What is a pine sawfly?

Pine sawflies (Diprionidae: Diprion) are stout, wasp-like insects. They are not true flies, but are in the same group of insects as wasps, bees, and ants. Females lay their eggs in pine needles, on which the brightly colored, caterpillar-like larvae feed externally. Several species are pests of pine, causing direct harm by defoliation and making pines vulnerable to other pests. Damage from pine sawfly larvae can vary from mild to severe, with these insects sometimes defoliating whole forests.

Species of pine sawfly differ greatly in the scope of their food preferences, with some known to readily switch to novel pine hosts, while others seem narrow in host choice. Some species may even feed on non-pine conifers. Identification to species is easiest using the later stages of the larva, at least among those six species in which the larva is adequately known. Adults are more difficult to identify. Nonetheless, the Lucid keys provided in this tool allow for global identification of adult pine sawflies, of either sex, to species. These keys are fully illustrated and use external characters whenever possible. Collection of both larvae and adults in species for which these forms have not yet been associated will be of great help towards ongoing improvement of this identification tool.

Conifer sawflies (Diprionidae), the family to which pine sawflies belong, are most conspicuously distinguished from other sawflies by the condition of the antennae: there are 15 or more flagellomeres; the female antenna is saw-like, whereas the male flagellumflagellum:
the third segment of the antenna, which is subdivided into many articulated components called flagellomeres.
is an elaborate comb, with two tines on most flagellomeres. Other conditions that (in part) distinguish pine sawflies from their relatives are the absence of a mesoscutellar appendage, and the separation of the metapleuron from abdominal tergitetergite:
the dorsal plate of an abdominal segment.
I.

Pine sawflies (Diprion) are distinguishable from all other conifer sawflies (Diprionidae) by the following characteristics, in combination:

• Anterior clypeal margin emarginate.
• Forewing anal cell with crossvein.
• ICDICD:
  ( = inter-cenchral distance) minimum distance between medial vertices of cenchri.
  ≥ CWCW:
  ( = cenchral width) maximum transverse span of cenchrus.
  ; MTLMTL:
  ( = metascutellar length) maximum anteroposterior length of metascutellum.
  ≥ CWCW:
  ( = cenchral width) maximum transverse span of cenchrus.
  .
• Female antenna not biramosebiramose:
  produced into two distinct branches, not necessarily of the same length.
  or biserratebiserrate:
  produced into two distinct tines or teeth, not necessarily of the same length
  .
• Distal flagellomereflagellomere:
  the articulated components of the flagellum, which is the third of three anatomical segments of the insect antenna. In Diprion males, most flagellomeres bear elongated, hairy processes.
  of female tapering.
• Second female flagellomereflagellomere:
  the articulated components of the flagellum, which is the third of three anatomical segments of the insect antenna. In Diprion males, most flagellomeres bear elongated, hairy processes.
  with projection.
• ≤ 26 male flagellomeres.
• Distaldistal:
  remote from the body.
  2–4 male flagellomeres uniramoseuniramose:
  not produced into two distinct branches.
  .
• Tarsal claw with subapical tooth.
• Somalsomal:
  of or pertaining to the body ( = soma).
  sclerites not metallic.
• Feed on PinaceaePinaceae:
  a family of plants including pines, cedars, larches, and other conifers.
  (rather than CupressaceaeCupressaceae:
  a family of plants including junipers, redwoods, cypresses, and related conifers.
  ).

 

Anterior clypeal margin (marked in blue), Diprion pini

 

Forewing, anal crossvein marked with arrow, Diprion pini

 

Female antenna, second flagellomere marked with arrow, distal flagellomere highlighted, Diprion liuwanensis

 

Distal male flagellomeres, ventral view, Diprion pini

For more about Diprion and related genera see ITP's Sawfly GenUS tool.

What is a pine sawfly?

• What is a pine sawfly?
• Anatomy
• Plant associations table
• Authors and acknowledgments
• Copyright, citation, and disclaimers
• References