In this study we investigated
the larval dispersal associated with larval predation in experimental populations
of
Chrysomya albiceps
and
Cochliomyia macellaria
.
Frequency distribution of sampling units (G test) in the substrate was used to
evaluate variation in larval dispersal. An experimental acrylic channel (1 x 0.1
x 0.2 m) covered with wood shavings was used to observe larval dispersal prior
to pupation. The acrylic channel was graduated at 0.05 m intervals, each representing
a sampling unit; hence, 20 sampling units were set up. A Petri dish containing
third instar larvae of single and double species was deposited at one edge of
the acrylic channel allowing larvae to disperse. The number of buried pupae (0,
1, 2, …n) present in each sampling unit was recorded. For double species,
the number of recovered larvae of
C. albiceps was similar to the number
initially released on the dish Petri. On the other hand, the number of recovered
larvae of
C. macellaria was significantly smaller than the initially released
number. The results show that
C. albiceps attacks
C. macellaria
larvae during the larval dispersal process. The larval distribution of
C. albiceps
did not differ significantly from
C. macellaria in double species, but
it differed significantly in single species. The larval aggregation level of
C.
macellaria decreased when
C. albiceps was present and the larval aggregation
level of
C. albiceps increased when
C. macellaria was present. The
implications of such findings for the population dynamics of these species are
discussed.
