Parasitism Please do not use the images in these PowerPoint slides without permission. Wikipedia “Cordyceps” page; accessed 02-X-2014 Photo of Cordyceps fungus growing out of the insect it parasitized from Wikimedia Commons

Exploitation (+/- or antagonistic interaction) Parasites consume tissues or fluids of their host organisms; typically infecting just 1 individual, generally without killing it (at least not immediately) Ectoparasite (external) vs. Endoparasite (internal) Macroparasite vs. Microparasite Free-living vs. Symbiont Complex Life Cycle (generally involving multiple host species) vs. Simple Life Cycle Horizontally Transmitted vs. Vertically Transmitted Please do not use the images in these PowerPoint slides without permission. Wikipedia “Parasitism” page; accessed 09-X-2014 A louse is an ectoparasitic, symbiotic, macroparasite. Photo of human head louse from Wikimedia Commons

Exploitation (+/- or antagonistic interaction) Pathogens Parasites that cause disease (which manifests as pain, dysfunction or death) Please do not use the images in these PowerPoint slides without permission. Wikipedia “Ebola virus disease” page; accessed 09-X-2014 This example illustrates that parasites can be living organisms or infectious non-living particles (such as viruses). Photomicrograph of an Ebola virion (a complete virus particle) from Wikimedia Commons

Rely on other organisms to raise their young Brood Parasites Rely on other organisms to raise their young Please do not use the images in these PowerPoint slides without permission. Photo from Wikimedia Commons: "Reed warbler cuckoo" by Per Harald Olsen - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Reed_warbler_cuckoo.jpg#mediaviewer/File:Reed_warbler_cuckoo.jpg Photo of Reed Warbler & Cuckoo chick from Wikimedia Commons

Thieves (many are therefore competitors) Kleptoparasites Thieves (many are therefore competitors) Please do not use the images in these PowerPoint slides without permission. Photo from http://antediluviansalad.blogspot.com/2012_09_02_archive.html

Symbionts Live in close association with their hosts; amensal, commensal, parasitic, or mutualistic Some mutualistic defensive symbionts protect their hosts against parasitic symbionts Please do not use the images in these PowerPoint slides without permission. Photomicrograph of endophytes in a plant from http://www.entm.purdue.edu/turfgrass/research.html

Co-cladogenesis & co-speciation Two associated lineages (especially symbionts) diverge together, and potentially co-speciate Dipodomys merriami Fahrenholzia pinnata Please do not use the images in these PowerPoint slides without permission. Wikipedia “Merriam’s kangaroo rat” page; accessed 16-X-2014 Wikipedia “Fahrenholzia pinnata” page; accessed 16-X-2014 Light, Jessica E. & Mark S. Hafner. 2008. Codivergence in heteromyid rodents (Rodentia: Heteromyidae) and their sucking lice of the genus Fahrenholzia (Phthiraptera: Anoplura). Systematic Biology 57:449-465. “FIGURE 4. Results of reconciliation analysis (TreeMap 2.0β) for heteromyid rodents and their ectoparasitic lice of the genus Fahrenholzia. Gray lines between taxa indicate host-parasite associations. Shaded circles at nodes indicate instances of perfect cophylogeny (i.e., putative codivergence events). The number of reconstructed codivergence events (Table 2) was greater than expected by chance (P < 0.001).” Photos from Wikimedia Commons; figure from Light & Hafner (2008) Systematic Biology

Horizontal vs. Vertical Transmission Horizontal – between individuals that are not linked by a parent-child relationship Vertical – from mother to offspring Mother Horizontal Other non-offspring member of the population Vertical Please do not use the images in these PowerPoint slides without permission. Daughter Son Other non-parent member of the population Horizontal or

Host switch Cospeciation Duplication Host Parasite Failure to speciate Missing the boat Extinction Coexistence Please do not use the images in these PowerPoint slides without permission. Think of these as macro-evolutionary trajectories… From Jason Weckstein, who completed a Ph.D. at LSU in 2003 Which are most likely under strictly vertical transmission? From J. Weckstein (2003)

*When is it Coevolution? Reciprocal adaptive evolution in each of 2 interacting species in response to adaptations in the other species Tribolium castaneum is infected by microsporidian Nosema whitei; parasite virulence and host recombination frequencies co-evolve Please do not use the images in these PowerPoint slides without permission. Wikipedia “Host-parasite coevolution” page; accessed 16-X-2014 Recombination – in eukaryotes, genetic exchange between DNA molecules during meiosis. Virulence – host’s parasite-induced loss of fitness. Your textbook provides many examples of adaptations, counter-adaptations, and co-evolutionary adaptations of parasites and hosts. Bérénos, C., P. Schmid-Hempel & K. M. Wegner. 2009. Evolution of host resistance and trade-offs between virulence and transmission potential in an obligately killing parasite. Journal of Evolutionary Biology 10:2049–2056. Fischer, O. & P. Schmid-Hempel. 2005. Selection by parasites may increase host recombination frequency. Biology Letters 22:193-195. Janzen, D. H. 1980. When is it coevolution? Evolution 34:611-612. Photo of T. castaneum flour beetle from Wikimedia Commons; *original idea from Janzen (1980) Evolution

Macroparasite vs. Microparasite Catagories based on function rather than taxonomy or phylogenetics Macroparasites – parasites grow, but have no direct reproduction within the host (they produce infective stages that must colonize new hosts); typically much larger and have longer generation times than microparasites; immune response in host is typically absent or very short-lived; infections are often chronic as hosts are continually reinfected; e.g., helminthes, arthropods, etc. Microparasites – parasites that reproduce within the host, often within the host’s cells, and are generally small and have short lifespans relative to their hosts; hosts that recover often have an immune period after infection (sometimes for life); infections are often transient; e.g., bacterial, viral, fungal infectious agents, as well as many protozoans, etc. Please do not use the images in these PowerPoint slides without permission.

Parasites can influence individuals, populations, interactions between species, communities & ecosystems Tribolium castaneum outcompetes T. confusum when both are healthy; T. confusum outcompetes T. castaneum in the presence of protist parasite Adelina tribolii (which is especially virulent towards T. castaneum) Please do not use the images in these PowerPoint slides without permission. Parasites can influence individuals, populations, communities & ecosystems (and, of course, we could say this about predators, herbivores, competitors, etc.). Park, T. 1948. Experimental studies of interspecies competition. I. Competition between populations of flour beetles, Tribolium confusum Duvall and Tribolium castaneum Herbst. Ecological Monographs 18:267-307. Cain, Bowman & Hacker (2014), Fig. 14.17; after Park (1948)

“Proportion of grouse treated… Parasites can influence individuals, populations, interactions between species, communities & ecosystems Please do not use the images in these PowerPoint slides without permission. Peter J. Hudson, Andy P. Dobson & Dave Newborn. 1998. Prevention of Population Cycles by Parasite Removal. Science 282:2256-2258. Fig. 3. The influence of treatment on the cycling of grouse populations. Changes in the number of grouse are shown in relation to the proportion of grouse treated. No treatment, dashed line; 5%, dotted line; 10%, thick solid Line; and 20%, thin solid line. Red Grouse are naturally infected by a nematode parasite; antihelminthics cure the infected hosts “Proportion of grouse treated… No treatment, dashed line; 5%, dotted line; 10%, thick solid Line; and 20%, thin solid line.” Photo of from http://www.pbase.com/wildbirdimages/image/129932709; fig. from Hudson et al. (1998) Science

Modeling Microparasite Disease Dynamics The SIR Model – a compartmental model (population is sub-divided into compartments) for epidemiology Birth a a a Susceptible hosts (S) β Infected hosts (I) v Recovered & Immune hosts (R) transmission recovery Please do not use the images in these PowerPoint slides without permission. Epidemiology – the science that studies the patterns, causes, and effects of disease in populations. Anderson, Roy M. & Robert M. May. 1979. Population biology of infectious diseases: Part I. Nature 280:361-367. Anderson, Roy M. & Robert M. May. 1979. Population biology of infectious diseases: Part II. Nature 280:455-461. May, Robert M. 1983. Parasitic infections as regulators of animal populations. American Scientist 71:36-45. b α + b b Death  After Anderson & May (1979ab) & May (1983)

Modeling Microparasite Disease Dynamics Coupled differential equations; one for each host compartment: dS/dt = fxn; dI/dt = fxn; dR/dt = fxn S, I & R are numbers of individuals; the other variables are rates Birth a a a Susceptible hosts (S) β Infected hosts (I) v Recovered & Immune hosts (R) transmission recovery Please do not use the images in these PowerPoint slides without permission. We are only going to look in detail at dI/dt… Anderson, Roy M. & Robert M. May. 1979. Population biology of infectious diseases: Part I. Nature 280:361-367. Anderson, Roy M. & Robert M. May. 1979. Population biology of infectious diseases: Part II. Nature 280:455-461. May, Robert M. 1983. Parasitic infections as regulators of animal populations. American Scientist 71:36-45. b α + b b Death  After Anderson & May (1979ab) & May (1983)

Modeling Microparasite Disease Dynamics dI/dt = βSI – (α + b + v)I dI/dt = βSI – mI βSI = Disease transmission rate m = combined death & recovery rate Birth a a a Susceptible hosts (S) β Infected hosts (I) v Recovered & Immune hosts (R) transmission recovery Please do not use the images in these PowerPoint slides without permission. Your textbook uses m in place of (α + b + v). SI = encounter rate between a susceptible individual and an infected individual. β = transmission coefficient. Anderson, Roy M. & Robert M. May. 1979. Population biology of infectious diseases: Part I. Nature 280:361-367. Anderson, Roy M. & Robert M. May. 1979. Population biology of infectious diseases: Part II. Nature 280:455-461. May, Robert M. 1983. Parasitic infections as regulators of animal populations. American Scientist 71:36-45. b α + b b Death  After Anderson & May (1979ab) & May (1983)

Modeling Microparasite Disease Dynamics If dI/dt > 0, disease will establish & spread βSI – mI > 0 ST > m / β We refer to this as the threshold density for disease progression What are the public policy or management implications? Please do not use the images in these PowerPoint slides without permission. Reduce susceptible population (ST) by culling or vaccinations, increase m by improving early detection and clinical treatment, or reduce β by quarantining infected individuals, etc. βSI – mI > 0 βSI > mI βS > m S > m/β

Transmission & Virulence Transmission – passing a parasite or pathogen from an infected host to another individual Virulence – the host’s parasite-induced loss of fitness Host Fitness (Inversely related to Pathogen Virulence) Please do not use the images in these PowerPoint slides without permission. Production & spread of disease organisms from a host (Transmission)

Darwinian (Evolutionary) Agriculture & Darwinian (Evolutionary) Medicine The application of modern evolutionary theory to understand crop & livestock production (Darwinian Agriculture) and human health & disease (Darwinian Medicine) E.g., Why do new diseases continue to appear in human, crop & livestock populations? Please do not use the images in these PowerPoint slides without permission.

Mind-Controlling Parasites “Cocoon web” of spider parasitized by specialist wasp Please do not use the images in these PowerPoint slides without permission. Eberhard, William G. 2000. Spider manipulation by a wasp larva. Nature 406:255-256. Eberhard, William G. 2001. Under the influence: webs and building behavior of Plesiometa argyra (Araneae, Tetragnathidae) when parasitized by Hymenoepimecis argyraphaga (Hymenoptera, Ichneumonidae). Journal of Arachnology 29:354-366. Normal web Bill Eberhard Cain, Bowman & Hacker (2014), Fig. 14.22, from Eberhard (2000) Nature & (2001) Journal of Arachnology; photo of Eberhard from http://www.stri.si.edu/english/about_stri/ headline_news/news/article.php?id=1015