Attelabus Nitens (Scop.) - an Abundant but Biologically Little Known Species from the Family of Attelabidae (Coleoptera)

Abstract

The study deals with the biology of Attelabus nitens (Scop.) in the Brno region. In the growing season of 2014, 35 field inspections were made at 10 sites in the intervals of three‑to‑seven days. Leaf rolls were found on Quercus petraea, Q. dalechampii, Q. robur, Q. pubescens and Q. cerris, rarely on Castanea sativa. Hibernating in the shed leaf rolls are larvae of the second instar. These pupate in the rolls during the second half of April and beginning of May. At the turn of April and May, beetles fly onto host woody plants of the 1st age class. They damage about 30 cm2 of leaves in two months. Females create about 30 leaf rolls into which they lay 1 to 5 (on average 1.1) eggs. The species develops through two larval instars, which damage 1.7 to 2.3 cm2 of leaves and come of age towards the end of the growing season. On the primary shoots of oaks (with relatively large leaves), the females rolled below‑average sized leaves. On the secondary shoots (with relatively small leaves), they rolled leaves of average to above‑average size. The female gnaws a deep mine into the main vein (in a third of its length) from the adaxial side first. Then she makes a cross cut into the blade from both sides up to the main vein, which is damaged only on the surface. Into thicker sections of veins she bites out (mainly from the abaxial side) on average 350 cross cuts. Only then, the female folds the wilted leaf part adaxially along the main vein and after having laid an egg (eggs), she rolls the blade from the end into a transversal cylindrical roll. On the leaves of Quercus spp. with an average area of 14.3 cm2, the females roll on average 11.9 cm2 (83.2 %). During the growing period, 36 % of individuals died in the leaf rolls on primary shoots and 28 % of individuals died in the leaf rolls on secondary shoots.