Cross species breeding in spadefoot toads

This video about spadefoot toads says about itself:

Awesome toads that only come out during massive rain-storms. Found this guy sitting in the middle of the road. Released him out in a pond afterwards.

From New Scientist:

Mating toads cross the species barrier

* 17 November 2007
* From New Scientist Print Edition. Subscribe and get 4 free issues.

YOU’D think it would be a bad idea to mate with another species, but not if you’re a spadefoot toad.

Because spadefoot toads breed in temporary pools their tadpoles must race to mature before the pools dry up. When Spea bombifrons females mate with males of a quicker-maturing species, S. multiplicata, their tadpoles grow faster than if they mate with their own species.

When the pools are shallow, Karin Pfennig of the University of North Carolina at Chapel Hill found that female S. bombifrons are more likely to choose mates of the other species (Science, DOI: 10.1126/science.1146035). This behaviour suggests the female toads‘ choice of mates depends on the need for faster-developing young, says Pfennig.

Females who mate with the other species do better than non-hybrid toads even though their offspring are often sterile or produce fewer eggs.

Plains spadefoot toad ringtone: here.

2 thoughts on “Cross species breeding in spadefoot toads

  1. By Karen Jeffrey

    May 16, 2010

    The early arrival of spring with its buckets-full of rain followed by the recent chilly spell is bad news if you’re a mosquito, but good news if you’re an amphibian on Cape Cod.

    Cooler air temperatures have kept water temperatures low in favorite mosquito breeding sites and this means eggs are developing slowly, said entomologist Gabrielle Sakolsky of the Cape Cod Mosquito Control Project.


    Bye-bye, bugs

    How to minimize mosquito breeding on your property:

    * Add goldfish to your ornamental pond for looks and mosquito control.
    * Don’t let bilge water accumulate in your boat. Store small boats upside down or cover them to keep out the rain and water from sprinklers.
    * Remove and dispose of all unused containers that will collect rain or water from sprinklers, and check your yard for objects that can collect water such as tarps, old tires, and buckets.
    * Be sure to change water weekly if you are rooting plant cuttings in vases or buckets.
    * Store containers upside down to prevent accumulation of water.

    Source: Cape Cod Mosquito Control Project


    The plethora of precipitation this spring — with record rainfall in March — has kept pond levels high, and that encourages amorous behavior among spadefoot toads, said Robert Cook, wildlife ecologist at Cape Cod National Seashore.

    “We’ve seen an eruption of activity among spadefoot toads, earlier this year than in previous years,” he said. And by eruption of activity, Cook means the toads are happily hopping into reproduction.

    The old truism that a wet spring portends a buggy summer is not always true, because “there are so many variables in nature,” Sakolsky said.

    “We’ve got to get crews out there now,” she said of the control project’s campaign to keep the mosquito population at bay. “And the weather has been working for us.”

    This spring’s early, wet arrival has not had an impact on the Cape’s tick population, said David Simser, entomologist for the Cape Cod Cooperative Extension. “The tick population is what it is right now,” he said. “We’re not seeing an increase or a decline.”

    Depth of water in favorite mosquito breeding areas in salt marshes and ponds is also working against the mosquito and in favor of the population control, Sakolsky said. “That’s slowing egg growth.”

    Nonetheless, she warns that property owners should be checking clearing gutters, ornamental ponds, and objects like tarps, old tires and buckets that trap water. These are favorite breeding grounds for the species of mosquitoes that carry West Nile virus, Sakolsky said.

    In the meantime, amphibians are loving the deeper water, and aren’t so affected by the drop in temperature as the insects. If it gets cold, they just slow down, said Cook, who works out of the Seashore’s Atlantic Research Center in North Truro.

    Among those loving the results of a rainy start to spring are the spadefoot toads, plump little critters with golden lyre-shaped spots on their backs. They are listed as “threatened” by the state of Massachusetts, according to the National Seashore website.

    This species tends to breed in what Cook described as “ephemeral ponds,” ponds that are apt to generally shallow and shrink in dry weather. The March rains brought many of these ponds back to life.

    When the water table is high, as it is now, and when the temperature rises above 48 degrees, the little buggers are apt to be found crossing roads willy nilly in the Province Lands, vulnerable to passing traffic. This can cause sporadic road closures from late March to October when the toad is out and about breeding and feeding.

    Known for their spade-like protrusions on hind feet and the ability to dig into sand, spadefoot toads are called “explosive breeders.” This means they make hay when the sun shines, or rather, they make babies when the rain falls. They are one of 12 species of amphibian found in the National Seashore.

    Even with the favorable breeding conditions this spring, there’s no absolute guarantee there will be a bumper crop of spadefoot toads later, although Cook thinks conditions point to that eventuality.

    The toad eggs usually hatch into tadpoles within a week, and the tadpoles develop into toadlets within about two weeks — if they survive predators and if their birthplace doesn’t dry out. Breeding conditions in 2008 and 2009 were not so favorable to this tiny toad.

    “I would expect this year we’ll see high reproductive success,” Cook said. “Nature tends to be adaptive and over a period of years things seem to even out.”


  2. Pingback: Big snakes in love, video | Dear Kitty. Some blog

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.