Researchers aim to define host-parasite interactions by modeling the effects of coinfection on community dynamics
By Andy Flick, Evolutionary Studies Initiative scientific coordinator
Research conducted at 国产原创 has been published in 颈苍听The American Naturalist that models how parasites interact to affect their host鈥檚 behavior. The results of the research,聽conducted by Faith Rovenolt, BA鈥20, and Ann Tate, assistant professor of biological sciences, reinforce an understanding of the influence of disease in community dynamics.
The pair created a new model to study coinfection of hosts and developed a table of known interactions between parasites infecting the same hosts.
鈥淚 wanted to create a model that involved resistance and tolerance to parasites, since they should have different impacts on host ecology and evolution,鈥 said Rovenolt, now a graduate student at the University of Pittsburgh. 鈥淲e already had some experimental data suggesting that our hosts, two flour beetles (Tribolium), fared differently under infection, so it made sense to incorporate it all under the same framework.鈥
| Host | Outcome | Parasite | Mechanism | System |
|---|---|---|---|---|
| Mortality | Down | Competition | Cross Immunity | Trypanosoma brucei strains in mice |
| Mortality | Up | Competition | Resource Competition | NPVs and entomopoxvirus in the tea tortix Adoxophyes honmai |
| Mortality | Up | Facilitation | Tissue Damage | Legionella pneumophila and influenza virus in mice |
| Recovery | Up | Competition | Space or resource competition | Helminth and Giardia in humans |
| Recovery | Down | Facilitation | Tissue Conditioning | Influenza A virus, Streptococcus pneumoniae, and Staphylococcus aureus in mice |
An example of some of the known interactions from Table 1 in the manuscript. See the manuscript for the full table.
Creating the table above turned out to be a thought experiment about what it means to define parasite interactions.
鈥淚t blew my mind just how difficult it is to define interactions,鈥 Rovenolt said. 鈥淚n one context, like high host food availability, two parasites might facilitate each other, while under low food they might compete.鈥
鈥淚t is important to know the relative strength of within versus between species competition in the absence of parasites, and whether the two hosts are sharing one or both parasites, since it affects feedbacks on prevalence and transmission to each host,鈥 said Tate, also a member of the Evolutionary Studies Initiative.
Flour beetles are a great system to test questions about parasitic interactions and community dynamics because they are well-studied and frequent agricultural pests. 鈥淭he rich body of literature on natural history and population biology of Tribolium is complemented by a modern molecular genomics toolbox and the ease of collecting beetles and their parasites in the 鈥榳ild鈥欌攍ike in grain elevators and feed mills around the U.S. and the world,鈥 Tate said. 鈥淚t makes it an ideal system to test these cross-scale feedbacks.鈥
This work was partly inspired by a 1948 study focused on the interactions between two species of flour beetles. The paper was among the first to suggest that parasites could alter community dynamics of their hosts. 鈥淚鈥檝e known about and been inspired by this paper for as long as I鈥檝e worked on the beetles, so it was fun to resurrect it to serve as a motivating example for this study,鈥 Tate said.
While Rovenolt wrote this paper as part of her senior honors thesis, she and Tate will soon test their model鈥檚 usefulness as they design new lab experiments that aim to predict coinfection and community dynamics.
This research was funded by National Science Foundation DEB/IOS award 1753982.