach with their thread-like front legs.

    The females of many species plaster their eggs to the underside of their abdomen and carry them about until the hatchlings are born. The hatchlings of some species then climb to their mother's upper side for some time. Members of genera like Phrynus exhibit social behaviors beyond the merely maternal. Small youngsters placed separated from one another will seek each other out and huddle together for protection.

Order Thelyphonidae: Whip Scorpions

    Members of the similar order Thelyphonidae have, additionally, a long and whip-like appendage on the tip of their segmented abdomens. These, the true whipscorpions or vinegaroons, eject a foul-smelling fluid when they feel threatened. In some species, this substance is composed partially of acetic acid, and has an odor like that of vinegar, hence their common name. Like amblipigids, they have their pedipalps modified as hunting weapons to grab and hold their prey. These creatures lack venon-producing glands and are harmless to humans. Some can still deliver a painful pinch with their strong pedipalps if they are harmed.

Whip scorpions, Mastigoproctus proscorpio.
First two photographs: Rabo de Gato, south-western Dominican Republic, Hispaniola.
Last photograph: Los Haitises National Park, northern Dominican Republic, Hispaniola.

These animals are sometimes called "vinegaroons", for their defense mechanism of squirting

a vinegar-smelling substance onto their attackers. The gland producing the offensive fluid

is located at the base of the long, thin "tail".

Mastigoproctus baracoensis. El Yunque de Baracoa, north-eastern Cuba.

(Photograph courtesy of Mr. David Ortíz Martínez).

Mastigoproctus sp. feeding on an Anolis egg. South-eastern Cuba.
(Photograph courtesy of Mr. David Ortíz Martínez).

Whip scorpion, Ravilops whetherbeei, male and female. Dominican Republic.
Cute little things.

Order Schizomida: Short-Tailed Whip Scorpions

    Short-tailed whip scorpions are tiny creatures that inhabit leaf litter and debris in humid places. Poorly studied and understood, they are known to be active predators of even smaller animals.

Short-tailed whip scorpion, species undetermined. Florida, central Puerto Rico.

Order Araneae: Spiders

    Spiders are the typical eight-legged creatures that most people think of when the word "arachnid" comes to mind. Like the amblipigids and uropigids, all spiders have a "waist" that separates the cephalothorax from their abdomen.

    Unlike most other arachnid orders, spiders do not have segmented abdomens. The only exception to that rule are the primitive Old World mygalomorphs of the family Liphistiidae.

    Modern spiders are divided into two basic groups: Mygalomorphae and Araneomorphae. Mygalomorphs are the more primitive, though they still share with "typical" spiders (araneomorphs) the same basic body and appendage structure. However, they two groups can be immediately distinguished by looking closely at their chelicerae. In mygalomorphs, the fangs move in a vertical and front-to-back fashion. On the other hand, the fangs of typical spiders move and bite in a sideways fashion, "pinching" their prey as they feed or in defense from their attackers.

    Many spiders in both suborders exhibit protective maternal behavior. They enclose their eggs in silken sacks and, once the neonates are born, they often stay close to the mother, which cares for them for some time.

Suborder Mygalomorphae: Tarantulas and Their Kin

    As far as size goes, the most impressive spiders are the Mygalomorphae, many of them commonly known as "tarantulas". In fact, the name is something of an historical misnomer, since it was originally applied to some large wolf spiders near the village of Taranto, in Italy, and which belong to the unrelated araneid family Lycosidae. Some mygalomorphs are actually very small, but the largest species of South America and Africa have leg-spans wider than an adult human's spread hand.

    Like typical spiders, mygalomorphs produce silk, yet they do not spin nets. Their silk 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.

    There are several families in this suborder with West Indian members, like Theraphosidae, Barychelidae, Ctenizidae, and Dipluridae.

    Perhaps the largest family of the group is Theraphosidae, the true tarantulas. Most theraphosids are ground dwellers, and some are the largest living arachnids. Indeed, the most massive spiders are both South American: the Goliath tarantula, Theraphosa blondi, and its sister, Theraphosa apophysis.

    All tarantulas prey mainly on insects and other arthropods, and the largest will kill and devour small vertebrates like lizards and mice. In fact, some are called "bird-eating spiders", maybe for being occasionally found resting inside birds' nests after devouring the chicks.

    In spite of their menacing appearance, many tarantulas are actually docile creatures toward humans, and will never attack a person unless it is in self-defense. All the same a large, a cornered tarantula raised on its hind legs and baring its long, shiny black fangs is a sobering sight for anyone intending to pick it up with his bare hands. During the mating season, the males of some species are particularly ill-tempered and may indeed lunge to bite at the least provocation.

    Apart from their fangs and venom, some American tarantulas have a peculiar defense mechanism. Upon feeling threatened, they will vibrate their hind legs against their upper abdomens. Tiny barbed hairs ("setae") covering the abdomen will then fly through the air, finding their way to the mucous membranes of the mouth, nostrils, and eyes of the attacker. For many predators - and humans - the result is an obnoxious irritation that may last for hours.

    The males of many species are more mobile than the females, especially during mating season. Then, each of them may wander far and wide in search of a cantankerous - and often much larger - female that must be seduced by some sort of mating ritual, if he is not to find an ignominious end as her dinner, instead of her lover. Through stereotyped movements and touches, which vary by species, the male immobilizes his mate and then introduces into her genitals a pack of sperm (a "spermatophore") previously attached to the tips of his own pedipalps. During this operation, the male usually keeps the female's fangs at bay by holding them back with his front legs, which often have a sort of spurs for this purpose. If something does not go horribly wrong for him during the mating process, he then will make a hasty retreat and search for another prospective mate. Adult males that have mated several times will sometimes die soon after. Females, on the other hand, may live for many years.

A male greater Puerto Rican tarantula, Cyrtopholis portoricae, courts a female (inside the burrow) by tapping the entrance gently.

This individual is missing a leg, perhaps lost to a predator or rival.

Juncos, east-central Puerto Rico.

The tibial spurs of a male Cyrtopholis bartholomaei are used to keep at bay the long fangs of the female during amorous encounters.

Guana Island, British Virgin Islands.

    For most practical purposes, tarantulas are blind. Their tiny ocelli can only distinguish between light and darkness and since, at any rate, the organisms are nocturnal they find their way by the use of sensitive hairs on their legs and bodies. In fact, a tarantula usually senses your approach just by detecting the vibrations caused by your moving feet.

    Somewhat at odds with their fearsome appearance, tarantulas (like all spiders, really) 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 their prey and other debris. They daintily lick the tips of their pedipalps and legs to the same purpose.

    Mygalomorphs are widespread in the West Indies, though the group is strangely absent or very poorly represented in some insular banks, like Jamaica's and some of the Lesser Antilles.

FAMILY THERAPHOSIDAE: TARANTULAS

Subfamily Theraphosinae

    Most Caribbean tarantulas belong to the theraphosid subfamily Theraphosiinae. And perhaps the most widespread genus of that subfamily in the region is Cyrtopholis. It is found in all the Greater Antilles save Jamaica, and several of the Lesser Antilles. These are medium-sized terrestrial tarantulas that frequently inhabit burrows made by themselves. Males in search of females will often be found during the day simply lying under rocks and logs.

Subfamily Ischnocolinae

    The genus Holothele of the theraphosid subfamily Ischnocolinae contains small tarantulas with rather long, spindly legs. Lighting-fast when attacking their prey or fleeing danger, these spiders are found under debris like termitaria, rocks, and fallen tree trunk. They make rather flimsy silken nests in such places. In the Caribbean region, these tarantulas inhabit the Greater Antilles and some of the Lesser Antilles.

Subfamily Aviculariinae

    The members of another theraphosid subfamily, Aviculariinae, are adapted to a life on trees. They have velvety pads made of microscopic hooks under the distal portion of the legs and pedipalps which help them to walk nimbly on branches and leaves. (Many terrestrial theraphosids have similar structures, but in them they are much less developed). Aviculariines are represented in the West Indies by the genera Antillena, Caribena and Tapinauchenius. The first two taxa are small to medium-sized arboreal tarantulas, are endemic to the West Indies, in the Hispaniolan, Puerto Rican and Martinican insular banks.

Aviculariine tarantulas make silken nests in their arboreal hideouts. This is the nest of a male Puerto Rican pink-toed tarantula, Caribena laeta.

Virgin Islands National Park, Saint John, United States Virgin Islands.

(Photograph courtesy of Dr. Luis O. Nieves).

Nest of Caribena laeta, well camouflaged with silk and tree bark. Cambalache State Forest, north-western Puerto Rico.

Puerto Rican pink-toed tarantulas, Caribena laeta, adult male and juvenile. Virgin Islands National Park, Saint John, United States Virgin Islands.

This arboreal species makes tubular silk nests in holes in tree-trunks or in crevices in large boulders and limestone cliffs.

However, Virgin Islands' individuals seem especially adept at making their nests in the central rosettes of some species of bromeliads.

I had to peel away the leaves of the plant in order to photograph these individuals.

 

The colors of neonates and small juveniles of Caribena laeta are markedly differently from those of adults.

They were once thought to be a different species, called A. caesia.

Cambalache State Forest, north-western Puerto Rico.

Martinican pink-toed tarantula, Caribena versicolor, male. Captive specimen from Le Precheur, north-western Martinique, Lesser Antilles.
(Photograph courtesy of Dr. Rick C. West).

Hispaniolan pinktoe, Antillena rickwesti. Jaragua National Park, south-western Dominican Republic, Hispaniola.

Subfamily Psalmopoeinae

    This group contains both terrestrial and arboreal members. Several tree-dwelling species are found in the Lesser Antilles and resemble the aviculariines found on other islands. For the most part, the two groups do not overlap being, thus, allopatric.

    Tapinauchenius polybotes and P. rasti are endemic to the Saint Lucian and Grenadian island banks, respectively. They are large, velvety-brown or -black species that makes flimsy nests in crevices of tree trunks and boughs.

Windward tree tarantula, Tapinauchenius polybotes, female. Grande Anse, north-eastern Saint Lucia, Lesser Antilles.
These large and elegant spiders seem to be covered in brown velvet.


A captive female Tapinuchenius polybotes defends its spiderlings from an intruding camera lens.
This represents the first time the species has been bred in captivity. Notice the offspring huddling under her.
(Photograph courtesy of Dr. Rick C. West).


Arboreal tarantula, possibly Tapinauchenius rasti. Union, Saint Vincent and the Grenadines, Lesser Antilles.
(Photographs courtesy of Mr. Joseph Burgess).

FAMILY BARYCHELIDAE

    The spiders of the family Barychelidae are small and resemble the aforementioned Holothele. However, some of the Caribbean species, mostly belonging to the genus Trichopelma, possess definite climbing abilities, and during the day inhabit burrows excavated under bark on tree trunks, or among root tangles in cloud forests. These hideouts are lined with silk and their entrances may be additionally covered with debris held together with yet more silk. About half of the know species in the genus are Antillean.

Barychelid spider, Trichopelma sp. Dominican Republic, Hispaniola.

(Photograph courtesy of Dr. Rick C. West).

Barychelid spider, Trichopelma corozali. El Yunque National Forest, north-eastern Puerto Rico.

FAMILY CTENIZIDAE: TRAP-DOOR SPIDERS

    Some trap-door spiders of the family Ctenizidae are also found in the Antilles. Small in size, these species usually excavate their burrows under debris, and create a hinged door of soil held together with silk, and which seals the entrance when the animal hides inside.

Trap-door spider, genus Ummidia (undescribed species). Near Rabo de Gato, south-western Dominican Republic, Hispaniola.

Suborder Araneomorphae: Typical Spiders

    Many typical spiders are best known for their ability to spin webs which serve mainly as traps for their prey, usually insects (though some are able to entrap and kill even small bats and birds that fly into their webs). Some species, like those of the genus Nephila, produce silk which is stronger than a steel wire of the same width. As in mygalomorphs, the substance is produced from spinnerets located at the rear end of the abdomen. The ability to produce silk, and the precise uses given to it, vary greatly from one species to another.

    This group also contains the only known spiders that feed partially or mostly on plant matter, mainly nectar and pollen.

    Many families of this suborder are found in the Antilles and many, like Araneidae, contains huge numbers of species.

Spiny-backed orbweaver, Gasteracantha cancriformis. El Yunque National Forest, north-eastern Puerto Rico.

Military orbweaver, Micrathena militaris. Cambalache State Forest, northern Puerto Rico.

 

Araneid spider, Eriophora ravilla.
First photograph: immature female, Blue Mountains, east-central Jamaica.
Second photograph: female, Cambalache State Forest, northern Puerto Rico.

 

Araneid spider, Eriophora sp. Mount Sage, west-central Tortola, British Virgin Islands.

Araneid spider, Eriophora sp. Barbecue Bottom. north-central Jamaica.

Araneid spiders, Eustala sp., females.
First photograph: Guayanilla, south-western Puerto Rico.
Second photograph: Camp Santiago, south-eastern Puerto Rico.

Araneid spider, Verrucosa arenata. Carite State Forest, east-central Puerto Rico.

Araneid spider, Eriophora sp., with its prey. Padre Nuestro Nature Reserve, eastern Dominican Republic, Hispaniola.

Silver argiope, Argiope argentata (family Araneidae).
First photograph: Guanica State Forest, south-western Puerto Rico.
Second photograph: Cambalache State Forest, north-western Puerto Rico.

 

"Cleptoparasytism" is a behavior that denotes an organism stealing another's food.

Here an Argiope sp. has uninvited guests for dinner: two other, smaller spiders, Argyrodes nephilae.

La Parguera, south-western Puerto Rico.

Spider, Neoscona moreli, female. Camp Santiago, south-eastern Puerto Rico.

 

A member of the family Nephilidae: a golden orbweaver spider, Nephila clavipes, female, feeding on the proverbial fly.

The webs of this species can span two meters across, and can even trap hummingbirds and other small vertebrates.

Although only mildly venomous to humans, the fangs of a female can inflict quite a bite.

Camuy Caverns Park, Camuy, north-western Puerto Rico.

Looking like a miniature version of the comparatively immense female of Nephila clavipes,

this is the tiny tropical orb weaver, Leucage regnyi, female. (Family Tetragnathidae).

El Yunque National Forest, north-central Puerto Rico.

 

Leucage argyra, female. San Juan Botanical Garden, San Juan, north-eastern Puerto Rico.

 

Tetragnathid spider, Alcimosphenus licinus. El Yunque National Forest, north-eastern Puerto Rico.

    Although by far most araneomorph spiders are harmless to humans, the Antilles have their share of dangerously venomous forms. Some species of the genus Latrodectus (including the widespread black widow, L. mactans) are found in the region. Several species of Loxosceles (the genus that includes the equally infamous brown recluse) also inhabit some of these islands.

    A number of spiders, like those of the family Salticidae (jumping spiders), Thomisidae and Sparassidae (crab spiders), Selenopidae (huntsman spiders), and Lycosidae (wolf spiders) do not rely on web-spinning to capture their prey, but actively pursue their quarry, pouncing on them once the distance allows.

    Jumping spiders, in particular, are peculiar arachnids in that they exhibit a trait more often thought of from mammals and birds: curiosity. They seem to be intrigued by anything that moves near them. Often, if you approach a hand towards them, they will actually come closer to, and even jump on it in order to inspect the fascinating "intruder" better. Moreover, jumpers are tetrachromats: they possess four types of color receptor cells in their retinas (as opossed to our three types), and thus their color vision is better than a human's. They can even detect ultraviolet light. Like some birds, reptiles, and fish, they can distinguish colors that look identical to us.

Puerto Rican giant crab spider, Neostasina portoricensis, females. (Family Sparasidae).

First two photographs: Virgin Islands National Park, Saint John, United States Virgin Islands.
Third photograph: Bosque del Milenio, San Juan, north-eastern Puerto Rico.
Last photograph: Cambalache State Forest, northern Puerto Rico.

The first individual was sitting on its eggs inside its silken nest, which I had to remove from its original location inside a bromeliad, and then open, in order to photograph it.

When threatened they will defend themselves readily with their large fangs. Indeed, the bite of this species can be quite dangerous.

Giant crab spider, Neostasina sp., male. Guaynabo, north-eastern Puerto Rico.

Giant crab spider, Olios sp., male feeding on a scarabeid beetle. Layou Valley, south-western Saint Vincent, Saint Vincent and the Grenadines, Lesser Antilles.

A crab spider, Mecaphesa bubulcus feeds on a flower fly, Pseudodorus clavatus.

Camp Santiago, south-eastern Puerto Rico.

Crab spider, species undetermined. San Juan Botanical Garden, north-eastern Puerto Rico.
(Photograph courtesy of Mr. Alfredo Colon Archilla).

Crab spider, species undetermined. Guanica State Forest, south-western Puerto Rico.

Huntsman spiders, Selenops lindborgi, (family Selenopidae).

First photograph: Guanica State Forest, south-western Puerto Rico.

Last two photographs: Humacao, east-central Puerto Rico.

Wolf spider (family Lycosidae) species undetermined. Near Cabral, south-western Dominican Republic, Hispaniola.

Wolf spider, species undetermined, female. Camp Santiago, south-eastern Puerto Rico.

Wolf spider, species undetermined. Cat Island, The Bahamas.
(Photograph courtesy of Mr. Joseph Burgess).

Fishing spider, (family Pisauridae), Dolomedes sp. Monte Iberia, Guantanamo, south-eastern Cuba.

(Photograph courtesy of Mr. David Ortiz Martinez).

Fishing spider, probably Thaumasia marginella. San Juan Botanical Garden, San Juan, north-eastern Puerto Rico.

    Although social behavior is commonly known among some insects like ants, wasps, and termites, the same is rather uncommon among arachnids. However, some araneomorph spiders construct complex and seemingly chaotic webs which are the arachnid equivalent of a beehive. Many individuals, sometimes hundreds, inhabit the single structure, and cooperate in the capture and submission of their prey. These spiders are frequently very small, and when a large and powerful prey item say, a butterfly or grasshopper, falls into their trap they take turns biting and injecting venom into their victim. Given their tiny fangs, they do this in areas where the prey's chitin is thin, like the joints of the legs or neck. Sometimes after several hours and many such bites, the prey is finally immobilized, and all the spiders approach it safely to feed on its bodily fluids.

Collective web of social spiders, species undetermined.

The spiders themselves are tiny and hardly visible yet, collectively, still very efficient in killing prey far larger than they are.

Near Duverge, south-western Dominican Republic, Hispaniola.