Centruroides gracilis

(Latreille, 1804)

Slender Brown Scorpion, Florida Bark Scorpion, Brown Bark Scorpion, Red Bark Scorpion, Slender Red Scorpion, Alacran Prieto, Alacran Azul

Centruroides gracilis is a to large in the Buthidae, notable for its wide color variation and extensive range. Females reach up to 10 cm, while males can exceed 15 cm. The exhibits remarkable phenotypic plasticity, with individuals in single or even litters showing colors ranging from reddish to dark with contrasting leg and coloration. It is to northern Central America but has been introduced to numerous regions including Florida, the Caribbean, South America, Africa, and the Canary Islands, often occurring in .

Centruroides gracilis by (c) lazarus, some rights reserved (CC BY), uploaded by lazarus. Used under a CC-BY license.

Centruroides gracilis (243) by Já. Used under a Public domain license.

Centruroides gracilis (232) by Já. Used under a CC BY-SA 3.0 license.

Pronunciation

How to pronounce Centruroides gracilis: /sɛn.trʊˈɔɪ.diːz ˈɡræ.sɪ.lɪs/

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

Identification

Distinguished from Florida Centruroides (C. hentzi, C. guianensis) by larger size and color variability. C. hentzi and C. guianensis show more consistent striping patterns. C. gracilis males notably larger than females, unlike some . Fluoresces -green under ultraviolet light due to beta-carboline and 4-methyl-7-hydroxycoumarin compounds in —a trait shared with other but useful for . In ranges, identification relies on size, variable coloration, and association with human structures.

Images

Appearance

Large, slender with pronounced in size. Females reach approximately 10 cm in length; males commonly exceed 15 cm. Coloration highly variable: individuals may be uniformly reddish, black with reddish , dark with yellowish legs and red chelae, or dark brown with alternating reddish and black tail . Color variation can occur within single and even within single litters. () well-developed for capture. Tail (metasoma) slender with bearing .

Habitat

Natural include areas under rocks and beneath tree bark. Strongly : readily colonizes wall voids, building crevices, and rubbish in residential areas. In tropical regions, occurs in rainforest floor litter and under fallen logs. thrive in disturbed habitats and human-modified environments.

Distribution

to northern Central America: Mexico, Guatemala, Belize, Honduras. to Cuba, Panama, Colombia, Ecuador, Jamaica, Florida (USA), Cameroon, Gabon, and Tenerife (Canary Islands). In Florida, with native C. hentzi and C. guianensis.

Seasonality

. Activity likely year-round in tropical range; in temperate areas, activity probably seasonal with warmer months. Laboratory studies indicate sexual maturity reached at 235–300 days, with females living approximately 38 months and males 33 months on average.

Diet

: feeds on , particularly . In captivity, accepts and . Specific natural spectrum otherwise undocumented.

Life Cycle

: females give birth to live young. Litter size typically 25–35, with exceptional litters of 91 recorded. climb onto female's back and remain there until first at approximately 8 days. Development through seven (some males mature at sixth). Females reach maturity at ~300 days; males at 235–281 days depending on instar. Females can reproduce via . Males produce and engage in .

Behavior

forager. Rapid movement when disturbed. When threatened, raises tail with curved over back. exhibit post-birth maternal association, riding on female's back until first . Exhibits negative ; whole-body fluorescence may function in light , with UV exposure triggering rapid movement toward dark refugia. In laboratory conditions, males show involving deposition.

Ecological Role

of small , particularly . for tarantulas (documented: Tliltocatl vagans). In ranges, may compete with . habits bring it into regular contact with humans, though ecological impacts in introduced ranges remain unstudied.

Human Relevance

Venomous : neurotoxic and cardiotoxic, causing catecholamine release. Local effects include pain, redness, itching, swelling. effects can include arrhythmia, pulmonary edema, tachycardia or bradycardia, hyper- or hypotension, nausea, vomiting, sweating, diarrhea, shock, convulsions, coma; fatalities possible but considered much less toxic than . Sting pain compared to honeybee or . Regularly enters human dwellings in and ranges. Occasionally kept as pet. Common cause of envenomation in areas where it occurs.

Similar Taxa

Centruroides hentzi to Florida; distinguished by smaller size and consistent striping pattern
Centruroides guianensis to Florida; distinguished by smaller size and consistent striping pattern
Centruroides vittatus to south-central USA; more consistent striped pattern, not known from Florida naturally

Misconceptions

"Florida bark " is misleading: is not to Florida but . Name "alacran azul" ( scorpion) refers to fluorescence under UV light, not normal coloration. Despite being less toxic than some , not harmless—envenomation can produce serious effects.

More Details

Fluorescence

contains beta-carboline and 4-methyl-7-hydroxycoumarin, which absorb UV light and emit -green fluorescence. Entire body may function as photoreceptor to detect light levels and locate dark refugia.

Parthenogenesis

Females capable of ; documented in laboratory conditions.