Terrestrial Invertebrates

Cabrillo: Terrestrial Invertebrates

Terrestrial invertebrates include a wide range of animals that live on land and lack a backbone. While insects are the most numerous and diverse group of terrestrial invertebrates, the category also includes other groups such as arachnids (spiders and scorpions), myriapods (centipedes and millipedes), and various other invertebrate phyla like mollusks (land snails and slugs) and annelids (earthworms).

Cabrillo National Monument and the Point Loma peninsula are home to a remarkable variety of terrestrial invertebrates. This diverse group includes insects, spiders, millipedes, centipedes, and snails, each playing a vital role in the local ecosystem. The presence of some unique species makes Point Loma a significant area for invertebrate biodiversity.

Some Notable Species at the Park

One of the most intriguing residents of Cabrillo National Monument is a genus of trap door spider found nowhere else in the world. These spiders construct burrows with a cork-like lid, which they use to ambush unsuspecting prey. This adaptation not only showcases the spider's ingenuity but also highlights the unique evolutionary pathways that have developed in the isolated environment of Point Loma.

Black beetles, commonly known as stink bugs, are another ubiquitous presence in the area. Known for the defensive odor they release when threatened, these beetles play a crucial role in nutrient cycling by feeding on decaying plant material. Their ability to thrive in various environments makes them a vital component of the local ecosystem.

Adding a touch of enchantment to the nocturnal landscape, two species of glow worm beetle larvae have been identified on Point Loma. These larvae emit a faint glow, an adaptation used to deter predators and attract mates. Their presence is a testament to the peninsula’s diverse habitat, which supports a wide range of species.

The discovery of silk-spinning crickets on Point Loma in 1995 expanded our understanding of their distribution. Previously found only on Catalina Island and in the Tijuana hills, these wingless crickets are now known to produce silk to create shelters. This unique behavior among crickets adds another layer of ecological interest to the area.

Summary of Notable Species

Trap Door Spider

One of the most fascinating invertebrates found at Cabrillo National Monument is a genus of trap door spider that is endemic to the area. These spiders are known for their unique burrowing behavior. They construct burrows with a cork-like lid, which they use to ambush prey. This genus is found nowhere else in the world, highlighting the ecological uniqueness of Point Loma.

Black Beetles (Stink Bugs)

Black beetles, commonly known as stink bugs due to the defensive odor they release, are widespread in the area. These beetles play a crucial role in the ecosystem by feeding on decaying plant material and helping in nutrient cycling.

Glow Worms

Point Loma is home to two species of glow worm beetle larvae. These larvae emit a faint glow, which is a fascinating adaptation often used to deter predators and attract mates. Their presence adds a magical touch to the nocturnal landscape of the peninsula.

Silk-Spinning Crickets

Silk-spinning crickets are another intriguing species found on Point Loma. Until 1995, these wingless crickets were only known to exist on Catalina Island and in the Tijuana hills. The discovery of these crickets on Point Loma expanded our understanding of their distribution. These crickets produce silk to create shelters, a unique behavior among crickets.

Other Notable Invertebrates

Jerusalem Cricket (Potato Bug)

The Jerusalem cricket, also known as the potato bug, is a large, flightless insect found under rocks and wood in Point Loma. Despite their somewhat intimidating appearance, these crickets are harmless to humans. They play an important role in the food web, serving as prey for larger animals such as foxes and coyotes. Jerusalem crickets are nocturnal and feed on decaying organic matter, contributing to soil health.

Shoulderband Snail

The shoulderband snail is a small, land-dwelling mollusk that emerges from under rocks during the rainy season. These snails are primarily nocturnal and require moist environments to survive. They feed on plant material, algae, and fungi, playing a role in nutrient cycling and decomposition. The shoulderband snail’s activity is a key indicator of the health of the microhabitats within Cabrillo National Monument.

Ecological Significance

The invertebrates of Cabrillo National Monument are not only fascinating in their own right but also crucial to the ecological balance of the area. They contribute to various ecological processes such as pollination, decomposition, and soil aeration. Invertebrates also serve as a food source for many other animals, thus supporting higher trophic levels.

Conservation and Research

The unique invertebrate fauna of Cabrillo National Monument underscores the importance of conservation efforts in the area. Protecting these species and their habitats is vital for maintaining biodiversity. Ongoing research at the monument helps scientists understand the distribution, behavior, and ecological roles of these invertebrates, which in turn informs conservation strategies.