Orthoptera of North Carolina
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View Gryllidae Members: NC Records

Allonemobius sparsalsus (Fulton, 1930) - Salt-Marsh Ground Cricket


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Taxonomy
Family: Gryllidae Subfamily: Nemobiinae Tribe: PteronemobiiniSynonym: Nemobius sparsalus
Comments: One of ten species in this genus, all of which occur in North America north of Mexico (Cigliano et al., 2017). Eight species have been recorded in North Carolina.
Species Status: The type locality is Carolina Beach, North Carolina (Fulton, 1930)
Identification
Field Guide Descriptions: Online Photographs: BugGuide, Google Images,  iNaturalist, GBIFTechnical Description, Adults/Nymphs: Fulton (1930)                                                                                  
Comments: A small, blackish cricket associated with coastal Spartina marshes. Fulton (1930) described its color as a "nearly uniform dark sepia, becoming nearly black on the occiput, pronotum, dorsal field and upper lateral field of the tegmina". Only faint traces are present of the four light lines on the occiput characteristic of most species of Allonemobius (Fulton, 1930).
Singing Behavior: Calling songs consist of a series of short trills interrupted by pauses. Fulton (1930) described the trill rate of about one per second at 80 F, with the rate decreasing to 3/5 per second at 70 F. However, examples shown on the Macaulay Library show trills lasting from 2-3 seconds, with pauses lasting longer than 3 seconds. Within each trill, the amplitude increases from start to finish (Fulton, 1930); in examples provided by the Macaulay Library, the change in amplitude seems to occur fairly abruptly about halfway through the trill. The dominant pitch in these examples is around 7 kHz but increasing to 7.5 kHz in the second half of each trill, accompanying the increase in amplitude. As in Allonemobius maculatus, the pulses composing each trill are grouped into short series of 3-4 pulses, giving the trill a pulsing quality (see examples in the Macaulay Library). The calling songs of Allonemobius fultoni -- another species associated with marsh edges, although in this case, freshwater -- also consist of short trills with increasing in amplitude. The trill of that species, however, lack the pulsed quality of sparsalsus and are usually longer, lasting between 3-5 seconds, and the pauses between trills are shorter.
Distribution in North Carolina
County Map: Clicking on a county returns the records for the species in that county.
Adult Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

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Habitats and Life History
Habitats: Apparently confined to Spartina marshes along the coast. According to Fulton (1930), individuals reside up in crowns of the plants, out of reach of the fiddler crabs that are abundant in the same habitats.
Diet: Probably omnivorous
Observation Methods: Most easily detected by song. Fulton noted that they can be captured by driving them towards a net but that sweeping the vegetation is not very productive.
Abundance/Frequency:
Adult Phenology:
Status in North Carolina
Natural Heritage Program Status: [W3]
Natural Heritage Program Ranks: [GNR] [SU]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands
Comments: We currently have very few records for this species, which appears to be a narrow habitat specialist. The habitat of this species, moreover, is likely to be highly affected by sea-level rise, with the possibilities for landward migration limited by coastal development. More surveys are needed to determine both the current status of this species in North Carolina and its risk due to the changes in its habitat.