Gammarus Duebeni
The Gammarus Duebeni is an amphipod species found in freshwaters in North America. The Gammarus Duebeni is also commonly referred to as freshwater shrimp. This species’ preferred habitat is in the temperate region, specifically in clear, cold waters. This includes springs, ponds, streams, pools, and lakes. When the Gammarus Duebeni is found in rivers, they tend to be found near the edges of backwaters. The Gammarus Duebeni has a salinity tolerance and therefore can also be found in estuaries. The species cannot tolerate warm temperatures and will die in temperatures higher than 34C.
The Gammarus Duebeni reproduces sexually. Mating occurs after the females molt and ovulate. The species is monogamous. Once the male makes bodily contact with a female, he “chases her, touches her with his divergent antennae and catches her by an appendage” (Sutcliffe). When the male ejaculates sperm, his female partner then puts it in her pouch. Once in there, her oviducts open and the eggs can begin to fertilize. After the mating, the males disperse while the females carry the eggs in their pouches until they hatch and the juveniles grow appendages. The gestation period is between one and three weeks and breeding usually takes place between April and November, depending on water temperatures. After the juveniles have grown appendages, they are released into the open water and the mother is relieved of her maternal duties. The offspring of some Gammarus Duebeni pairs can sometimes be either all males or all females. Juveniles of Gammarus Duebeni, “are sensitive to fluctuations in day length; more males develop after exposure to long daylight hours whereas more females develop at short daylight hours” (Sutcliffe).
The Gammarus Duebeni is a motile creature. However it often holds onto vegetation or digs itself into the ground in order to avoid being swept away by strong currents. The creature can crawl on the bottoms of freshwaters by using its appendages in order to propel themselves forward. Furthermore, the Gammarus Duebeni is able to swim and by using its legs to help itself swim. The nutrition of the Gammarus Duebeni consists of various small aquatic animals and small algaes. The Gammarus Duebeni feed on detritus, zoo-plankton, micro plankton as well as algae . They are categorized as scavengers although they rarely attack living animals. When they do, they often attack aquatic animals that have already been injured or are newly dead.
1. Sutcliffe, David W. "Reproduction in Gammarus (Crustacea, Amphipoda): Basic Processes.” Freshwater Forum 2.2 (1992): 102-28. Web..

2. Macneil, Calum, Jaimie T. A. Dick, and Robert W. Elwood. "The Trophic Ecology Of Freshwater Gammarus Spp. (Crustacea:amphipoda): Problems And Perspectives Concerning The Functional Feeding Group Concept." Biological Reviews 72.3 (1997):