Bottom-up regulation of malaria population dynamics in mice co-infected with lung-migratory nematodes

Emily C. Griffiths, Karen Fairlie-Clarke, Judith E. Allen, Charlotte Jessica Eland Metcalf, Andrea Linn Graham

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


When and how populations are regulated by bottom up vs. top down processes, and how those processes are affected by co-occurring species, are poorly characterised across much of ecology. We are especially interested in the community ecology of parasites that must share a host. Here, we quantify how resources and immunity affect parasite propagation in experiments in near-replicate 'mesocosms'' - i.e. mice infected with malaria (Plasmodium chabaudi) and nematodes (Nippostrongylus brasiliensis). Nematodes suppressed immune responses against malaria, and yet malaria populations were smaller in co-infected hosts. Further analyses of within-host epidemiology revealed that nematode co-infection altered malaria propagation by suppressing target cell availability. This is the first demonstration that bottom-up resource regulation may have earlier and stronger effects than top-down immune mechanisms on within-host community dynamics. Our findings demonstrate the potential power of experimental ecology to disentangle mechanisms of population regulation in complex communities.

Original languageEnglish (US)
Pages (from-to)1387-1396
Number of pages10
JournalEcology letters
Issue number12
StatePublished - Dec 2015

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics


  • Co-infection
  • Community ecology
  • Effective propagation
  • Immune profile
  • Parasite ecology
  • Predator community
  • Resource regulation
  • Target cell limitation


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