The question is not whether bees leave the hive to die, but whether
they do it intentionally. It is generally accepted that these
behaviours are instinctive and hard wired.

Jasna Kralj wrote in 2004

> Workers infested by nosema (Nosema apis) foraged in unsuitable weather condition more frequently as healthy individuals. This was interpreted as diseased workers with low life expectancy more readily engage in risky tasks in order to optimize the collection of nectar in relation to life expectancy.

> However, changes in foraging behavior may be also interpreted differently. It appears conceivable, that diseased workers sacrifice themselves for the benefit of the colony to reduce infestation of the colony. To sacrifice for benefit of a colony is not uncommon in honeybees. Workers defend the colony by stinging intruders regardless of fatality of such action to themselves.

> In this perspective it would be possible that workers do not return to the colony as a result of a suicidal mechanism of infested workers to decrease infestation and increase survival of the colony. Both explanations are not mutually exclusive but might have worked in the same direction. It must be noted, that such a change in bee behavior facilitating non returning of infested foragers might also benefit the parasite as it increases its chance to spread.

FROM:

"Parasite–host interactions between Varroa destructor Anderson and
Trueman and Apis mellifera L.: Influence of parasitism on flight
behaviour and on the loss of infested foragers"

Dissertation, Jasna Kralj, Ljubljana

* * *

Bob writes:
> Actually Peter I think you are the first beekeeper which has suggested suicide bees are only a hypothesis.

In science, a hypothesis is an good explanation for what we see. It is
not the same as proof. It would be very difficult if not impossible to
prove that bees "commit suicide". It "appears" that they do, but that
is not proof. If there are other explanations for this behavior that
fit equally well to the observations, then you can't simply pick the
one that you like the best and go with it. Not in science.

pb

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