Siricidae

Common Name

Horntails or Wood Wasps

Overview

The family Siricidae, commonly known as horntails or wood wasps, includes a variety of large, robust wasp species that are known for their wood-boring larvae. These insects are often seen around dead or dying trees, where they lay their eggs.

Taxonomy

Key Characteristics

  • Appearance: Robust and cylindrical bodies, often brightly colored.
  • Ovipositor: Females possess a strong, pointed ovipositor used for boring into wood.
  • Antennal Shape: Filiform (thread-like) antennae.
  • Size: Generally large, ranging from 1 to 6 cm in length.
  • Wing Structure: Transparent wings with a well-defined venation pattern.

Life Cycle

  1. Egg: Laid inside wood by the female using her ovipositor.
  2. Larva: The grub-like larva bores into the wood, feeding on the wood tissue and sometimes on symbiotic fungi.
  3. Pupa: The larva pupates within the wood, undergoing metamorphosis.
  4. Adult: Emerges from the wood, ready to reproduce and continue the cycle.

Behavior and Ecology

  • Habitat: Primarily found in forests, particularly around dead or dying trees.
  • Feeding: Larvae feed on wood and symbiotic fungi; adults do not feed.
  • Fungal Symbiosis: Many species have mutualistic relationships with fungi, which help in breaking down the wood for larval consumption.
  • Natural Predators: Include birds, parasitic wasps, and other predatory insects.

Notable Species

  • Sirex noctilio: Known as the European woodwasp, invasive in several parts of the world, causing significant damage to pine forests.
  • Urocerus gigas: Also known as the giant woodwasp, commonly found in Europe and Asia.

Conservation

  • Generally, species in the family Siricidae are not of conservation concern, but invasive species can impact native ecosystems and commercial forestry.

Significance to Humans

  • Forestry Impact: Larvae can cause significant damage to timber by boring into wood, especially when associated with invasive species.
  • Natural Indicators: Presence may indicate the health and age of forest ecosystems, often being seen in older, decaying trees.

Fun Fact Section

  • Unlike many other wasps, adult horntails do not sting.
  • The ovipositor of the female contains specialized valves that allow it to drill into hard wood efficiently.
  • Siricidae larvae can live within wood for years, depending on environmental conditions and availability of food.
  • They are called "horntails" because of the horn-like projection on the females’ abdomen.
  • Some species have been recorded as living in wood for up to 11 years before emerging as adults.