Gammarus lacustris

Classification

Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Superorder: Peracarida
Order: Amphipoda
Suborder: Senticaudata
Family: Gammaridae
Genus: Gammarus
Species: lacustris

Pronunciation

How to pronounce Gammarus lacustris: //ˈɡæmərəs ləˈkʌstrɪs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Gammarus lacustris 63100868 by msieges. Used under a CC0 license.

Gammarus lacustris 63100873 by msieges. Used under a CC0 license.

Gammarus lacustris 4868131 by Erin McKittrick. Used under a CC BY 4.0 license.

Gammarus lacustris 2273541 by Ken-ichi Ueda. Used under a CC BY 4.0 license.

Gammarus lacustris 22336145 by Matt Muir. Used under a CC BY-SA 4.0 license.

Gammarus lacustris 22336150 by Matt Muir. Used under a CC BY-SA 4.0 license.

Summary

Gammarus lacustris is a freshwater amphipod that plays a crucial role in aquatic ecosystems as a detritivore and food source for various animals. It exhibits distinct physical characteristics, complex life cycles, and varying reproductive strategies based on environmental conditions.

Physical Characteristics

Gammarus lacustris is semi-transparent and lacks a webbed tail. It may be colorless, brown, reddish, or bluish in color depending on the local environment. It has seven abdominal segments, a fused cephalothorax, and two pairs of antennae. The body is laterally compressed without a carapace, resembling a freshwater shrimp.

Identification Tips

Look for semi-transparent bodies, absence of webbed tails, and laterally compressed shapes. The presence of two pairs of antennae is also distinctive.

Habitat

Found in freshwater ecosystems, including shallow or deep lakes and slow-moving rivers. It can inhabit both low altitude calcium-rich lakes and high altitude cold calcium-poor lakes.

Distribution

Reported in northwestern Europe, Russia, and North America. The precise range is yet to be defined, but it follows the thermocline in the water.

Diet

Gammarus lacustris is a detritivore and may also consume algae, predominantly diatoms.

Life Cycle

Females carry eggs in a brood pouch on their ventral side. They undergo several molts, with juveniles resembling adults, and show variation in egg size based on elevation.

Reproduction

G. lacustris reproduces through brooding; at low altitudes, they may die after first reproduction, while in colder waters, they are known to reproduce multiple times.

Predators

Preyed upon by birds, fishes, and some insects.

Ecosystem Role

Considered an indicator species for ecosystem health and stability; an important food source for various organisms.

Similar Taxa

Misconceptions

Often mistaken for shrimp, but Gammarus lacustris is an amphipod and lacks a carapace, distinguishing it from typical shrimp.