For species dependent on monsoon flooding in desert southwest, mosquitoes unwelcome competition

Newly metamorphosed Couch’s Spadefoots. (Photo credit: Philip C. Rosen)
Newly metamorphosed Couch’s Spadefoots. (Photo credit: Philip C. Rosen)

The American southwest is typically a dry and dusty desert, yet during the summer torrential rains can spawn, streets flood and ponds suddenly appear, making prime breeding habitat for mosquitoes.

In the cities, local officials try to get rid of the standing water — but for some desert animals those brief pools can mean the difference between life and death.

Amphibians are pretty much the last animals you expect to find in a dry, dusty, desert town like Tucson, but after one, recent rain storm, a crowd gathered around a drainage pond and marveled at literally dozens of the creatures in the temporary body of water.

Phil Rosen, a research scientist in natural resources and the environment at the University of Arizona, said the animals were likely Couch’s spadefoot toads, which capitalize on these short-lived water supplies to breed.

"They’re uniquely explosive breeders with very short tadpole stages," he said.

The toads spend most of their lives underground, emerging each summer for maybe only a few nights of frantic feeding and breeding. Their eggs hatch within hours, and only seven or eight days later the tadpoles become toads.

"It’s the fastest metamorphosing species here, probably one of the fastest in the world," he said.

Unfortunately, the water in that drainage pond probably won't even last that long, meaning these tadpoles are unlikely to become frogs.

Listen to the rest of this September 21 Living on Earth feature (Public Radio International) at the link below.

Date released: 
Sep 25 2012
Contact: 
Phil Rosen