Larval descriptions of three Dromica species with some bionomical remarks (Coleoptera, Cicindelidae)
Author
Schuele, Peter
Rosenstrasse 9, 71083, Herrenberg, Germany
sei.schuele@gmx.de
Author
Putchkov, Alexander
Institute of Zoology, National Academy of Sciences of Ukraine, vul. B. Khmelnytskogo, 15, Kyiv- 30, MSP, 01030, Ukraine
Author
Markina, Tetiana
H. S. Skovoroda Kharkiv National Pedagogical University 61002, Alchevskykh str., 29, Ukraine
text
ZooKeys
2021
2021-06-16
1044
511
525
http://dx.doi.org/10.3897/zookeys.1044.61993
journal article
http://dx.doi.org/10.3897/zookeys.1044.61993
1313-2970-1044-511
C708D008403642078306119AE2A8E14C
8279058FE9E4558EB6ECB337E8703416
Dromica (s. str.) alboclavata Dokhtouroff, 1883
Instar III.
Measurements
: FL 1.30; FW 2.25; PNL 1.48; PNW 2.58.
Head
. Dark brown above, sometimes almost black, with greenish copper metallic luster. Ventral side of head light brown medially, lateral portions brown. Mandibles dark brown (more darkened apically). Other appendages of head light brown except A3-4 darkened dark brown. Setae of
head's
capsule and A1 transparently white, on A2-4 dark brown. Setae of maxillae and labium light brown. Most setae thin and acuminate, only a few setae near ST1 slightly flattened and truncated apically. Lateral plates of clypeus short, almost rectangular. Tubercles between ST1 and ST2 small, but distinct. Lateral portions of head (below eyes) without distinct tubercles. Maximum width of head on level ST1. Antennae relatively large; A1 1.30 time wider than A2 and 2.0-2.6
x
wider than A3, A4. A1 slightly longer than A2 and almost 2
x
wider than A3 and A4. A1 slightly flattened dorsoventrally on anterior margin and with 6-7 setae (five of them on median part). A2 with five setae on apical part. Ratios of lengths A1:A2:A3:A4 = 1.0:0.9:0.5:0.6. Maxillary palpus distinctly longer than galea. LP2 not shorter than LP1. Seta on LP2 situated slightly before middle. Epicranial suture absent.
Thorax
. PN yellow brown on anterior portions, PNa slightly darkened. Setae transparently white (except 10-13 black setae on anterior margin and near PNa). Callous elevations and swellings of PNa not highly elevated but distinct. Maximum width of PN before middle (Fig.
3F
). Anterior margin of PN slightly concave in the middle. PNa widened, its apices almost rounded, directed forwards (Fig.
3F
). Ratio PNW/PNL - 1.75. Most setae flattened, some of them truncated apically, only a few setae on anterior margin and near PNa long and acuminate apically. PN1 with 10-12 setae, swellings of PNa with one seta (Fig.
3F
).
Abdomen
. Sclerotized areas of abdomen indistinct. T3 with 8-10 setae. HY consisting of one large posterior and one or two small anterior sclerites. AT5 almost fused with CTL5 and connected with CT5 on inner side (Fig.
4A
). CT5 with eight or nine stout setae on anterior half and with 6-8 thinner setae medially and on posterior half. MH with two stout setae displaced asymmetrically. Upper half of MH narrower and curved (Fig.
4A
). Apex of MH reaching the middle of AT5. MH basally almost 1.20
x
wider than long. (Fig.
4A
). IH with two almost symmetrical stout setae. Upper part of IH slightly curved. IH 1.3-1.4
x
shorter than MH. AT5 with more than ten thin setae, CTL5 with 5 long setae (Fig.
4A
). Posterior margin of EU9 with 8 long setae. PY with 8 setae dorsally (two of them shortened). Ventrally PY glabrous. Apex of PY with 16 dorsally stouter setae (Fig.
4D
).
Figure 4.
Morphological features of
Dromica alboclavata
larvae
A
pronotum, III instar (right half, above)
B
hump, III instar (right part, dorsal view)
C
hump, II instar (right part, dorsal view)
D
segment IX and pygopod of abdomen, III instar (dorsal view)
E
segment IX and pygopod of abdomen, II instar (left half, dorsal view)
F
segment IX and pygopod of abdomen, II instar (left half, ventral view).
Instar II.
Measurements
: FL - 0.93-0.95 (0.94); FW - 1.50-1.60 (1.53); PNL - 1.00-1.05 (1.02); PNW - 1.63-1.75 (1.68).
Head
. Dark brown with bright greenish metallic reflection. Appendages brown or light brown. Setae of head capsule white and transparently white. Setae of A2-4 and other appendages brown or light brown (in A1 sometimes white with brown hue). Nasale long, distinctly trapezoid. Adnasalia small. Lateral teeth relatively wide. Tubercles between ST1 and ST2 distinct. Most setae of head acute but some of them (near eyes) flattened and obtuse on top. A1 with three or four setae on anterior side. A2 with four or five setae on dorsal half. A3 with two, A4 with three long and several short setae. Maxillary palpus slightly longer than galea. LP1 with five or six spinelets (three median ones very short). LP2 with one seta slightly before middle. Epicranial suture distinct but short.
Thorax
. PN light brown without metallic luster. Posterior half of PN light brown. Anterior half and lateral margins of PN light yellow. Most setae of PN white except 10-12 dark brown setae on anterior margin. Tips of PNa with flattened and obtuse setae. Other setae acuminate. Anterior margin of PN slightly concave and longer than PNa. Maximum width of PN in the middle. Callous elevations and swellings of PNa indistinct. PN1 with eight or nine, swellings of PNa with one (rarely two) setae. Legs dorsally light brown, ventrally almost yellow.
Abdomen
. Sclerotized areas of abdomen indistinct. T3 with seven or eight light brown setae. HY consisting of one large posterior and one small anterior sclerite. Tergites of hump not connected. CT5 with seven or eight stout and 4-6 thin setae (Fig.
4B
). CTL5 with three to four long setae. MH and IH very widened in basal half but distinctly narrower and bent on apical half (Fig.
4B
). MH basally 1.66-1.68
x
wider than long. MH with 2 spines placed asymmetrically (one after another) (Fig.
4B
). IH 1.65-1.67
x
shorter than MH. IH basally 1.22-1.25
x
shorter than long. IH with two (rarely three) spines placed almost symmetrically (Fig.
4B
). EU9 with eight long setae posteriorly. PY with eight or nine setae dorsally (but apex glabrous) and usually glabrous ventrally. Apex of PY with 15-16 setae on dorsal and lateral areas (eight or nine of them dorsally stouter) (Fig.
4E, F
).
Instar I.
Measurements
: FL - 0.57-0.65 (0.60); FW - 0.90-1.04 (0.98); PNL - 0.57-0.65 (0.61); PNW - 0.90-1.07 (0.99).
Head
. Dark brown with greenish luster. Setae transparently white. Lateral teeth of clypeus shorter, lateral margin of adnasalia slightly curved. Setae on clypeus thin and acuminate, setae near eyes distinctly flattened and truncated. Epicranial suture short.
Thorax
. PN light brown or brown with slight metallic luster. PN 1.38
x
wider than long. Maximum width of PN shortly before apex of PNa. Anterior margin of PN almost straight in the middle (sometimes slightly concave) and longer than rounded apices of PNa (Fig.
3G
). PN1 with four setae. Setae of PN thin, acute and transparently white, except two long, flattened and brown setae on anterior margin. Callous elevations of PN1 and swellings of PNa distinct.
Abdomen
. Sclerotized areas of abdomen indistinct. Tergites of abdominal segment V divided (Fig.
4B
). Base of MH and IH very wide but narrow and distinctly curved in upper half. Their apex not reaching posterior margin of AT5. MH with one, IH with two stout lateral setae. Length of central spine of IH shorter (or equal) than lateral setae. CT5 with 3-5, CTL5 with one and AT5 with six setae (Fig.
4B
). EU9 and PY slightly darkened dorsally. EU9 with six setae posteriorly. Apex of PY with ten setae (six of them relatively stouter).
Distribution and ecology.
Dromica alboclavata
is a South African species which range is restricted to the Northern parts of the country (
Cassola 2002
). It lives in dry savanna areas on sandy or loamy-sandy ground. The larvae were hatched ex ovo.
Short diagnostic remarks
The larvae of
Dromica
instars II and III can be distinguished from those of other genera of the
Prothymina
complex by the following characters: MH comparatively shortened, basally distinctly widened with curved apices; two short stout spines of MH are situated one after the other; sclerotized areas of abdomen are indistinct or slightly distinct; CT5 with less than 17 spine-like setae (usually 8-13); PNa small and short; PN1 with 9-13 setae; luster on PN indistinct or moderately distinct. All larvae of
Dromica
, described here and in earlier papers (Arndt, 1998;
Putchkov et al. 2018
; Putchkov, 2020) show some specific morphological features both at subgeneric and specific level. It is possible to separate them by chaetotaxy pattern of MH, IH, PN, coloration of head or pronotum and morphometrically data (sizes, correlation of PNW/PNL, MH/IH).
Dromica tuberculata
(instars II and III) differs from other
Dromica
species by ventrolateral portions of head (underneath the eyes) with a flattened area and a group of 8-10 basally bulbous setae; the anterior margin of PN is almost even, without an impression in front of the small PNa; CT5 usually bears 7-9 bristles; its apices are moderately curved (
Putchkov et al. 2018
). The antennomere I of
Dromica alboclavata
and
D. clathrata
larvae (instars II and III) is distinctly flattened dorsoventrally. It is at least 1.3-1.4
x
wider than antennomere 2; the antennae are more massive than in the other known species; apices of CT5 are distinctly curved and not reaching AT5.
D. kolbei
can be distinguished from these species by relatively thin antennae (Fig.
1C
), antennomere I at most 1.2
x
wider than antennomere II; CT5 with 12-16 stout setae (Fig.
2C, D
, Table
2
).
Larvae of instars I of
Dromica
also show some specific morphological features. CT5 of the known larvae of instar I of the
subgenus Pseudodromica
is glabrous (
Putchkov et al. 2018
), while those of species of the
subgenus Dromica
(s. str.) have a row of (3-9) stout setae on anterior margin (Fig.
3A, E, G
). First instar of
D. alboclavata
can be distinguished from those of
D. kolbei
and
D. helleri
by distinctly shorter hooks, 3-5 setae on CT5 (Fig.
3G
) and smaller size of PN (Table
1
). First instars of
D. helleri
can be distinguished from
D. kolbei
by different number of setae on CT5 (Fig.
3A, E
), less by size and form of PN (Figs
2B
,
3D
). In addition, in larvae of different instars there are some differences in the sizes of head and pronotum (Table
1
).
Nevertheless, some other characters (form and chaetotaxy of the head, pronotum, hooks, pygopod) are often similar (or overlapping) in all so far known larvae of
Dromica
species (Table
2
). Nevertheless the material of the larvae of the genus is very scarce and its comparative analysis presently is still difficult. Currently it is problematically to characterize the taxonomic and phylogenetic significance of the morphological characters of
Dromica
larvae now. For a reliable key the number of described species is still too sparse.
Table 1.
Measurements of head and pronotum with growth ratio of pronotal width/length of
Dromica
larvae.
Species |
Instars |
Measurements in mm, mean in parentheses |
FL |
FW |
PNL |
PNW |
PNW/ PNL |
D. clathrata
|
I |
1.25-1.38 (1.29) |
2.05-2.23 (2.14) |
1.18-1.23 (1.20) |
2.08-2.13 (2.12) |
1.73-1.76 |
II |
1.70 |
3.20 |
1.90 |
3.01 |
1.58 |
III |
2.50-2.70 (2.57) |
4.00-4.40 (4.20) |
2.70-2.90 (2.83) |
4.40-4.75 (4.55) |
1.62-1.64 |
D. tuberculata
|
I |
1.05 |
1.80 |
1.05 |
1.85 |
1.76 |
II |
1.40-1.50 |
2.43-2.63 |
1.55-1.73 |
2.65-2.85 |
1. 65-1.70 |
D. kolbei
|
I |
0.8 |
1.35 |
0.95 |
1.50 |
1.58 |
II |
1.17-1.19 |
2.00-2.20 |
1.35-1.40 |
2.05-2.08 |
1,48-1,52 |
III |
1.70-1.90 (1.80) |
2.80-3.15 (3.01) |
2.05-2.25 (2.14) |
3.40-3.75 (3.59) |
1.66-1.68 |
D. alboclavata
|
I |
0.57-0.65 (0.60) |
0.90-1.04 (0.98) |
0.57-0.65 (0.61) |
0.90-1.07 (0.99) |
1.38 |
II |
0.93-0.95 (0.94) |
1.50-1.60 (1.53) |
1.00-1.05 (1.02) |
1.63-1.75 (1.68) |
1.64-1.67 |
III |
1.30 |
2.25 |
1.48 |
2.58 |
1.75 |
D. helleri
|
I |
0.85 |
1.48 |
0.95 |
1.58 |
1.66 |
Table 2.
Chaetotaxy of main segments and sclerites of
Dromica
larvae instar III (abbreviations in Materials and methods).
Species |
PN1 |
PNa |
T3 |
CT5 |
CTL5 |
Tip of PY |
D. clathrata
|
9-10 |
2 |
8-10 |
8-10 |
6-8 |
16-17 |
D. kolbei
|
11-13 |
2 |
8-10 |
12-16 |
7-9 |
16-17 |
D. alboclavata
|
10-12 |
1 |
8-10 |
7-9 |
5 |
16 |