General Discussion
All New World arboreal tarantulas (Theraphosidae) are members of the Aviculariinae SIMON, 1874 subfamily. Six genera are currently recognized:

Avicularia LAMARCK, 1818 (53 species/2 sub-species)

Ephebopus SIMON, 1892 (4 species)

Iridopelma POCOCK, 1901 (3 species)

Pachistopelma POCOCK, 1901 (2 species)

Psalmopoeus POCOCK, 1895 (11 species)

Tapinauchenius AUSSERER, 1871 (9 species)

Due to the rarity of members of the genus Pachistopelma in the arachnocultural hobby and the terrestrial habits of members of the genus Ephebopus, neither genus will be discussed in this article.

The taxonomy of Avicularia is highly problematic and the species and sub-species within this genus are those that are currently recognized. However, as the systematics and taxonomy of the species and sub-species within this genus are mostly incomplete or unknown at this time, many future taxonomic changes are inevitable.

New World arboreal tarantulas range from Mexico throughout Meso and South America and several of the Greater and Lesser Antilles Islands. Although several species were described from North America, to date, no preserved material (specimens in private collections or museums) or natural populations (in the wild) have been discovered to confirm the past or present existence of the described species in North America.

All New World arboreal tarantulas inhabit tropical rain forest/forest systems throughout their range. Typical habitat includes, but is not limited to, tube or tent webs in/upon living and dead standing timber, exposed root systems, undergrowth, bromeliads (typically epiphytic plants), manmade structures, road banks and tall grass.

Description
New World arboreal tarantula species vary in size from several small Avicularia and Tapinauchenius species, which may only attain leg spans of 7.5 cm (3") to several members of the genera Avicularia and Psalmopoeus, which may attain leg spans of 17.5 cm (7") or slightly larger. Most species will average in size from 10 cm (4") to 12.5 cm (5") in leg span and are less robust in body size than

comparatively sized terrestrial species. Most are colourful (Avicularia, Iridopelma and Tapinauchenius) or patterned (Psalmopoeus) and many are coloured in bright metallic hues of bronze, pink, green, blue, purple or gold on the carapace, trochanters and femurs of the legs (several species within the various genera).

Members of the genera Avicularia and Iridopelma are covered in both short and long setae with a profusion of longer setae on the legs (primarily on legs III and IV) and around the anterior and lateral dorsal surfaces of the abdomen. Psalmopoeus and Tapinauchenius species are less profusely adorned with long setae than the members of the two above genera, with the abdomens of most species being densely covered in short, silky setae. The setae covering the legs of many species within these two genera give these tarantulas a sculpted, streamlined appearance in comparison to the members of Avicularia and Iridopelma, which typically appear more robust and "shaggy" in appearance. The males of all species within the above four genera currently available in the hobby are more profusely covered in longer setae than the females. Another characteristic feature of the males of many species of Psalmopoeus and Tapinauchenius is that the length of the legs in sexually mature specimens is greatly disproportionate to the length of the much smaller body, giving these tarantulas an almost comedic appearance.

Arboreal tarantulas are easily differentiated from their terrestrial cousins by the typically elongated abdomen and the presence of laterally widened and thickened scopulate pads on the metatarsi and tarsi. All tarantulas possess these pads, which are comprised of thousands of minute "hairs" (scopulae). The greater sizes of these pads on arboreal tarantulas are evolutionary modifications for life on a vertical surface. The enlarged pads allow arboreal tarantulas to move over smooth surfaces and the ventral surfaces of tree braches, as easily as terrestrial tarantulas move across the ground. It has also been reported that some New World arboreal tarantulas may jump from vertical surfaces (tree trunk, limb, etc.) to a stream or river below to elude predators. Such enlarged pads would surely assist the tarantula in moving quickly over the water's surface.

Behaviour
Aside from several popular members of the genus Avicularia, that are maintained in captivity and are known for their complacent and calm behaviours, the majority of the members of the remaining five genera, and several Avicularia species common in the arachnocultural (arachnoculture – keeping, maintaining and breeding arachnids in captivity) hobby are typically high-strung, fast, nervous, unpredictable and display varying degrees of defensiveness when disturbed, startled or handled. Defensive behaviours range from the tactile introduction of abdominal urticating setae by members of the genera Avicularia

and Iridopelma (Psalmopoeus and Tapinauchenius species do not possess urticating setae) to striking with the forelegs and/or rapid single or multiple bites (all species may exhibit these behaviours). Members of the genera Iridopelma, Psalmopoeus and Tapinauchenius should never be handled. Many Avicularia species are popular in the arachnocultural hobby and are widely known for their calm temperaments and tolerance of disturbances. However, there are several species such as Avicularia caesia, A. versicolor and A. huriana, which may be high-strung, nervous, unpredictable and some specimens bite with little provocation. Fortunately most Avicularia species, even those listed above, are easy to work with and maintain in captivity.

Some suggested Avicularia species for the novice:

Avicularia aurantiaca BAUER, 1996: Peru

Avicularia avicularia (LINNAEUS, 1758): Brazil, French Guiana, Guyana, Trinidad and Venezuela

Avicularia juruensis MELLO-LEITAO, 1923: Brazil

Avicularia metallica AUSSERER, 1875: Colombia and Surinam

Avicularia minatrix POCOCK, 1903: Venezuela

Avicularia purpurea KIRK, 1990: Ecuador

Avicularia urticans SCHMIDT, 1994: Peru

 

Aside from the species listed above, the following species are also commonly available in the hobby:

*Avicularia braunshausenii TESMOINGT, 1999: Peru

Avicularia geroldi TESMOINGT, 1999: Brazil

*Avicularia huriana TESMOINGT, 1996: Ecuador

*Avicularia caesia (C.L. KOCH, 1842): Puerto Rico

*Avicularia versicolor (WALCKENAER, 1837): Guadeloupe, Martinique & Dominica Islands

*Iridopelma hirsutum POCOCK, 1901: Brazil

*Iridopelma zorodes (MELLO-LEITAO, 1926): Brazil

*Psalmopoeus cambridgei POCOCK, 1895: Trinidad

*Psalmopoeus irminia SAAGER, 1994: Venezuela

*Psalmopoeus pulcher PETRUNKEVITCH, 1925: Panama

*Psalmopoeus reduncus (KARSCH, 1880): Costa Rica

*Tapinauchenius gigas CAPORIACCO, 1954: French Guiana

Tapinauchenius latipes AUSSERER, 1875: Venezuela

*Tapinauchenius plumipes (C.L. KOCH, 1842): Brazil, Peru, Surinam and Trinidad

 

*These species are capable of sudden bursts of movement and are typically

unpredictable in temperament and may bite if startled, disturbed or handled.

Other factors to consider when contemplating keeping arboreal tarantula species is that all species are capable of sudden bursts of high-speed movement and all are capable of making short lateral jumps of 25 cm or less when annoyed or startled. Some species such as Avicularia minatrix are highly accomplished jumpers and will jump with little provocation. Members of the genera Avicularia and Iridopelma possess urticating “hair” (setae) which are used in defence. These "hairs" (not true hairs that grow) are barbed and when the tarantula’s abdomen makes physical contact with the skin of another animal the urticating setae are imbedded into the predator’s skin.

In captivity, most New World arboreal tarantulas are shy and retiring, and are generally inactive during diurnal (day light) periods. As most tarantula species are active during crepuscular (dawn and dusk) and/or nocturnal (night) periods in the wild, most will replicate this behaviour in captivity. Few specimens will be seen moving about their containers during day light periods. Most will begin actively moving about their containers during the late evening hours. Many will become active during overcast days or if maintained in vivaria or in rooms with decreased light levels.

Growth and Longevity
All New World arboreal species exhibit fast to moderate growth rates with typical female specimens reaching sexual maturity within 22 to 30 months, and typical male specimens within 14-18 months. Atypical specimens may reach sexual maturity several months earlier or later than stated above. In captivity, growth rates are dependent on many factors such as temperature, diet, number of feedings per week, amount at each feeding, etc. Tarantulas maintained at higher temperatures and offered large numbers of prey items three to four times per week will normally, exhibit faster growth rates than tarantulas maintained at lower temperatures and fed sparingly.

Life spans for most tarantula species are unknown, but based on hobbyist reports and available information in various publications, the typical life span for New World arboreal species is believed to be in the range of 7 to 14-years.

Venom Potential
To date, those few individuals that have reported rare bites from New World arboreal tarantula species have indicated nothing more than the initial pain caused by the mechanical action of the bite itself, and minor local effects such as redness and swelling at the site of the bite.

Maintenance in Captivity
All New World arboreal species are hardy and easy to maintain in captivity with no special requirements. As for any arboreal species, the main requirement is a vertical piece of structure such as a slab or tube of cork bark or other barks that the tarantula can construct a tube web upon, behind or within. Other options are available such as short sections of dead tree limbs where the wood is decayed and can be removed to provide a hollow space for the retreat of a arboreal species, plastic PVC piping or small wooden birdhouses affixed to a wall within the vivarium. Always use aquarium silicone sealant to secure a vertical structure to the floor and/or wall of the vivarium to avoid the possibility of the structure toppling over when the vivarium or container is moved.

Getting Started
Research, research, research! Find out as much information on the tarantula species you are interested in acquiring and on tarantulas in general. A basic understanding of the tarantula's behaviours, anatomy, habits, habitat types, moulting and growth will allow you to not only better understand your tarantula(s), but will provide answers to many of the questions that the novice keeper will want answered. Whether you acquire one or more books, surf the web for tarantula-related sites, join a discussion group or one or more arachnocultural (hobbyist) societies, do enough initial research to allow you to acquire a basic understanding of tarantulas, their behaviours and their requirements in captivity.

Tools and equipment
Before acquiring your first tarantula, there are several basic tools and pieces of equipment that will make maintenance of your tarantula and its environment easier for you, and less stressful for your tarantula by decreasing disturbances within the vivarium.

The following items are suggested:

If you've acquired a spiderling or immature specimen then, it is also advisable to plan in advance and have a larger container or series of appropriately sized containers to accommodate the tarantula as it moults and grows.

Housing and Maintenance
Unlike their terrestrial kin, arboreal tarantulas only need a thin layer of substrate in their container/vivarium to provide a natural appearing environment, retain moisture and as material to use to conceal their retreats. Many arboreal species, after constructing a web retreat will add various materials such as substrate, bark chips or sphagnum moss to the outer surface of their web to camouflage and conceal it from predators. In captivity, this behaviour may decrease the likelihood of captivity-related stress, by providing the tarantula with a secure retreat in which it feels safe. As for substrate types, good substrate choices are any of the following, or a combination of them: premium grade topsoil, potting soil, peat or vermiculite (some arboreal specimens refuse to walk on vermiculite). A good mix is one that contains 50-60% topsoil and 40-50% peat (or, vice versa). This

mixture will retain a moderate amount of moisture and due to the acidic nature of the peat, will retard the decomposition of prey remains. As peat is hard to re-hydrate (wet), do not allow any substrate with peat to thoroughly dry out.

A few advantages and disadvantages in using the various substrates listed above:

Topsoil and potting soil: heavier than other substrates. Provides a "natural" look to the vivarium environment.

Peat: Hard to re-hydrate when dry. Lightweight and the acidic nature of peat retards the decomposition of prey remains, moulds and fungi.

Vermiculite: Many tarantulas dislike walking on vermiculite. It has an "unnatural" appearance. Lightweight. High moisture retention.

Contrary to the belief that arboreal tarantulas require exceptionally tall containers to thrive, all arboreal tarantula species can be maintained in enclosures where the height is equal to the outstretched leg span of the tarantula, plus fifty percent of that measurement. A standard 37 L (10-Gallon) aquarium offers more than enough space for a arboreal tarantula with a 15 cm (6") to 17.5 cm (7") leg span.

Suggested containers, sizes and basic set-ups:

40 to 50-dram clear plastic vials with removable lids. Using a heated nail or ice pick, melt 3-5 small holes in the vial and the lid to allow ventilation.

Add:

1 cm (0.5") of moistened substrate

Small piece of cork bark or other bark 1 cm (0.5") less than the vial’s length.

Small wad of dried sphagnum moss (to retain moisture in the substrate and for the tarantula to use to camouflage its retreat.

 

944 ml (32-oz.) clear plastic deli-containers with clear plastic lids, glass or plastic jars, small "Pet Pal" type plastic vivaria or small glass vivaria. Supply ventilation holes in any of the listed containers to provide airflow.

Add:

2.5 cm (1") to 5 cm (2") of moistened substrate

Vertical piece of cork bark, other bark or structure i.e., cork bark tube, hollow tree limb, etc.

A wad of dried sphagnum moss (see above)

Bottle cap, jar lid, small plastic deli-container (in larger containers) or another small container to use as a water dish for the tarantula and to assist in adding humidity (via the evaporative process) to the closed-environment.

Leg span from 7.5 cm (3") to 15 cm (6")
3.7 L (1-Gallon) glass or plastic jars, medium to large "Pet Pal" type vivaria or 20 L (5.5-Gallon) or 37 L (10-Gallon) glass vivaria. If using glass vivaria and commercially produced mesh screen lids, the lids should be modified as the tarantula's tarsal claws may become trapped in the mesh causing the tarantula harm or possibly death. Modify the lid by replacing the mesh screen with a piece of Plexiglas (drill 10-12 holes into it to provide ventilation). Hardware cloth can also be used as a substitute, but ensure that 50-60% of this material is masked with plastic to avoid excessive loss of humidity (aquarium sealant can be used to fix the material in place). Only use lids that can be securely locked onto the vivarium.

Add:

5 cm (2") of moistened substrate (in larger vivaria, adding a thin layer of moistened sphagnum moss over 50-80% of the substrate will allow a greater amount of moisture to be retained in the substrate for a longer period of time, decreasing the frequency of mistings per week).

One or two large vertical slabs of cork bark, cork bark tubes or other structure material.

A water dish. A good container to use for a water dish is a clear plastic 236 ml (8-oz.) deli-container.

Additional vivarium decorations: potted plants, artificial plants and vines, a piece of cork bark on top of the substrate. Keep the addition of extra vivarium decorations to a minimum as too many decorations will make maintenance a real chore and will afford the tarantula too many hiding places making it difficult to keep track of your tarantula's location when you are working in the vivarium. A potted Pothos plant in a corner of the vivarium makes a wonderful vivarium addition and along with the green of the sphagnum moss, adds a great deal of colour and life to the closed environment within the vivarium.

 

Have fun with decorating your tarantula's container/vivarium, but keep decorations to a minimum to avoid making vivarium maintenance a chore and to decrease the number of hiding places that your tarantula can utilize during maintenance.

Provide a piece of bark on top of the substrate as many arboreal tarantula species during various life-stages may utilize ground retreats. Many young Psalmopoeus and Tapinauchenius specimens will construct and/or excavate ground retreats.

Add peat if you're using topsoil or potting soil as a substrate. Its acidic nature will retard the decomposition of prey remains in the vivarium and it has a moderate moisture retention capacity.

What size tarantula?
What size tarantula you'll acquire as your first specimen will typically be influenced by your own personal opinion as to your abilities in working with a certain size specimen, cost and interests.

Spiderlings or small immature specimens seem the perfect choice for the novice arachnoculturist. Captive bred spiderlings of many arboreal species are

inexpensive and readily available from many breeders worldwide. Arboreal tarantulas of this size are also, easier to house, feed and maintain. Another benefit for the first time keeper is that he/she will be able to learn about the tarantula by observing its growth and behaviour throughout its development.

Regardless of the size tarantula you choose, remember that as an arachnoculturist, it is your responsibility to aid in the conservation of tarantula populations in the wild by acquiring captive-bred specimens thereby, supporting captive breeding efforts worldwide. Acquiring captive bred specimens will lessen collecting pressures on wild tarantula populations and ease the demand for wild-caught specimens. Although some wild-caught specimens are necessary to provide genetic diversity in existing and future breeding groups, there is little justification in taking hundreds or thousands of specimens annually from wild tarantula populations. Fortunately, many of the New World arboreal tarantula species are commonly bred, inexpensive and readily available in the hobby.

Feeding and diet
All arboreals will accept insect prey such as locusts, grasshoppers, crickets, mealworms and various species of cockroach. Larger specimens may accept pre-killed "pinkie" and "fuzzy" mice, anoles (Anolis carolinensis), prawns, crayfish and pieces of diced beef heart.

Spiderlings and smaller immature specimens should be offered prey at least 3-4 times per week and larger specimens 2-3 times per week. The size of prey should not be more than half the size of the tarantula. As each individual tarantula will exhibit varying eating habits, the number and/or amount of prey offered can vary greatly. Offer the tarantula several prey items and those not consumed within a 24-hour period should be removed.

Never allow living, non-eaten prey items to remain in the tarantula's container/vivarium during the moult stage as upon completion of its moult, the tarantula's integument and fangs are soft, unhardened and pliant and some prey items may attack the defenceless tarantula, feeding on its unhardened integument causing it injury and possibly death. If you suspect your tarantula may be in the pre-moult stage, cease offering prey and remove any prey items from the vivarium.

If your tarantula begins to refuse food items placed in the container/vivarium, it may be in the pre-moult stage (this stage may last several days to several weeks depending on species, the individual tarantula and its size). It is normal behaviour for tarantulas to stop feeding during the pre-moult and moult stages and for a short post-moult period that may last 2-12 days. Once again this depends on the species, the individual tarantula and its size. If the tarantula seals itself in its web and shows no signs of an impending moult then, the environment within the

vivarium may be too dry and/or too hot. Try a moderate misting or several light mistings over a 2-3 day period to elevate humidity levels within the vivarium. If your tarantula refuses to feed and use its retreat, the environment within the vivarium may be too humid and/or hot. Do not mist - allow the vivarium to dry out for 3-5 days. Both of the above-described behaviours are indicators that the tarantula is suffering captivity-related stress. Another indicator of captivity-related stress is when a tarantula is maintained in a high-temperature/high-humidity environment with restricted airflow. In this situation the tarantula may interpret the entire vivarium as the inside of its retreat and may cease using its regular retreat in favour of remaining in the open. In such environments, the tarantula may exhibit an increase in defensive behaviours during disturbances in the vivarium, and may rapidly rush about the vivarium perceiving that a "threat" is within its retreat.

Acknowledgements
As always, a 'special' thanks to Richard Gallon for his ever-valuable and kindly assistance in preparing this article.

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