BIOS 230 Lecture Notes - Lecture 20: Dutch Elm Disease, Corn Smut, Bark Beetle
17 Nov 2016
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Document Summary
Symbiosis- intimate and protracted association between organisms of different species. Parasitism- close association between 2 species, benefits one and harms the other. Exploit hosts for food, habitat and dispersal. Are smaller, more specialized and reproduce more rapidly than hosts. Hemiparasitic vs holoparasitic plants: hemiparasitic, holoparasitic. Hosts are habitat for parasites: ecotparasites, endoparasites. Mosquitos transmit >50% of arboviruses that produce disease in humans. Animals transmit parasites among plants: bark beetle carry spores of fungus that causes dutch elm disease. Definitive host- species in which parasite matures. Host adaptations minimize impact of parasites intermediate hosts- harbor early stages. Fighting infections requires resources: lizards have smaller egg clutches when infected. May indirectly affect host mortality by altering behavior. Vertical transmission: parasites are transmitted from mother to offspring: low virulence. Usually native parasites infecting a small number of carrier individuals. Outbreaks occur when host density is high. Cleptoparasitism- occurs when one animal steals food gathered by another.
