Spatio-temporal variation of insects with immature phase in the soil of Cerrado Northeast of Brazil

Abstract

Holometabolous insects use multiple substrates for ovipositon, laying their eggs on fruits, seeds, and animal tissues, with many species deposit them directly on the soil. The study aimed to identify the families of winged insects with an immature phase in the soil and to verify the effect of climatic seasonality in this insect guild in different conditions of soil cover in a cerrado area in Northern Brazil. The adult insects were sampled at four sites: I - capoeira forest with litter, II - capoeira forest without litter, III - gallery forest with litter, and IV - gallery forest with litter. In each sample site was installed 6 emergency traps, equidistant 5 m from each other. The traps remained in the field for 20 months, occupying five different points in the 150 m transections plotted at each sampling site. The collect of newly emerged adult insects was carried out weekly, using a suction tube, and identified in family level. The soils of the sampling sites were characterized chemically and physically, as well as the climatic factors (humidity and temperature). In this study, a large number of families of insects with immature phase were sampled in soils of a region that makes up three larges Brazilian biomes: Cerrado, Caatinga, and Amazon. The number of insect families sampled was affected by climatic seasonality but was not affected by spatial variation. The diversity rates recorded in this study were high, with the highest values recorded in the sampling sites where the litter layer was preserved, evidencing the role of litter and soil organic matter in preserving and maintaining the biological diversity of the soil.