Stem borer (Coleoptera: Curculionidae) in Sanicula [0488]

OrderColeoptera
FamilyCurculionidae[M,L,A]
Lower taxonundetermined
No. spp. involvedOne confirmed [1-C]  but unsure if the two larvae figured here are conspecific
Feeding modeStem borer
Host plantSanicula sp. (Apiaceae)

Two examples of beetle borer larvae in Sanicula were located in the current study, one in June 2022 and the second in July 2023. Both larvae began their tunneling in the uppermost portion of the stem and proceeded downward from there. The 2022 larva had already been killed by a parasitoid when the author located it, and thus had not succeeded in tunneling very far down the stem, although its activity did result in the stem tip dying back. The 2023 larva was located due to the conspicuous wilting of the host plant, and when found it had already completed its tunneling in the inflorescence stem branch and from there had entered the main stem. This larva was successfully reared to adulthood.

IMG#: 0488-01
Upper stem of Sanicula with a necrotic shoot tip, the result of a beetle larva tunneling inside the stem. (Photo date: June 9, 2022)
IMG#: 0488-02
Interior of stem from previous photo (0488-01), showing tunneling and larva.
IMG#: 0488-03
Larva in tunnel in stem.
IMG#: 0488-04
Beetle borer larva, with parasitoid attached to it.
IMG#: 0488-05
Larva and parasitoid.
IMG#: 0488-06
Larva and parasitoid.
IMG#: 0488-07
Head of larva.
IMG#: 0488-08
Sanicula plant that has reached the flowering stage and then wilted due to the presence of a beetle larva tunneling in the stem. (Photo date: July 7, 2023)
IMG#: 0488-09
Affected Sanicula plant from the previous photo, dissected, revealing brownish tunnel in inflorescence stem branch, leading down into the main stem.
IMG#: 0488-10
Tunnel leading from inflorescence stem branch (at left) to main stem (at right). See also image 0488-13 (below).
IMG#: 0488-11
Tunnel in inflorescence stem branch.
IMG#: 0488-12
Tunnel in inflorescence stem branch.
IMG#: 0488-13
Detail, tunnel leading from inflorescence stem branch (at left) into main stem (at right). See also image 0488-10 (above).
IMG#: 0488-14
Larva in tunnel in main stem.
IMG#: 0488-15
Larva in tunnel in main stem.
IMG#: 0488-16
Larva.
IMG#: 0488-17
Larva.
IMG#: 0488-18
Head of larva.
IMG#: 0488-23
Head of larva, front view, showing mandibles.
IMG#: 0488-19
Reared adult, dorsal.
IMG#: 0488-20
Reared adult, lateral.
IMG#: 0488-21
Adult peering out from the stem in which it grew to maturity in a rearing container.
IMG#: 0488-22
Portrait of adult.

Specimen data for images

Coll. 06/09/22, field photo same day (01), additional photos on 06/10/22 (02-07); coll. 07/07/23, field photo same day (08), larva and damage photos same day (09-18, 23), larva still alive in stem on 07/26/23 (no photos), teneral adult em. 08/04/23 (no photos), hardened and darkened adult photographed on 08/06/23 (19-22).

References

[none]

Page created 10/01/23. Last update: 11/18/24