Journal archives for September 2014

September 21, 2014

Dragonflies Eating Ant Gasters

On 20 Sep 2014 at about 2 pm I noticed a large aggregation of Anax junius in the yard. There were at least 30 individuals apparently foraging between 1.5 and 20 m above the ground. They were circling around above the driveway and the adjacent yard. There is no aquatic habitat in the vicinity and I took this to be a migratory event and reported it as such to I still think this may be the case. An hour later I noticed winged ants crawling up the edge of the garage, but most of them lacked a gaster. I saw at least 40 individuals and all but a few lacked a gaster. I posted a photo to bugguide ( and almost immediately got a response from John and Jane Balaban that they had seen a similar event. At the same time, I posted the photo to the Hymenopterist's Forum on Facebook and got a response from Bolívar Rafael Garcete Barrett that he had also witnessed such an event (dragonflies eating the gaster of emerging alate ants). Though I didn't witness a predation event directly, I now feel fairly certain that this is what happened. I think a large number of migrating Anax junius found an ant emergence and proceeded to gastrate many of the emerging alates. I haven't identified the ant species yet, but I'm working on it. According to Brendon E. Boudinot at Bugguide (, the ants belong to the genus Crematogaster.

Posted on September 21, 2014 02:06 PM by lfelliott lfelliott | 2 comments | Leave a comment

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