Vanek, S.J., & Potter, D.A. 2010 An Interesting Case of Ant-Created Enemy-Free Space for Magnolia Scale (Hemiptera: Coccidae). . Journal of Insect Behavior 23: 389-395

Notes: It has long been known that honeydew-producing insects are sometimes harbored within shelters constructed by ants (Wheeler 1910; Nixon 1951; Way 1963). The North American ant Crematogaster lineolata (Say) (Hymenoptera: Formicidae), for example, constructs so-called carton sheds composed of chewed soil and debris in which aphids and mealybugs are concealed, and other ant species construct similar structures harboring soft scales on undersides of leaves, on fruits, and along plant stems (Wheeler 1910). In many cases, ants conceal homopteran associates within their nests in tree canopies, in hollow stems or thorns, in natural plant cavities, or in crevices and tunnels excavated by other insects or by the ants themselves (Nixon 1951; Way 1963; Hölldobler and Wilson 1990). Ant-constructed shelters may serve to physically prevent the ants' homopteran associates from dispersing (Wheeler 1910; Das 1959), and to protect both ants and attended Homoptera from adverse environmental conditions (Wheeler 1910; Way 1963; Helms and Vinson 2002). Additionally, such structures can act as barriers against predators and parasitoids (Nixon 1951; Das 1959; Moya-Raygoza and Larsen 2008). This short communication describes a previously unreported case of antconstructed shelters harboring magnolia scale, Neolecanium cornuparvum (Thro) (Hemiptera: Coccidae), and presents evidence that these structures protect the anttended scales from a parasitic fly, Ocyptamus costatus (Say) (Diptera: Syrphidae), which until now has not been reported feeding on this scale (G. F. G. Miranda, Insect Systematics Laboratory, University of Guelph, Guelph, Ontario, Canada; personal communication). Observations concerning scale parasitism by O. costatus are also included.