Dryocosmus demartinii (agamic)

Dryocosmus juliae (sexgen)

Dryocosmus juliae (agamic)

Dryocosmus rileypokei (sexgen)

Dryocosmus rileypokei (agamic)

Dryocosmus castanopsidis (agamic)

Dryocosmus demartinii, new species

Gall (Figs 14–17) [see page 8 of the pdf for these color photos]. A roughly spherical axillary bud gall found on shoots of the same year, approximately 6–7 mm  in  diameter.  Superficially  similar  to asexual  gall  of  D.  rileypokei,  but  typically  smaller and  rounder with smooth surface. Gall surface is smooth; purple in colour in growing galls turning yellow-brown in mature galls. The gall remains solid as it matures, with no air space between the larval cell and surrounding parenchyma tissue.

Biology. Only asexual females are known, inducing bud galls on Chrysolepis chrysophylla which develop from late summer. Galls are mature by September/October and fall to the ground to overwinter. Under laboratory conditions adults emerge the following year in summer.

Distribution. USA, California.

Dryocosmus juliae, new species

Gall (Figs 36–43) [see page 12 of the pdf for these color photos of each gall variant]
The sexual generation of Dryocosmus juliae, new species has four different galltypes, collected from Chrysolepis chrysophylla and C. sempervirens, and here listed under the field codes assigned to our collections. All galltypes occur at the same time (and often on the same individual plant) and probably reflect variation in the exact oviposition site within dormant buds before the buds develop into new growth/leaves with concurrent gall formation.

spCAl13  (Figs  36–37)—an  integral  leaf  gall,  typically  developing  in  July,  about  6–7  mm  in  diameter,  
protruding mainly from lower surface of the leaf, sitting totally within the lamina of the leaf, never on the leaf edge, with a free-rolling inner larval cell. This is an undescribed galltype listed by Weld (1957). 

spCAl14 (Fig. 38)—an integral leaf gall, developing in July, about 3–4 mm long and 2 mm across, on the edge 
of the leaf blade, causing infolding of the lamina (sometimes all the way to the midrib), with a free-rolling inner 
larval cell. Very similar to the previous galltype (spCAl13); however, located on the edge of the leaf blade.

spCAb5 (Figs 39–41)—a small green gall that appears to be induced in terminal or axillary buds, conical, 
slightly pointed, up to 8 mm long, 4–5 mm diameter, with a free-rolling inner larval cell. Further investigation has 
shown that this gall is actually induced on a leaf, and the apparent position on a bud is because gall development stops leaf growth. Collected primarily in June and July, although some galls (one containing a viable pupa) were collected in October, perhaps indicating some proportion of larvae undergo a period of diapause.

spCAs5 (Figs 42–43)—an integral stem gall, collected in July and August, causing swelling of the terminal 
bud and immediately adjacent new twig growth.

Biology. Alternate sexual and asexual generations are known, developing on Chrysolepis sempervirens and C. 
chrysophylla. Galls of the sexual generation typically develop in June-August, adults emerge during the same 
period. Asexual galls on catkins starting to develop in September, adults probably emerge next spring.

Distribution. USA, California.

Dryocosmus juliae, new species

Gall. The  asexual  generation  of  this  species  induces  catkin  galls,  which  were  collected  from Chrysolepis sempervirens at the two sites near Manzanita Lake (USA, California) on 2008.09.11 and 2012.09.24. However, at the time galls were collected only small larvae were inside the galls and no adults were subsequently reared. DNA sequences from these larvae matched those obtained from the sexual generation described above, confirming that this  catkin  gall  is  the  alternate  asexual  generation  of  D.  juliae,  new  species.  These asexual  generation  galls  (galltype code spCAc4) develop on staminate catkins, are around 4 mm in diameter, with a fluffy buff coloured surface. The internal structure shows an inner larval cell located at the bottom of the gall with a "dummy" cell above that contains a small opening on the upper surface (Figs 44–45). [See page 12 of the pdf for color photos of this gall].

Biology. Alternate sexual and asexual generations are known, developing on Chrysolepis sempervirens and C. chrysophylla. Galls of the sexual generation typically develop in June-August, adults emerge during the same period. Asexual galls on catkins starting to develop in September, adults probably emerge next spring.

Distribution. USA, California.

Dryocosmus rileypokei 

Hosts: Chrysolepis chrysophylla

Gall. Sexual generation galls develop in the cupule part of the fruit (Figs 80–81). The larval chambers are 
within the mesocarp tissue of the developing fruit; infested fruit do not develop seeds. A detailed description of 
galls is given in Buffington & Morita (2009).

[See page 20 of the pdf for color photos of these galls]


Dryocosmus rileypokei

Hosts: Chrysolepis chrysophylla

[See page 20 of the pdf for color photos of these galls]

Asexual generation galls develop in axillary buds (Figs 82–85). Galls are typically ovoid, occasionally more 
spherical, narrowing towards the point of attachment with the host plant at the base of the gall; approximately 8–9 mm in diameter. The gall surface is textured, with scattered pubescence or small raised bumps (similar to the catkin galls of D. castanopsidis); brownish-purple in colour. As the gall matures, an air space develops between the larval cell and surrounding parenchyma tissue, although the larval cell is never completely free. Galls are quite similar to those of D. demartinii and are induced on the same part of the plant as that species, but are more ovoid in shape, have a textured surface and develop an air space around the larval cell when mature.

Biology. Alternating sexual and asexual generations are known. Sexual galls in fruit were collected from July to the first half of September. Adults emerged under laboratory conditions soon after collection. Asexual bud galls develop during late summer/autumn, are mature by October, and fall to the ground to overwinter. Adults emerge the following spring. A proportion of asexual larvae have an extended period of diapause and emerge in early spring two years after galls were induced.

Distribution. USA, California

Dryocosmus castanopsidis

Gall (Figs 97–99) [See page 22 of the pdf for photos of this gall]. Galls on staminate catkins, 12–24 mm in diameter, round, reddish, slightly pubescent, the inner cell has no air space around it.

Biology. Only asexual generation females are known which induce galls on Chrysolepis chrysophylla and C. 
sempervirens. Galls start to develop in late May-early summer, mature in September-October and fall to the ground and overwinter in the leaf litter. Some galls remain on the trees and can be collected through winter, although these galls may remain on the trees due to attack by inquilines that could inhibit complete development of the galls (the authors collected some in January that contained only inquiline larvae).

Distribution. USA, California and Oregon.

New species of Dryocosmus Giraud gallwasps from California (Hymenoptera: Cynipidae: Cynipini) galling Chrysolepis Hjelmq.(Fagaceae)