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New Mexico Rare Arthropod Resource

The New Mexico Rare Arthropod Resource

 
Euphilotes rita (Rita Blue)  


Taxonomy

  • Class: INSECTA
  • Order: LEPIDOPTERA
  • Family: LYCAENIDAE
  • Genus: Euphilotes
  • Scientific Name: Euphilotes rita (Barnes and McDunnough, 1916)
  • Common Name: Rita Blue
  • Synonyms:

Taxonomic Name Source


Pelham, J. P. 2008. A catalogue of the butterflies of the United States and Canada with a complete bibliography of the descriptive and systematic literature. The Journal of Research on the Lepidoptera. Volume 40. 658 pp. Revised 14 February, 2012.
Steve Cary ()
Species Occurrence Data From: Global Biodiversity Information Facility (GBIF)

Agency Conservation Status



  • SGCN
  • NMDGF:
  • USFWS:
  • BLM:
  • USFS:
  • IUCN Red List: Not Evaluated
  • Nature Serve Global: G3
  • NHNM State: SNR
  • NM Endemic NO


Agency Conservation Status



SGCN NMDGF USFWS BLM Status USFS IUCN
Red List		 Nature Serve
Global		 NHNM State NM Endemic
Not Evaluated G3 SNR NO


Description

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Rita’s Blue follows the general Euphilotes look, but minor differences are apparent. The topside orange band on female hindwings is rather broad. On males, the dorsal hindwing pink/orange aurora is more fully expressed and is accompanied by four or five well-defined, circular black spots in the submargin. The dorsal forewing black margin is thin, no more than 10% of the wing radius, as in Ellis’ Blue but not Central Blue. Fringe checkering is weak. Ventral forewing black spots are prominent, less smeared.

Description courtesy of Steven J. Cary, Butterflies of New Mexico, 2024

Habitat and Ecology

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This species mostly lives in lower and upper Sonoran zone deserts and prairies but can also be found in pinyon juniper and oak woodlands and on sand dunes and plateaus (Scott 1986, Opler and Wright 1999, Glassberg 2001, Cary and Toliver 2024). All of this species host plants are Buckwheats (Eriogonum) and known host plants include Effuse Buckwheat (Eriogonum effusum), Wright's Buckwheat (Eriogonum wrightii),  Yellow Buckwheat (Eriogonum flavum), and Sorrel Buckwheat (Eriogonum polycladon)(Scott 1986, Opler and Wright 1999, Glassberg 2001, Cary and Toliver 2024). Glassberg (2001) also reports the use of “Loose Buckwheat” however, we could not find a species with this common name (Glassberg 2001). 

This species has one flight which usually occurs from July to late September with the species numbers peaking in August (Scott 1986, Opler and Wright 1999, Glassberg 2001, Brock and Kaufman 2003, Cary and Toliver 2024). During flight adults feed on nectar especially from their host flowers and also sip on mud for moisture (Scott 1986, Cary and Toliver 2024). Adults never wander far from their host plants, mostly perching and nectar on them; however, males can be seen patrolling around host plants seeking females (Scott 1986, Cary and Toliver 2024). After mating eggs are laid in the flowers of the host plant and the larvae eat the flowers and young fruits (Scott 1986). Larvae of this species like many Lycaenidae are also ant tended and don't make nests (Scott 1986). This species overwinters as a pupae (Scott 1986). 

Geographic Range

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This species is described as living from southern Wyoming south into west Texas and northern Chihuahua before the species distribution heads west into southern Utah, Nevada and eastern Arizona (Mattoni 1995, Scott 1986, Opler and Wright 1999, Cary and Toliver 2024, NatureServe 2024). In older sources the species is also described in southern California, and in Mono county California however these records now belong to the Pallid Blue (Euphilotes rita pallescens) which has now been elevated to a full species (Scott 1986, Pelham 2024). Butterflies of America does list a subspecies of this taxa in Montana Euphilotes rita montanensis however this population is not fully documented and there is little to no information on it so at this time we omit it from the geographic range of this species however, it is thought to occur or have occurred in Carbon county Montana (Kohler and Warren 2021, Pelham 2024). In New Mexico this species is described as living between 1460 and 2440 meters in elevation (4800 to 8000 feet)(Cary and Toliver 2024).

Conservation Considerations

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Threats

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et al. 1995). In fact Noss et al. (1995) stated that grasslands in the American southwest are now a critically endangered ecosystem having declined by more than 98% (Noss et al. 1995). However, while seeing large declines here this species still remains in desert foothills, and arid savannahs in New Mexico, Arizona, Colorado, Wyoming, and Utah although the species appears to be much less common than it once was in these areas.

Not only has this butterfly seen declines but all of the remaining known habitats this species resides in are sensitive to invasion by exotic plants this species host buckwheats are highly susceptible to declines from invasive species and wildfires (USFWS 2010, Tilley 2012). These two threats can also compound with each other as this invasion by exotic grasses can increase the rate and severity of fires to the detriment of the host plant (Allen et al. 2011, McDonald and McPherson 2013, Fusco et al. 2019). This increase in fire frequency and severity is very likely to cause the extirpation of these colonies and will likely continue to result in declines in species numbers, available habitat, and number of subpopulations. This threat has also become much more pronounced in recent years as drought and grazing have vastly accelerated the decline of this species' host plant and of native grassland ecosystems (Souther et al. 2019). The southwest is expected to continue to get hotter and drier still as climate change progresses and the effects of drought have been accelerated in these grasslands as invasive species have decreased diversity making these grasslands less drought tolerant at the same time that this area is seeing longer and more severe droughts leading to further declines in native species (Cook et al. 2009, Cook et al. 2015, Ludwig et al. 2017, Williams et al. 2022). Off road vehicle use has also further destroyed habitats for this species (NatureServe 2024). 

This species is also described to be locally uncommon by most sources and subspecies E.r. coloradensis is no longer found in many areas where it was formerly abundant (Glassberg 2001, NatureServe 2024). There are also several life history factors that may put this species at increased risk of extinction. Firstly this species is univoltine and species that are univoltine are thought to have decreased dispersal abilities, which limits the area they can utilize, in turn making them less resilient to stressors (Eskildsen et al. 2015). This can make them prone to extinction and as a result has been used as a potential indicator of extinction risk in butterflies it can also make species more prone to phonological mismatch (Singer and Parmesan 2010, Eskildsen et al. 2015, Patterson et al. 2019, Forister et al. 2023). This species also uses one genera of host plant giving it somewhat of a specific ecological association that may put at additional risk from other stressors as any threats that affect Buckwheats (Eriogonum spp.) will also lead to declines in this species population. 

Population

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The population size and trend are not known for this species. Determination of population size and monitoring of population trends is necessary to ensure the population is stable. Especially as several widespread, relatively common species of butterfly are in decline across the American west (Forister et al. 2021).

References

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