Dramatic Increase in Spiders Reported on Guam After Invasive Treesnake Wipes Out Native Birds

Posted on September 13, 2012

Biologists from Rice University, the University of Washington and the University of Guam have found that the Pacific island's jungles have as many as 40 times more spiders than are found on nearby islands like Saipan. The huge increase in spiders follows the invasive brown treesnake wiping out native forest birds on the island. The Guam jungles are now thick with spiderwebs.

Haldre Rogers, Huxley Fellow in Ecology and Evolutionary Biology at Rice and the lead author of a new study published here in PLoS One, said in the announcement, "You can't walk through the jungles on Guam without a stick in your hand to knock down the spiderwebs."

Rogers also says the difference between the number of spiders she and her colleagues counted on Guam and three nearby islands that still have birds "was far more dramatic than what any small-scale experiments had previously found."

Rogers also says, "There isn't any other place in the world that has lost all of its insect-eating birds. There's no other place you can look to see what happens when birds are removed over an entire landscape."



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