Umbonia crassicornis

Distinguished from other treehoppers by the combination of: (1) large size (~10 mm) relative to most membracids; (2) tall, perpendicular pronotal horn; (3) pronounced sexual dimorphism in horn angle and apical expansion; and (4) green to yellow ground color with reddish linear markings. Males can be identified by the more posteriorly angled and apically expanded pronotal horn compared to females' straighter, pointed process. Similar congeneric species such as Umbonia reclinata differ in pronotal horn orientation and geographic distribution.

Tropical and subtropical regions where mean temperatures remain above freezing. Found on bark and branches of host trees, particularly leguminous trees. Females select branches approximately 3.8 mm in diameter for oviposition, requiring sufficient girth to wrap their legs around the substrate.

Native range extends from northern South America through Central America to Mexico. Introduced and established in southern Florida and Puerto Rico (first detected in Puerto Rico in May 1972, now spread across multiple towns and coasts). Distribution limited by freezing temperatures, which cause 10–90% population mortality.

Active year-round in tropical climates; population dynamics influenced by temperature thresholds with freezing events causing significant mortality.

Feeds on xylem or phloem sap extracted from host plants using piercing-sucking mouthparts.

• Pithecellobium dulce - primary hostFavorite host in Puerto Rico; leguminous tree.
• Ornamental trees - hostOccasional pest in southern Florida.
• Fruit trees - hostOccasional pest in subtropical regions.
• Leguminous trees - host categoryMainly attacks this group; 11 different host trees recorded in Puerto Rico.

Females deposit approximately 100 eggs into plant stems or under bark, occasionally in leaf petioles. Before hatching, females create spiral bark slits with the ovipositor; first-instar nymphs aggregate along these slits. Females remain with the brood until nymphs reach adulthood, actively maintaining aggregation by using front tarsi to stroke straying nymphs back to the cluster. Nymphal development occurs in aggregations; upon reaching sexual maturity, adult aggregations fragment and dispersal occurs. Mating takes place before and during dispersal. Females typically mate once in their lifetime.

Exhibits extensive subsocial maternal care rare among insects. Females guard eggs and nymphs until adulthood; offspring survival drops from 53% to 27% without maternal presence. Nymphs communicate through substrate-borne vibrational signals in synchronized bursts to elicit maternal antipredator defense; asynchronous signals are ignored. Males employ a 'fly-call-walk' strategy for mate location: flying between plants, walking and strutting, then producing vibrational courtship signals upon female contact. Courtship calls consist of continuous tones decreasing in frequency with periodic high-frequency clicks generated by abdominal muscles pulling on the pronotal horn. Older males (25–33 days) lose flight ability and walk to search for females; despite lower encounter rates, females prefer older males due to increased sexual advertisement and courtship frequency. Nymphs exhibit sibling rivalry for central positions in aggregations (safer from predation) and positions closest to the mother.

Phytophagous sap-feeder that can reach high densities on host trees. Secretes honeydew that promotes sooty mold growth, causing foliar blackening. Serves as prey for vespid wasps and potentially other predators; maternal defense behavior suggests significant predation pressure on nymphs. No documented mutualistic ant associations, unlike many other treehopper species.

Occasional pest of ornamental and fruit trees in southern Florida and Puerto Rico. Massive infestations can destroy twigs and branches, affecting tree appearance. The female's splinter-like pronotal horn poses a physical nuisance to barefoot people and those handling the insect. Honeydew secretion leads to sooty mold outbreaks. Controlled with insecticides including diazinon, carbaryl (Sevin), malathion, and endosulfan. Accidentally introduced to Puerto Rico, likely via infested plant material or hitchhiking fertile female in airplane baggage.

• Umbonia reclinataCongeneric species with similar pronotal modifications but differs in horn orientation and geographic distribution; both occur in Mexico.
• Other MembracidaeMany treehoppers have expanded pronota, but U. crassicornis is distinguished by large size (~10 mm), perpendicular thorn-like pronotum, and pronounced sexual dimorphism in horn structure.

• subsocial behavior
• maternal care
• vibrational communication
• sexual dimorphism
• thorn mimicry
• pest species
• introduced species

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Bizarre, beautiful extremes | Beetles In The Bush
• Alarm Behavior of Brooding Female Umbonia crassicornis (Homoptera: Membracidae)
• AGGREGATING BEHAVIOR OF UMBONIA CRASSICORNIS (HOMOPTERA: MEMBRACIDAE)
• Reproductive Behavior and Dispersal in Umbonia crassicornis (Homoptera: Membracidae)
• OFFSPRING-PARENT COMMUNICATION IN A SUBSOCIAL TREEHOPPER (HEMIPTERA: MEMBRACIDAE: UMBONIA CRASSICORNIS)
• Umbonia crassicornis (Amyot & Serville, 1843) (Hemiptera: Membracidae) nymphal aggregation size and density affect host plant and treehopper growth
• Influence of Freezing Temperatures on the Distribution ofUmbonia crassicornis(Hemiptera: Membracidae) in Florida
• Notes on the Accidental Introduction of Umbonia crassicornis (Amyot and Serville)— (Hemiptera: Membracidae) into Puerto Rico and its Control
• Colonization and Abandonment of Host Trees in a Natural Setting on Key Largo, Florida by the Treehopper, Umbonia crassicornis (Amyot and Serville) (Hemiptera: Membracidae)