egg. Increase in spore load or parasite, increase of infected eggs. Cost being that you might not go beyond crissilus stage and never mate. Migrational populations of monarch. Resident population has higher infection rate. Weak stay behind and strong migrate. Self-medication. Prophylactic for healthy individual. Therapeutic for diseased individual. Therapeutically heal themselves. Baboon eat leaves which clear out systems which is prophylactic. Caterpillar has disease, they switch food source that will help out clean diseases. Self-medication. Transgenerational. Have to prove 4 things, therapeutic medication. So that caterpillar can do better. Proving therapeutic medication: 1. Behavior involves ingesting a 3 rd species or chemical compound. 2. Behavior initiated by parasite infection. 3. Behavior increases fitness of infected. 4. Behavior costly for healthy individuals. Ant gets fungal infection. Supplemental food, they decreased. Fungal population. Survivorship increased with supplemental food. Have to see if ants are actually choosing towards eating food with oxidative compounds. Majority eat the standard food. Colonies with fungus, about 50% are choosing supplemental food which helps them clear out infections. Transgenerational. Female butterflies who are infected lay their eggs on toxic milkweed. Eating toxic compounds decreases incidence of disease. Decreases spore load and increases lifetime fitness. For non-infected, toxic milkweed detrimental effect. Healthy individuals don’t eat it because they do worse. As concentration increases, spore load decreases. Zoonoses. Rabies has reproductive rate of 0. Less than 1 fades out. Greater than 1 so you can have epidemic in population. Spilled over into human populations. Ro=0 is reservoir only, agent only in animals. Ro <1 transmission to humans. Estimate when it drops below 1 so epidemic won’t occur. Spillover: increased biodiversity will increases disease transmission. Dilution effect. Increase biodiversity (hosts that aren’t competent, dead end host) will decrease transmission. Virus doesn’t do well, doesn’t replicate. Increased
biodiversity also increases the number if non-competent hosts. That is species who are poor hosts for the virus or even dead-end hosts. Lyme disease. Mice that have disease spread it to ticks. Not competent host, opossum. Sometimes it is just the species matters. But can we tell which species is competent or not? Maybe- tend to be weedy species. Climate change. Slope determines transmission of disease. Heterogeneous where some are susceptible to disease and some are resistant to disease. Fall armyworm. Raise temperature of plots, control. iButtons so temp won’t go over. See who went splat, who had h=the infection. Individuals in population becoming more alike. Increased transmission under warmer conditions. Don’t evolve to maximum virulence. Emergence of zoonotic from spillover effect. Humans into closer contact with these species. • Transmission-Virulence Tradeoff • Evolve to maximum transmission, which doesn’t mean evolve to maximum virulence. • Migration may have evolved (in certain populations) to escape disease.
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