Spider bonanza in Guam

Spider bonanza in Guam. Photo by: Isaac Chellman.

The accidental introduction of the brown tree snake (native to Australia and Papua New-Guinea) has led to a decline in bird numbers which has in turn – led to a spider explosion on the island of Guam, a U.S territory in the Pacific.

  • Guam was once home to a rich diversity of birdlife until the invasion of the brown tree snakes.  9 bird species have become locally extinct (and 5 of these were found no-where else, including the Guam flycatcher).
  • The birds were largely insectivorous and helped control spider numbers.
  • The result is surprising.  A research team found no less than 18 spider webs every 10 meters in the dry season and 26 webs every 10 meters in the wet season.
  • Spider numbers on Guam blitzed those of neighboring islands (where birds are unaffected by brown tree snakes). They were found to be twice as large in the dry season and an incredible 40 times larger in the wet season.
  • Efforts to rid the Guam of snakes include ‘bombing’ the island with poisoned frozen mice.
  • The loss of birdlife has implications on many environmental factors like pollination, controlling pest species and now spider numbers.
  • Guam is currently a living example of what can happen if one type of animal is totally wiped out from an area.
  • So if you are a fan of spiders and snakes, the forests of Guam would be a great place to visit!

Want to learn more? See http://news.mongabay.com/2012/0917-hance-guam-spiders.html


Article published by