Libellula composita is a medium sized dragonfly with a white face, white eyes, white costal veins, an amber spot at each wing base, and wing nodus and black stigmas. The front of the female’s thorax is brown, her sides are white and her abdomen is black with interrupted dorsolateral yellow stripes. In males, the thorax and the base of the abdomen turn pale blue, while the rest of the abdomen turns black. The larva has no lateral spines on abdominal segments 8 or 9 but has brown dorsolateral stripes on segments 7-10. The total length is 1.65-1.88 in (42-48 mm); the abdomen is 1.10-1.29 in (28-33 mm); and the hindwing is 1.29-1.45 in (33-37 mm).
Found in scattered localities (known only from 14 counties) in arid Great Basin, from southeastern Oregon to northern Utah, south to eastern California and southern Arizona and New Mexico, and also found in Texas and Kansas.
In hot springs the adults oviposit directly into the hot water, and the larvae live in cooler spring runs. The larvae overwinter and the flight season is mid June to late August.
The adults forage in brushlands, and as adults and immatures they are invertivores.
They can be found in ponds and streams with emergent vegetation, usually spring fed, sometimes alkaline, in open arid country. They can also be found in hot springs in the northern part of their range. The nymphs live among the muck at the bottom of ponds and stream pools.
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) Scattered localities from Oregon to Kansas, south to Texas, as well as Sonora and Coahuila, Mexico. Erroneously listed as occurring in Chihuahua by Paulson (2009) (D. Paulson, pers. comm, 2009).
Length: 4.5 cm
Coloration is diagnostic. Larva of composita was described by Musser (1962), it has no lateral spines on abdominal segments 8 or 9, but has brown dorsolateral stripes on segments 7-10. The larva of L. SUBORNATA mistakenly described as COMPOSITA in Needham & Westfall, 1955.
Comments: Found in alkaline spring-fed streams and marshes. Hot springs in northern part of range, where adults oviposit directly into hot water, larvae live in cooler spring runs, adults forage in brushlands.
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Adults must disperse many miles.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 21 - 80
Comments: Widespread in Great Basin although in specialized habitat, perhaps relatively few occurrences.
10,000 to >1,000,000 individuals
Comments: Usually common where it occurs.
Habitat is ponds and streams with emergent vegetation, usually spring fed, sometimes alkaline, in open arid country.
Life History and Behavior
Comments: Larvae overwinter, flight season mid June to late August.
Molecular Biology and Genetics
Statistics of barcoding coverage: Libellula composita
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: G3 - Vulnerable
Reasons: This species is locally uncommon with specialized habitat which is vulnerable to overgrazing. Now known to occur in Mexico, so more populations are likely to exist.
Global Short Term Trend: Relatively stable (=10% change)
Comments: No known instances of declines.
Degree of Threat: Unknown
Comments: Most ponds and springs in arid West have emergent vegetation eliminated by livestock. Species seems rare, local, and sporadic, but may just be specialized; possibly competes poorly with fish or other dragonflies.
Biological Research Needs: (1) Basic larval ecology, especially temperature and alkalinity tolerance in comparison with other odonates.
Global Protection: Few (1-3) occurrences appropriately protected and managed
Comments: Exemplary site protected; most sites probably on private land.
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