Parasites are likely to play an important role in structuring host populations. Many adaptively manipulate host behaviour, so that the extended phenotypes of these parasites and their distributions in space and time are potentially important ecological variables. The fungus Ophiocordyceps unilateralis, which is pan-tropical in distribution, causes infected worker ants to leave their nest and die under leaves in the understory of tropical rainforests. Working in a forest dynamic plot in Southern Thailand we mapped the occurrence of these dead ants by examining every leaf in 1,360 m2 of primary rainforest. We established that high density aggregations exist (up to 26 dead ants/m2), which we coined graveyards. We further established that graveyards are patchily distributed in a landscape with no or very few O. unilateralis-killed ants. At some, but not all, spatial scales of analysis the density of dead ants correlated with temperature, humidity and vegetation cover. Remarkably, having found 2243 dead ants inside graveyards we only found 2 live ants of the principal host, ant Camponotus leonardi, suggesting that foraging host ants actively avoid graveyards. We discovered that the principal host ant builds nests in high canopy and its trails only occasionally descend to the forest floor where infection occurs. We advance the hypothesis that rare descents may be a function of limited canopy access to tree crowns and that resource profitability of such trees is potentially traded off against the risk of losing workers due to infection when forest floor trails are the only access routes. Our work underscores the need for an integrative approach that recognises multiple facets of parasitism, such as their extended phenotypes.
grave yards on the move . com
The International Syndicate of Cult Film Critics aim to celebrate shoddy B-movies and straight-to-video films. We will cover these flicks fondly, with tongues firmly kept in our cheeks. The one thing we ask of those who contribute to the Club is that you must watch the film in its entirety, even if this means having to strap yourself down onto a chair and getting your eyelids locked out like Alex DeLarge from ‘A Clockwork Orange’. It is imperative that you absorb the visual treats.
If you want to contact us, then we can be reached at: aprilmaymarch777@yahoo.co.uk






"Drunk at the matinee" is a collection of candid poetry about stupid shit that we all experience from day to day.




0 comments:
Post a Comment