Andricus atrimentus (unisexual generation)

Gall:
Monothalamous, conical, flat-based, detachable, on lower leaf margin. Sides nearly straight, flaring slightly at base. Basal larval cell oval in side view, 1.6 mm in diameter, 0.8 mm high, pubescent. Upper surface of larval cell coriaceous with sparse pubescence; brown, darker towards center. Red and yellow striped.

Host:
Quercus douglasii

Unknown gall.

Fig 146. Q-dumosa. On under side of leaf. Larval cell basal. On last year's leaves and empty in April and May.

Andricus atrimentus (unisexual generation)

These volcano-shaped, cream-colored galls with red stripes are flat-bottomed and flared at the base and measure 4 mm high and 4 mm wide.

Host:
Quercus douglasii

Feron atrimentum (Kinsey, 1922)

Gall. Asexual galls (Fig. 50) are monolocular, conical, flat-based, detachable, on lower leaf margin. Sides nearly straight, flaring slightly at base. Red and yellow striped when fresh, turning to brown and yellow with age. Basal larval cell oval from lateral view, 1.6 mm in diameter, 0.8 mm high, pubescent. Upper surface of larval cell coriaceous with sparse pubescence; brown, darker towards center. Gall height 3.6–4.6 mm, width 3.0–4.6 mm.

Biology. Matching of generations was first presented in Dailey & Sprenger (1973b). Alternate sexual and asexual generations are also confirmed herein using DNA data, with four individuals (three asexual females, one sexual female) sequenced for cytb. Cytb sequences were on average 0.35% divergent between individuals (range 0–0.70%; GenBank accessions OK041496, OQ446191–OQ446193).

Feron atrimentum is associated with Q. douglasii, Q. dumosa, Q. john-tuckeri and Q. lobata (section Quercus, subsection Dumosae). The sexual generation females emerge throughout April and usually oviposit in the lower leaf surface near the margin. Asexual galls develop over the following three months. Pupation occurs during late October to November; asexual females emerge in late winter and oviposit in leaf buds. Sexual generation galls usually reach full size by mid-March (Dailey & Sprenger 1973b).

Distribution. USA: California.