Locust swarms have infested large swaths of Africa, north and south of the Sahara.Locusts have been reported as far west as the Canary Islands and Cape Verde Islands in the Atlantic, Mauritania, Northern Nigeria, Chad, and sub-saharan Africa, they moved to North Africa, and even Southern Italy, then east to Egypt (first time since 1962) Jordan, Israel and Saudi Arabia, north to Lebanon (first time since World War I), and even crossed over from there to the island of Cyprus, the first such case in living memory. The BBC has some pictures of locust swarms.In Egypt, relatives tell me of things they never saw before. Swarms are present in many places, from Cairo, Alexandria, Borg El Arab west of Alexandria, the Oases, all the way east to the shores of the Red Sea (Ein El Sokhna). Swarms are seen in the sky as dark clouds over cities. If they descend, spraying of pesticides has to be performed. At one hotel, workers sweeped away the locusts and carried them away in sacks. In Borg El Arab, farmers burn tires when they see swarms in the sky to prevent them from descending. Some strawberry farms there have been devastated. At one relative's resort home, the door could not be opened because of countless locusts blocking it. It had to be sprayed to get rid of them. Swarms of locusts have also plagued eastern Australia. This is not the first time in recent memory, because it happened four years ago in Australia. Plagues of locusts have been known in history, such as the biblical event of a locust plague in Egypt at the time of Moses.Many people do not know that locusts are edible in many parts of the world. The book of Leviticus permits eating them, in contrast with other insects, which are forbidden. The gospel of Matthew and of Mark says that John the Baptist's food was locusts and wild honey. Similary, nomadic Arabs are known to eat locusts, as prophet Muhammad demonstrated, and this practice has been made acceptable in Islam. Two creative Australians have rebranded locusts as 'Sky Prawns' and published a book with more than 20 recipes for eating them. The UN Food and Agriculture Organization (FAO) has a frequently asked questions on locusts, that includes some recipes for cooking locusts. If you have a recipe, send it to them, and they will publish it. In Saudi Arabia, it is considered a delicacy, and fetches up to 200 US Dollars per kilogram! However, because of heavy use of pesticides to spray the swarms, eating them may be unsafe in such areas. While the government in Yemen is preparing to fight the swarms, the Yemenis are welcoming the locusts in order to eat them! Whether roasted, salted or boiled, they are an eagerly awaited delicacy over there.Why locusts change their behavior and form swarms in some years and not others has always been a topic of study.