Immatures of Palaearctic species of the weevil genus Sibinia (Coleoptera, Curculionidae): new descriptions and new bionomic data with suggestions on their potential value in a phylogenetic reconstruction of the genus
Author
Skuhrovec, Jiří
Author
Gosik, Rafał
Author
Caldara, Roberto
Author
Košťál, Michael
text
Zootaxa
2015
2
151
187
journal article
http://dx.doi.org/10.11646/zootaxa.3955.2.1
ef3ddc5d-a90b-49df-a2b8-01282c0509fe
1175-5326
239116
2C428174-7C02-4F0C-BB34-E1BC81F58CB1
Sibinia viscariae
(Linnaeus,
1760
)
Caldara,
1985
:
33
.
Material examined
.
31
larvae
from seeds of
Silene vulgaris
(Moench)
collected
3
.vii.
1982
at Levanto (Liguria, northern
Italy
), leg. R. Caldara, and
12
(
5
♂♂,
7
♀♀) pupae obtained from larvae collected similarly to the others, all determined by association with reared adults.
Differential diagnosis.
See Key to the immatures of the Palaearctic species of the genus
Sibinia
and
Table.
3
.
Description of mature larva.
COLORATION. Head brown to dark yellow. All thoracic and abdominal segments light yellow.
HEAD
CAPSULE AND
MOUTH
PARTS
. Head width:
0.68–0.75 mm
(see
Table.
1
). Endocarinal line present, reaching middle of frons.
Des
1
very short, located near frontal suture;
des
2
very short, located almost in central parts of epicarnium;
des
3
long, located along frontal suture;
des
4
absent;
des
5
long, located anterolaterally (
Fig.
46
).
Fs
1
and
fs
2
absent;
fs
3
minute, located medially;
fs
4
long, located anteromedially (along epistoma);
fs
5
very long, located anterolaterally (along epistoma),
fs
5
2.5
times as long as
fs
4
(
Fig.
46
).
Les
almost as long as
des
3
; both
ves
short. Postepicranial area with
1
pes
and with
3
sensilla. Antennal segment membranous, bearing conical sensorium and
2
very short, conical, sensilla (
Fig.
49
).
Clypeus (
Fig.
50
)
3
times as wide as long; without setae, and
1
sensillum, all located posterolaterally; anterior margin slightly rounded inside. Labrum (
Fig.
50
) approximately
3.5
times as wide as long;
lms
1
distinctly shorter than
lms
2
, and as long as
lms
3
; anterior margin slightly sinuate. Epipharynx (
Fig.
51
) with
2
short, finger-like
als
, similar in length; with
3
short
ams
, similar in length; with
2
relatively short and finger-like
mes
(see comments about
ams
and
mes
in Material and Methods); labral rods elongate, kidney-shaped, strongly converging posteriorly. Mandibles (
Fig.
48
) with
1
moderately long
mds
. Maxilla (
Fig.
47
): stipes with
1
long
stps
, and with
2
long
pfs
,
pfs
1
1.5
times as long as
pfs
2
;
1
very short
mbs
; mala with
4
slightly curved
dms
, different in length; with
3
very short
vms
, almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres
1
:
1.7
; basal palpomera with
1
short
mxps
; distal palpomera with group of
3–4
conical, cuticular apical processes. Prementum (
Fig.
47
) almost rounded, with
1
prms
; margin of ligula slightly curved inside; ligula with
2
ligs
; premental sclerite clearly visible. Postmentum (
Fig.
47
) with
2
pms
,
pms
1
absent, long
pms
2
,
2.5
times as long as
pms
3
.
THORAX AND ABDOMEN. Body length
4.20–5.30 mm
(see
Table.
1
), elongate (
Fig.
52
). Abdominal segments I– V almost equal in length, slightly larger than abdominal segment VI and VII (
Fig.
52
). Spiracles on abdomen in median parts of segments (abdominal seg. I–VIII).
Chaetotaxy of body rather reduced. Setae long to very short and light yellow.
Thorax.
Prothorax (
Fig.
53
) with
9
prn
,
8
macro- and
1
microsetae;
2
moderately long
ps
of same length;
1
moderately short
eus
. Meso- and metathorax (
Fig.
53
) with
1
long
prs
;
2
long
pds
, different in length; alar area with moderately long
1
as
;
1
long
ss
(mesothorax with very short
ss
);
1
moderately long
eps
;
2
moderately long
ps
; and
1
moderately short
eus
. Each pedal area of thoracic segments well-separated and with
2–4
pda
.
Abdomen.
Abdominal segments I–VII (
Figs. 54, 55
) with
1
moderately long
prs
;
3
pds
of different length,
pds
1
and
pds
3
very short to short,
pds
2
long;
2
ss
of different length,
ss
1
very short,
ss
2
moderately long;
2
moderately long
eps
in equal length;
2
ps
of different length,
ps
1
short and
ps
2
moderately long;
1
moderately long
lsts
; and
2
short
eus
. Abdominal segment VIII (
Fig.
55
) with
1
moderately long
prs
;
3
pds
of different length,
pds
1
and
pds
3
short,
pds
2
moderately long;
2
ss
of different length,
ss
1
minute,
ss
2
moderately long;
2
moderately long
eps
in equal length;
2
ps
of different length,
ps
1
short and
ps
2
moderately long;
1
moderately long
lsts
; and
2
very short
eus
. Abdominal segment IX (
Fig.
55
) with
2
long
ds
;
2
ps
of different length,
ps
1
short and
ps
2
moderately long; and
2
moderately long
sts
in equal length. Anal lobes on abdominal segment X (
Fig.
55
) without setae.
Description of pupa.
COLORATION. Body yellow.
MORPHOLOGY (
Figs.
56–60
). Body length
2.95–3.90 mm
; widest part
1.90–2.40 mm
(see
Table.
2
). Body moderately stout. Rostrum long, approximately
5
times as long as wide, reaching mesocoxae. Pronotum
1.85
times as wide as long.
FIGURES 56–60.
Sibinia viscariae
pupa habitus: 56—ventral view; 57—detail of head; 58—dorsal view; 59—detail of pronotum; 60—lateral view; (HW—head width; BW—body width; BL—body length; setae;
as
—apical s.,
d
—dorsal s.,
ds
— discal s.,
l
—lateral s. on abdomen,
ls
—lateral s. on pronotum,
os
—orbital s.,
pas
—postantennal s.,
pls
—posterolateral s.,
sos
— superorbital s.,
vs
—vertical s.; pc—pseudocerci).
CHAETOTAXY (
Figs.
56–60
). Setae distinct, short to moderately long, unequal in length, light brown, on head, rostrum and thorax hair-like, on abdomen almost as thorn-like.
Sos
and
pas
slightly shorter than other setae of head and rostrum (
Fig.
57
). All pronotal setae moderately long and equal in length (
Fig.
59
). Setae on abdominal segments I–VIII located posteromedially and posterolaterally; all abdominal setae short, curved, located on thornlike protuberances. Pseudocerci elongated, slightly curved to inside.
Biological observations.
The larvae fed on seeds, and mature larvae left the capsule and entered the soil to pupate. Pupation was observed
10
days after the larvae entered the soil. Adults were found in the cells
9
days later.
Remarks.
This common species with a wide Euro-Asiatic distribution was reported to live on several species belonging to the genera
Silene
(
S
.
dioica
L.,
S
.
nutans
L., and
S
.
vulgaris
L.) and
Lychnis
(
L
.
viscaria
L.:
Hoffmann
1955
;
Caldara
1985
;
Dieckmann
1988
;
Rheinheimer & Hassler
2010
). The larva and the pupa were described synthetically by
Scherf (
1964
)
, who reported on only length and coloration of the body, without comments on chaetotaxy.