Leech Erpobdella

Freshwater leech, Erpobdella octoculata, adults, Upstream (18 pg Zn/L) from zinc-polluted 116... 

Populations of freshwater oligochaetes and leeches were reduced in numbers of individuals and numbers of taxa in mine tailing effluents containing 146 to 213 pg Zn/L or sediments containing >20 g Zn/kg DW (Willis 1985b). Leeches (Erpobdella octoculata) experienced a reduction in density and reproductive capacity in streams containing 25 to 310 pg Zn/L from mine wastes and did not avoid these harmful concentrations (Willis 1989). 

Elliott EJ (1986) Chemosensory stimuli in feeding behavior of the leech Hirudo medicinalis. J Comp Physiol A Neuroethol Sensory Neural Behav Physiol 159 391-401 Kreuter K, Baier B, ABmann C, Steidle JLM (2008) Prey location and prey choice by the freshwater leech Erpobdella octoculata using foraging kairomones. Freshwater Biol 53 1524-1530... 

Although laboratory studies have value for specific purposes, it is in the natural ecosystem that we must determine the behavior of a pesticide and its possible effect. Studies of the cycling of radionuclide-labeled pesticides in natural ecosystems are limited, since introduction of radionuclides into the environment involves public-health and public-relations issues as well as possibly difficult technical considerations. However, an ecosystem study was conducted by spraying a 4-acre marsh in western Sandusky Bay, Ohio, with Cl-labeled DDT. One aspect of the study involved the incorporation of the pesticide in some invertebrates of this aquatic ecosystem as determined by autoradiography (Webster, 1967). An amount of the pesticide suitable for mosquito control was applied to the study area by helicopter. Samples of leeches (Erpobdella punctata), am-phipods (Hyallela sp.), and copepods (Cyclops bicuspidatus, Diaptomus orga-nensis) were collected, fixed, sectioned, and autoradiographed. It was observed that leeches contained the pesticide or a Cl-compound, but none was detected in amphipods or copepods. 

Among freshwater leeches, the Old-World Erpobdella octoculata feeds on prey such as Tubifex spp., Chironomus spp., and Asellus aquaticus. Living and freshly killed larvae of Chironomus sp., Tubifex sp., and A. aquaticus attract these leeches. Amino acids such as histidine and glutamic acid are the active stimuli (Kreuter et al. 2008). 

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