Circellium bacchus (Flightless
dung beetle, Addo flightless dung beetle)
Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Ecdysozoa > Panarthropoda > Tritocerebra > Arthopoda > Mandibulata > Atelocerata > Panhexapoda > Hexapoda
> Insecta
(insects) > Dicondyla > Pterygota > Metapterygota > Neoptera > Eumetabola >
Holometabola > Coleoptera
(beetles)
> Polyphaga > Superfamily: Scarabaeoidea
> Family: Scarabaeidae > Subfamily:
Scarabaeinae
This scarab beetle was
once widespread throughout South Africa but is now limited to a few pockets of
populations, the largest being at Addo Elephant Park in the Eastern Cape
Province. Another stable population occurs at the Buffalo Valley Game Farm near
Knysna.
Historical collection records in the Western Cape Province include Palmiet in 1882, Houwhoek in 1907, Riversdale in 1908, Knysna
in 1915, Somerset West in 1927, George and Hermanus in 1931, Herbertsdale in 1940, Genadendal
in 1945 and more recently at the Berg River Mouth in 1976 and De Hoop Nature
Reserve and surrounding areas in the 1980s and 1990s.
While this species is not included on
the IUCN list of threatened species, it complies with most of the
criteria and therefore qualifies as "vulnerable". Its vulnerability is
attributed to: small, restricted and isolated populations; the habitat
is constantly under threat from agriculture and general human
encroachment; climate change; low fecundity (breeding capacity); low
dispersability as it is flightless; habitat specialisation; co-evolution
with and dependence on falling numbers of vertebrates (elephant and
buffalo).
While they are generalist dung
feeders, they have a preference for elephant dung but have been recorded
feeding on rabbit, baboon, various antelope, human, ostrich and baboon
dung/faeces. Feeding might take place at the dung site or a small ball
prepared and rolled away and eaten in a protected location. The younger
adults usually do this.
However, buffalo dung is preferred for
breeding.
Females produce only one off-spring per breeding cycle, usually one but
sometimes two per year so fecundity is therefore low. When breeding, the
female removes a portion of dung from the pile, pats it onto a ball and
rolls it away, from 7 to 80m, depending on when she finds a suitable
site. Unlike other dung beetles, the male trails her by a few
centimeters and does not help roll the ball. When the ideal site is
decided on, the female excavates the hole and the male then positions
himself on top of the dung ball and sinks down with it, the depth
varying from 17 to 37 cm. Mating then takes place and the egg is
deposited. The male returns to the surface and the female remains with
her brood throughout the early (larval) development. This is critical
for the survival of the larva as she constantly clears away fungus that
develops on the outside of the dung ball. The development time from egg
to adult ranges from 120 to 140 days. The young adult then feeds for
another 50 to 65 days before becoming sexually mature.
Publication
-
Chown, S. L., Scholtz, C. H., Klok, C. J., Joubert,
F. J. & Coles, K. S. 1995. Ecophysiology, range contraction and
survival of a geographically restricted dung beetle (Coleoptera:
Scarabaeidae). Functional Ecology 9: 30-39.
-
Kryger, U. Cole, K. S., Tukker, R. and Scholtz, C.H.
2006. Biology and ecology of Circellium bacchus (Fabricius
1781) (Coleoptera Scarabaeidae), a South African dung beetle of
conservation concern. Tropical Zoology 19: 185 - 207.
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