17 Year Cicadas: Emerge

a17 Year Cicadas: Emerge

mbience: cicadas

For the past 17 years, billions of cicada nymphs have been living in underground burrows across the country. Well, this summer these nymphs simultaneously emerged from their burrows, transformed into adult cicadas and began mating. But living underground, how did the nymphs know precisely when to emerge? I’m Jim Metzner, and this is the Pulse of the Planet. Dr. Mike Raupp is professor of Entomology at the University of Maryland.

“Underground the cicada nymphs are deprived of light. Most animals use light as an important cue for regulating their development. But these guys have no light underground. How do they know when the 16 years go by? They’re tapped into the sap of the tree and what scientists think, is they are actually measuring the annual fluxes – the annual changes in nutrients and perhaps hormones – in the roots of that tree, and using a biological clock, are able to count those 16 years. Once the 17th spring arrives, we think they use soil temperatures, basically as a cue – an indicator – for the fact that the air temperature is actually warm enough for them to emerge, evade predators, sing, mate and reproduce successfully. When the soil temperatures reach the middle sixties, that’s when they come out of those exit holes and make the mad dash for life – for the tree trunk.”

That mad dash for the tree trunk signals the next stage in the cicadas development from a nymph to an adult. We’ll hear more in future programs.

Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.

music

17 Year Cicadas: Emerge

How do billions of cicada nymphs know how to emerge simultaneously?
Air Date:08/05/2004
Scientist:
Transcript:

a17 Year Cicadas: Emerge

mbience: cicadas

For the past 17 years, billions of cicada nymphs have been living in underground burrows across the country. Well, this summer these nymphs simultaneously emerged from their burrows, transformed into adult cicadas and began mating. But living underground, how did the nymphs know precisely when to emerge? I'm Jim Metzner, and this is the Pulse of the Planet. Dr. Mike Raupp is professor of Entomology at the University of Maryland.

"Underground the cicada nymphs are deprived of light. Most animals use light as an important cue for regulating their development. But these guys have no light underground. How do they know when the 16 years go by? They're tapped into the sap of the tree and what scientists think, is they are actually measuring the annual fluxes - the annual changes in nutrients and perhaps hormones - in the roots of that tree, and using a biological clock, are able to count those 16 years. Once the 17th spring arrives, we think they use soil temperatures, basically as a cue - an indicator - for the fact that the air temperature is actually warm enough for them to emerge, evade predators, sing, mate and reproduce successfully. When the soil temperatures reach the middle sixties, that's when they come out of those exit holes and make the mad dash for life - for the tree trunk."

That mad dash for the tree trunk signals the next stage in the cicadas development from a nymph to an adult. We'll hear more in future programs.

Pulse of the Planet is made possible by the National Science Foundation. I'm Jim Metzner.

music