Avtor/Urednik		Toman, Michael J; Dall, Peter C
Naslov		The diet of Erpobdella octoculata (Hidrudinea: Erpobdelliadae) in two Danish lowland streams
Tip		članek
Vir		Arch Hydrobiol
Vol. in št.		Letnik 140, št. 4
Leto izdaje		1997
Obseg		str. 549-63
Jezik		eng
Abstrakt		The diet of leeches and the effect of prey size on feeding success were examined using gut analyses of Erpobdella octoculata from two Danish lowland streams. Five weight (size) classes of leeches were examined. For each insect prey found in the guts the width of the head capsue was measured. Gut contents were compared to invertebrate abundaces by means of kick-samples from the streams. Nine prey groups were common in leech guts. Insect larvae dominated making up 79 to 82% of the total prey number. The mean prey number per leeck varied from 2.1 to 2.4. A comparison of gut contents with the occurrence of prey taxa in benthos samples indicated that turbellarians and all groups of chironomids were over-exploited, oligochaetes were preyed in proportion to frequency in the benthos, whilst Baetis rhodani, Hydropsyche angustipennis and Simuliidae appeared partly to avoid predation by E. octoculata. The results demonstrated that E. octoculata feeds mainly on chironomids when available. Prey size alone will cause differences in the diet of E. octoculata of different sizes, chironomids being the dominating prey in small leeches, but less so in large individuals which feed on a greater variety of, and larger prey items. The abundance of the trichopteran Hydropsyche angustipennis equalled 4 do 30% of the strean benthos, but contributed only 1-3% in the overall leech diet, escapingpredation because of its large size.
Deskriptorji		LEECHES ANIMAL NUTRITION DIET INTESTINES INVERTEBRATES FEEDING BEHAVIOR DENMARK FRESH WATER INSECTS TURBELLARIA NEMATODA DIPTERA