Due to the feeding on prickly shrub of Astragalus adscendes by an insect (Cyamophila dicora Loginva), a kind of the manna named Gaz-angubin is produced which it’s harvesting has a long history in Isfahan province. This manna is exclusively produced in Isfahan, Iran. In this research, a map of spatial distribution of this prickly shrub was provided. By random-systematic sample of line transects, biological criteria such as insect density, canopy coverage, branch and the soil moisture were measured. Multiple linear regression and nested design were used to analyses the response and predictor variables. The results indicated that the prickly shrub of Astragalus adscendens occupied the wet parts of mountainous areas of Isfahan and density of insect is highly related to the age, canopy coverage and soil moisture. By increasing the age of prickly shrub, the densities of insect are also increased. Regression analysis showed that the age of plant are more important in two areas of Kloseh and Lashokhm, while in Dareh-sibe area, soil moisture and the moisture of branches are more important. In other words, when the moisture is enough (e.g. Kloseh and Lashokhm areas), the age of plant has the paramount effects on insect density but when the area was suffered from drought, branches and soil moisture are more important.

Keywords: Astragalus adscendens, Gaz, insect density, plant age, plant moisture, soil moisture.

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