A swarm of poisonous grasshoppers crawl over a leaf in rarely seen footage.

The clip filmed on February 23 in Pretoria, South Africa shows tens of the critters all clambering on top of each other while trying to reach the top of the plant.

Wildlife enthusiast Bob Humphries told Newsflare: "They are known locally as foam or lubber grasshoppers, and many produce a foul, foamy defensive secretion when disturbed. Their bright colouration serves as a warning to potential predators – eat me at your peril!"

South Africa has a rich fauna of large, brightly coloured grasshoppers belonging to the family Pyrgomorphidae. They are known locally as foam or lubber grasshoppers, and many produce a foul, foamy defensive secretion when disturbed. Their bright colouration serves as a warning to potential predators – eat me at your peril! This video shows two species of lubber grasshoppers. The first is the black and red Koppie Foam Grasshopper (Dictyophorus spumans) sitting on a Clivia leaf. This species accumulates heart poisons (cardiac glycosides) from the milkweeds that it eats and is exuding the foam on its back. These grasshoppers are known to kill dogs if eaten. The second species is the Elegant Grasshopper (Zonocerus elegans) and this video contains views of single adults, a mating pair and a Milkweed (their preferred food) covered in juvenile hoppers.