Overview

Overwintering of fundatrix as 1st (rarely 2nd) instar nymph is unique. Heteroecious. Hosts are conifers (Pinaceae); primary host, Picea (spruce); secondary hosts, Abies, Larix, Pseudotsuga, Tsuga and Pinus . Highly host-specific. True galls formed on primary host. Complete life cycle complex, typically involving several morphs and only 5 generations on 2 hosts over a period of 2 years. First instar fundatrices overwinter on Picea . The 2nd generation (gallicolae), as immatures, induce formation of cone-like galls and, as alate adults, migrate to secondary hosts, where their progeny (3rd generation) overwinter as 1st instars. Some of 4th generation are alate sexuparae, which fly to Picea and produce the sexuales. Fundatrices hatch promptly from the resultant fertilised eggs, and the cycle is complete. Instances are becoming increasingly known of variously incomplete but always agamic cycles.

Description

Hind wings with 1 oblique vein. Wax glands abundant in all morphs. Ovipositor present. Sexuales small, larviform, rostrate, with 4-segmented antennae; sexual female uniparous. All females, both parthenogenetic and sexual, are oviparous.

Distribution

Holarctic. Only 8 genera and about 50 spp. world-wide. Only 3 spp., all exotic, are definitely known from Australia: Adelges sp. or spp. on Picea and Pseudotsuga (Douglas fir), and Pineus sp. or spp. on Pinus . The anholocyclic species widespread on P. radiata is probably P. pini . [Heinze 1962; Shaposhnikov 1967; Carter 1971.]