Invertebrates
Crustaceans
Unlike Lake Tanganyika with its many endemic freshwater crabs and shrimp, there are few such species in Lake Malawi. The Malawi blue crab, Potamonautes lirrangensis (syn. P. orbitospinus), is the only crab in the lake and it is not endemic. The atyid shrimp Caridina malawensis is endemic to the lake, but it is poorly known and has historically been confused with C. nilotica, which is not found in the lake. Pelagic zooplanktonic species include two cladocerans (Diaphanosoma excisum and Bosmina longirostris), three copepods (Tropodiaptomus cunningtoni, Thermocyclops neglectus and Mesocyclops aequatorialis), and several ostracods (including both described and undescribed species).
Lake Flies
Huge swarms of lake flies
The Malawi lake flies (Chaoborus edulis), resembling distant plumes of smoke over the water
Lake Malawi is famous for the huge swarms of tiny, harmless lake flies, Chaoborus edulis. These swarms, typically appearing far out over water, can be mistaken for plumes of smoke and were also noticed by David Livingstone when he visited the lake. The aquatic larvae feed on zooplankton, spending the day at the bottom and the night in the upper water levels. When they pupate they float to the surface and transform into adult flies. The adults are very short-lived and the swarms, which can be several hundred metres tall and often have a spiraling shape, are part of their mating behaviour. They lay their eggs at the water’s surface and the adults die. The larvae are an important food source for fish, and the adult flies are important both to birds and local people, who collect them to make kungu cakes/burgers, a local delicacy with a very high protein content.
