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Old pythons stay fit; effects of haematozoan infections on life history traits of a large tropical predator

Madsen, Thomas LU ; Ujvari, Beata LU and Olsson, M (2005) In Oecologia 142(3). p.407-412
Abstract
We document the impact of blood parasite infections caused by Hepatozoon sp. on water python (Liasis fuscus) life history traits such as growth rates, condition, reproductive output and survival. Individual snakes maintained similar among-year parasite loads. Hepatozoon infections affected python growth rate, i.e. snakes suffering from high infection levels exhibited significantly slower growth compared to individuals with low parasite loads. Our results suggest that the parasites also affected the pythons' nutritional status ( condition), as snakes with low condition scores suffered from higher parasite infection levels than snakes with high scores. Furthermore, our data suggest that parasitaemia may affect female reproductive output, as... (More)
We document the impact of blood parasite infections caused by Hepatozoon sp. on water python (Liasis fuscus) life history traits such as growth rates, condition, reproductive output and survival. Individual snakes maintained similar among-year parasite loads. Hepatozoon infections affected python growth rate, i.e. snakes suffering from high infection levels exhibited significantly slower growth compared to individuals with low parasite loads. Our results suggest that the parasites also affected the pythons' nutritional status ( condition), as snakes with low condition scores suffered from higher parasite infection levels than snakes with high scores. Furthermore, our data suggest that parasitaemia may affect female reproductive output, as reproductive female pythons harboured lower parasite loads compared to non-reproductive adult females. High levels of parasite infections also affected juvenile python survival, as recaptured snakes harboured significantly lower parasite loads compared to non-recaptured yearling pythons. In our study area, water python have very few natural predators and, hence, experience low mortality rates and commonly reach an age of > 15 years. In contrast to results obtained in other studies, parasite loads in larger/ older pythons were lower compared to younger snakes, suggesting that only snakes harbouring lower levels of parasitaemia were able to survive to old age. We suggest that a possible cause for the opposing results regarding parasite prevalence and host age may be due to different levels of extrinsic mortality rates and longevity. Long-lived organisms, such as water pythons, may invest relatively more into crucial self-maintenance functions such as parasite defence, compared to short-lived organisms. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Oecologia
volume
142
issue
3
pages
407 - 412
publisher
Springer
external identifiers
  • pmid:15517406
  • wos:000226357400008
  • scopus:12944250795
ISSN
1432-1939
DOI
10.1007/s00442-004-1742-9
language
English
LU publication?
yes
id
7c73cbac-5412-4703-ba44-eec0432e39e3 (old id 145329)
date added to LUP
2007-06-25 14:58:55
date last changed
2017-10-22 03:54:43
@article{7c73cbac-5412-4703-ba44-eec0432e39e3,
  abstract     = {We document the impact of blood parasite infections caused by Hepatozoon sp. on water python (Liasis fuscus) life history traits such as growth rates, condition, reproductive output and survival. Individual snakes maintained similar among-year parasite loads. Hepatozoon infections affected python growth rate, i.e. snakes suffering from high infection levels exhibited significantly slower growth compared to individuals with low parasite loads. Our results suggest that the parasites also affected the pythons' nutritional status ( condition), as snakes with low condition scores suffered from higher parasite infection levels than snakes with high scores. Furthermore, our data suggest that parasitaemia may affect female reproductive output, as reproductive female pythons harboured lower parasite loads compared to non-reproductive adult females. High levels of parasite infections also affected juvenile python survival, as recaptured snakes harboured significantly lower parasite loads compared to non-recaptured yearling pythons. In our study area, water python have very few natural predators and, hence, experience low mortality rates and commonly reach an age of > 15 years. In contrast to results obtained in other studies, parasite loads in larger/ older pythons were lower compared to younger snakes, suggesting that only snakes harbouring lower levels of parasitaemia were able to survive to old age. We suggest that a possible cause for the opposing results regarding parasite prevalence and host age may be due to different levels of extrinsic mortality rates and longevity. Long-lived organisms, such as water pythons, may invest relatively more into crucial self-maintenance functions such as parasite defence, compared to short-lived organisms.},
  author       = {Madsen, Thomas and Ujvari, Beata and Olsson, M},
  issn         = {1432-1939},
  language     = {eng},
  number       = {3},
  pages        = {407--412},
  publisher    = {Springer},
  series       = {Oecologia},
  title        = {Old pythons stay fit; effects of haematozoan infections on life history traits of a large tropical predator},
  url          = {http://dx.doi.org/10.1007/s00442-004-1742-9},
  volume       = {142},
  year         = {2005},
}