Aggregation Behavior of the Southern Chinch Bug (Hemiptera: Blissidae)

The southern chinch bug, Blissus insularis Barber, forms dense, multigenerational aggregations in St. Augustinegrass lawns leading to grass death from sap feeding. We conducted laboratory bioassays to better understand the signals responsible for the formation and maintenance of southern chinch bug aggregations. In small arena assays, chinch bugs demonstrated a stronger aggregation response over time and aggregated more often on or beneath St. Augustinegrass leaf blades than on or under artificial leaf-like shelters constructed from white or green paper. In Y-tube olfactometer assays, bugs of different age and sex were attracted to volatiles from mixed-sex chinch bug aggregations and showed particular attraction to groups of adult female chinch bugs. Adult males and nymphs were also attracted to adult males. Nymphs were attracted to nymphs and were also more attracted to aggregation volatiles when they could see bugs in the arm of the Y-tube. Adult males were more attracted to short-winged than long-winged adults, while females and nymphs demonstrated no preference. All bugs were attracted to St. Augustinegrass volatiles when presented alone, but only males preferred the odor of grass over odor released from a chinch bug mixed-sex aggregation. When presented with a choice of grass and grass + aggregation volatiles, males preferred the combined treatment. The results of these assays suggest that a complex combination of life stage, sex, as well as plant and insect-derived signals influence chinch bug aggregation behavior.