Druon quercuslanigerum
(Ashmead, 1881)
Druon quercuslanigerum is a cynipid gall wasp that alternates between sexual and on live oaks. The sexual generation forms small galls on catkins in spring, while the asexual generation produces distinctive woolly galls on leaf undersides. It is one of only two in the Druon with documented alternating generations.
Pronunciation
How to pronounce Druon quercuslanigerum: //ˈdruːɒn kwərˌkʌs.lænˈɪdʒ.ərəm//
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Identification
The is recognized by its woolly leaf galls: 1.0–7.0 mm diameter, 2–3 mm high, with a creamy white to yellowish-white woolly covering and light brown inner capsule, typically clustered along leaf mid-. The sexual generation forms minute (~1 mm) ovate swellings on catkin stems. are small: asexual females 2.0–2.5 mm reddish-brown; sexual females 1.4–2.1 mm dark red-brown to black; sexual males 1.2–1.6 mm similar in color to sexual females. A new morphological variety from Mexico has been described.
Images
Habitat
Associated with oak woodlands and urban plantings of live oaks in subtropical to warm temperate regions.
Distribution
Native to the southern United States (Georgia, Florida, Alabama, Missouri, Louisiana, Texas) and Mexico (Hidalgo, Chihuahua). Introduced to California (Stockton) with its Quercus virginiana.
Seasonality
Sexual emerges from catkin galls mid-March to early April, mates, and oviposits into new leaves. females emerge September through February, with an period approximately ten times longer than the sexual generation. Woolly galls develop mid-summer through fall and winter.
Host Associations
- Quercus virginiana - plant on leaves, sexual generation on catkins
- Quercus geminata - plant on leaves
- Quercus fusiformis - plant on leaves
- Quercus oleoides - plant on leaves
Life Cycle
Alternating heterogonic with distinct sexual and . Sexual generation: emerges spring, reproduces on catkins. Asexual generation: develops in woolly leaf galls, emerges over extended period autumn through winter.
Behavior
females oviposit into catkin buds coinciding with their period. Sexual oviposits into leaf mid-ribs after emergence and mating.
Ecological Role
Induces gall formation on oaks, providing microhabitat structure. Documented prey of green parakeet (Psittacara holochlora).
Human Relevance
Forms conspicuous woolly galls on ornamental live oaks, potentially affecting aesthetic value. Introduced in California associated with planted trees.
Similar Taxa
- Druon ignotumOnly other Druon with documented alternating ; distinguished by gall and associations
- Andricus speciesFormerly classified in Andricus; distinguished by woolly gall structure and metasomal ; transferred to Druon in 2022 based on phylogenetic analysis