Gammarus
Gammarus
Classification
- Phylum: Arthropoda
- Subphylum: Crustacea
- Class: Malacostraca
- Superorder: Peracarida
- Order: Amphipoda
- Suborder: Senticaudata
- Family: Gammaridae
- Genus: Gammarus
Pronunciation
How to pronounce Gammarus: /ˈɡæməˌrəs/
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Summary
Gammarus is a diverse genus of amphipods belonging to the family Gammaridae, which includes over 200 species adapted to a range of aquatic habitats. They are essential in their ecosystems for nutrient recycling and as prey for various higher trophic levels.
Physical Characteristics
Gammarus species typically exhibit a laterally compressed body shape with distinct segments and a streamlined appearance, aiding in their swimming abilities. They possess a pair of large compound eyes, antennae, and pleopods adapted for swimming.
Identification Tips
Gammarus can be identified by their elongated bodies, presence of a carapace that covers the first few segments, and their characteristic swimming movement. Specific identifying features may vary by species.
Habitat
Members of the genus Gammarus inhabit a variety of aquatic environments, including freshwater, brackish, and estuarine ecosystems, with specific species adapted to particular salinity levels.
Distribution
Gammarus species are found throughout the Holarctic region, with a significant presence in North America and many species occurring in Southeast Asia and the Northern Hemisphere tropics.
Diet
They are primarily detritivores and scavengers, feeding on organic matter, algae, and other small particles in their environment.
Life Cycle
The life cycle of Gammarus includes several stages: eggs, juveniles, and adults. They typically have a breeding season in spring or summer, with females carrying eggs in their brood pouch until they hatch.
Reproduction
Gammarus reproduce sexually, with females carrying fertilized eggs to maturity in a brood pouch. The number and timing of egg production can vary between species based on environmental conditions.
Predators
Common predators of Gammarus include fish, amphibians, and various invertebrates, which utilize them as a food source due to their high abundance in aquatic ecosystems.
Ecosystem Role
Gammarus plays a vital role in aquatic ecosystems by contributing to nutrient cycling and serving as a food source for various predators. Their feeding habits help break down organic material, which aids in the overall health of aquatic environments.
Collecting Methods
- Dip nets
- Sieving substrate
- Hand collection
Preservation Methods
- Ethanol preservation
- Freezing
- Drying
Evolution
Gammaridae is a well-represented family within the amphipods, showing significant evolutionary diversity with adaptations to various aquatic environments, including freshwater and estuarine habitats.
Misconceptions
Many people mistakenly think all amphipods are aquatic insects; however, amphipods like Gammarus are crustaceans, distinct from insects and are more closely related to shrimp.
Tags
- Crustaceans
- Amphipods
- Freshwater
- Estuarine