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1. Rapid evolution rescues hosts from competition and disease but—despite a dilution effect—increases the density of infected hosts

   https://doi.org/10.1098/rspb.2017.1970  

   Strauss, Alexander T. ; Hite, Jessica L. ; Shocket, Marta S. ; Cáceres, Carla E. ; Duffy, Meghan A. ; Hall, Spencer R. ( December 2017 , Proceedings of the Royal Society B: Biological Sciences)
2. Parasite spillover to native hosts from more tolerant, supershedding invasive hosts: Implications for management

   https://doi.org/10.1111/1365-2664.13906  

   Ortega, Nicole ; Roznik, Elizabeth A. ; Surbaugh, Kerri L. ; Cano, Natalia ; Price, Wayne ; Campbell, Todd ; Rohr, Jason R. ( November 2021 , Journal of Applied Ecology)

   Introduced hosts are capable of introducing parasite species and altering the abundance of parasites that are already present in native hosts, but few studies have compared the tolerances of native and invasive hosts to introduced parasites or identified the traits of introduced hosts that make them supershedders of non‐native parasites.

   Here, we compare the effects of a nematodeAplectana hamatospiculathat is native to Cuba but appears to be introduced to Florida on the native Floridian treefrog,Hyla femoralis, and on the Cuban treefrog (CTF),Osteopilus septentrionalis. We were particularly interested in CTFs because their introduction to Florida has led to reported declines of native treefrogs.

   In the laboratory, infection withA. hamatospiculacaused a greater loss in body mass ofH. femoralisthan CTFs despiteH. femoralisshedding fewer total worms in their faeces than CTFs. Field collections of CTFs,H. femoralis, and another native Floridian treefrog,H.squirella(Squirrel treefrog) from Tampa, FL also showed that CTFs shed more larval worms in their faeces than both native frogs when controlling for body size. Hence, the non‐native CTF is a supershedder of this non‐native parasite that is spilling over to less tolerant native treefrogs.

   Any conservation intervention to reduce the effects of CTFs on native treefrogs would benefit from knowing the traits that contribute to the invasive host being a supershedder of this parasite. Hence, we conducted necropsies on 330 CTFs to determine how host sex and body size affect the abundance ofA. hamatospicula, and two other common parasites in this species (acuariid nematodes and trematode metacercariae).

   There was a significant linear increase inA. hamatospiculaand encysted acuariids with CTF body size, but there was no detectable relationship between host body size and the intensity of metacercariae. Female CTFs were bigger, lived longer and, on average, had moreA. hamatospiculathan male CTFs.

   Synthesis and applications. These results of the study suggest that there is parasite spillover from the invasive Cuban treefrog (CTF) to native treefrogs in Florida. Additionally, at least some of the adverse effects of CTFs on native treefrogs could be caused by the introduction and amplification of this introduced parasite, and female and larger CTFs seem to be amplifying these infections more than males and smaller CTFs, respectively, suggesting that management could benefit from targeting these individuals.

    

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3. The visual ecology of selective predation: Are unhealthy hosts less stealthy hosts?

   https://doi.org/10.1002/ece3.8464  

   Wale, Nina ; Fuller, Rebecca C. ; Johnsen, Sönke ; Turrill, McKenna L. ; Duffy, Meghan. A. ( December 2021 , Ecology and Evolution)

   Predators can strongly influence disease transmission and evolution, particularly when they prey selectively on infected hosts. Although selective predation has been observed in numerous systems, why predators select infected prey remains poorly understood. Here, we use a mathematical model of predator vision to test a long‐standing hypothesis about the mechanistic basis of selective predation in aDaphnia–microparasite system, which serves as a model for the ecology and evolution of infectious diseases. Bluegill sunfish feed selectively onDaphniainfected by a variety of parasites, particularly in water uncolored by dissolved organic carbon. The leading hypothesis for selective predation in this system is that infection‐induced changes in the transparency ofDaphniarender them more visible to bluegill. Rigorously evaluating this hypothesis requires that we quantify the effect of infection on the visibility of prey from the predator's perspective, rather than our own. Using a model of the bluegill visual system, we show that three common parasites,Metschnikowia bicuspidata,Pasteuria ramosa, andSpirobacillus cienkowskii, decrease the transparency ofDaphnia, rendering infectedDaphniadarker against a background of bright downwelling light. As a result of this increased brightness contrast, bluegill can see infectedDaphniaat greater distances than uninfectedDaphnia—between 19% and 33% further, depending on the parasite.PasteuriaandSpirobacillusalso increase the chromatic contrast ofDaphnia. These findings lend support to the hypothesis that selective predation by fish on infectedDaphniacould result from the effects of infection onDaphnia's visibility. However, contrary to expectations, the visibility ofDaphniawas not strongly impacted by water color in our model. Our work demonstrates that models of animal visual systems can be useful in understanding ecological interactions that impact disease transmission.

    

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4. The application of community ecology theory to co‐infections in wildlife hosts

   https://doi.org/10.1002/ecy.3253  

   Ramsay, Chloe ; Rohr, Jason R. ( March 2021 , Ecology)

   null (Ed.)
5. Science Extraction from TESS Observations of Known Exoplanet Hosts

   https://doi.org/10.1088/1538-3873/abc610  

   Kane, Stephen R. ; Bean, Jacob L. ; Campante, Tiago L. ; Dalba, Paul A. ; Fetherolf, Tara ; Mocnik, Teo ; Ostberg, Colby ; Pepper, Joshua ; Simpson, Emilie R. ; Turnbull, Margaret C. ; et al ( January 2021 , Publications of the Astronomical Society of the Pacific)

   null (Ed.)