Behavior-altering parasite

Behavior-altering parasites are parasites capable of causing changes in the behavior of their hosts species to enhance their transmission, sometimes directly affecting the hosts' decision-making and behavior control mechanisms. By way of example, a parasite that reproduces in an intermediate host may require, as part of their life cycle, that the intermediate host be eaten by a predator at a higher trophic level, and some parasites are capable of altering the behavior of the intermediate host to make such predation more likely;[1][2] a mechanism that has been called parasite increased trophic facilitation[3] or parasite increased trophic transmission.[4] Examples can be found in bacteria, protozoa, viruses, and animals. Parasites may also alter the host behavior to increase protection of the parasites or their offspring; the term bodyguard manipulation is used for such mechanisms.[5]

Among the behavioral changes caused by parasites is carelessness, making their hosts easier prey.[6][4] The protozoan Toxoplasma gondii, for example, infects small rodents and causes them to become careless and may even cause them to become attracted to the smell of feline urine, both of which increase their risk of predation and the parasite's chance of infecting a cat, its definitive host.

Parasites may alter the host's behavior by infecting the host's central nervous system, or by altering its neurochemical communication (studied in neuroparasitology).[7]

  1. ^ Seppala, O.; Valtonen, E.; Benesh, D. (2008). "Host manipulation by parasites in the world of dead-end predators: adaptation to enhance transmission?". Proceedings of the Royal Society B: Biological Sciences. 275 (1643): 1611–1615. doi:10.1098/rspb.2008.0152. PMC 2602814. PMID 18430644.
  2. ^ Luong, L.; Grear, D.; Hudson, P. (2014). "Manipulation of host-resource dynamics impacts transmission of trophic parasites". International Journal for Parasitology. 44 (10): 737–742. doi:10.1016/j.ijpara.2014.05.004. PMID 24929136.
  3. ^ Mouritsen, K.; Poulin, R. (2003). "Parasite-induced trophic facilitation exploited by a non-host predator: a manipulator's nightmare" (PDF). International Journal for Parasitology. 33 (10): 1043–1050. doi:10.1016/s0020-7519(03)00178-4. PMID 13129526. Archived (PDF) from the original on 2021-06-02. Retrieved 2020-09-08.
  4. ^ a b Lafferty, K.D. (1999). "The Evolution of Trophic Transmission". Parasitology Today. 15 (3): 111–115. doi:10.1016/s0169-4758(99)01397-6. PMID 10322324.
  5. ^ Maure, Fanny; Brodeur, Jacques; Droit, Anaïs; Doyon, Josée; Thomas, Frédéric (2013). "Bodyguard manipulation in a multipredator context: Different processes, same effect". Behavioural Processes. 99: 81–86. doi:10.1016/j.beproc.2013.06.003. PMID 23791577. S2CID 13154407.
  6. ^ Moore, J. (2002). Parasites and the behavior of animals. Oxford: Oxford University Press.[ISBN missing][page needed]
  7. ^ Libersat, Frederic (1 May 2018). "Mind Control: How Parasites Manipulate Cognitive Functions in Their Insect Hosts". Frontiers in Psychology. 9: 572. doi:10.3389/fpsyg.2018.00572. PMC 5938628. PMID 29765342.