The effect of chemical defenses on the density of insect herbivores between high, medium and coastal elevations of Al Jebel Al Akhdar

Abstract EN

The study area is dominated by Juniperus sp and Pistacia sp, the two species, the study aimed to investigate the effect of chemical defences on the density of insect herbivores, and the results showed that the two species differed very much in their levels of phenols.

Pistacia had the highest concentrations (overall 2308 ± 43 ppm, n = 45), with Juniperus quite a bit lower (1516 ± 43, n = 45).

Overall levels of phenols were highest in plants from the middle and lowest in those from the bottom elevation level.

This effect of the level was significant, showing that the two species showed the same pattern with elevation.

There were substantial differences among plots within levels.

This has affected the numerical density of the insects, where it was observed that their density on the tested Juniperus sp shrubs was more than the intensity on the tested Pistacia sp shrubs.