"Marauders are even more organized when they harvest grasses, one of their pastimes in the Singapore Botanic Gardens. When a raid passes a fruiting grass plant, only minor workers and small medias can climb up the slim stalk. The first minors gnaw the attached seeds ineffectually, but productivity skyrockets when a media (ant) arrives. The ants now set up a little assembly line, in which the media extracts one seed after another and then appears to hand it to a minor to haul away. What is really happening, however, is that the minor who is too weak to pull a seed free from the stalk on her own, snatches the seed from the media before the larger ant can depart with it. The media dutifully plucks another seed, which another minor grabs. With minor workers so numerous, a media seldom has an opportunity to exit with her find."
Marauder ants are ants that belong to the genus Pheidolegeton (photos at http://www.myrmecos.net/myrmicinae/pheidologeton.html).
Moffet, Mark W., 2010. University of California Press. Adventures Among Ants: A Global Safari with a Cast of Trillions.