Starving grasshoppers? How rising carbon dioxide levels may promote an ‘insect apocalypse’
https://www.sciencemag.org/news/2020/04/starving-grasshoppers-how-rising-carbon-dioxide-levels-may-promote-insect-apocalypse
Source: By Elizabeth Pennisi, Science Magazine.
Excerpt: Empty calories may be grasshoppers’ downfall. Many insect populations are declining, and a provocative new hypothesis suggests one problem is that rising levels of atmospheric carbon dioxide (CO2) are making plants less nutritious. That could spell trouble not just for insects, but for plant eaters of all sizes. ...Ellen Welti, Kaspari’s postdoc, had been analyzing data on 44 species of grasshoppers at the Konza Prairie Biological Station, a 3487-hectare native tallgrass preserve in northeastern Kansas that is the site of a long-term ecological research (LTER) program. She tracked population trends in two surveys of grasshopper abundance, one done in undisturbed habitats from 1996 to 2017 and another done from 2002 to 2017 where bison grazed. Population booms and busts coincided with major climatic events, such as El Niño, a Pacific Ocean disturbance that alters temperature and rainfall. But when Welti factored out those events, it became clear to her and Kaspari that over the long term, the grasshoppers were declining, by 30% over 2 decades. “I was actually quite surprised,” Welti recalls. She and other researchers have assumed that habitat loss and pesticides underlie most of the reported drops in insect numbers. But those factors are not thought to be in play on the Konza Prairie. ...as Harvard University planetary health scientist Samuel Myers and his colleagues demonstrated in 2014, plants including wheat, maize, rice, and other major crops grown under expected future CO2 levels accumulate less nitrogen, phosphorous, sodium, zinc, and other nutrients than they do under current CO2 levels. The thinking is that roots cannot keep up with the growth stimulated by the extra carbon and therefore don’t provide adequate supplies of other elements....
Source: By Elizabeth Pennisi, Science Magazine.
Excerpt: Empty calories may be grasshoppers’ downfall. Many insect populations are declining, and a provocative new hypothesis suggests one problem is that rising levels of atmospheric carbon dioxide (CO2) are making plants less nutritious. That could spell trouble not just for insects, but for plant eaters of all sizes. ...Ellen Welti, Kaspari’s postdoc, had been analyzing data on 44 species of grasshoppers at the Konza Prairie Biological Station, a 3487-hectare native tallgrass preserve in northeastern Kansas that is the site of a long-term ecological research (LTER) program. She tracked population trends in two surveys of grasshopper abundance, one done in undisturbed habitats from 1996 to 2017 and another done from 2002 to 2017 where bison grazed. Population booms and busts coincided with major climatic events, such as El Niño, a Pacific Ocean disturbance that alters temperature and rainfall. But when Welti factored out those events, it became clear to her and Kaspari that over the long term, the grasshoppers were declining, by 30% over 2 decades. “I was actually quite surprised,” Welti recalls. She and other researchers have assumed that habitat loss and pesticides underlie most of the reported drops in insect numbers. But those factors are not thought to be in play on the Konza Prairie. ...as Harvard University planetary health scientist Samuel Myers and his colleagues demonstrated in 2014, plants including wheat, maize, rice, and other major crops grown under expected future CO2 levels accumulate less nitrogen, phosphorous, sodium, zinc, and other nutrients than they do under current CO2 levels. The thinking is that roots cannot keep up with the growth stimulated by the extra carbon and therefore don’t provide adequate supplies of other elements....