Aphonopelma chalcodes is often a victim of parasitism. A species of fly lays its eggs on the tarantula's back, and when the larvae hatch, they devour the tarantula. A species of wasp, known as tarantula hawks, attack these tarantulas, and if successful, inject their victim with poison and paralyze it. The wasp then drags the tarantula back to its nest and places it next to its eggs. The tarantula can often live for a few months in this paralyzed state, until the eggs hatch and then eat the tarantula.
Aphonopelma chalcodes is a solitary creature which lives the majority of its life alone. It makes no sounds, and since tarantulas have poor vision, this species communicates with the outside world and the opposite sex primarily by touch. (Miller, 1988).
Communication Channels: tactile
Perception Channels: visual ; tactile ; vibrations
Aphonopelma chalcodes is not endangered in any way.
When young A. chalcodes emerge from an egg, they all resemble females (Milne and Milne, 1980). It is not until later that sexual differentation occurs. Most spiderlings do not survive to reach sexual maturity (Jackman, 1997). They are either eaten by predators or do not find enough food to survive.
Aphonopelma chalcodes does not have a great negative impact on humans. Although its bite is painful, it is not highly poisonous. The venom is similar to that of a mosquito or a bee sting.
Negative Impacts: injures humans (bites or stings, venomous )
Aphonopelma chalcodes has little economic value to humans. It is sometimes sold as a pet, due to its gentle nature and easy maintenance (Miller, 1988). Desert tarantulas also control pests by eating beetles, grasshoppers, millipedes, and other spiders (Miller, 1988).
Positive Impacts: pet trade ; controls pest population
These spiders presumably impact insect population through their predatory behaviors. As a possible prey species, A. chalcodes may have some positive influence on the populations of its predators and parasites.
Aphonopelma chalcodes spends much of the day hiding in its burrow. When the sun sets, it emerges and begins to search for food.
Foods eaten: lizards, crickets, beetles, grasshoppers, cicadas and caterpillars.
Animal Foods: reptiles; insects
Primary Diet: carnivore (Insectivore )
Desert tarantulas, Aphonopelma chalcodes, are common throughout the Southwestern United States, especially Arizona, New Mexico, and Southern California.
Biogeographic Regions: nearctic (Native )
Aphonopelma chalcodes often resides in desert soil. It makes its home in burrows by digging itself under stones or by utilizing burrows discarded by rodents. It may live in the same burrow for decades. Since it lives in the desert, A. chalcodes is acclimated to harsh weather conditions. It does not require much water to survive, and can therefore survive in the extreme heat of the desert.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: desert or dune
Male and female desert tarantulas have very different life expectancies. While it takes approximately 8 to 10 years to become sexually mature for both sexes (Miller, 1988), males, after molting for the last time, live for approximately 2 to 3 months. Females, however, continue to molt (shed their exoskeleton as they grow), and may live for up to 20 years. In captivity, females have been known to live for 25 years (Milne and Milne, 1980).
Range lifespan
Status: captivity: 20 (high) years.
While sexual dimorphism is apparent in adult A. chalcodes, it is not as drastic as seen in other species. Males have a diameter of 49 to 61 mm, whereas females range from 49 to 68 mm, with a leg span of approximately 98 mm. Desert tarantulas, like other tarantula species, have a body covered entirely with hair. Like all spiders, they are divided into two body segments: the cepholothorax and the abdomen. The cepholothorax is gray to dark brown and the abdomen is dark brown to black. Iridescent hair forms a pad below the tip of each of the eight legs (Milne and Milne, 1980). Tarantulas inject poison into their victims by biting them with fangs on the end of the chelicerae (Jackman, 1997).
Other Physical Features: ectothermic ; bilateral symmetry ; venomous
Sexual Dimorphism: female larger
Humans pose no real threat to desert tarantulas at this time, and A. chalcodes has few natural predators. Only birds and two parasitic insect species (a fly and a tarantula wasp) have been recorded as killing these spiders. When disturbed, desert tarantulas maneuver to face the threat, raise up on their hind legs, and stretch their front legs in a threatening posture. Aphonopelma chalcodes may also rapidly brush the top of its abdomen with its hind legs, which dislodges urticating hairs that can irritate the eyes or skin of an attacker (Jackman, 1997). These poisonous hairs can cause rashes or even partial blindness in the attacker (Miller, 1988).
Known Predators:
The male emerges from its burrow at sunset and then again near dawn. A male tries to maintain contact with the female, and if she pulls away, he will actively pursue her.
Males have two specialized claws that are shaped like syringes on the ends of its two pedipalps. Male A. chalcodes weave a purse to hold the sperm, which he then loads into the specialized claws. Females have two pouches on the abdomen that are designed to hold the sperm sacks. Sperm sacs can be stored for weeks or months in the female's abdomen until she is ready to lay her eggs. As a female lays her eggs, she bathes each egg in the sperm (Miller, 1988). She weaves a silken sheet and lays up to 1,000 eggs on it. After laying all her eggs, she weaves another sheet, covers the eggs, and then seals the edges. After making this egg sac, a female carries it up to the edge of her burrow to warm it in the sun. Females guard their egg sac until the eggs hatch in up to 7 weeks (Miller, 1988). Three to six days after hatching, the young leave the nest and venture out on their own.
Breeding season: June through December
Range number of offspring: 100 to 1000.
Average number of offspring: 600.
Average gestation period: 7 weeks.
Range : 3 to 6 days.
Range time to independence: 3 to 6 days.
Range age at sexual or reproductive maturity (female): 8 to 10 years.
Range age at sexual or reproductive maturity (male): 8 to 10 years.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous ; sperm-storing
Females care for their offspring in a number of ways. In addition to making a safe place for the eggs to hatch, and provisioning those eggs with nutrients, females actively help the eggs incubate by keeping them warm in the sun. Presumably, the female provides protection for the young spiderlings as they live in and around her burrow until they are three to six days old.
Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Protecting: Female)
Aphonopelma chalcodes, commonly known as the western desert tarantula, Arizona blonde tarantula or Mexican blonde tarantula, is a species of spider belonging to the family Theraphosidae. It has a limited distribution in the deserts of Arizona and adjacent parts of Mexico but can be very common within this range. The common name "blonde tarantula" refers to the carapace, which is densely covered in pale hairs, and contrasts strongly with the all-dark legs and abdomen. Additionally, these spiders have low toxicity, a long life expectancy, and several offspring.[2]
This 3 to 5 in (8 to 13 cm) large bodied, burrowing spider is commonly seen during the summer rainy season in southwestern deserts. The female is usually a uniform tan color. The male has black legs, a copper-colored cephalothorax and a reddish abdomen. The female body length is up to 56 mm, males only reaching 44 mm. Their burrows can be as large as 1 to 2 in (25 to 51 mm) in diameter, with some strands of silk across the opening.[3]
Multiple lectins have been detected in the serum of Aphonopelma chalcodes. Simply, lectins are proteins that bind to carbohydrates.[4] Research studies illustrate that the lectins within the serum of A. chalcodes have the ability to bind to sialic acid.[4] The function of sialic acids is diverse, including contributing significantly to protein folding, neural development, and metabolism.[5] However, the implications of the lectins binding to sialic acid must be investigated further.
The visual system of A. chalcodes is critical to its survival as spiders rely on their spectral sensitivity and visual acuity in order to survive. These spiders have two sets of eyes, referred to as the primary and secondary sets. Spectral sensitivity within these eyes is critical as it is essential in distinguishing different wavelengths.[6] The peak response amplitudes of these spiders were directly correlated to the intensity of light that was exhibited. However, it was also found that the period of depolarizations, pertaining to receptor potentials, was longer for longer flashes.
Additionally, the spectral sensitivity of the species was assessed. The range of wavelength sensitivity in all ocular cells was between 350 and 640 nm. The most sensitive spectral sensitivity was around 500 nm and the least sensitive point was at 640 nm.[6] Both the primary and secondary sets of eyes had very similar spectral sensitivities and waveforms. Research studies have demonstrated that the receptor potentials of the tarantula photoreceptors in response to light flashes was characterized by smooth depolarizations. Lastly, secondary eyes in these spiders have tapeta, which are used to amplify and detect dim light more effectively than primary light. The function of both the primary and secondary eyes in A. chalcodes resembles the functions of rods and cones in other vertebrates.[6]
Molting is a biological process that invertebrates often go through. Molting in spiders consists of shedding the exoskeleton and forming a new covering through different developmental stages.[7] This process allows spiders to grow as they go through different stages of development.[7] The molting of A. chalcodes has been determined to occur through ten primary stages, with a total of twenty-five molts occurring over a two-year period.[8] Each stage of molting corresponds to shedding of a different portion of their exoskeleton ranging from the dorsum to the abdomen and ultimately the legs. Additionally, each stage of molting does not take the same amount of time, with the first stage being the most extensive.[8]
Additionally, tarantulas are able to molt any time of the day. Research studies have illustrated that molting is not restricted by any time of day.[8] Although molting is not dependent on the time of day, it is seasonally dependent. In A. chalcodes, molting is especially apparent during March and April.[8] The reason for why tarantulas tend to molt during spring are not currently known, however it has been established that is seasonally dependent.
The spider undergoes sexual differentiation later in development, as it is born resembling a female. After several years, the spider may begin to display male traits after further differentiation.[9] Male A. chalcodes develop palpal bulbs, intended to store sperm and insert it into the female's genital opening. Females possess abdominal pouches (spermatheca) that are utilized in order to store sperm until reproduction occurs through the laying of eggs. When reproduction occurs, females lay eggs in the male's sperm in order to provide nutrients for the offspring.[10] The average number of offspring is 600, with an average gestation period of about six to seven weeks.
The life expectancy of an average A. chalcodes is about 24–30 years for females, and 5–10 years for males. This is highly dependent on the habitat and respective development of each spider, however in general, one can expect a high life expectancy in this particular species. The significantly higher life expectancy for females in comparison to males can be attributed to differences in development and reproductive organs.[11]
Aphonopelma chalcodes, the western desert tarantula, occupies several states within the southwestern United States. Specifically, these spiders are known to be common in New Mexico and Arizona within the United States.
This spider often lives in desert soil and is resistant to harsh weather. These spiders often reside in burrows which they create for themselves. These burrows are very deep in order to help the spider resist and adapt to fluctuations in environmental temperature. However, when temperatures are between 23˚C and 31˚C, these spiders leave the burrows into the general outdoors.[12] A. chalcodes makes residence in burrows through digging under a stone or living in isolated burrows that are not being used.[13] The entrance to the burrow is surrounded by strands of silk, which allow the spider to detect that prey are present while it is hiding in the burrow.
The nocturnal activity of this spider begins when the silk covering surrounding the burrow is broken. Potential reasons explaining the breaking of the silk covering include the spider's circadian rhythm, decreased environmental light intensity, and surface temperatures.[12] During the night, tarantulas remain inside the burrow entrance expecting the arrival of prey. At dawn, the tarantula goes into the burrow.[12] Although A. chalcodes is particularly active at night, it is not strictly nocturnal because they are seen in the upper portion of the burrow early in the day.[8]
In general, spider venoms contain several classifications of neurotoxins that are relevant to the development of insecticides and other pharmaceutical preventative measures.[14] Specifically, the venom of A. chalcodes contains two compounds referred to as Apc600 and Apc728. Analysis of these neurotoxins within the venom revealed the presence of spermine, a polyamine involved in cellular metabolism, and 1,3-diaminopropane. These toxins have not been investigated significantly, however are theorized to function in short term paralysis or immobilization of the tarantulas' prey.[14]
The venom of A. chalcodes is not highly dangerous to humans. When compared to a bee sting, the level of venom is not significantly higher.[10] Specifically, these spiders are one of the least dangerous within their family of Theraphosidae.
They are popular among beginner tarantula keepers due to their long lifespan (5–10 years for males, up to 30 years for females) and docile nature.[3]
Preston-Mafham, Ken (1998). Spiders: Compact Study Guide and Identifier. Angus Books. ISBN 978-1-904594-93-2.
Aphonopelma chalcodes, commonly known as the western desert tarantula, Arizona blonde tarantula or Mexican blonde tarantula, is a species of spider belonging to the family Theraphosidae. It has a limited distribution in the deserts of Arizona and adjacent parts of Mexico but can be very common within this range. The common name "blonde tarantula" refers to the carapace, which is densely covered in pale hairs, and contrasts strongly with the all-dark legs and abdomen. Additionally, these spiders have low toxicity, a long life expectancy, and several offspring.
