The Aeolian Ecology of White Mountain Peak, California: Windblown Insect Fauna

Abstract

The composition of the windblown insect fauna at the summit of White Mountain Peak (4342 m), California, was investigated for 44 days in July/August 1974 and August 1975. Thermal convection currents and westerly winds transport large numbers of insects and deposit them on the east (leeward) slope of the summit. Insects in accumulated deposits of windblown debris are predominantly Hemiptera, Homoptera, and Coleoptera. The most common species are Nysius raphanus (Lygaeidae), Rhytidolomia spp. (Pentatomidae), Hippodamia convergens (Coccinellidae), and Psylla magna and P. omani (Psyllidae).

The density of arthropod fallout on a snowfield near the summit was 1380 m⁻² in July and 560 m⁻² in August 1974. The relative proportions of small (< 5 mm) arthropods on the snow revealed several groups not easily identified in the fell field debris: Araneida (2%), Aphididae (27%), Diptera (13%), and Hymenoptera (19%). Some of the most common windblown insects probably originate in alfalfa fields 3000 m below the summit. Eleven species of Diptera and Lepidoptera appear to be hilltopping.

The summit is an extremely cold, arid, and sparsely vegetated (cover 0.3%) environment where the major source of nutrients for the resident biota is windblown insects.