Sirex rufiabdominis

Taxonomy

Family: Siricidae
Subfamily: Siricinae
Genus: Sirex Linnaeus, 1760
Species: Sirex rufiabdominis Xiao and Wu, 1983
Common names: red-bodied horntail

Background

Sirex rufiabdominis is a black and yellowish-brown species from China (Xiao and Wu 1983Xiao and Wu 1983:
Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.).

Diagnostic characteristics

See Sirex for genus-level diagnostic characteristics.

Females:

• head and thoraxthorax:
  the second and middle segment of the body, between the head and abdomen
  dark blue (Xiao and Wu 1983Xiao and Wu 1983:
  Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.)
• abdominal tergites 1 and 9 black, 2–8 yellowish-brown (Xiao and Wu 1983Xiao and Wu 1983:
  Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.)
• ratio of ovipositorovipositor:
  the female organ that deposits eggs and is used to drill into plant tissue, located at the apex of the abdomen, made up of the lance and lancet
  length to fore wingfore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  length about 1:1.3 (Xiao and Wu 1983Xiao and Wu 1983:
  Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.)
• cornus cornus:
  a pointed horn-like process on the apical end of the abdomen in Siricidae sawflies; on tergite 10 in females, sternite 9 in males
  long (Xiao and Wu 1983Xiao and Wu 1983:
  Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.)

Males:

• legs black (Xiao and Wu 1983Xiao and Wu 1983:
  Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.)
• gena gena:
  the area of the head between the compound eye and clypeus; also called the cheek
  metallic blue (Xiao and Wu 1983Xiao and Wu 1983:
  Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.)
• apical apical:
  towards the apex; farthest away from the body
  tergites yellowish-brown (Xiao and Wu 1983Xiao and Wu 1983:
  Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.)

May be confused with

Female S. rufiabdominis is unique in its range for having several light-colored abdominal segments. Males can be distinguished from S. nitobei by the median and laterallateral:
of or towards the side of the body
post ocellarocellar:
of or pertaining to the ocellus or ocelli
furrows (Xiao and Wu 1983Xiao and Wu 1983:
Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.).

Morphological and geographical variation

none recorded

Host associations

Sirex rufiabdominis has been reared from Pinus massoniana (Chinese red pine) (Xiao and Wu 1983Xiao and Wu 1983:
Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.).

Life history

Female Sirex harbor symbiotic basidiomycete fungus in abdominal glands called mycangia. During oviposition, the site is inoculated with the fungus (Amylostereum spp.), which begins to decompose the surrounding wood. LarvaeLarva:
the immature stage of holometabolous insects
feed on the fungus, and in the process bore galleries through the wood (Schiff et al. 2012Schiff et al. 2012:
Schiff NM, Goulet H, Smith DR, Boudreault C, Wilson AD, and Scheffler BE. 2012. Siricidae (Hymenoptera: Symphyta: Siricoidea) of the Western Hemisphere. Canadian Journal of Arthropod Identification 21: 1-305.).

Larvae are creamy white and grub-like in appearance with a dark head capsule. As with adults, larvaelarva:
the immature stage of holometabolous insects
possess a short dorsaldorsal:
of or on the top surface of the body or structure
horn on the posterior end of the body. The larvaelarva:
the immature stage of holometabolous insects
bore galleries into wood, feeding until pupation and subsequent emergence. Throughout this process, the larvaelarva:
the immature stage of holometabolous insects
use their horn to pack the tunnel behind them with sawdust. Emergence holes are perfectly circular. The fungal symbiont is carried in specialized organs in female larvaelarva:
the immature stage of holometabolous insects
that develop into the mycangia after metamorphosis (Schiff et al. 2012Schiff et al. 2012:
Schiff NM, Goulet H, Smith DR, Boudreault C, Wilson AD, and Scheffler BE. 2012. Siricidae (Hymenoptera: Symphyta: Siricoidea) of the Western Hemisphere. Canadian Journal of Arthropod Identification 21: 1-305.).

The specific biology of S. rufiabdominis is unknown.

Distribution

World: Sirex rufiabdominis is found in eastern China in the provinces Zhejiang, Anhui, and Jiangsu (Xiao and Wu 1983Xiao and Wu 1983:
Xiao G and Jian W. 1983. The siricid wood wasps of China (Hymenoptera, Symphyta). Scientia Silvae Sinicae Memoirs of Forest Entomology 8: 1-29.).

North America: not recorded

Map data from: GBIF.org (26 June 2019) GBIF Occurrence Download Sirex

Details about data used for maps can be found here.