Anisomorpha buprestoides

(Stoll, 1813)

Southern Two-striped Walkingstick, Devil Rider, Musk Mare, Twostriped Walkingstick

Anisomorpha buprestoides is among the largest insects in the continental United States, with females reaching nearly 100 mm. This phasmid exhibits extreme sexual size dimorphism, with females substantially larger than males. The is notable for its potent chemical defense spray containing anisomorphal and related compounds, which can cause severe irritation in humans. Three regionally distinct color morphs occur: brown, white, and orange forms, with the latter two restricted to specific areas of Florida.

Pronunciation

How to pronounce Anisomorpha buprestoides: /ˌænɪˈsɒmɔːrfə ˌbjuːprɛsˈtɔɪdiːz/

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

Identification

Distinguished from other North American phasmids by large size, stout build, and three prominent longitudinal black stripes. Differs from Anisomorpha ferruginea by geographic range (A. ferruginea occurs further west and north, with some overlap). The paired thoracic gland openings behind the are diagnostic for the . Color morph identification requires geographic knowledge: white and orange forms are geographically restricted within Florida.

Habitat

Arboreal, typically found in trees and shrubs. Associated with crepe myrtle, roses, oaks, rosemary, and other woody vegetation. Following disturbance such as hurricanes, has been observed on ground-level structures including houses, automobiles, and roads.

Distribution

Southeastern United States: Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, and Texas. White and orange color forms restricted to specific localities in Florida.

Seasonality

most abundant in late summer and autumn, particularly during mating season. Peak mating activity occurs in autumn. Following Hurricane Charley in 2004, unusual surface activity peaked approximately one month post-disturbance and declined by two months.

Diet

Folivorous; feeds on leaves of crepe myrtle (Lagerstroemia), roses (Rosa), oaks (Quercus), rosemary (Rosmarinus), and other trees and shrubs.

Host Associations

Lagerstroemia - food plantcrepe myrtle
Rosa - food plantroses
Quercus - food plantoaks
Rosmarinus - food plantrosemary

Life Cycle

with , nymph, and stages. Females produce more eggs than smaller females due to size-dependent . Nymphs of the brown form produce defensive secretions containing anisomorphal, dolichodial, and peruphasmal; adult chemical profiles vary by color morph.

Behavior

Typically . Exhibits strong sexual size dimorphism with females larger than males. Males frequently ride on females' backs in mating pairs, giving rise to 'devil rider' . When threatened, arches body and discharges irritating chemical secretion from thoracic glands. Defensive spray can be directed at attackers and causes severe pain upon contact. Following disturbance, may exhibit unusual including movement onto artificial structures.

Ecological Role

Herbivore; serves as prey for various . Chemical defense compounds (anisomorphal and related monoterpene dialdehydes) studied as model for chemical research.

Human Relevance

Can cause severe injury through defensive chemical spray; one documented case described pain 'as severe as if it had been caused by molten lead.' Caution advised when handling. Subject of foundational chemical research by Eisner and Meinwald. Featured on covers of Annals of the Entomological Society of America (2009) and Journal of Natural Products (2011).

Similar Taxa

Anisomorpha ferrugineaCongeneric with overlapping chemical defense and ; distinguished by more western and northern distribution, though ranges may overlap with A. buprestoides
Diapheromera femorataNorthern walkingstick; much smaller, more slender, lacks bold striping pattern, and occurs in more northern regions

More Details

Chemical Defense Research

The defensive spray was first studied by Thomas Eisner and Jerrold Meinwald, who identified anisomorphal as the primary compound. Later research found color morphs produce different chemical profiles: white and orange forms produce primarily anisomorphal, while brown form produces anisomorphal or peruphasmal depending on . Nymphs produce varying mixtures of anisomorphal and dolichodial.

Hurricane-Associated Behavior

Following Hurricane Charley in August 2004, researchers documented unusual daytime surface activity on vegetation and man-made structures, interpreted as possible response to disturbance. Activity peaked one month post-hurricane and declined by two months.