Aphonopelma chalcodes

This spider lives in the dry desert.

It digs deep holes in the soil. These holes keep the spider safe from the weather. The spider puts silk over the hole. The silk helps it feel when food is near.

Female spiders are tan. Males have black legs and a red body.

Spiders must shed their old skin to grow. This is called molting.

They can live a long time. Females can live for 30 years. This is a very long life for a spider.

The western desert tarantula lives in the dry desert.

It is also called the blonde tarantula. This name comes from its pale hairs. The hairs cover its top part. Its legs stay dark. These spiders live in Arizona and Mexico. They dig deep burrows in the soil. The holes help them stay safe from heat. The spider puts silk over the hole. This silk helps it feel when prey is near.

Females and males look different. Females are often a solid tan color. Males have black legs and a reddish body. Spiders must shed their old skin to grow. This way is called molting. They can molt twenty-five times in two years.

These spiders have two sets of eyes. The secondary eyes have tapeta. These are parts that help them see in dim light. They can live a very long time. Females can live up to 30 years. Males live for 5 to 10 years. Their venom is not very dangerous to humans. It is like a bee sting.

The western desert tarantula is a fascinating spider. You might know it by other names too. Some people call it the Arizona blonde tarantula. Others call it the Mexican blonde tarantula.

This name comes from the pale hairs on its carapace. The carapace is the top part of its body. These light hairs stand out against its dark legs. These spiders live in the deserts of Arizona and Mexico. They are very common in those dry areas. They are part of a large family called Theraphosidae.

These spiders have a very interesting way of growing. They must go through a thing called molting. Molting is when a spider sheds its hard outer skin. It then forms a new covering to help it grow. This spider goes through ten main stages of molting. It can molt twenty-five times over two years.

Each stage involves shedding a different part of the body. It might start with the back and end with the legs. This process usually happens during the spring months of March and April. They can molt at any time of the day.

Seeing the world is very important for their survival. These spiders have two sets of eyes. They have primary eyes and secondary eyes. The secondary eyes have something called tapeta. This is a special part that helps them see in dim light. Their eyes can sense light waves between 350 and 640 nm. They are most sensitive to light around 500 nm. Their eyes work a bit like the rods and cones in our own eyes. This helps them find food and stay safe.

Most of the spider's life happens in a deep burrow. They dig these holes in the desert soil. The deep holes help them stay safe from changing temperatures. They often live under stones or in old burrows. They place strands of silk across the entrance. This silk helps them feel when prey is nearby. When it is between 23°C and 31°C, they may leave their homes. They are often active at night, but they are not strictly nocturnal. They can sometimes be seen in the upper burrow during the day.

These spiders are known for living a long time. Females can live between 24 and 30 years. Males have shorter lives of about 5 to 10 years. When they reproduce, a female can lay about 600 offspring. The babies stay inside the mother for six to seven weeks. Their venom is not very dangerous to people. It is similar to the sting of a bee. Because they are gentle, people often keep them as pets. This makes them great for people learning to keep tarantulas.

The western desert tarantula, known scientifically as *Aphonopelma chalcodes*, is a significant species within the Theraphosidae family. It is recognized by several common names, including the Arizona blonde tarantula and the Mexican blonde tarantula. These spiders are primarily found in the deserts of Arizona and adjacent regions of Mexico, where they can be quite common. The name "blonde tarantula" specifically describes the appearance of the carapace, which is covered in dense, pale hairs. This light coloration creates a sharp visual contrast against the spider's dark abdomen and legs.

To survive in harsh desert environments, these spiders utilize a complex visual system. They possess two distinct sets of eyes, categorized as primary and secondary sets. These eyes allow for spectral sensitivity, which is the ability to distinguish between different wavelengths of light. The ocular cells in *A. chalcodes* are sensitive to wavelengths ranging from 350 to 640 nm. Their peak sensitivity occurs at approximately 500 nm, while their least sensitive point is at 640 nm. The secondary eyes feature a structure called a tapetum, or tapeta, which functions to amplify and detect dim light. This visual mechanism is similar to how rods and cones function in vertebrate eyes.

Growth in these invertebrates is achieved through a biological process called molting. Because they possess a hard exoskeleton, they must periodically shed this outer covering to increase their body size. For *A. chalcodes*, this process involves ten primary stages. Over a two-year period, an individual may undergo a total of twenty-five molts. Each stage involves the shedding of specific body parts, starting with the dorsum and moving toward the abdomen and legs. While molting can occur at any time of day, it is seasonally dependent. In this species, molting is most apparent during the spring months of March and April.

Life in the desert requires specific habitat adaptations to manage temperature fluctuations. *A. chalcodes* creates deep burrows in the soil, sometimes digging under stones or occupying abandoned burrows. These deep structures protect the spider from extreme environmental changes. The spiders typically remain inside these burrows unless temperatures reach between 23°C and 31°C. To assist with hunting, they stretch strands of silk across the burrow entrance. This silk acts as a sensor; when the silk is broken, it signals the presence of prey. While they are often active at night, they are not strictly nocturnal, as they may appear in the upper burrow during daylight hours.

Reproduction in this species involves distinct sexual differentiation that occurs later in development. All spiders are born resembling females, but males eventually develop male-specific traits. Males develop palpal bulbs, which are used to store and transfer sperm into the female's genital opening. Females possess abdominal pouches called spermathecae, which store sperm until they are ready to lay eggs. During reproduction, the female lays eggs in the male's sperm to provide necessary nutrients. A single female can produce an average of 600 offspring following a gestation period of six to seven weeks.

There is a significant difference in the life expectancy between the sexes. Females are known for their longevity, often living between 24 and 30 years. In contrast, males have a much shorter lifespan, typically ranging from 5 to 10 years. This disparity is attributed to differences in their reproductive organs and overall development. Because of their long lives and generally docile nature, these spiders are popular choices for beginner tarantula keepers.

Finally, the chemical makeup of their venom and serum provides interesting scientific data. The venom contains neurotoxins known as Apc600 and Apc728, which include compounds like spermine and 1,3-diaminopropane. These toxins are theorized to cause short-term paralysis in prey. However, the venom is not highly dangerous to humans and is comparable to a bee sting. Beyond venom, researchers have identified lectins in their serum. Lectins are proteins that bind to carbohydrates, specifically sialic acids. Since sialic acids are vital for metabolism and neural development, the way these lectins bind to them remains a subject for further investigation.