Nematodes PDF

Species Discovery: The devil worm (Halicephalobus mephisto) was discovered 2.2 miles underground in South African gold mines.  Before 2011, no animals were thought to survive more than 1.2 miles underground. In 2011, devil worms were discovered thriving 1.2 miles below Earth’s surfa...

Species Discovery: The devil worm (Halicephalobus mephisto) was discovered 2.2 miles underground in South African gold mines.  Before 2011, no animals were thought to survive more than 1.2 miles underground. In 2011, devil worms were discovered thriving 1.2 miles below Earth’s surface in ancient groundwater. This suggests many undiscovered subterranean species may exist.  NEMATODES 50% Salt Water 25% Soil and fresh water 25% parasitic (Insect/ Domestic animals/Humans) (15% animals, 10% Plants like Important crops  Some entomopathogenic nematodes parasitize insects, reducing populations of insect pests. These nematodes have been used as a natural form of pest control, known as “biological pesticides.” They offer an eco-friendly alternative to chemical pesticides in managing pest species.  NEMATODES CHARACTERISTICS Triploblastic bilaterally symmetrical pseudocoelomates Cylindrical in shape flexible with unique body wall muscles lack cilia demonstrate eutely (cell constancy) Most are microscopic (5-100 µm by 0.1-2.5 mm) some free-living species can reach lengths of 5 cm some parasitic species can reach lengths of 1 m NEMATODE ANATOMY their heads are radially symmetrical 3 or 6 lips series of teeth NEMATODE ANATOMY NEMATODE ANATOMY NEMATODE ANATOMY NEMATODE ANATOMY NEMATODE ANATOMY Sensory bristles provide a sense of touch amphids provide chemoreception  NEMATODE ANATOMY Dioecious: either male or female androdioecious: hermaphroditic or rare males - males are smaller than females/hermaphrodites – males have copulatory spicules that insert into the female – fertilization is internal (eggs are stored in the uterus) NEMATODE ANATOMY NEMATODE ANATOMY Hermaphroditic self- fertilization  NEMATODE ANATOMY EGG LARVA  NEMATODE ANATOMY Microscopic and protected by a EGG tough outer shell  Role of nematodes in soil - Regulate populations of other organisms - mineralize nutrients into plant-available forms - provide a food source for other organisms - consume disease-causing organisms  Parasitic Nematodes Enter plant roots as larvae mature/mate within roots and lay eggs in soil knots block flow of water and nutrients Thank you!!