Notes on the first instar larvae of Ctenophora and Nephrotoma (Diptera, Tipulidae)
Author
Podeniene, Virginija
Author
Naseviciene, Nijole
Author
Podenas, Sigitas
text
Zootaxa
2014
3764
2
152
168
journal article
46493
10.11646/zootaxa.3764.2.3
7f3952c3-0f54-40f8-bb3e-a17fb9cb6a49
1175-5326
228666
82E13B7A-C007-4345-B4CF-D4921194DBA2
Nephrotoma pratensis
Linnaeus, 1758
(
Figs. 41–48
)
First instar larvae.
Length
1.75–1.85 mm
; width
0.32–0.33 mm
. Body covered with pale pubescence. Cuticle is transparent.
Head capsule.
Length
0.38–0.39 mm
; width
0.22–0.23 mm
. In general is very similar to that of
N. flavescens
. Differences were noticed in shape of hypostomium, mandible, antenna and arrangement of sensory structures on labrum. Hypostomium bears five blunt teeth. There is a prominent incision on posterior part of hypostomium (
Fig. 41
). Mandible in general is very similar to that of
N. flavescens
, but shape of teeth is slightly different (
Fig. 42
). Basal segment of antenna is cone-shaped, but membranous apical part is much smaller than in
N. flavescens
(
Fig. 43
). There are several small peg-like sensillae on the apex of basal segment. Labrum in general is very similar to that of
N. crocata
(
Fig. 44
).
FIGURES 33–40.
Nephrotoma crocata
, first instar larva: 33. Hypostomium. 34. Mandible. 35. Right antenna. 36. General view of labrum. 37. Dorsal abdominal setae (segments II–VII). 38. Ventral abdominal setae (segments II–VII). 39. Lateral abdominal setae (segments II–VII). 40. Spiracular field.
Thorax.
In general is very similar to that of
N. flavescens
.
Abdomen.
In general is very similar to that of
N. flavescens
. Setae D1 and D6 are the shortest. They both are of equal length. D2 is the longest among all setae. It is nearly seven times as long as D1 (
Fig. 45
). D3 is twice as short as D2; D2 and D3 are very close to each other; D3 and D5 are very similar in length and are four times as long as D1; D2 and D3 are very close to each other. Seta
V2
is very long;
V1
is almost three times as short as
V2
(
Fig. 46
). Seta
V4
is very short, half the length of
V3
and less than 1/
6x
the length of
V2.
Setae
V1
,
V2 and V3
,
V4
make pairs and are very close to each other. Seta L1 is as long as L4; both are three times as long as L2, which is the shortest lateral seta. Seta L3 is half the length of L1 (
Fig. 47
).
Spiracular disc.
Spiracular field is surrounded by four almost equal round-tipped lobes, which are flat and elongate (
Fig. 48
). Lobes are almost as long as wide at the base. They have no sclerites. Lateral lobe has three long stout apical bristles, which are about six times as short as the whole body. On dorsal part it has two tufts, each consisting of two short bristles. Above the spiracles there are three tufts, each composed of two bristles of different length. The bristles of outermost tuft are the longest. Ventral lobe has apical tuft of three long bristles; tuft of two approximately equal in length bristles are located on inner margin; tuft of two short bristles present on outer margin and a long bristle, almost as long as lobe itself, is next to them. Tuft of three long bristles is at the base of ventral lobe. Spiracles are large, oval and close to each other. Distance between them is smaller than diameter of a spiracle itself.
FIGURES 41–48.
Nephrotoma pratensis
, first instar larva: 41. Hypostomium. 42. Mandible. 43. Right antenna. 44. General view of labrum. 45. Dorsal abdominal setae (segments II–VII). 46. Ventral abdominal setae (segments II–VII). 47. Lateral abdominal setae (segments II–VII). 48. Spiracular field.
Anal field.
Anus is surrounded by four long, cone-shaped, white and fleshy anal papillae. There are a few long setae on anal segment.
Specimens examined.
229 egg-larvae from female captured in Vilnius,
N54.68263
,
E25.24766
,
15 V 2011
, eggs were laid on
17 V 2011
, egg-larvae hatched on
31 V 2011
; 182 egg-larvae from female captured in Vilnius,
N54.68419
,
E25.29904
,
19 V 2011
, eggs were laid on
21 V 2011
, egg-larvae hatched on 0
2 VI 2011
; 45 egg-larvae from female captured in Vilnius,
N54.68662
,
E25.30054
,
15 V 2011
, eggs were laid on
28 V 2011
, egg-larvae hatched on 0
8 VI 2011
; 317 egg-larvae from female captured in Naujoji Vilnia environs, Vilnius district,
N54.70365
,
E25.40598
,
22 V 2011
, eggs were laid on
26 V 2011
, egg-larvae hatched on
17 VI 2011
; 10 egg-larvae from female captured in Naujoji Vilnia environs, Vilnius district,
N54.70365
,
E25.40598
,
11 VI 2011
, eggs were laid on
14 VI 2011
, egg-larvae hatched on 0
5 VII 2011
; 132 egg-larvae from female captured in Naujoji Vilnia environs, Vilnius district,
N54.70365
,
E25.40598
,
19 V 2012
, eggs were laid on
20 V 2012
, egg-larvae hatched on
27 V 2012
.