Literature Cited
Abrams, P.A. & Rowe, L. (1996). The Effects of Predation on the Age and Size of Maturity of Prey. Evolution , 50, 1052–1061.
Acharya, L. (1995). Sex-biased predation on moths by insectivorous bats.Anim. Behav. , 49, 1461–1468.
Adamo, S.A., Easy, R.H., Kovalko, I., MacDonald, J., McKeen, A., Swanburg, T., et al. (2017). Predator exposure-induced immunosuppression: trade-off, immune redistribution or immune reconfiguration? J. Exp. Biol. , 220, 868–875.
Aeby, G.S. (1998). A digenean metacercaria from the reef coral, Porites compressa, experimentally identified as Podocotyloides stenometra.J. Parasitol. , 1259–1261.
Agboton, B.V., Hanna, R., Onzo, A., Vidal, S. & von Tiedemann, A. (2013). Interactions between the predatory mite Typhlodromalus aripo and the entomopathogenic fungus Neozygites tanajoae and consequences for the suppression of their shared prey/host Mononychellustanajoa. Exp. Appl. Acarol. , 60, 205–217.
Anderson, R.M. & May, R.M. (1979). Population biology of infectious diseases: Part I. Nature , 280, 361–367.
Apfelbach, R., Blanchard, C.D., Blanchard, R.J., Hayes, R.A. & McGregor, I.S. (2005). The effects of predator odors in mammalian prey species: A review of field and laboratory studies. Neurosci. Biobehav. Rev. , Defensive Behavior, 29, 1123–1144.
Baverstock, J., Baverstock, K.E., Clark, S.J. & Pell, J.K. (2008). Transmission of Pandora neoaphidis in the presence of co-occurring arthropods. J. Invertebr. Pathol. , Special Issue for SIP 2008, 98, 356–359.
Baverstock, J., Clark, S.J., Alderson, P.G. & Pell, J.K. (2009). Intraguild interactions between the entomopathogenic fungus Pandora neoaphidis and an aphid predator and parasitoid at the population scale.J. Invertebr. Pathol. , 102, 167–172.
Ben-Ami, F. (2019). Host Age Effects in Invertebrates: Epidemiological, Ecological, and Evolutionary Implications. Trends Parasitol. , 35, 466–480.
Bostock, R.M. (2005). SIGNAL CROSSTALK AND INDUCED RESISTANCE: Straddling the Line Between Cost and Benefit. Annu. Rev. Phytopathol. , 43, 545–80.
Brown, J.S., Kotler, B.P., Smith, R.J. & Wirtz, W.O. (1988). The effects of owl predation on the foraging behavior of heteromyid rodents.Oecologia , 76, 408–415.
Burnham, K.P. & Anderson, D.R. (2002). Model selection and multimodal inference: A practical information-theoretic approach . Springer, New York.
Buss, N. & Hua, J. (2018). Parasite susceptibility in an amphibian host is modified by salinization and predators. Environ. Pollut. , 236, 754–763.
Byers, J.E., Malek, A.J., Quevillon, L.E., Altman, I. & Keogh, C.L. (2015). Opposing selective pressures decouple pattern and process of parasitic infection over small spatial scale. Oikos , 124, 1511–1519.
Cáceres, C.E., Knight, C.J. & Hall, S.R. (2009). Predator–spreaders: predation can enhance parasite success in a planktonic host–parasite system. Ecology , 90, 2850–2858.
Chacón, J.M., Landis, D.A. & Heimpel, G.E. (2008). Potential for biotic interference of a classical biological control agent of the soybean aphid. Biol. Control , 46, 216–225.
Chailleux, A., Droui, A., Bearez, P. & Desneux, N. (2017). Survival of a specialist natural enemy experiencing resource competition with an omnivorous predator when sharing the invasive prey Tuta absoluta.Ecol. Evol. , 7, 8329–8337.
Chantanao, A. & Jensen, H.J. (1969). Saprozoic nematodes as carriers and disseminators of plant pathogenic bacteria. J. Nematol. , 1, 216.
Cinel, S.D., Hahn, D.A. & Kawahara, A.Y. (2020). Predator-induced stress responses in insects: A review. J. Insect Physiol. , 122, 104039.
Clay, P.A., Cortez, M.H. & Duffy, M.A. (2021). Dose relationships can exacerbate, mute, or reverse the impact of heterospecific host density on infection prevalence. Ecology , 102, e03422.
Clemens, E. & Brandt, M.E. (2015). Multiple mechanisms of transmission of the Caribbean coral disease white plague. Coral Reefs , 34, 1179–1188.
Clinchy, M., Sheriff, M.J. & Zanette, L.Y. (2013). Predator-induced stress and the ecology of fear. Funct. Ecol. , 27, 56–65.
Clinchy, M., Zanette, L., Charlier, T.D., Newman, A.E.M., Schmidt, K.L., Boonstra, R., et al. (2011). Multiple measures elucidate glucocorticoid responses to environmental variation in predation threat.Oecologia , 166, 607–614.
Cornelissen, T., Wilson Fernandes, G. & Vasconcellos-Neto, J. (2008). Size does matter: variation in herbivory between and within plants and the plant vigor hypothesis. Oikos , 117, 1121–1130.
Cossentine, J.E. (2009). The parasitoid factor in the virulence and spread of lepidopteran baculoviruses. Virol. Sin. , 24, 305–314.
Creel, S. & Christianson, D. (2008). Relationships between direct predation and risk effects. Trends Ecol. Evol. , 23, 194–201.
Creel, S., Schuette, P. & Christianson, D. (2014). Effects of predation risk on group size, vigilance, and foraging behavior in an African ungulate community. Behav. Ecol. , 25, 773–784.
Daversa, D.R., Hechinger, R.F., Madin, E. & Fenton, A. (2019). Beyond the ecology of fear: non-lethal effects of predators are strong whereas those of parasites are diverse. bioRxiv , 766477.
Dietrich, R., Ploss, K. & Heil, M. (2005). Growth responses and fitness costs after induction of pathogen resistance depend on environmental conditions. Plant Cell Environ. , 28, 211–222.
Dobson, A.P. (1989). The population biology of parasitic helminths in animal populations. In: Applied Mathematical Ecology . Springer, New York, pp. 145–175.
Donnelly, C.A., Wei, G., Johnston, W.T., Cox, D.R., Woodroffe, R., Bourne, F.J., et al. (2007). Impacts of widespread badger culling on cattle tuberculosis: concluding analyses from a large-scale field trial. Int. J. Infect. Dis. , 11, 300–308.
Donnelly, C.A., Woodroffe, R., Cox, D.R., Bourne, F.J., Cheeseman, C.L., Clifton-Hadley, R.S., et al. (2006). Positive and negative effects of widespread badger culling on tuberculosis in cattle.Nature , 439, 843.
Donnelly, C.A., Woodroffe, R., Cox, D.R., Bourne, J., Gettinby, G., Le Fevre, A.M., et al. (2003). Impact of localized badger culling on tuberculosis incidence in British cattle. Nature , 426, 834.
Duffy, M.A. (2009). Staying alive: The post-consumption fate of parasite spores and its implications for disease dynamics. Limnol. Oceanogr. , 54, 770–773.
Duffy, M.A., Caceres, C.E. & Hall, S.R. (2019). Healthy herds or predator spreaders? Insights from the plankton into how predators suppress and spread disease. In: Wildlife Disease Ecology: Linking Theory to Data and Application . Cambridge University Press, Cambridge, pp. 458–479.
Duffy, M.A., García-Robledo, C., Gordon, S.P., Grant, N.A., Green, D.A., Kamath, A., et al. (2021). Model systems in ecology, evolution, and behavior: A call for diversity in our model systems and discipline.Am. Nat. , 198, 53–68.
Duffy, M.A., Housley, J.M., Penczykowski, R.M., Caceres, C.E. & Hall, S.R. (2011). Unhealthy herds: indirect effects of predators enhance two drivers of disease spread. Funct. Ecol. , 25, 945–953.
Dwyer, G., Elkinton, J.S. & Buonaccorsi, J.P. (1997). Host heterogeneity in susceptibility and disease dynamics: Tests of a mathematical model. Am. Nat. , 150, 685–707.
Elderd, B.D. (2018). Modeling insect epizootics and their population-level consequences. In: Ecology of Invertebrate Diseases (eds. Hajek, A.E. & Shapiro-Ilan, D.). Wiley.
Elderd, B.D. (2019). Bottom-up trait-mediated indirect effects decrease pathogen transmission in a tritrophic system. Ecology , 100, e02551.
Elderd, B.D. & Dwyer, G. (2020). Population structure and disease spread in insect baculoviruses. In: Wildlife diseases: Linking theory to data and application (eds. Wilson, K., Fenton, A. & Tompkins, D.). Cambridge University Press.
Flick, A.F., Acevedo, M.A. & Elderd, B.D. (2016). The negative effects of pathogen-infected prey on predators: A meta-analysis. Oikos , 125, 1554–1560.
Flick, A.F., Coudron, T. & Elderd, B.D. (2020). Intraguild predation increases pathogen transmission in a herbivore host and decreases predator fitness. Oecologia , 193, 789–799.
Garvey, M., Creighton, C. & Kaplan, I. (2020a). Pepper domestication enhances parasitoid recruitment to herbivore-damaged plants.Arthropod-Plant Interact. , 14, 695–703.
Garvey, M.A., Creighton, J.C. & Kaplan, I. (2020b). Tritrophic interactions reinforce a negative preference–performance relationship in the tobacco hornworm (Manduca sexta). Ecol. Entomol. , 45, 783–794.
Geervliet, J.B.F., Vet, L.E.M. & Dicke, M. (1996). Innate responses of the parasitoidsCotesia glomerata andC. rubecula (Hymenoptera: Braconidae) to volatiles from different plant-herbivore complexes.J. Insect Behav. , 9, 525–538.
Gignoux-Wolfsohn, S.A., Marks, C.J. & Vollmer, S.V. (2012). White Band Disease transmission in the threatened coral, Acropora cervicornis.Sci. Rep. , 2, 804.
Gotelli, N.J. & Ellison, A.M. (2004). A primer of ecological statstics . Sinauer Associates.
Gwynne, D.T. (1987). Sex-biased predation and the risky mate-locating behaviour of male tick-tock cicadas (Homoptera: Cicadidae). Anim. Behav. , 35, 571–576.
Hamilton, D.R. (1974). Immunosuppressive effects of predator induced stress in mice with acquired immunity to Hymenolepis nana. J. Psychosom. Res. , 18, 143–150.
Han, B.A., Searle, C.L. & Blaustein, A.R. (2011). Effects of an infectious fungus, Batrachochytrium dendrobatidis, on amphibian predator-prey interactions. PLoS One , 6, e16675.
Harrison, A., Scantlebury, M. & Montgomery, W.I. (2010). Body mass and sex-biased parasitism in wood mice Apodemus sylvaticus. Oikos , 119, 1099–1104.
Hawlena, D., Abramsky, Z. & Bouskila, A. (2010). Bird predation alters infestation of desert lizards by parasitic mites. Oikos , 119, 730–736.
Hilborn, R. & Mangel, M. (1997). The ecological detective: Confronting models with data . Princeton University Press, Princeton, NJ.
Hobbs, N.T. & Hooten, M.B. (2015). Bayesian models: A statistical primer for ecologists . Princeton University Press.
Hoffland, E., Niemann, G.J., Van Pelt, J.A., Pureveen, J.B.M., Eijkel, G.B., Boon, J.J., et al. (1996). Relative growth rate correlates negatively with pathogen resistance in radish: the role of plant chemistry. Plant Cell Environ. , 19, 1281–1290.
Holt, R.D. & Roy, M. (2007). Predation can increase the prevalence of infectious disease. Am. Nat. , 169, 690–699.
Hudson, P.J., Dobson, A.P. & Newborn, D. (1992). Do parasites make prey vulnerable to predation? Red grouse and parasites. J. Anim. Ecol. , 61, 681–692.
Inouye, B.D. (2001). Response surface experimental designs for investigating interspecific competition. Ecology , 82, 2696–2706.
Johnson, P.T., Dobson, A., Lafferty, K.D., Marcogliese, D.J., Memmott, J., Orlofske, S.A., et al. (2010). When parasites become prey: ecological and epidemiological significance of eating parasites.Trends Ecol. Evol. , 25, 362–371.
Johnson, P.T., Stanton, D.E., Preu, E.R., Forshay, K.J. & Carpenter, S.R. (2006). Dining on disease: how interactions between infection and environment affect predation risk. Ecology , 87, 1973–1980.
Jones, E.I. & Dornhaus, A. (2011). Predation risk makes bees reject rewarding flowers and reduce foraging activity. Behav. Ecol. Sociobiol. , 65, 1505–1511.
Kaneko, S. (2006). Predator and parasitoid attacking ant-attended aphids: effects of predator presence and attending ant species on emerging parasitoid numbers. Ecol. Res. , 22, 451.
Karban, R. (2015). Plant sensing and communication. In: Plant Sensing and Communication . University of Chicago Press.
Kester, K.M. & Barbosa, P. (1994). Behavioral responses to host foodplants of two populations of the insect parasitoid Cotesia congregata (Say). Oecologia , 99, 151–157.
King, R.B. (2002). Predicted and observed maximum prey size - snake size allometry. Funct. Ecol. , 16, 766–772.
Koprivnikar, J. & Urichuk, T.M. (2017). Time-lagged effect of predators on tadpole behaviour and parasite infection. Biol. Lett. , 13, 20170440.
Kortet, R., Hedrick, A.V. & Vainikka, A. (2010). Parasitism, predation and the evolution of animal personalities. Ecol. Lett. , 13, 1449–1458.
Krasnov, B.R., Morand, S., Hawlena, H., Khokhlova, I.S. & Shenbrot, G.I. (2005). Sex-biased parasitism, seasonality and sexual size dimorphism in desert rodents. Oecologia , 146, 209–217.
Kuris, A.M. (2003). Evolutionary ecology of trophically transmitted parasites. J. Parasitol. , 89, S96–S100.
Kuris, A.M. (2005). Trophic transmission of parasites and host behavior modification. Behav. Processes , 68, 215–217.
Lafferty, K.D. (1999). The evolution of trophic transmission.Parasitol. Today , 15, 111–115.
Lin, G., Guertin, C., Di Paolo, S.-A., Todorova, S. & Brodeur, J. (2019). Phytoseiid predatory mites can disperse entomopathogenic fungi to prey patches. Sci. Rep. , 9, 19435.
Lodé, T., Holveck, M.-J., Lesbarreres, D. & Pagano, A. (2004). Sex–biased predation by polecats influences the mating system of frogs.Proc. R. Soc. Lond. B Biol. Sci. , 271, S399–S401.
Lopez, L.K. & Duffy, M.A. (2021). Mechanisms by which predators mediate host–parasite interactions in aquatic systems. Trends Parasitol. , S1471492221001628.
de Lourdes Ramírez-Ahuja, M., Rodríguez-Leyva, E., Lomeli-Flores, J.R., Torres-Ruiz, A. & Guzmán-Franco, A.W. (2017). Evaluating combined use of a parasitoid and a zoophytophagous bug for biological control of the potato psyllid, Bactericera cockerelli. Biol. Control , 106, 9–15.
Martin, L.B. (2009). Stress and immunity in wild vertebrates: timing is everything. Gen. Comp. Endocrinol. , 163, 70–76.
Mauck, K.E., Smyers, E., De Moraes, C.M. & Mescher, M.C. (2015). Virus infection influences host plant interactions with non-vector herbivores and predators. Funct. Ecol. , 29, 662–673.
McCurdy, D.G., Shutler, D., Mullie, A. & Forbes, M.R. (1998). Sex-biased parasitism of avian hosts: relations to blood parasite taxon and mating system. Oikos , 303–312.
Middlemis Maher, J., Werner, E.E. & Denver, R.J. (2013). Stress hormones mediate predator-induced phenotypic plasticity in amphibian tadpoles. Proc. R. Soc. B Biol. Sci. , 280, 20123075.
Navarro, C., De Lope, F., Marzal, A. & Møller, A.P. (2004). Predation risk, host immune response, and parasitism. Behav. Ecol. , 15, 629–635.
Ng, W.H., Myers, C.R., McArt, S.H. & Ellner, S.P. (2022). Pathogen transport amplifies or dilutes disease transmission depending on the host dose-response relationship. Ecol. Lett. , 25, 453–465.
Nilsson, P.A. & Brönmark, C. (2000). Prey vulnerability to a gape-size limited predator: behavioural and morphological impacts on northern pike piscivory. Oikos , 88, 539–546.
Nykyri, J., Fang, X., Dorati, F., Bakr, R., Pasanen, M., Niemi, O.,et al. (2014). Evidence that nematodes may vector the soft rot-causing enterobacterial phytopathogens. Plant Pathol. , 63, 747–757.
Ostfeld, R.S. & Holt, R.D. (2004). Are predators good for your health? Evaluating evidence for top-down regulation of zoonotic disease reservoirs. Front. Ecol. Environ. , 2, 13–20.
Otti, O., Gantenbein-Ritter, I., Jacot, A. & Brinkhof, M.W. (2012). Immune response increases predation risk. Evol. Int. J. Org. Evol. , 66, 732–739.
Packer, C., Holt, R.D., Hudson, P.J., Lafferty, K.D. & Dobson, A.P. (2003). Keeping the herds healthy and alert: implications of predator control for infectious disease. Ecol. Lett. , 6, 797–802.
Palme, R., Rettenbacher, S., Touma, C., El-Bahr, S.M. & Moestl, E. (2005). Stress hormones in mammals and birds: comparative aspects regarding metabolism, excretion, and noninvasive measurement in fecal samples. Ann. N. Y. Acad. Sci. , 1040, 162–171.
Preisser, E.L., Orrock, J.L. & Schmitz, O.J. (2007). Predator hunting mode and habitat domain alter nonconsumptive effects in predator–prey interactions. Ecology , 88, 2744–2751.
Price, P.W. (1975). Reproductive Strategies of Parasitoids. In:Evolutionary Strategies of Parasitic Insects and Mites (ed. Price, P.W.). Springer US, Boston, MA, pp. 87–111.
Ramirez, R.A. & Snyder, W.E. (2009). Scared sick? Predator–pathogen facilitation enhances exploitation of a shared resource. Ecology , 90, 2832–2839.
Reilly, J.R. & Hajek, A.E. (2012). Prey-processing by avian predators enhances virus transmission in the gypsy moth. Oikos , 121, 1311–1316.
Reimchen, T.E. & Nosil, P. (2001). Ecological causes of sex-biased parasitism in threespine stickleback. Biol. J. Linn. Soc. , 73, 51–63.
Relyea, R.A. (2007). Getting out alive: how predators affect the decision to metamorphose. Oecologia , 152, 389–400.
Renzi, J.J., Shaver, E.C., Burkepile, D.E. & Silliman, B.R. (2022). The role of predators in coral disease dynamics. Coral Reefs .
Richards, R.L., Drake, J.M. & Ezenwa, V.O. (2022). Do predators keep prey healthy or make them sicker? A meta-analysis. Ecol. Lett. , 25, 278–294.
de Rijk, M., Dicke, M. & Poelman, E.H. (2013). Foraging behaviour by parasitoids in multiherbivore communities. Anim. Behav. , 85, 1517–1528.
Rivera, N.A., Brandt, A.L., Novakofski, J.E. & Mateus-Pinilla, N.E. (2019). Chronic Wasting Disease In Cervids: Prevalence, Impact And Management Strategies. Vet. Med. Res. Rep. , 10, 123–139.
Roy, H.E., Pell, J.K. & Alderson, P.G. (2001). Targeted dispersal of the aphid pathogenic fungus Erynia neoaphidis by the aphid predator Coccinella septempunctata. Biocontrol Sci. Technol. , 11, 99–110.
Sánchez, C.A., Becker, D.J., Teitelbaum, C.S., Barriga, P., Brown, L.M., Majewska, A.A., et al. (2018). On the relationship between body condition and parasite infection in wildlife: a review and meta-analysis. Ecol. Lett. , 21, 1869–1884.
Schmitz, O.J., Beckerman, A.P. & O’Brien, K.M. (1997). Behaviorally mediated trophic cascades: effects of predation risk on food web interactions. Ecology , 78, 1388–1399.
Schmitz, O.J., Hambäck, P.A. & Beckerman, A.P. (2000). Trophic cascades in terrestrial systems: a review of the effects of carnivore removals on plants. Am. Nat. , 155, 141–153.
Smith, J.L., De Moraes, C.M. & Mescher, M.C. (2009). Jasmonate-and salicylate-mediated plant defense responses to insect herbivores, pathogens and parasitic plants. Pest Manag. Sci. Former. Pestic. Sci. , 65, 497–503.
Stephenson, J.F., Van Oosterhout, C., Mohammed, R.S. & Cable, J. (2015). Parasites of Trinidadian guppies: evidence for sex-and age-specific trait-mediated indirect effects of predators.Ecology , 96, 489–498.
Stout, M.J., Thaler, J.S. & Thomma, B.P. (2006). Plant-mediated interactions between pathogenic microorganisms and herbivorous arthropods. Annu Rev Entomol , 51, 663–689.
Strandin, T., Babayan, S.A. & Forbes, K.M. (2018). Reviewing the effects of food provisioning on wildlife immunity. Philos. Trans. R. Soc. B Biol. Sci. , 373, 20170088.
Strauss, A.T., Shocket, M.S., Civitello, D.J., Hite, J.L., Penczykowski, R.M., Duffy, M.A., et al. (2016). Habitat, predators, and hosts regulate disease in Daphnia through direct and indirect pathways.Ecol. Monogr. , 86, 393–411.
Szuroczki, D. & Richardson, J.M. (2012). The behavioral response of larval amphibians (Ranidae) to threats from predators and parasites.PLoS One , 7, e49592.
Tait, A.S., Butts, C.L. & Sternberg, E.M. (2008). The role of glucocorticoids and progestins in inflammatory, autoimmune, and infectious disease. J. Leukoc. Biol. , 84, 924–931.
Thaler, J.S., McArt, S.H. & Kaplan, I. (2012). Compensatory mechanisms for ameliorating the fundamental trade-off between predator avoidance and foraging. Proc. Natl. Acad. Sci. , 109, 12075–12080.
Travis, J. (2006). Is It What We Know or Who We Know? Choice of Organism and Robustness of Inference in Ecology and Evolutionary Biology: (American Society of Naturalists Presidential Address). Am. Nat. , 167, 303–314.
Turchin, P. (2003). Complex population dynamics: A theoretical/empirical synthesis . Princeton University Press.
Vance-Chalcraft, H.D., Rosenheim, J.A., Vonesh, J.R., Osenberg, C.W. & Sih, A. (2007). The Influence of Intraguild Predation on Prey Suppression and Prey Release: A Meta-Analysis. Ecology , 88, 2689–2696.
VanderWaal, K.L. & Ezenwa, V.O. (2016). Heterogeneity in pathogen transmission: mechanisms and methodology. Funct. Ecol. , 30, 1606–1622.
Viney, M.E. & Riley, E.M. (2014). From Immunology to Eco-Immunology: More than a New Name. In: Eco-immunology: Evolutive Aspects and Future Perspectives (eds. Malagoli, D. & Ottaviani, E.). Springer Netherlands, Dordrecht, pp. 1–19.
Vlot, A.C., Dempsey, D.A. & Klessig, D.F. (2009). Salicylic acid, a multifaceted hormone to combat disease. Annu. Rev. Phytopathol. , 47, 177–206.
Wale, N. & Duffy, M.A. (2021). The use and underuse of model systems in infectious disease ecology and evolutionary biology. Am. Nat. , 198, 69–92.
Weinstein, S.B., Buck, J.C. & Young, H.S. (2018a). A landscape of disgust. Science , 359, 1213–1214.
Weinstein, S.B., Moura, C.W., Mendez, J.F. & Lafferty, K.D. (2018b). Fear of feces? Tradeoffs between disease risk and foraging drive animal activity around raccoon latrines. Oikos , 127, 927–934.
Wielkopolan, B., Jakubowska, M. & Obrępalska-Stęplowska, A. (2021). Beetles as Plant Pathogen Vectors. Front. Plant Sci. , 12.
Yin, M., Laforsch, C., Lohr, J.N. & Wolinska, J. (2011). Predator-Induced Defense Makes Daphnia More Vulnerable to Parasites.Evolution , 65, 1482–1488.
Zhang, Y.-X., Sun, L., Lin, G.-Y., Lin, J.-Z., Chen, X., Ji, J.,et al. (2015). A novel use of predatory mites for dissemination of fungal pathogen for insect biocontrol: The case of Amblyseius swirskii and Neoseiulus cucumeris (Phytoseiidae) as vectors of Beauveria bassiana against Diaphorina citri (Psyllidae). Syst. Appl. Acarol. , 20, 177–187.
Figure 1. Six mechanisms of predator spreading. The main mechanisms by which predators facilitate parasite transmission and infection, discussed in detail in the main text, and depicted here. Created with BioRender.com.
Figure 2. Dose-infectivity relationships (a) can interact with partial predation (b) and whether parasites remain viable after passing through predators (c) to influence predator spreading. a) Infection rate generally increases with increasing parasite dose, with a relationship that can be accelerating, linear, or decelerating. Moreover, as the curve shows, a sigmoidal dose-infectivity relationship can appear to be accelerating, linear, or decelerating depending on the particular range of parasite doses that are considered. b) In the case of partial predation predator spreading, the impact of the predator on parasitism should depend on the nature of the dose-infectivity relationship. A partial predator (such as a corallivorous fish) that carries a moderate dose of the parasite between predators should be a very effective predator spreader for parasites with a low minimum infectious dose (and correspondingly low dose yielding 50% infections, known as the ID50 and indicated by a star on the figure), but not for those with a high minimum infectious dose (and ID50). c) In cases where parasites pass through the predator’s digestive tract, we expect there to be an interaction between the density of fecal material and the dose-infectivity curve: if there is a rapidly saturating dose-infectivity curve (and low ID50; dotted line) parasites passing through the digestive tract of a predator with diffuse feces (represented by the feces in the lower left of the figure) that spreads over a wide area should lead to substantial predator spreading. However, if there is an accelerating dose-infectivity curve and high ID50 (solid curve) predator spreading might be most pronounced when predators produce compact feces that contain a large number of parasites in comparison to the diffuse feces; in these cases, the predator spreading should be more localized. Created with BioRender.com.
Figure 3. The impact of predator preference on infection levels depends on the relationship between the trait (in this example, prey size) and infection likelihood and between the trait and predation risk. If predators prefer the type of prey that is more likely to be infected, that should reduce parasitism, as shown with the blue curves in a & b; if predators prefer the type of prey that is less likely to be infected, that should drive predator spreading, as shown with the red curves. Created with BioRender.com.