Despite Arizona’s reputation as a dry, arid state, leeches are indeed present in its aquatic environments. These organisms belong to the phylum Annelida, classifying them as segmented parasitic or predatory worms closely related to earthworms. Leeches are aquatic invertebrates that possess suckers at both ends, which they use for locomotion and to attach to a host or prey. Their existence in Arizona is concentrated in areas with stable water sources.
Identifying Arizona’s Aquatic Worms
The leeches found across Arizona’s diverse waterways represent a variety of feeding types, with most native species being non-hematophagous. This means the majority are predatory and do not seek blood meals from large animals like humans. They commonly prey on smaller invertebrates such as insect larvae, snails, and aquatic worms, which they may swallow whole using a toothless mouth. One notable example is the unique Motobdella montezuma, a species found only in Montezuma Well, which is a specialized predator that consumes endemic aquatic shrimp. Other species are equipped with a piercing proboscis to suck the soft tissues of their prey, while the blood-feeding types possess jaws and tiny razor-sharp teeth.
Where Leeches are Found Across the State
Leech populations in Arizona are confined to permanent freshwater sources, which are often found in the state’s higher elevations and specific geological features. They require stable, unpolluted aquatic environments, thriving where there is minimal current and plenty of submerged vegetation or debris for shelter. These conditions are typically met in high-elevation lakes, perennial streams, and certain riparian zones. Significant populations are found in the mountainous regions, including the White Mountains and the Mogollon Rim, which feature numerous cold-water creeks and ponds. The presence of these organisms often indicates a healthy, functioning aquatic ecosystem, where leeches serve as a food source for fish and waterfowl.
What to Do If Bitten
A leech attachment is often unnoticed because the organism injects a local anesthetic along with its bite to prevent detection. Once attached, the leech uses a powerful anticoagulant to ensure a steady, prolonged flow of blood. The proper method for removal is simple and avoids causing the leech to regurgitate its stomach contents, which could lead to minor infection. To remove an attached leech, gently find the narrow end near the bite site and slide a fingernail or a thin, blunt object underneath the sucker to break the seal. Avoid using harsh methods like salt, fire, or forcefully pulling the leech, as this can cause it to vomit bacteria into the wound. After removal, clean the small wound with soap and water, as the bite will likely bleed for a short time due to the anticoagulant.