Invasive crayfish lead to more mosquitoes and risk of disease in Southern California

August 7, 2018

Invasive red swamp crayfish are a serious problem in the Santa Monica Mountains and other parts of Southern California. They devastate native wildlife, including threatened species such as the California red-legged frog, throwing off the natural balance of ecosystems.

They also pose a threat to people, according to a new paper in the journal Conservation Biology. The study is based on field research in the Santa Monica Mountains and lab experiments at UCLA La Kretz Center for California Conservation Science.

Mosquitos are notorious vectors that spread diseases such as malaria, Zika and West Nile virus. In the mountains, mosquito populations are kept in check by dragonfly nymphs, which voraciously consume their aquatic larvae. But invasive crayfish disrupt that predator-prey relationship, killing and driving dragonfly nymphs from waterways. And while crayfish also consume mosquito larvae, they’re simply not as good at it, the researchers found.

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