Twelve-spotted Skimmer

TWELVE-SPOTTED SKIMMER
Libellula pulchella

To date there is only one MTY record of Twelve-spotted Skimmer: 19 Sep 2006 at Laguna Grande Park in Seaside. It was discovered by Don Roberson, who had been there the day before and on several days thereafter, but it had not been present on 18 Sep nor was it refound afterwards. It is probably best considered a vagrant at this point, but it would also not be surprising if it proved to be regular in the county.

All the photos (below) were taken on 19 Sep 2006. The skimmer was obviously old and worn. The distal spots on the wings are very faded, and the wings themselves beat up and ragged. Including the faded wing-tip spots, there are 12 spots (basal, nodus, tips of each of four wings). The spots are the base of each wing and the middle spots are comparatively similar in extent, a pattern shown on many photos of Twelve-spotted, rather than the smaller basal spots and larger middle spots more typically shown on female Common Whitetail Plathemis lydia. Common Whitetail has a different abdominal pattern as well.

The wings were very clear except for the spots (above), and the abdomen was brown, but an oddity was the presence of apparent pruinescence on the distal half of the abdomen. This could suggest a male. The terminal appendages (see close-up, below) show that this was a female.

Using Manolis (2003) as a primary guide, but also reviewing the photos and scans on Kathy Biggs's and Dennis Paulson's web sites, the abdominal pattern are consistent with Twelve-spotted Skimmer: composed of yellow stripes, not dashes or spot, with the pale yellow stripe covering each segment from front to back, broken only by the segmentation of the abdomen. Also, the two thoracic stripes are pale yellow, with deeper yellow at the anterior ends, but without a small yellow dot in front and below the anterior stripe, as is shown on photos and scans of female Common Whitetail.

There was some on-line discussion of these photos regarding Eight-spotted Skimmer and/or hybrids, but nothing about this ode suggests hybridization. Tim Manolis (in litt.) stated that faded distal wing spots is not atypical in Twelve-spotted Skimmer.

The map (right) shows the only locale so far for this species. It is a common species across much of North America. In California, its range includes the top 2/3ds of the State, and coastal southern California (Manolis 2003).

Walt Koenig, the PhD research biologists at Hastings Natural History Reservation who studied the ecology of Common Whitetail in depth in the 1980s, tells me that he saw an occasional "Ten-Spot" back then. "Ten-Spot" is an old name for Libellula pulchella. So it is very likely that this ode has occurred in MTY before, and possibly regularly.

The only date for MTY is 19 Sep 2006, but elsewhere in California it flies April-October (Manolis 2003), with a peak in mid-summer. Widespread wandering is known.

Literature cited:

Manolis, T. 2003. Dragonflies and Damselflies of California. Univ. of Calif. Press, Berkeley.

Web resources:
Major identification web sites with much information on California odes include:

Kathy Biggs's site [photos, i.d. discussions & keys to all California species]
Dennis Paulson pages [very useful scans of dragonflies, including many California species]

For sites with excellent photos to compare for identification or to simply enjoy, see:

Ray Bruun's pages [mostly northern California, esp. Lassen & Shasta counties]
Eric Preston's pages [mostly S.F. Bay area; separate portals to dragonflies and to damselflies]
Greg Lasley's site [emphasis on Texas but widespread North American photos]
Doug Aguillard's site [odonates of San Diego & Imperial counties]
John Sterling's site [his personal checklist of odes of California]

Many of these sites have links to other useful pages. Kathy Biggs's site is particularly useful in her selection of links.

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Page created 19 Sep 2006, updated 7 Nov 2006