Immatures of Palaearctic species of the weevil genus Tychius (Coleoptera, Curculionidae): new descriptions and new bionomic data with an evaluation of their value in a phylogenetic reconstruction of the genus
Author
Skuhrovec, Jiří
Author
Gosik, Rafał
Author
Caldara, Roberto
text
Zootaxa
2014
2014-07-23
3839
1
1
83
journal article
5426
10.11646/zootaxa.3839.1.1
6d32f9c2-3094-425b-bb7e-9c6e0517d4fd
1175-5326
4927721
AA7FEED5-5C1F-48D0-A172-5C25C4001DF3
Tychius
(s. str.)
schneideri
(Herbst, 1795)
Caldara, 1990: 158
.
Material examined
.
13 larvae
from pods of
Anthyllis vulneraria polyphilla
(DC.) Nyman
collected
25.vi.1981
at
Bobbio
,
Piacenza province
,
Emilia
(northern
Italy
), leg.
R
.
Caldara
, and
14 pupae
obtained from larvae collected similarly to the others, all determined by association with reared adults.
Differential diagnosis.
See
Tables 2
and
3
.
Description of mature larva.
COLORATION. Head brown. All thoracic and abdominal segments white to whitish yellow.
HEAD CAPSULE AND MOUTH PARTS. Head width:
0.40–0.46 mm
(see
Table. 1
). Endocarinal line present, reaching middle of frons.
Des
1
located almost in central parts of epicarnium;
des
2
located very near frontal suture, near
des
3
;
des
3
located along frontal suture;
des
4
absent;
des
5
located anterolaterally;
des
2
4 times shorter than others (
des
1
,
des
3
,
des
5
) (
Fig. 73
).
Fs
1
and
fs
2
absent;
fs
3
short, located posteromedially;
fs
4
located anteromedially (along epistoma);
fs
5
located anterolaterally (along epistoma), 3 to 4 times longer than
fs
3
(
Fig. 73
).
Les
distinctly shorter than
des
3
.
Ves
1–2
very short. Post-epicranial area with 1 minute
pes
. Antennal segment membranous, bearing conical sensorium and 5 very short, conical, sensilla (
Fig. 76
).
Labrum (
Fig. 77
) approximately 3 times as wide as long;
lms
1
2 times longer than
lms
3
,
lms
2
some shorter than
lms
1
; anterior margin rounded. Clypeus (
Fig. 77
) 2.4 times as wide as long. with 2 pairs of very short
cls
of same length, and 1 sensillum, all located posterolaterally; anterior margin slightly rounded inside. Epipharynx (
Fig. 78
) with 2 pairs of
als
, different in length; with 2 pairs of short and triangular
ams
; with 2 moderately long finger-like and 1 short
mes
; labral rods short, kidney-shaped, almost parallel. Mandibles (
Fig. 75
) with 2 short
mds
, almost of equal length. Maxilla (
Fig. 74
): stipes with 1
stps
, and with 2
pfs
of different length; with 4 slightly curved
dms
, different in length; with 2
vms
, short and almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:0.7; basal palpomera with 1 short
mpxs
; distal palpomera with group of 2–3 conical, cuticular apical processes. Prementum (
Fig. 74
) heart-shaped, with 1
prms
; margin of ligula rounded; ligula with 1
lig
; premental sclerite distinct. Postmentum (
Fig. 74
) with 3 pairs of
pms
, different in length.
THORAX AND ABDOMEN. Body length
2.3–3.2 mm
(see
Table. 1
), elongate (
Fig. 79
). Abdominal segments I–V almost equal in length, slightly larger than abdominal segment VI and VII (
Fig. 79
). Spiracles on abdomen in median parts of segments (abdominal seg. I–VIII).
Chaetotaxy of body rather reduced. Setae moderately long or short and light yellow.
Thorax.
Prothorax (
Fig. 80
) with 8
prn
, 7 macro- and 1 microsetae; 2 moderately long
ps
of same length; 1
eus
. Meso- and metathorax (
Fig. 80
) with 2
prs
, different in length; 3
pds
, different in length; alar area with 1 very short
as
; 1 very short
ss
; 1
eps
; 1
ps
; and 1 short
eus
. Each pedal area of thoracic segments well-separated and with 2
pda
.
Abdomen.
Abdominal segments I–VII (
Fig. 81
) with 1
prs
; 3
pds
of different length; 2
ss
of different length; 1
eps
; 2
ps
of different length; 1
lsts
; and 2
eus
. Abdominal segment VIII (
Fig. 82
) with 2
pds
of different length; 2
ss
of different length; 1
eps
; 2
ps
of different length; 1
lsts
; and 2 moderately long
eus
. Abdominal segment IX (
Fig. 82
) with 2
ds
of different length; 1
ps
; and 1
sts
. Anal lobes on abdominal segment X (
Fig. 82
) with 2 very short, feebly visible setae.
Description of pupa.
COLORATION. Body whitish yellow.
MORPHOLOGY (
Figs. 83–85
). Body length 2.0–
2.7 mm
; widest part
1.2–1.5 mm
(see
Table. 1
). Body elongate. Rostrum long, approximately 4.5 times as long as wide, reaching mesocoxae. Pronotum 1.9 times as wide as long.
CHAETOTAXY (
Figs. 83–85
). Setae distinct, moderately long, unequal in length, light brown; on pronotum and head placed on conical protuberances. Head capsule including 1
vs
, 1
os
, and 1
pas
. Rostrum with 1
rs
located medially.
Vs
and
os
as long as setae on pronotum, distinctly longer than
pas
and
rs
. Pronotum with 2
as
, 2
ls
, 2
ds
, and 1
pls
;
ds
as long as other setae on pronotum. Dorsal parts of meso- and metathorax with 1 seta. Each apex of femora without seta. Setae on abdominal segments I–VIII placed posteromedially and posterolaterally; all abdominal setae located on small, conical protuberances. Pseudocerci short, slightly curved inside.
Biological observations.
Pupation was observed 15 days after the introduction of the larvae in the soil. The duration of the pupal stage was about 12 days. Adults began to emerge from the cells 7 days later.
Remarks.
Tychius schneideri
is monophagous on
Anthyllis vulneraria
L.
s. l.
and is widely distributed in Europe. The larva was described, although incompletely, by
Karasyov (1991)
on specimens collected at
Minsk
(
Bielorussia
).