Deer mice like the one above are small parts of a complex and interconnected world. When two pieces of their world work against them simultaneously, how are these mice affected? (Image Credit: USDA, CC BY 2.0).
Botfly infections impair the aerobic performance and survival of montane populations of deer mice, Peromyscus maniculatus rufinus (2019) Wilde et al., Functional Ecology, https://dx.doi.org/10.1111/1365-2435.13276
Parasites are bad news for the organisms that host them. Some parasites are so bad, they can actually make the host kill itself. Despite these clear and obvious costs to infection, the common consensus is that parasites are not too big of a deal for the host, because of how rare parasitic infection is on average. For example, in my research system only one in ten animals have parasites.
But when these ill-effects of parasitism are combined with other detrimental factors, such as a harsh environment, an organism with parasites is forced to deal with not one but two stressors. The authors of today’s paper were interested in how these effects of parasites may change depending on the environment that the host lived in.
Many organisms are vulnerable to a wide array of diseases and parasites throughout the course of their lives, but could scavengers help reduce that vulnerability? (Image Credit: The High Fin Sperm Whale, CC BY-SA 4.0, Image Cropped)
Do scavengers prevent or promote disease transmission? The
effect of invertebrate scavenging on Ranavirus transmission (2019) Le Sage et al., Functional Ecology, https://doi.org/10.1111/1365-2435.13335
As intimate as the host-parasite relationship is, it is important to keep in mind that it is embedded within a complex web of other interactions within the local ecological community. To add to this complexity, all of these interactions can feed back on and effect the host-parasite relationship. One ubiquitous part of all communities is the scavenger, an organism that feeds on dead and decomposing organisms. The authors of this paper wanted to investigate how scavengers affect disease transmission in local communities.
This question in interesting because it can easily go either way, depending on the community in question. Scavengers could lower disease transmission by eating infected organisms, thus removing contagious elements from the environment. However, scavengers could also increase transmission by promoting the spread of contagious elements in the community via their own waste after they consume infected tissues.
Host defense triggers rapid adaptive radiation in experimentally evolving parasites (2019) Bush et al., Evolution Letters, p. 1-9
Adaptive radiation is a fascinating ecological concept, one with which anyone who knows the tale of Darwin’s finches will be familiar with. The basic premise is that an organism may evolve different forms (and ultimately become different species) in response to pressures exerted upon them.
But whilst this may have been observed in many vertebrates, it’s often overlooked in parasites, whereby host defenses can prompt divergence in parasite morphology. Today’s paper wanted to test the two basic concepts of evolution. 1) Can host defenses prompt physical changes in parasites? 2) Are these changes heritable?
Fields full of herbaceous plants such as these can be incredibly diverse and complicated ecosystems, and the multitudes of species that inhabit them can influence the magnitude of disease that the organisms that inhabit it may encounter (Image Credit: LudwigSebastianMicheler, CC BY-SA 4.0, Image Cropped)
Past is prologue: host community assembly and the risk of infectious disease over time (2018) Halliday, F.W. et al., Ecology Letters, 22, https://dx.doi/10.1111/ele.13176
Everything in ecology is based around the environment that a focal organism inhabits, including the interactions it has with other organisms and the non-living aspects of the habitat itself (temperature, water pH, etc.). That being said, it’s no surprise that disease dynamics are likely to depend on the environment that a host inhabits, and that the environment itself is a product of what came before. That is to say, the group of organisms that originally populate a given ecosystem can have an effect on how that ecosystem will look in the future (lakes with freshwater mussels will have clearer water than those without).
The scientific literature is full of experiments, observations, and hypotheses about which environmental conditions lead to fluctuations in disease dynamics. As such, it is difficult to come to a consensus with a “one-size-fits-all” rule for disease dynamics and community structure. The authors of today’s study used a long-term experiment to determine what exactly moderates disease over time. Read more
Parasites like this leech can be found all over the world, and anyone growing up near freshwater knows to check for them. But many consider these animals “gross”, so how can we motivate the public and scientists to care about them? (Image credit: John Douglas, CC BY-SA 2.0, Image Cropped)
As someone who works with parasites, I have to confess that I love them. They are beyond interesting, and I delight in telling people about them and what they do to their host organisms to survive. More often than not, people cringe or look like they would rather run away than hear more about such disgusting creatures. I know that as a disease ecologist I am very much in the minority when it comes to how I feel about parasites, but I think it’s important that we understand how vital these organisms are to the natural world, and the benefits they offer to scientists and their research.
Image Credit: The Two Towers, 2002
This week we look at the Ents, of the little known cult comedy Lord of the Rings. Adam really just nerds right out (we get it you read), Dave reveals he doesn’t believe in new Zealand and Sam rediscovers the art of the pun.
Movie History – 0.04.55
Movie Any Good? – 0.16.38
Ent Physiology – 0.21.06
Ent Ecology – 1.01.02
Treebeard vs. Christopher Lee – 1.24.30
Listen to the full episode below. For a more detailed breakdown, head over to Cinematica Animalia.