Hymenocera
Hymenocera is a genus of squat lobsters, also known as “decorator crabs” or “sponge crabs,” in the family Achaeidae. These fascinating crustaceans are known for their striking color patterns and their unique habit of decorating their shells with sponges and other materials.
Common Names
Hymenocera species are commonly referred to as "decorator crabs," "sponge crabs," or "harlequin crabs." These names reflect their distinctive behavior of adorning their shells with colorful sponges and other marine organisms.
Characteristics
Hymenocera crabs are small, typically reaching a maximum carapace width of about 3 cm. They are characterized by their vibrant, contrasting colors, often featuring a combination of red, orange, yellow, and black. The most well-known species, Hymenocera picta, displays a striking red body with white spots. The crabs are also recognizable by their flattened carapace, short legs, and prominent antennae.
Environments
Hymenocera crabs are found in tropical waters of the Indo-Pacific region. They are typically found in coral reefs, where they can blend in effectively with their colorful surroundings. These crabs are highly mobile and are often observed crawling across the reef substrate in search of food.
Diet
Hymenocera crabs are primarily carnivorous, feeding on sponges, anemones, and other small invertebrates. They use their powerful chelae (claws) to break apart their prey and consume the soft tissues.
Decorative Behavior
The unique decorating behavior of Hymenocera crabs serves several purposes:
- Camouflage: The sponges and other materials they attach to their shells provide excellent camouflage, allowing them to blend in with their surroundings and avoid predators.
- Defense: Some of the sponges and anemones they use contain toxins that can deter predators.
- Attracting mates: The vibrant colors and patterns of the decorations may play a role in attracting mates.
The crabs carefully select and attach the sponges and other materials to their shells using their specialized claws. They often rearrange these decorations over time, creating a unique and constantly evolving camouflage.