Amblyomma cajennense

Fabricius, 1787

Cayenne tick

, commonly known as the , is a hard historically considered to range from the southern United States through Central America and the Caribbean to northern Argentina. Molecular studies have revealed this 'species' is actually a complex of multiple cryptic species, with A. cajennense sensu stricto now restricted to the Amazonian region of South America. The is of significant medical and veterinary importance as a of and other rickettsial .

Amblyomma cajennense by (c) Francisco Farriols Sarabia, some rights reserved (CC BY), uploaded by Francisco Farriols Sarabia. Used under a CC-BY license.

Ciclo de vida do Carrapato-estrela by Henriqueandradelira. Used under a CC BY-SA 3.0 license.

The life history and bionomics of some North American ticks (1912) (14748516866) by Internet Archive Book Images. Used under a No restrictions license.

Pronunciation

How to pronounce Amblyomma cajennense: /ˌæm.blɪˈɒm.ə kaˈjɛn.sɛne/

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

Identification

The A. cajennense complex has historically been identified by morphological features, but -level identification within the complex now requires molecular analysis. A. cajennense sensu stricto occurs in the Amazon biome. Other members of the complex are geographically separated: A. mixtum from Texas to western Ecuador, A. patinoi in the Eastern Cordillera of Colombia, A. interandinum in the northern Inter-Andean valley of Peru, A. tonelliae in dry Chaco regions of Argentina/Bolivia/Paraguay, and A. sculptum in humid northern Argentina and adjacent regions.

Images

Habitat

Amazon biome; riparian forest fragments. The broader occupies diverse environments from dry Chaco regions to humid tropical forests, reflecting to wide environmental conditions.

Distribution

A. cajennense sensu stricto: Amazonian region of South America, specifically documented from Rondônia, Brazil. The broader (sensu lato) historically reported from southern United States through Mexico, Central America, Caribbean, and South America to northern Argentina. GBIF records confirm presence in: Argentina, Belize, Bermuda, Bolivia, Brazil, Colombia, Rica, Cuba, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Jamaica, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Trinidad and Tobago, United States, Venezuela.

Diet

Blood-feeding of vertebrate . Documented hosts include mammals (especially horses, dogs), amphibians, reptiles, birds. First recorded instance of on a fish: two A. cajennense were found embedded in an electric eel (Electrophorus varii) specimen collected in Brazil in 1873.

Host Associations

horses - primary (females collected from)Study specimens from Rio de Janeiro and Minas Gerais, Brazil
dogs -
amphibians -
reptiles -
birds -
mammals - general groupespecially those with hooves
Electrophorus varii - unusual recordfirst known instance of on fish; 1873 museum specimen

Life Cycle

Engorged females oviposit masses in sheltered locations. Eggs are exposed to environmental conditions and vulnerable to desiccation and . Laboratory conditions for egg development: ~93% relative humidity, 26°C, 14h:10h . Bacterial associates identified from eggs may assist in hatching through secretion.

Behavior

Questing : climbs vegetation and extends forelegs to encounter . Saliva exhibits immune-modulatory activity, increasing anti-inflammatory cytokines (IL-6, IL-10), reactive oxygen production, and phagocytic activity in macrophages. Saliva composition changes dynamically throughout the feeding process.

Ecological Role

of rickettsii, the agent of . Primary vector role in the complex now attributed to A. sculptum. harbor associated bacteria (Staphylococcus sciuri predominant) that may provide chemical defense against environmental threats through antifungal, bacteriocin, and bioactive metabolite production.

Human Relevance

Medical significance: of , affecting humans and domestic cattle. Research interest: saliva contains bioactive molecules including Factor X active protein, which has demonstrated anti-cancer properties in laboratory studies. Climate change may expand suitable for some members of the complex while contracting others.

Similar Taxa

Amblyomma sculptumFormerly considered ; now recognized as distinct occupying humid areas of northern Argentina, Bolivia, Paraguay, and Brazil; primary of rickettsii in those regions
Amblyomma mixtumFormerly considered ; occurs from Texas to western Ecuador
Amblyomma patinoiFormerly considered ; occurs in Eastern Cordillera of Colombia
Amblyomma interandinumFormerly considered ; occurs in northern Inter-Andean valley of Peru
Amblyomma tonelliaeFormerly considered ; occurs in dry Chaco region from central-northern Argentina to Bolivia and Paraguay
Amblyomma americanumSimilar (lone star tick) and former broad distribution; distinct white spot on , different geographic range in North America, of different including alpha-gal

Misconceptions

The name '' and broad historical distribution from southern US to Argentina referred to what is now recognized as multiple cryptic . Older literature using 'A. cajennense' may refer to any of several distinct species with different competencies and geographic ranges.