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Badgers and Badger Fleas: Strategies and
Counter-Strategies
Journal
Ethology, Volume
109,Number 9, September 2003, pp. 751-764(14) -
Blackwell Publishing
Authors
Stewart P.D.; Macdonald
D.W. from the WildCRU, Department of Zoology, Oxford
Abstract
We examined the broad hypothesis that one function of grooming by the
badger is to disadvantage (possibly by removal)
parasitic badger fleas (Paraceris melis). We pursued two lines of
investigation. First, we used infra-red video analysis to examine the body areas
reached by self- and allo-grooming badgers. We expected that if grooming was
important to disadvantage fleas then allo-grooming would cover areas that could
not be reached by self-grooming. Badgers preferred dorsal allo-grooming and
ventral self-grooming, and when combined, the overall amount of grooming per
square centimetre of skin area provided even body coverage, pointing to a
hygienic function, rather than a purely social function. Secondly, we examined
fleas’ responses to simulated fur disturbance, characteristic of grooming. If
grooming had no flea disadvantage effect, we would expect no response from
fleas, and no directionality in their movement away from direct touch. The
number of fleas encountered rapidly declined in successive 10-s counts during
simulated ‘grooming’ at the same site. When badgers were ‘groomed’ on alternate
sides (mimicking the badgers’ rapid alternation of grooming position), there was
a marked increase in fleas when grooming resumed on the original side.
Similarly, when ‘grooming’ was suspended for 40 s, there was an initial increase
in the number of fleas when ‘grooming’ was resumed. Disturbed fleas tended to
run downwards relative to gravity and towards the posterior of the badger,
following the direction of hair growth. This contrasted with the behaviour of
fleas removed from badgers which tended to run upwards and jump. We concluded
that the pattern of badger grooming and the fleas’ response to disturbance was
consistent with a hypothesis that badgers and badger fleas have strategies and
counter strategies to maximize and minimize contact (respectively) during
grooming.
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