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Tamarisk Beetles in the Lower Gila

July 3rd, 2017
On June 8th, tamarisk beetles were found on the Hassayampa River in the Lower Gila River watershed, an area occupied by Southwestern Willow Flycatcher (an endangered bird that has adapted to nest in non-native tamarisk). The population of beetles was found in Wickenburg, Arizona by a scientist conducting beetle monitoring for Tamarisk Coalition. It is likely that these beetles moved into the area from the Bill Williams watershed, more specifically the Big Sandy River, where they were observed last year. 
The discovery of beetles in this area comes as a surprise since population movement models had predicted the beetles to arrive in the Upper Gila from New Mexico, not in the Lower Gila. 
However, the longer-term fate of this population in the Lower Gila is unknown; macroclimatic factors may come into play as the summer days get hotter. Dr. Dan Bean of the Colorado Department of Agriculture’s Palisade Insectary advised that beetle pupae (the life stage between larvae and adult, which takes place in the litter below the plants) cannot survive past 106°F in the lab. So, if the near 120°F temperatures that have been occurring lately take place while this population is in pupation, the population could be wiped out.  
Tamarisk Coalition will continue to monitor and report on beetle population movements and, as always, appreciates any and all new partners that would like to become involved in beetle monitoring. If you are interested in helping, wherever in the country you may reside, contact Ben Bloodworth at

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