White-whiskered grasshopper (Ageneotettix deorum)
| Ageneotettix deorum White-whiskered grasshopper | |
|---|---|
 | |
| Distribution | |
| British Columbia, Alberta, Saskatchewan, Manitoba, Washington, Oregon, California, Idaho, Nevada, Utah, Arizona, Montana, Wyoming, Colorado, New Mexico, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Texas, Minnesota, Iowa, Missouri, Arkansas, Wisconsin, Illinois, Indiana, Michigan | |
| Taxonomy | |
| Family: | Acrididae |
| Subfamily: | Gomphocerinae |
| Genus: | Ageneotettix |
| Additional resources | |
| Full taxonomy at OSF | |
The white-whiskered grasshopper (Ageneotettix deorum) is found throughout the grasslands of North America. Its antennae can be thread-like and white, giving it its name. This species periodically causes damage to North American rangelands.
Nomenclature
Ageneotettix deorum (Scudder, 1876). For full nomenclature, see this taxon's page on Orthoptera Species File
Identification
White-whiskered grasshopper adults are small to medium sized, light brown to reddish brown in coloration with dark markings, and a whitish [1] or yellow underside[2] [3]. Their color generally doesn't vary much from a combination of brown, black, and tan. [4] The faces are slightly slanted and with white stripes extending to the pronotum. A light than colored patch can be seen below the compound eye and on the lateral lobe.[4] The antennae are often white on the dorsal side, giving it the common name, “white-whiskered grasshopper". [5][2] Forewings have brown central speckles and vary in length but are usually the length of the abdomen. There is a dark triangular spot on the central upper side of the hind femora. Hind tibia are red or orange. [2]
For detailed identification descriptions see Brusven 1967 [1]
Quick ID
The white-whiskered grasshopper is small to medium-sized, a combination of brown and tan with dark markings, and a pale underside. It has white antennae, pale patches below the eyes, and white facial stripes. Its forewings are speckled brown, the hind legs have a dark triangle, and the lower legs are red or orange.
| Instar | Color [4] | Wings[2] | Body length [5] | Hind femur [5] | Antennal segment number [5] | Description |
|---|---|---|---|---|---|---|
| Eggs | Pale yellow or whitish [5] | 5.0-5.3 mm | ||||
| Egg pods | Tough and curved in appearance, with the cap being slanted and facing upwards within the soil [5] | 4 mm diameter and 10-12 mm long | ||||
| 1 | Shades of brown, black, and tan | 4.7-5.1 mm | 2.1-3.3 mm | 13 | ||
| 2 | Shades of brown, black, and tan | 6.4-6.7 mm | 4-4.2 mm | 15-17 | ||
| 3 | Shades of brown, black, and tan | 8.3-9.2 mm | 5.1-5.6 mm | 20 | ||
| 4 | Shades of brown, black, and tan | 9.9-11 mm | 7.3-7.7mm | 22 | ||
| 5 | Shades of brown, black, and tan | 14-15 mm | 9.1-9.8 mm | 24 | ||
| Adult Males | Shades of brown, black, and tan | Forewings have brown central speckles | 11-28 mm [2] or 15-16 mm [4] | 9-9.7 mm | 25 | |
| Adult females | Shades of brown, black, and tan | Forewings have brown central speckles | 15-28 mm [2] or 21-24 mm [4] | 12-12.5 mm | 25 |
Identification resources
Distribution
The white-whiskered grasshopper (Ageneotettix deorum) is found throughout the grasslands of North America west of the Mississippi River and also in the Great Lakes area. [5][2]
Biology
A. deorum is an early hatching species in mid-spring during a four to six-week period. [4] The total time for nymphal development is 40-48 days. [5] Nymphs begin to appear in June, while adults of this species can be seen around July to October. [6][2] Adult individuals will remain in the area where eggs were hatched and nymphal development was completed. Over the summer adult populations gradually decline. Eggs begin embryonic growth in the summer of deposit, and once growth reaches 50%, diapause begins. This diapause continues until winter but will resume once temperatures rise in spring. [5] This species produces one generation per year. [3]
Males actively roam the ground in search of mates, initiating pair formation by approaching moving females.[7] Courtship involves visual displays, mainly the rhythmic movement of their hind legs and antennae. Males produce a high-pitched, squeaky stridulation while pursuing females.[8] Copulation lasts approximately five minutes. Females lay their first clutch of eggs at 14 days old and continue depositing eggs roughly every three days. Each egg pod contains an average of four [5] or 12 according to Shell et al. 2005 [4]. Although in the lab, there is a record of 107.[4] Females prefer to lay eggs in blue grama or buffalograss sod but may also use bare soil. [5]
Like most grasshoppers, Ageneotettix deorum must balance foraging with the risk of predation, particularly from arthropod predators like lycosid spiders. This trade-off is most pronounced in younger nymphs, which are more vulnerable to predation. Studies show that third- and fourth-instar nymphs reduce their feeding activity and increase defensive behaviors when exposed to spiders, prioritizing survival over foraging. However, as A. deorum grows, this trade-off diminishes—fifth-instar nymphs and adults show no significant changes in behavior when exposed to predators, likely due to their larger size and reduced susceptibility. Grasshoppers reacted similarly to both lethal and nonlethal spiders, indicating that the presence of a predator alone is enough to influence behavior in younger instars.[9]
In another study by Danner and Joern, A. deorum grew faster and larger on high-quality food but showed slower growth and smaller size when exposed to both poor nutrition and spider predation. However, high-quality food offset the negative effects of predation. Grasshoppers exposed to spiders produced fewer eggs due to delayed reproduction, though daily egg production rates remained unchanged. Overall, predation risk significantly reduced growth, development, and reproduction, but improved food quality helped mitigate these effects, highlighting the role of resource availability in buffering against predation pressure. [10]
Ageneotettix deorum is primarily active during the day, with distinct daily activity patterns influenced by temperature and sunlight. At night, individuals seek shelter on the ground or among litter, often beneath canopy trees. Shortly after sunrise, they move to the east side of grass crowns to bask in the sun for about an hour, positioning themselves perpendicular to the sun’s rays to maximize heat absorption. Once warmed, they engage in essential activities such as feeding, mating, egg-laying, and general movement. As temperatures rise in the afternoon—often reaching around 90°F in the air and 120°F at the soil surface—grasshoppers reduce their activity and seek shade under small shrubs. Before sunset, they bask again on the west side of grass crowns before settling for the night.[5]
The white-whiskered grasshopper is a vigorous flier although there has been no record of this species migrating in swarms. Flights are usually straight, silent, and low.[5]
Habitat and Ecology
The white-whiskered grasshopper is most abundant in mixed-grass and bunchgrass prairies and is also common in the short-grass prairie regions of the Great Plains and, to a lesser extent, in tallgrass prairie.[5][11] This species is a generalist, graminivorous grasshopper. A. deorum often inhabit sparsely vegetated areas and feed on grasses and sedges. [2] Different populations of A. deorum exhibit similar food preferences.[11] Important host plants include blue grama, western wheatgrass, needleandthread, Kentucky bluegrass, threadleaf sedge, and needleleaf sedge, although no particular species is preferred.[4] However, other found that this species opts to feed on C3 grasses instead of C4 in locations where both are present, a preference potentially stemming from the differences in the anatomy of the leaves in the two differing vegetation types. [12] This grasshopper feeds not only on green grass leaves but also on ground litter,[13] including fallen leaves, seeds, livestock dung, and dead insects. When consuming attached green leaves, this species often severs them from the plant without eating the whole thing. [5] [4] This "waste" behavior is notable because it impacts the quality of forage for rangeland livestock.
In tallgrass prairies, A. deorum can reach high densities, particularly in areas with blue grama on high ridges or in grazed pastures with vegetation like smooth brome and Kentucky bluegrass. Preferred oviposition sites include blue grama and Buffalograss sod, though eggs are sometimes laid in bare ground. White-whiskered grasshopper populations may gradually increase 1.5- to 3-fold annually over four years, followed by a sudden sixfold surge that triggers an outbreak. However, after 3–5 years of high densities, the population crashes just as abruptly. These crashes occur because the species is highly sensitive to weather conditions and predation.[5]
Land-Use Change
White-whiskered grasshoppers have been recorded in “accidental places,” or places in which adult grasshoppers can not complete their life cycle. For example, populations have been found in the center of large cities on cement sidewalks, parking lots, paved streets, along with high altitudes on mountains. [5]
Pest Status
The white-whiskered grasshopper is one of the top dozen species monitored by USDA APHIS because of its impact on rangelands. The highest densities of the white-whiskered grasshopper develop in mixed grass and bunchgrass prairies. It is often the dominant species during outbreaks in mixed grass prairies, with densities increasing up to 25 adults per square yard, making up 50% of the grasshoppers within the area. [5]
Outbreaks
Populations of the white-winged grasshopper were at outbreak density in 1981 and 1982 in a mixed grass prairie site near Livermore, Colorado.[14]
Outbreak media coverage
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Associated organizations
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Resources
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References
- ↑ 1.0 1.1 Brusven MA (1967) Differentiation, ecology, and distribution of immature slant-faced grasshoppers (Acridinae) in Kansas. Kansas Agricultural Experiment Station Technical Bulletin 149. https://hopperwiki.org/images/6/68/Differentiation%2C_ecology%2C_and_distribution_of_immature_slant-faced_grasshoppers_%28Acridinae%29_in_Kansas.pdf
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Capinera JL, Scott RD, Walker TJ (2005) Field guide to grasshoppers, katydids, and crickets of the United States. Cornell University Press, Ithaca, New York, 280 pp.
- ↑ 3.0 3.1 Vickery VR, Kevan DKM (1985) The Insets and Arachnids of Canada: Part 14. The grasshoppers, crickets, and related insects of Canada and adjacent regions: Ulonata: Dermaptera, Cheleutoptera, Notoptera, Dictuoptera, Grylloptera, and Orthoptera. Publication 1777. Research Branch, Agriculture Canada, 918 pp. https://publications.gc.ca/collections/collection_2016/aac-aafc/agrhist/A42-42-1985-14-eng.pdf.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 Schell SP, Latchininsky AV, Shambaugh BA (2005) Common Wyoming Pest Grasshoppers. 2nd Edition B-1161.Laramie, WY: University of Wyoming Cooperative Extension Service and Department of Renewable Resources. 76 p. https://hopperwiki.org/images/5/51/Common_Wyoming_Pest_Grasshoppers.pdf
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 5.11 5.12 5.13 5.14 5.15 5.16 5.17 Pfadt RE (1994) Whitewhiskered Grasshopper 'Ageneotettix deorum' (Scudder). Wyoming Agricultural Experiment Station Bulletin 912. Species Fact Sheet. https://www.ars.usda.gov/ARSUserFiles/30320505/grasshopper/Extras/PDFs/Species%20Fact%20Sheets/Whitewhs.pdf
- ↑ Montana Field Guide (n.d.) White-whiskered grasshopper (Ageneotettix deorum). https://FieldGuide.mt.gov/speciesDetail.aspx?elcode=IIORT60010
- ↑ Otte D (1970) A comparative study of communicative behavior in grasshoppers. Miscellaneous Publications, Museum of Zoology, University of Michigan 141: 1–168.
- ↑ Buckell ER (1922) A list of Orthoptera and Dermaptera recorded from British Columbia prior to the year 1922, with annotations. Proceedings of the Entomological Society of British Columbia 20: 3–41.
- ↑ Danner BJ and Joern A (2003) Stage-Specific Behavioral Responses of Ageneotettix deorum (Orthoptera: Acrididae) in the Presence of Lycosid Spider Predators. Journal of Insect Behavior 16, 453–464. https://doi.org/10.1023/A:1027337405495
- ↑ Danner BJ and Joern A (2004) Development, growth, and egg production of Ageneotettix deorum (Orthoptera: Acrididae) in response to spider predation risk and elevated resource quality. Ecological Entomology, 29: 1-11. https://doi.org/10.1111/j.0307-6946.2004.00571.x
- ↑ 11.0 11.1 Pruess KP (1970) Food Ingestion and Utilization by Two Populations of a Grasshopper, Ageneotettix deorum. Journal of the Kansas Entomological Society, 43(4), 471–473. http://www.jstor.org/stable/25082365
- ↑ Heidorn T and Joern A (1984) Differential Herbivory on C₃ versus C₄ Grasses by the Grasshopper Ageneotettix deorum (Orthoptera: Acrididae). Oecologia: 65(1) 19–25. http://www.jstor.org/stable/4217488
- ↑ Anderson NL, Wright JC (1952) Grasshopper investigations on Montana rangelands. Montana Agricultural Experiment Station Bulletin 486. https://hopperwiki.org/images/e/e1/Grasshopper_investigations_on_Montana_rangelands.pdf
- ↑ Pfadt RE (1984) Species richness, density, and diversity of grasshoppers (Orthoptera: Acrididae) in a habitat of the mixed grass prairie. The Canadian Entomologist 116(5): 703–709. https://doi.org/10.4039/ent116703-5