Page 45 - Volume 1, Issue 1, January 2008

Acalles barbarus on caper 43
widespread in countries of the Palaearctic
regions, as well as in the parts of America
and Australia that are washed by the Pacif-
ic Ocean. They occur on many plant spe-
cies (herbs, shrubs and trees), of various
families (Leguminosae, Compositae, Eu-
phorbiacae, Crassulaceae and others) and
feed on scrubby and weakish plants rath-
er than on healthy ones (6, 8, 11) .
Available literature on A. barbarus L.
from the Mediterranean basin reports its
presence on caper in Pantelleria, south of
Sicily (Italy), which is the dominant island
of caper culture and trade in the Mediter-
ranean (6, 8, 11). Αcalles species are not
generally characterized as pests (4, 6, 8 )
and therefore the damage they can cause
to various plants they feed on has not
been assessed.
A. barbarus feeds on plants weak-
ened by various biotic and abiotic factors
(pests, diseases, frost etc). Only the lar-
vae of the insect are harmful to the plants.
The slight damage caused by the adults is
considered non economically important.
On vigorous and healthy plants damage
is negligible while on plants parasitized
at the same time by other insect pests, in
particular by species of Diaspididae and
Pseudococcidae, damage may be consid-
erable (6, 8).
Preliminary observations on the bi-
ology and ethology of A. barbarus:
As the species is new to the insect fauna
of Greece, some preliminary observations
are presented on the biology and etholo-
gy of the insect. In addition, for the first
time the developmental stages of the in-
sect and the symptoms on caper are re-
corded (Fig. 2, 3, 4).
A. barbarus has one generation per
year. It hibernates at the larval stage inside
attacked twigs. Adults start appearing
from mid-June till beginning of July. Dur-
ing the day they are difficult to be found
as they are hiding in the 5 cm upper layer
of the soil, while at night they leave their
shelter and clamber up the caper plants
moving slowly and gnawing at the margin
of the leaves as all Acalles species do .
A. barbarus displays a curious behav-
iour when disturbed by conspicuous
sounds. It then shams death: it retracts its
legs, remains motionless and immediate-
ly lets itself drop to the ground where it
is difficult to spot because of the colour
it is taking. In this pose it may remain for
a considerable time. The male is smaller
than the female. There are records in the
literature of the male following a female
around for many days without copulation
being observed (6). The adult lives for a
Fig. 1. Acalles barbarus, female adult.
Fig. 2. Exit holes of the adults from infested caper shoots.