Genus Stylotermes · 杆白蚁属

Fauna Sinica account

The account below is a reorganized and rewritten adaptation of the genus-level description in Fauna Sinica, Insecta Vol. 17, Isoptera (2000) (the genus-level account in the original book's section on Stylotermes, rearranged and rewritten); the source keys and measurement tables are not reproduced here.

Morphology

Key characters

Soldier head capsule rectangular; labrum semicircular and lacking a hyaline tip; mandibles sabre-shaped, stout and strong, each with one or two small blunt teeth on the inner edge below the middle; tarsi with three tarsomeres, tibial spur formula 3:2:2, cerci with two segments.

Soldier

Soldier head capsule mostly rectangular, rarely oval-rectangular; fontanelle either small or raised. Labrum semicircular, without a hyaline tip, its apex projecting or straight, its surface bearing more than ten setae. Mandibles sabre-shaped, stout and strong, each with one or two small blunt teeth on the inner edge below the middle. Antennae with 13–19 segments. Compound eyes reduced to dots; ocelli small or absent. Postmentum club-shaped, narrowed at the waist. Pronotum flat, narrower than the head capsule. Femur swollen; tibial spur formula 3:2:2; tarsi with three tarsomeres. Without styli; cerci with two segments.

Alate

Alate body length (excluding wings) usually less than that of the soldier. Fontanelle very small; postclypeus varying in the degree of its protrusion. On the left mandible the first marginal tooth is larger than the second. Antennae with 18–22 segments. Pronotum flat, narrower than the head capsule. Forewing scale larger than the hindwing scale; wing membrane bare, without setae; venation reticulate. Femur not swollen; tibial spur formula 3:2:2; tarsi with three tarsomeres. Cerci with two segments, and without styli.

Biology and economic significance

A rather distinctive group, mostly entering the xylem through wounds in the trunk and damaging living trees; sap often exudes from the attacked sites, and in severe cases dark brown sludge-like faecal material accumulates on the outside. Colonies are small to medium in size. In China recorded from Sichuan, Yunnan, Guizhou, Guangxi, Guangdong, Hainan and Fujian, with 34 species known; abroad, about ten species in India and Bangladesh and one in Malaysia.

Distribution

Oriental Region; mainly in the provinces from south-western to southern China; outside China recorded from India, Bangladesh and Malaysia.

Summary

Stylotermes soldiers have a rectangular head, a semicircular labrum without a transparent tip, and stout sabre-like mandibles whose inner margins bear one or two small blunt teeth. Antennae have thirteen to nineteen segments, the compound eyes are reduced to dots, and the postmentum is club-shaped with a constricted waist. The tibial spur formula is three to two to two with three tarsal segments, and styli are absent. The genus bores living trunks through wounds, forming small to medium colonies.

Taxonomic note: Because the tarsi have only three tarsomeres, some authors have proposed treating this genus as a separate family, Stylotermitidae.

Sources cited: Huang Fusheng, Zhu Shimo, Ping Zhengming, Wang Zhiguo, Li Can and Xu Chungui, 2000. Fauna Sinica, Insecta Vol. 17, Isoptera. Beijing: Science Press. This text is a reorganized adaptation, not a verbatim transcription.