Nuptial flights of the seed-harvester ant Messor barbarus (LINNAEUS, 1767) (Hymenoptera: Formicidae) in the Iberian Peninsula: synchrony, spatial scale and weather conditions

Abstract

We describe the nuptial flights of the seed-harvester ant Messor barbarus (LINNAEUS, 1767) (Hymenoptera: Formicidae) across the Iberian Peninsula, using a total of 123 nuptial-flight observations from 2003 until 2009. Data from 2008 and 2009 were substantial enough to identify eight clusters of nuptial flights triggered by the same weather fronts. Our observations took place over seven weeks (1.75 lunar months) in September and October. Nuptial-flight clusters associated with the same front spanned a mean maximum distance of 637.6 +/- 356.9 km, with a maximum distance of 1075 km. The influence of the direction of the rain fronts associated with the flights was not significant as we observed similar clustering for two Atlantic fronts from the south-west, three Mediterranean fronts from the south-east, and two Atlantic fronts from the north-west. We consistently found that the days with the highest number of flights occurred two to three days after the fronts, when the rain had stopped and the fronts had disappeared from the Iberian Peninsula