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.)
parallelus
(Panzer, 1794)
Caldara 1990: 85
.
Material examined
.
2 larvae
from pods of
Cytisus scoparius
(L.) Link., collected
14.viii.1989
at
Navacerrada
,
Sierra
de Guadarrama
,
Madrid
(
Spain
),
1500 m
, leg.
A.J.
Velázquez de Castro
, determined by association with adults collected on the same plant
.
Differential diagnosis.
See
Table.2
.
Description of mature larva.
COLORATION. Head brown to dark yellow. All thoracic and abdominal segments light yellow.
HEAD CAPSULE AND MOUTH PARTS. Head width:
0.45–0.51 mm
(see
Table. 1
). Endocarinal line present, reaching middle of frons.
Des
1
located almost in central parts of epicranium;
des
2
absent;
des
3
located along frontal suture;
des
4
absent;
des
5
located laterally (
Fig. 1
).
Fs
1
and
fs
2
absent;
fs
3
very short, located medially;
fs
4
located anteromedially (along epistoma);
fs
5
located anterolaterally (along epistoma), 3 to 4 times longer than
fs
3
(
Fig. 1
). Both
les
almost as long as
des
3
;
ves
very short. Postepicranial area with 1 minute
pes
. Antennal segment membranous, bearing conical sensorium and 2 very short, conical, sensilla (
Fig. 4
).
Labrum (
Fig. 5
) approximately 2.5 times as wide as long;
lms
1
slightly longer than
lms
3
,
lms
2
distinctly longer than
lms
1
; anterior margin slightly sinuate. Clypeus (
Fig. 5
) 3.5 times as wide as long; with 2 pairs of short
cls
of same length, located posterolaterally; anterior margin slightly rounded inside. Epipharynx (
Fig. 6
) with 3 pairs of
als
, different in length; with 2 pairs of short
ams
,
ams
2
distinctly shorter than
ams
1
; with 3 relatively short and finger-like
mes
; labral rods short, kidney-shaped, strongly converging posteriorly. Mandibles (
Fig. 3
) with 2 short
mds
, different in length. Maxilla (
Fig. 2
): stipes with 1
stps
, and with 2
pfs
of equal length; mala with 5 slightly curved
dms
, different in length; with 4
vms
, moderately long and almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:1.4; basal palpomera with 1 short
mxps
; distal palpomera with group of 3–4 conical, cuticular apical processes. Prementum (
Fig. 2
) almost rounded, with 1
prms
; margin of ligula slightly curved inside; ligula with 2
lig
; premental sclerite distinct. Postmentum (
Fig. 2
) with 3 pairs of
pms
different in length.
THORAX AND ABDOMEN. Body length
3.9–4.9 mm
(see
Table. 1
), elongate. Abdominal segments I–VI almost equal in length (
Fig. 7
). Spiracles on abdomen in anteromedian parts of segments (abdominal segments I–VIII).
Chaetotaxy of body rather reduced. Setae moderately short or very short, and light yellow.
Thorax.
Prothorax (
Fig. 8
) with 8
prn
, 7 macro- and 1 microsetae; 2 moderately long
ps
of same length; 1
eus
. Meso- and metathorax (
Fig. 8
) with 1
prs
; 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 5
pda
, different in length (long, moderately long, short).
Abdomen.
Abdominal segments I–VII (
Fig. 9
) with 1
prs
; 3
pds
of different length; 1
ss
; 2
eps
of different length; 1
ps
; and 2 short
eus
. Abdominal segment VIII (
Fig. 10
) with 1
prs
; 3
pds
; 1
ss
; 1
ps
; and 2 short
eus
. Abdominal segment IX (
Fig. 10
) with 1
ds
; and 1
sts
. Anal lobes on abdominal segment X (
Fig. 10
) without setae.
Biological observations.
Larvae emerged in laboratory from pods collected a few days before (A.J. Velázquez de Castro, pers. comm.). No other information is available.
Remarks.
Tychius parallelus
lives on different species of
Cytisus
in central and southern Europe and in
Algeria
. Biological information on adults are reported by
Caldara & Velázquez de Castro (1991)
.