Spathius

Nees, 1818

Spathius is a of doryctine in the . within this genus are larval of wood-boring , with several species to North America as agents for the emerald ash borer (Agrilus planipennis). The genus includes both and introduced species that exhibit -specific relationships with their beetle hosts.

Spathius by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.

Spathius by (c) Saryu Mae 前朝琉, some rights reserved (CC BY), uploaded by Saryu Mae 前朝琉. Used under a CC-BY license.

Spathius by (c) Mark Richman, some rights reserved (CC BY), uploaded by Mark Richman. Used under a CC-BY license.

Pronunciation

How to pronounce Spathius: //ˈspeɪθiəs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Habitat

Forests and woodlands containing trees; specifically associated with ash trees (Fraxinus spp.) infested by wood-boring . Some inhabit concealed galleries within dry timber and wood products.

Distribution

Widespread across the Palaearctic, Oriental, and Nearctic regions. range includes northeastern China, the Russian Far East, and India. Several have been to North America (United States and Canada) for purposes.

Diet

are of wood-boring larvae. Documented include emerald ash borer (Agrilus planipennis), Hylurgopinus rufipes, and various beetles including Heterobostrychus aequalis, Dinoderus brevis, Dinoderus minutus, and Dinoderus ocellaris.

Host Associations

Agrilus planipennis - emerald ash borer; primary target for introductions
Hylurgopinus rufipes -
Heterobostrychus aequalis - lesser auger ; intercepted in wood packaging material
Dinoderus brevis -
Dinoderus minutus -
Dinoderus ocellaris -
Coraebus cavifrons -
Pempherulus affinis - laboratory
Hypolixus truncatulus - laboratory

Life Cycle

development. Females drill through bark using a long to reach concealed in wood, then on or near the host. Larvae feed externally on the host, consuming tissue before pupating within the host gallery. Some exhibit long-lived preimaginal stages capable of surviving extended periods within dry wood.

Behavior

Females use volatile chemical cues from -infested trees to locate hosts. length varies among , determining the maximum bark thickness through which hosts can be reached. Spathius galinae possesses an ovipositor approximately twice as long as that of Tetrastichus planipennisi, enabling of larger diameter trees. Females clutches of approximately 20 on host .

Ecological Role

agent of wood-boring . As , they reduce of pest beetles that damage forest and urban trees. Some may compete with where ranges overlap.

Human Relevance

Used in programs to manage emerald ash borer, an pest that has killed millions of ash trees in North America. Spathius galinae has shown particular promise, with rates reaching 49% and successful establishment in wild within two years of release. do not humans.

Similar Taxa

Tetrastichus planipennisiBoth are larval of emerald ash borer used in ; distinguished by shorter in Tetrastichus (1.5–2.5 mm vs. longer in Spathius), development in Tetrastichus versus in Spathius, and different timing
Oobius agriliBoth are of emerald ash borer; Oobius is an parasitoid with much smaller size and different stage targeted
Phasgonophora sulcata North of wood-boring ; shows opposing response to ash compared to Spathius galinae, with negatively associated with high ash density