Melanoplus rugglesi

Gurney, 1949

Nevada Sage Grasshopper

Melanoplus rugglesi is a -sized -throated to the cold desert shrublands of the western United States. The exhibits pronounced phase , with solitary and migratory forms differing in body size, length, and coloration. Named in honor of Arthur G. Ruggles, this grasshopper is notable for its extreme migratory and extended dynamics, with persisting at high for multiple years.

Pronunciation

How to pronounce Melanoplus rugglesi: /mɛˈlænoʊpləs ˈrʌɡlɛsi/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from the closely related Melanoplus occidentalis by male : M. rugglesi has a larger, quadrate and corkscrew-twisted aedeagal appendage, whereas M. occidentalis has a slightly smaller, triangular cercus with evenly rounded and straight (needle-shaped) lateral aedeagal appendage. identifiable by genal crescent, pattern with diagonal dark bar, and hind color pattern with three alternating bars.

Appearance

-sized with bright coloration. Inner and lower areas of hind bright orange; upper marginal and medial areas tan with three transverse dark bars, the middle bar of medial area usually chevron-shaped. Hind . long, extending 1–7 mm beyond of hind femur. Migratory phase individuals larger with brighter orange coloration; solitary phase individuals smaller with grayish rather than bright orange markings on and hind femur.

Habitat

Cold desert shrublands of the far West, dominated by sagebrush and associated shrubs with subdominant forbs and grasses in the understory. Preferred include areas with big sagebrush, black sagebrush, Douglas rabbitbrush, spiny hopsage, and shadscale.

Distribution

Mainly Nevada and Utah; also occurs in adjacent states including Oregon, Idaho, and British Columbia, Canada. Recorded from Glacier in Montana, presumably from long-distance .

Seasonality

Early-hatching . Hatching begins as early as April 1 in warm years, typically mid-April, continuing for 2–3 weeks. appear from mid-May to mid-June. occurs from June through July. One per year with .

Diet

Primarily a shrub feeder, with five preferred shrubs: big sagebrush (Artemisia tridentata), black sagebrush (A. nova), Douglas rabbitbrush (Chrysothamnus viscidiflorus), spiny hopsage (Grayia spinosa), and shadscale (Atriplex confertifolia). Also feeds on downy brome (Bromus tectorum), scarlet globemallow, and other forbs and grasses. Laboratory studies indicate preference for young wheat leaves, dandelion, downy brome, and sage.

Host Associations

Artemisia tridentata - preferred shrub
Artemisia nova - preferred shrub
Chrysothamnus viscidiflorus - preferred shrub
Grayia spinosa - preferred shrub
Atriplex confertifolia - preferred shrub
Bromus tectorum - important nymphal

Life Cycle

with . Embryonic development occurs primarily in summer following , with breaking during winter. Five nymphal ; development to adulthood requires approximately 6 weeks under field conditions, or 23 days at constant 90°F in laboratory. Preoviposition period approximately 21 days. Females produce 14–25 eggs per pod; pods 1–1.75 inches long. Long-lived females may produce up to 20 pods.

Behavior

Highly migratory in dense . migrate 2–4 miles daily, up to 40–75 miles per season, primarily in northerly direction. Swarm occur at heights of a few hundred feet, with updrafts lifting to several thousand feet. of IV–V migrate as coherent , traveling up to 200 yards per day. spending most time on ground; basks by flanking (turning side perpendicular to sun, lowering hindleg). Ovipositing females highly gregarious, often more than 100 depositing simultaneously in small areas.

Ecological Role

Significant in cold desert shrub . During , defoliates, barks, and kills shrubs, disrupting and promoting soil erosion and weed invasion. Serves as for various vertebrate and . Migratory may reduce local predator and buildup.

Human Relevance

Serious agricultural and rangeland pest during . The 1938–1951 Nevada outbreak and 1989–1996 Utah outbreak caused extensive damage to sagebrush, reducing winter forage for livestock and wildlife. Swarms destroyed garden including corn, lettuce, onions, radishes, beets, and potatoes. Minor damage to alfalfa and sweet clover. Despite control efforts, persisted for years due to into new .

Similar Taxa

Melanoplus occidentalisClosely related with similar general appearance; distinguished by male shape (triangular vs. quadrate) and straight vs. corkscrew-twisted aedeagal appendage
Melanoplus sanguinipesAnother highly migratory Melanoplus with phase ; differs in preference (grasslands vs. desert shrublands) and associations

More Details

Phase Polyphenism

Gurney (1949) recognized solitary and migratory phases differing in body size, length, and color intensity. Migratory individuals have larger bodies, longer wings, and brighter orange coloration; solitary individuals are smaller with grayish markings.

Outbreak Dynamics

persist for exceptionally long periods: 14 years in Nevada (1938–1951) and 7 years in western Utah (1989–1996). into new appears to safeguard from and buildup that typically collapse outbreaks of other .

Long-Distance Dispersal

Specimens recorded on Glacier in Montana in 1949, approximately 600 miles from the nearest known in southwestern Oregon, demonstrate potential for extreme long-distance transport by upper-level winds.