Saperda populnea

(Linnaeus, 1758)

small poplar borer

Saperda populnea is a longhorn () that forms distinctive woody on twigs of poplars and willows. The was described by in 1758 and has a broad distribution across the Northern Hemisphere. Females create characteristic horseshoe-shaped cuts on twigs where are deposited, leading to gall formation. The beetle is of economic concern in hybrid aspen plantations due to damage to young trees.

Saperda populnea brok beentree by wikipedia. Used under a CC BY-SA 3.0 license.

Saperda-populnea-02-fws by Francisco Welter-Schultes. Used under a CC0 license.

Saperda-populnea-04-fws by Francisco Welter-Schultes. Used under a CC0 license.

Pronunciation

How to pronounce Saperda populnea: /sæˈpɛrdə pɒˈpuːlniə/

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Identification

The is identified by the presence of its characteristic on twigs—symmetrical swellings up to 20 mm long on internodes, each containing a single elongate chamber with a yellowish or . are present from May to July. The northern Saperda populnea lapponica has shorter male and reduced compared to the nominate subspecies.

Images

Habitat

Found in areas with poplar and willow trees, particularly on young twigs of aspen (Populus tremula). Most common on young, vigorous growth in stands and plantations. In Britain, are most frequent on young aspen twigs.

Distribution

Recorded across Europe (including Albania, Austria, Belarus, Belgium, Bulgaria, Croatia, Czech Republic, France, Germany, Hungary, Italy, Poland, Romania, Russia, Scandinavia, Spain, Switzerland, Turkey, United ), Asia (China, Japan, Kazakhstan, Mongolia, North Korea), and North America (Canada, United States, Mexico). Also recorded in North Africa (Algeria, Morocco).

Seasonality

active from May to July. In Sweden, the is predominantly two-year (), with 90–97% of the flying in odd-numbered years; northern populations show less strict cycling.

Diet

feed internally within woody on poplar and willow twigs. plants include aspen (Populus tremula), black cottonwood (P. trichocarpa), black poplar (P. nigra), and goat willow (Salix caprea). respond electrophysiologically and behaviorally to volatile compounds from host plants, particularly from section Aigeiros poplars.

Host Associations

Populus tremula - larval aspen; most common in Britain and Sweden
Populus trichocarpa - larval black cottonwood
Populus nigra - larval black poplar
Salix caprea - larval goat willow
Salix lapponum - larval downy willow; exclusive of S. p. lapponica

Life Cycle

Two-year () in most . Female makes a horseshoe-shaped incision on twig and an . develops within a woody , creating a single elongate chamber. occurs within the gall. Exit hole is made in spring for .

Behavior

Females create distinctive horseshoe-shaped cuts on twigs prior to . A single female may produce over 136 such incisions. Prefers twigs of approximately 7–8 mm diameter for oviposition. show selective behavioral and electroantennogram responses to volatile from certain Populus varieties.

Ecological Role

and wood-borer in Populus and Salix trees. formation modifies twig growth. Serves as host for a complex including (Dolichomitus tuberculatus, Xylophrurus lancifer, Iphiaulax impostor, Schreineria populnea) and (Gelis ornatulus, Dendrocerus serricornis), as well as the Billaea irrorata. Parasitoid-caused mortality ranges from 2–33% depending on location and year.

Human Relevance

Economic pest in hybrid aspen plantations, where systematic treatment may be required for control. Larval can be treated by brushing horseshoe incisions with linseed with or without insecticide additives. attempts have included rearing the Ephialtes abbreviatus. The has been used as a model organism for mathematical analysis of pest .

Similar Taxa

Other Saperda speciesDistinguished by and ; S. populnea specifically associated with Populus and Salix twig galls
Saperda populnea lapponicaNorthern with shorter male and reduced ; specialized exclusively on Salix lapponum rather than multiple Populus

More Details

Subspecies

A northern , Saperda populnea lapponica, was described from Scandinavia based on divergent morphological traits and exclusive association with downy willow (Salix lapponum). The description prompted discussion on subspecies definitions in .

Parasitoid complex

Studies in Bulgaria and Turkey have documented extensive , with Billaea irrorata () and Dolichomitus populneus () being most abundant. such as Dendrocerus serricornis develop gregariously within .