TRACES AND BURROWING BEHAVIORS OF THE CICADA NYMPH MELAMPSALTA CALLIOPE: NEOICHNOLOGY AND PALEOECOLOGICAL SIGNIFICANCE OF MODERN SOIL-DWELLING INSECTS

This study documents the traces and burrowing behaviors of the meadow-cicada nymph, Melampsalta calliope. M. calliope is abundant in Kansas and throughout the Midwestern states. Nymphs spend approximately four years below the soil surface, feeding on xylem sap from the roots of grasses or woody plants. Fifth instars emerge from the soil between late May and early June and molt into sexually mature adults. M. calliope nymphs were collected from the B and C horizons of sandy fluvents along the Kansas River north of Lawrence, Kansas. The nymphs appeared to be fourth or fifth instars; 13 to 17 mm long and 6 to 7 mm wide. The nymphs were placed in plastic enclosures containing layers of colored, moist, very-fine-grained sand. Nymphs burrowed immediately, excavating air-filled, sediment enclosed cells between 20 to 50 mm long and averaging 9 mm in diameter. Burrowing was completed in three stages: 1) sediment in the forward portion of the cell was excavated and rolled into a ball with the forelimbs; 2) the nymph turned 180° using a forward roll, and moved to the cell aft; and 3) the sediment ball was pushed up against the aft cell wall and kneaded with the forelimbs into a thin layer. Resulting burrow traces are sinuous and distinctly meniscate. M. calliope nymphs and their traces are excellent analogs for meniscate trace fossils in paleosols, particularly adhesive meniscate burrows (AMB) common in Mesozoic and Cenozoic alluvial deposits throughout the Rocky Mountain region. Neoichnologic experiments such as this cicada study are important to understanding better the significance of continental trace fossils. Continental neoichnology has not kept pace with neoichnological investigations of modern marine tracemakers. Few neoichnological studies have examined experimentally the traces of temporary and permanent soil-dwelling insects despite their role as primary agents of pedoturbation and great abundance in modern soils.