GLOBAL SWARMING
A plague of grasshoppers in Las Vegas, clouds of flying ants in Britain, locusts on the menu in Yemen
A wet spring in Las Vegas, Nevada, has spawned hordes of grasshoppers so large they’re showing up on the weather radar. It looked as if there were two storms – one north of Las Vegas (that was actual rain) and another right over the city; but the second one wasn’t moving as rain normally would, and was actually massive swarms of grasshoppers. In late July they covered the city, often concentrated around the Vegas lights and green spaces. Practically the whole city is covered in ultraviolet lights, the most iconic being the Sky Beam shooting up from the pyramidshaped Luxor. Many videos on social media show grasshoppers swarming around the Sky Beam.
The pallid-winged grasshoppers are from the Acrididae family and range from Argentina to British Columbia, but are concentrated in North America, particularly in desert ecosystems. Between 1952 and 1980 there were six grasshopper outbreaks in Arizona, one of which lasted two years. Outbreaks are recorded in Arizona, New Mexico, Utah and California. In this instance, the invasion was associated with unusually high rainfall around Vegas and to the south. The city averages 5in (13cm) of rain per year. From January to June the same amount of rain fell, equalling the annual total in the first half of the year. There’s not much residents can do about the grasshoppers, which are harmless. Officials discourage the use of pesticides, as those insects killed will simply be replaced within 24 hours. [CNN] 28 July; forbes.com, 29 July 2019.
Around the same time, a swarm of flying ants invaded Britain. What looked like ordinary rain clouds were in fact alive. The ants were so dense weather satellites picked them up as raindrops. This insect invasion is an annual swarming event, commonly known as ‘Flying Ant Day’, although it’s more like a season, occurring at any time between June and the start of September, with a peak that lasts several days. After a period of hot and humid weather, the black garden ants (Lasius niger) take to the skies in droves, cluttering the horizon, flying into homes and mouths, and distracting tennis players at Wimbledon. While “Flying Ant Season” is usually considered a nuisance, it is also hugely beneficial to the ecosystem. The ants are a vital source of food for birds and the way that they tunnel and dig their nests has profound implications for soil quality. sciencealert.com, 28 July 2019.
Meanwhile in Yemen, desert locusts inundated rebel-held Sana’a and surrounding regions, devastating farms but also providing a bumper crop of this Yemeni delicacy. Crowds chased the swarms of locusts using special nets. Men stood on rooftops with large nets, scooping the insects out of the air. Some people catch locusts at night when they’re not flying, by throwing scarves or other large pieces of cloth to trap them and then sweeping them into bags using shovels or their hands. This was the second major swarm to hit the Yemeni capital in recent weeks, with another passing through in June. Locals and traders said that locusts were a good remedy for numerous health problems, as well as being a good source of protein. “We know from our fathers and grandfathers that locusts are used to treat various conditions such as diabetes,” said a man in Sana’a central market. “Its taste is delicious. If you eat one locust, you will end up wanting to eat five,” said Sana’a resident Wadai al-Nawdah. “I walk every day after breakfast to find locusts for dinner. I have become addicted.”
Farmers, however, are less enthusiastic. The famed Yemeni grape farmers in the area who cultivate the country’s best vines said they had been particularly affected. An adult locust can eat its body weight in fresh vegetation every day and even a small swarm can consume enough food for 35,000 people in 24 hours. Once they swarm, they become highly mobile and are able to fly 150km (90 miles) in a day. With a female locust able to lay 300 eggs in her short life, a swarm can quickly grow to hundreds of millions of insects and measure miles across.
This year has seen several major swarms across the region after two cyclones in May and October last year brought heavy rains to a large area of Saudi Arabia’s Empty Quarter, one of the main locust breeding grounds. Three generations were born in a short time before they were detected by ground monitoring teams. Swarms have hit Yemen, Saudi Arabia, Iran, Jordan and Egypt and have even crossed to Sardinia. Locusts breed and gather anywhere across millions of hectares of desert from Morocco to Pakistan. Jerusalem Post, 3 June; thenational.ae (UAE), 29 July 2019.