Big-headed Grasshopper - Aulocara elliotti
The following comes from Hebard (1928), Brooks (1958), Helfer (1971), Otte (1981), Capinera and Sechrist (1982), Vickery and Kevan (1985), McDaniel (1987), Pfadt (2002), Capinera et al. (2004), and Scott (2010). A medium-sized grasshopper usually with a gray body and dark markings. The dorsal surface of the pronotum possesses a light or weak “X” marking, but other patterns often exist within a population. Hind tibia is blue.
Overwinters in the egg stage. Nymphs appear in mid-spring. Adults occur from June through September, or until the first heavy frost (Capinera et al. 2004, Capinera and Sechrist 1982, Otte 1984, Pfadt 2002, Schell et al. 2005, Scott 2010, and Vickery and Kevan 1985).
The following is taken from Hebard (1928), Brooks (1958), Helfer (1971), Otte (1981), Capinera and Sechrist (1982), Vickery and Kevan (1985), McDaniel (1987), Pfadt (2002), Capinera et al. (2004), and Scott (2010). The body length to end of forewings for males is 16 to 25 mm, and for females 22 to 35 mm. Hind femur has black bars on the outer upper area which continue onto the upper surface and onto the upper area of the inner face. The shape of the female 8th ventral segment’s posterior margin has a small bump without deep clefts.
The Big-headed Grasshopper is similar to the White-crossed Grasshopper
). A quick separation can be made by comparing the shapes of the female 8th ventral segment’s posterior margins. A. femoratum
has deep clefts. See that species for other diagnostic characters.
A widely distributed grassland species of western North America. From the western Canadian provinces south to Mexico, and from western Minnesota and Iowa to Washington, Oregon, and California. In Montana, reported for 52 counties but probably occurs throughout the state (Capinera and Sechrist 1982, Capinera et al. 2004, Otte 1984, Pfadt 2002, Schell et al. 2005, Scott 2010, and Vickery and Kevan 1985).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Favors shortgrass prairies, especially areas with sparse vegetation and bare ground (Capinera and Sechrist 1982, Capinera et al. 2004, Otte 1984, Pfadt 2002, and Vickery and Kevan 1985).
The Big-headed Grasshopper feeds mainly on grasses and sedges (2 species of sedges and 22 species of grasses), preferring bluegrass, blue gramma
), western wheatgrass
), and cheatgrass
). Rarely feeds on forbs, but will scavenge litter, seeds, manure and dead insects (Capinera and Sechrist 1982, Otte 1984, Pfadt 2002, Schell et al. 2005, and Vickery and Kevan 1985).
Pair formation and courtship consists of visual cues. Males display themselves by hind femora tipping and antennae waving. When male mounts and makes genital contact, copulation lasts for 40 to 70 minutes. Females deposit their first eggs when they are 12 to 20 days old. Seven to nine eggs are laid in a hard, smooth, foam-like pod in the top half inch of bare soil. Hatching nymphs pass through 5 instars and usually takes 36 to 42 days to reach the adult stage (Capinera et al. 2004, Capinera and Sechrist 1982, Otte 1984, Pfadt 2002, Schell et al. 2005, and Vickery and Kevan 1985).
The Big-headed Grasshopper is often the dominant species in outbreaks on rangelands. High population densities destroy the value of rangeland for grazing and can even lay the land bare. Such high densities have been observed persisting for more than five years (Pfadt 2002, Schell et al. 2005).
- Literature Cited AboveLegend: View Online Publication
- Brooks, A.R. 1958. Acridoidea of Southern Alberta, Saskatchewan, and Manitoba (Orthoptera). The Canadian Entomologist (Supplement 9) 90:5-92.
- Capinera, J.L. and T.S. Sechrist. 1982. Grasshoppers of Colorado: Identification, Biology, and Management. Fort Collins, CO: Colorado State University Experiment Station, Bulletin 584S. 161 p.
- Capinera, J.L., R.D. Scott, and T.J. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States. Ithaca, NY. Cornell University Press.
- Hebard, M. 1928. The Orthoptera of Montana. Proceedings of the Academy of Natural Sciences of Philadelphia, Vol. 80:211-306.
- Helfer, J.R. 1971. How to Know the Grasshoppers, Crickets, Cockroaches, and Their Allies. Revised edition (out of print), Mineola, NY: Dover Publications.
- McDaniel, B. 1987. Grasshoppers of South Dakota. Brookings, SD: South Dakota Agricultural Experiment Station, Bulletin TB 89.
- Otte, Daniel. 1981. The North American Grasshoppers. Volume 1. Acrididae (Gomphocerinae and Acridinae). Harvard University Press. 275 pp.
- Pfadt, R.E. 2002. Field Guide to Common Western Grasshoppers, 3rd edition. Laramie, WY: Wyoming Agricultural Experiment Station, Bulletin 912, modified by S. Schell and S. Schell for electronic publication. Accessed 19 February 2020. http://www.uwyo.edu/entomology/grasshoppers/field-guide/index.html#fieldguidetoc
- Schell, S.P., A.V. Latchininsky, and B.A. Shambaugh. 2005. Common Wyoming Pest Grasshoppers. 2nd Edition B-1161.Laramie, WY: University of Wyoming Cooperative Extension Service and Department of Renewable Resources. 76 p.
- Scott, R.D. 2010. Montana Grasshoppers, Katydids, and Crickets A Pictorial Field Guide to the Orthoptera. MagpieMTGraphics, Billings, MT.
- Vickery, V. R. and D. K. M. Kevan. 1985. The grasshopper, crickets, and related insects of Canada and adjacent regions. Biosystematics Research Institute, Ottawa, Ontario. Publication Number 1777. 918 pp.
- Additional ReferencesLegend: View Online Publication
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- Anderson, N.L. 1962. Grasshopper-vegetation relationships on Montana grasslands. Ph.D Dissertation. Bozeman, Montana: Montana State University. 73 p.
- Gillespie, R.L.1992. Dynamics of grasshoppers (Orthoptera: Acrididae) at a rangeland-crop interference. Ph.D. Bozeman, MT: Montana State University. 111 p.
- Hebard, M. 1932. Notes on Montana Orthoptera. Proceedings of the Academy of Natural Sciences of Philadelphia. V. 84. pp 251-257.
- Henry, J.E. 1969. Protozoan and viral pathogens of grasshoppers. Ph.D. Dissertation. Bozeman, MT: Montana State University. 153 p.
- Laine, I.I. 1966. Temperature effects on the oxygen consumption during development of Aulocara elliotti (Thomas). Ph.D. Dissertation. Bozeman, Montana: Montana State University. 74 p.
- Larson, D.P. 1996. Evaluation of sweep sampling as a method for determining grasshopper community composition on rangeland. M.Sc. Thesis. Bozeman, MT: Montana State University. 92 p.
- Mussgnug, G.L. 1972. The structure and performance of an adult population of Aulocara elliotti (Thomas) (Orthoptera, Acrididae) near Billings, Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 97 p.
- Skinner, K.F. 1995. Plant and grasshopper community composition: indicators & interactions across three spatial scales. M.Sc. Thesis. Bozeman, MT: Montana State University. 144 p.
- Van Horn, S.N. 1963. The embryogenesis and embryonic variability of Aulocara elliotto Thomas (Acrididae Orthoptera). Ph.D. Dissertation. Bozeman, MT: Montana State University. 172 p.
- Wachter, D.H. 1995. The ecology of selected grasshopper species along an elevational gradient. M.Sc. Thesis. Bozeman, Montana: Montana State University. 59 p.
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