Dear All,
It is known that certain parasites alter the behaviour of their hosts inducing
risky behaviour as per this article. It may be stretching the analogy as the
ducks would have to be intermediate hosts of a canid parasite.
Behavioral changes induced by Toxoplasma infection of rodents are highly
specific to aversion of cat odors. 6442–6447 PNAS April 10, 2007 vol.
104 no. 15
The protozoan parasite Toxoplasma gondii blocks the innate aversion of rats for
cat urine, instead producing an attraction to the pheromone; this may increase
the likelihood of a cat predating a rat. This
is thought to reflect adaptive, behavioral manipulation by Toxoplasma in that
the parasite, although capable of infecting rats, reproduces sexually only in
the gut of the cat. The ‘‘behavioral
manipulation’’ hypothesis postulates that a parasite will specifically
manipulate host behaviors essential for enhancing its own transmission.
However, the neural circuits implicated in innate fear, anxiety,
and learned fear all overlap considerably, raising the possibility that
Toxoplasma may disrupt all of these nonspecifically. We investigated these
conflicting predictions. In mice and rats, latent Toxoplasma
infection converted the aversion to feline odors into attraction. Such loss of
fear is remarkably specific, because infection did not diminish learned fear,
anxiety-like behavior, olfaction, or nonaversive learning.
These effects are associated with a tendency for parasite cysts to be more
abundant in amygdalar structures than those found in other regions of the
brain. By closely examining other types of behavioral
patterns that were predicted to be altered we show that the behavioral effect
of chronic Toxoplasma infection is highly specific. Overall, this study
provides a strong argument in support of the behavioral
manipulation hypothesis. Proximate mechanisms of such behavioral manipulations
remain unknown, although a subtle tropism on part of the parasite remains a
potent possibility.
Bill Hall
-----Original Message-----
From: Con Boekel
Sent: Sunday, 26 November, 2017 9:54 PM
To:
Subject: Foxes at Kellys
Steve
Great footage. Just so interesting!
regards
Con
On 11/26/2017 9:27 PM, Wallaces wrote:
> I have now put up some of the video I took.
> https://www.hbw.com/ibc/1438131
>
>
> Steve
>
> -----Original Message-----
> From: Wallaces
> Sent: Saturday, 25 November 2017 6:59 PM
> To: Canberra birds
> Subject: [canberrabirds] Foxes at Kellys
>
> At Kellys yesterday, two foxes, one in the open and the other
> hidden (location marked with red arrow). The one in the open seemed to
> be looking for the swamphen chicks which emerged from the vegetation
> behind it after it left. The ducks moved towards the visible fox
> rather than away but stayed in the water at a respectful distance.
>
> Steve
>
>
>
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