The Arthropod Population of Pasture Soil

Abstract

From 20 samples of soil, each 4 inches in diam. and 12 in. deep, collected on Nov. 26, 1943, from a pasture near Cambridge, there were extracted 42,753 arthropods representing a population of 263.6 thousands per sq. meter, or 1068.8 millions per acre. The collection is incomplete by loss of small Acarina which, it is estimated, would raise the arthropod population to at least 1400 millions per acre. The groups in order of abundance were Acarina, Collembola, Hemiptera, Thysanura, Coleoptera, Symphyla, Protura, Thysanoptera, Diptera, Chilopoda, Pauropoda, Diplopoda, Hymenoptera, Psocoptera, Araneida, Lepidoptera, and Chelone-thida. Calculations of coeffs. of dispersion indicate that a non-random aggregated distribution is common to several groups. Collembola, Hemiptera, Coleoptera, and Acarina were commoner in the upper 6 inches and Pauropoda, Protura, and Symphyla in the 2d 6 inches.