User:Lettuce124/Erpobdella octoculata

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Erpobdella octoculata is a species of freshwater leech found in Europe, the Mediterranean, and the Middle East (Iran). It is one of the most common leeches in Britain. Its body color ranges from a greenish yellow to a reddish brown.

This species prefers fast moving streams with rocky bottoms. E. Octoculata prefers to attach itself to these stones. This species also serves as a bioindicator due to its preference for polluted waters.

Description
E. octoculata is one of the most common freshwater leeches in Europe. This tube- shaped species ranges from 3- 7mm long. E. octoculata is divided into 5 segments with each containing 3 annuli. Has a mouth and tail sucker that aid in feeding and movement. The tail sucker is larger.

Between the .... and ... anuli are its 2 pairs of black eyes. There are 2 labial eyes and 2 buccal eyes, which is characteristic of the Erpobdella genus.

Live under rocks.

Body color corresponds to the amount of pigment present on the dorsum. With light spots around the papillae, the body color becomes lighter and appears a yellow greenish

Distribution
E. octoculata has been spotted in approximately 25 countries in Europe.

Thrives in moderately dystrophic waters, where nutrients are low

Feeding
Erpobdella octoculata is a predator and exhibits scavenging behavior. It feeds primarily on chironomid larvae and oligochaetes. Due to its lack of jaws and proboscis, this species swallows its prey whole. In a laboratory study by Kutschera (2003), it was found that E. octoculata will use their pharynx to suck in pieces of dead/ wounded animals. They primarily. look for prey at night

The larva of this species feeds on insect larvae and wounded chr

Movement
E. octoculata uses vermiform crawling to move across the bottoms of stony streams. Vermiform crawling involves alternating shortening an extensions of the body along the tail and oral suckers.

Sensory systems
The cuticle functions as a layer of protection and

This species of freshwater leech has a nervous system composed o and has a brain that is a mass of ganglia.

Many leeches contain sensellae which sense water movement and light with photoreceptors. E. octoculata lacks developed sensellae and instead have sensory buds on its dorsal surface due to its predaceous nature and fast moving aqueous environment. Spread through the center of each anulli, these sensory buds have a round, raised appearance on the dorsum of this species. These sensory buds are composed of bipolar sensory cells, which are chemoreceptive and perceive water movement.

Osmoregulation
Freshwater leeches need to constantly remove excess water and wastes. Nephridia are organs that function similarly to kidneys in vertebrates for excretion and osmoregulation.

Digestion
Like other leeches in the Erpobdella genus, E. octoculata has a digestive tract that begins... and ends at the anus. Due ti this species lack of a caeca,

The pharynx ends at annulus 10.

Reproduction and Life Cycle
Adult leeches reach sexual maturity at 2 years old. Erpobdella Octulata is a hermaphrodite. It has male and female gonopores. Adults are distinguished by the presence of a clitellum, from which cocoons are secreted. Each oval shaped cocoon contains 5 -10 eggs.

The life cycle can shorten to one year in cases where environmental conditions

At the polluted site, there was evidence that (a) there was a delay in cocoon deposition and hence hatching of young, (b) the adult leeches produced more misshapened and empty cocoons, (c) no relationship existed between the area of cocoons with eggs and number of eggs present, and (d) the proportion of young to adult leech was smaller at the polluted site

Use as Bioindicators
E. octoculata can be used as a bioindicator for polluted waters. In a study bt Koperski (2005), a higher percentage of E. octoculata in comparison to other leech species was found in water with more pollutants. In addition, pharmaceuticals were found in