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New Mexico Rare Arthropod Resource

The New Mexico Rare Arthropod Resource

 
Microphotus octarthrus (Chihuahuan Pink Glow-worm)  


Taxonomy

  • Class: Insecta
  • Order: Coleoptera
  • Family: Lampyridae
  • Genus: Microphotus
  • Scientific Name: Microphotus octarthrus Fall, 1912
  • Common Name: Chihuahuan Pink Glow-worm
  • Synonyms: Microphotus abbreviatus E. Olivier, 1912 (E. Olivier, 1912)

Taxonomic Name Source


Green, J.W. 1959. Revision of the species of Microphotus, with an Emendation of the Lampyrini (Lampyridae). The Coleopterists Bulletin 13(3): 80-96.
Mike Quinn (2015)
Jason Wilder (2014)
Species Occurrence Data From: Global Biodiversity Information Facility (GBIF)

Agency Conservation Status



  • SGCN
  • NMDGF:
  • USFWS:
  • BLM:
  • USFS:
  • IUCN Red List: Data Deficient
  • Nature Serve Global: GU
  • 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
Data Deficient GU SNR NO


Description

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Like other species of Microphotus, M. octarthrus males are small, fragile beetles with very large eyes and barely visible, reduced mouthparts between the eyes. The antennae are shorter than the pronotum, have less than eleven segments, and have a small bead-like process, called a tuberculiform appendix, on the tip of the terminal segment. They have short, pale legs (femora do not extend beyond the margin of the body), and simple tarsal claws. Females are larviform without elytra or hindwings. They have small, elongate, retractable heads, with simple eyes, called lateral ocelli or stemmata. The antenna is similar to that of the male yet has fewer segments. In M. octarthrus specifically, the elytra are less than three times as long as the pronotum (averaging about 2.5 times as long), the antennae have eight segments, the eyes beneath are broadly contiguous posteriorly, and the pronotum is truncate at the base. The median longitudinal line on the pronotum is not impressed. This species is also relatively small (4.25-6.25 mm) and the elytra is pale brown with darker tips (Green 1959).

Habitat and Ecology

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Microphotus octarthrus is a desert-dwelling nocturnal firefly with flightless females (Usener and Cognato 2006). It is typically found in oak-pine transition zones, at least in southeastern Arizona (J. Cicero pers. comm. 2020). Populations in central and northern Arizona have different ecological niches that are uncharacterized. In New Mexico, the species can be found in the lower elevations of montane areas, such as the Sandia and Gila Mountains, in pinyon, oak, and juniper dominated shrublands and woodlands (Walker 2024). Like other fireflies, larvae in this genus have been observed feeding on snails, and may also feed on slugs, earthworms, and other soft bodied invertebrates. This species has been documented from several mountain ranges up to 6,000 feet in elevation (Green 1959). Collection records indicate that this species is active from April through September (Green 1959), depending on location.

Geographic Range

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Microphotus octarthrus has been reported from southwest Utah, Arizona, New Mexico, and western Texas, and from Chihuahua and Coahuila, Mexico (Fig. 41) (Green 1959, Zaragoza-Caballero et al. 2023, GBIF. org 2023, BugGuide 2023).

Conservation Considerations

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No conservation actions are currently in place for this species. However, historic localities appear to occur in a number of protected areas, including the Zion Wilderness in UT, Saguaro National Park in AZ, Middle Cherry Canyon Macrosite and Big Bend Proposed Wilderness in TX, and Reserva de la Biósfera in Chihuahua (Protected Planet 2020). Very few details are available regarding this species’ life history or habitat associations, so basic ecological research would be beneficial. Surveys at historic sites throughout this species’ range, as well as other citizen science efforts, would be helpful in determining the current range and distribution of this species. Adults appear to come readily to UV lights (BugGuide 2020), which could be useful for surveys.

Threats

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Specific threats to this species are not well studied. However, it is likely that climate change-related drought is a major threat. Fireflies typically need moisture to complete their life cycles; it prevents desiccation of vulnerable immature stages, and ensures the persistence of the soft-bodied invertebrates that are the preferred food source for the larvae. Other threats to this species include ground disturbances such as trampling by livestock, habitat alterations, roadside runoff and pollution, and impacts from off-road vehicle (ORV) use (J. Cicero pers. comm. 2019). Because females of this species are flightless with poor dispersal capabilities, they are especially vulnerable to these threats. Chemical pollution and flooding are also concerns. Microphotus octarthrus females have been observed climbing up the steep faces of road cuts to signal to males, while their larvae live down below in vegetation that accumulates along the road margin (J. Cicero pers. comm. 2019). Due to these roadside locations, individuals in these areas are subject to contamination from vehicles and flooding due to rain run-off (J. Cicero pers. comm. 2019). Specific threats to this species are not well studied. However, it is likely that climate change-related drought is a major threat to this species. Fireflies need moisture to complete their life cycles; it prevents desiccation of vulnerable immature stages, and it ensures the persistence of the soft-bodied invertebrates that are the larvae’s preferred foods. More generally, fireflies are threatened by habitat degradation, light pollution, and pesticide use (Lewis et al. 2020), all of which could impact this species. Light pollution can interfere with the bioluminescent courtship signals used by this species (Owens and Lewis 2018), which may have cascading effects on population size and health.

Population

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Detailed data on population size and abundance are not available for this species.

References

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