Anthia beetles mimicked by
Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Ecdysozoa > Panarthropoda > Tritocerebra > Arthopoda > Mandibulata > Atelocerata > Panhexapoda > Hexapoda
(insects) > Dicondyla > Pterygota > Metapterygota > Neoptera > Eumetabola >
Holometabola > Coleoptera
> Family: Carabidae
> Subfamily: Anthiinae
Adult Eremias lugubris
lizards in southern Africa are cryptically coloured and blend with the
red-tan colours of the Kalahari semi-desert. However, the juveniles are jet-black
and white and very conspicuous and yet they forage freely and actively.
While the adults' movements are typically lizard-like, the
juveniles move with stiff, jerky movements with their backs strongly arched
and with the paler-coloured tails pressed to the ground. The lateral
movements of the adults are not apparent in the juveniles. When
juveniles change to adult colouration, the arch-walking behaviour is 'switched
The conspicuous coloration and gait of the
juveniles led the
researchers to investigate how these young lizards survived predation.
While the colour black is a thermoregulatory advantage for insects, it
is not the case for reptiles in the desert and is a definite
disadvantage when it comes to predation. The back-arching does not seem
to be heat-avoiding behaviour as it is constant and is not limited to
when the body temperature is high.
It was shown that the juvenile beetles' confidence rests in the fact that they are
protected from predators because they mimic, in colour and behaviour, the notorious and noxious
'oogpister' beetles (genus Anthiinae, family Carabidae).
Predators avoid the threat
of the pungent, acidic fluid sprayed by these beetles when threatened or
This unique mimicry by a terrestrial vertebrate of an invertebrate, is
believed to be the first reported such case and seems to reduce
predation on juvenile lizards. The mimicry is so effective that even
the researchers confused the lizards for beetles when conducting
their field work.
To evaluate how effective the mimicry was against
predation, researchers examined the tails of various sympatric
(occupying the same region) lizard species for evidence of damage and comparisons were made between mimicking and non-mimicking,
paler-coloured lizard species. The results showed that there were more
damaged tails among the latter group than the mimicking group. It was
also found that arch-backing juvenile lizards were avoided in 100% of
interactions with snakes but were attacked if they moved normally. It
was also found that the lizards' behaviour was different for different
snakes. For a visual hunter, they remained immobile or arch-backed but
for a snake that used only olfaction, they ran away at high speed.
Furthermore, the lizards' distribution overlaps
with 15 species of Anthia and Thermophilum and it was
found (by Schmidt) that as the juvenile lizards grow, their colour
patterns change to match appropriately sized Anthiinae beetle species.
Images will be available in December.
Huey, R. B. and Pianka, E. R. 1977. Natural
selection for juvenile lizards mimicking noxious beetles.
Science, Vol 195, Issue 4274, 201-203.