Corresponding author: Jiří Skuhrovec (
Academic editor: M. Alonso-Zarazaga
Mature larva and pupa of
Skuhrovec J, Volovnik S, Gosik R (2017) Description of the immature stages of
The weevil genus
The species
Some species from the genus
The material used to describe the immature stages was collected and field observations were conducted in Ukraine in the following localities:
1) The eastern shore of Molochnyi Estuary between the two villages of Altagir (= Bogatyr) and Radyvonivka (
2) Man-made forest near the Kamyana Mohyla Reserve (
3) NE Cyrilivska Spit located between the Sea of Azov and Molochnyi Estuary (
In the above-mentioned localities, life cycle, including feeding of adults, oviposition, and early development of larvae were observed directly during the vegetation growing seasons of
The compound flower heads of globe thistles consist of simple capitula, each of which has only one floret. These primary capitula are aggregated in globose secondary capitula (
The second author collected all larvae and pupae of
Laboratory observations were conducted in Melitopol, Ukraine (
Geographical distribution and phenology were studied from several entomological collections, specifically: Schmalhausen Institute of Zoology of National Academy of Sciences of Ukraine (Kyiv), TG Shevchenko Kyiv National University Zoological Museum, Zoological Institute of Russian Academy of Sciences (St. Petersburg), VN Karazin Kharkiv National University Museum of Natural History, and Igor Maltzevs’ private collection (Odessa). In total, more than 130 pinned specimens were studied.
Part of the larval and pupal material was preserved in Pampel fixation liquid (see
The observations and measurements were conducted using a light microscope with calibrated oculars (Olympus BX 40, SZ 11, and Nikon Eclipse 80i). The following characteristics were measured for each larva: head width, length of the body (larvae fixed in a C-shape were measured in the middle of the segments in lateral view), and width of the body in the widest place (i.e., meso- and metathorax). For the pupae, the length and the width at the widest place were measured.
Drawings were created with a drawing tube on a light microscope and edited by the programs Adobe Photoshop 10, Corel Photo-Paint X7, and GIMP 2.
We used the terms and abbreviations for the setae of the mature larva and pupa found in
The counts of some of the setae on the epipharynx (particularly
To date, larvae of 16
According to
The immature stages of
Moreover, detailed descriptions of immature stages of
Larval setal index of species from the
Part of body | a | b | c | d | e | f | g | h | |
---|---|---|---|---|---|---|---|---|---|
|
Pronotal | ~24 | ~26 | 12 | 26–29 | 12 | Σ | 32 | ~30–35 |
Pleural | 18 | 2 | 2 | 11 | 2 | 5 | 2 | 20 | |
Eusternal | 5 | ? | 1 | 10 | 2 | 5 | 3 | 12 | |
Pedal area | 12 | ? | 7 | 11 | 8 | 12 | 7 | 10 | |
|
Prodorsal | 3–4 | 5–9 | 2 | 3 | 1 | 9 | 4 | 3 |
Postdorsal | 14 | 18 | 5 | 14 | 4 | 0 | 11–12 | 13 | |
Alar area | 4 | 1 | 3 | 7 | 1 | 11 | 3–4 | 6–7 | |
Spiracular area | 4–5 | ? | ? | ? | ? | ? | 6 | ||
Epipleural | 4–5 | 5 | 1 | 8–9 | 4? | 1–2 | 1 | 6–9 | |
Pleural | 12 | 2 | 2 | 8 | 2 | 5 | 2 | 14 | |
Eusternal | 5 | 6 | 1 | 4–5 | 2 | 5 | 2–3 | 13 | |
Pedal area | 12 | 7 | 7 | 11–12 | 8 | 12 | 8 | 10 | |
|
Prodorsal I-VII | 3 | 6 | 2 | 3 | 1 | 9 | 5 | 2 |
VIII | ? | ? | 1 | ? | ? | 3 | ? | 2 | |
Postdorsal I-VII | 19 | 24 | 8 | 17 | 8 | ~40 | 17 | 13 | |
VIII | ? | ? | 5 | ? | ? | 8 | ? | 10 | |
Spiracular I-VII | 3 | 3 | 2 | 6 | 1 | 9 | 3 | 7 | |
VIII | ? | ? | ? | ? | ? | 0 | ? | 2 | |
Epipleural I-VII | 8 | 3 | 2 | 12 | 2 | 6 | 3 | 10–14 | |
VIII | ? | ? | ? | ? | ? | 5 | ? | 13 | |
Pleural I-VII | 7 | 1 | 2 | 6 | 2 | 3 | 1 | 9 | |
VIII | ? | ? | ? | ? | ? | 3 | ? | 9 | |
Laterosternal I-VII | 1 | 1 | ? | 1 | 0 | 2 | 0 | 2 | |
VIII | ? | ? | ? | ? | 0 | 2 | ? | 2 | |
Eusternal I-VII | 4 |
|
|
2 | 0 | 3 | 2 | 2 | |
VIII | ? | ? | ? | ? | 0 | 1 | ? | 2 | |
|
Dorsal | 5 | ? | 6 | 12 | 5 | 6 | 7 | 7 |
Lateral | 9 | ? | 2 | 9 | 2 | 1 | 2 | 13 | |
Sternal | 11 | ? | 2 | 3 | 2 | 1 | 1 | 4 | |
|
Anal area |
|
|
|
|
|
|
|
|
|
Dorsal | 5 | 5 | 5 | 4 | 5 | 5 | 5 | 5 |
Posterior |
|
|
|
|
|
|
|
|
|
Lateral | 3 | 3 | 2 | 2 | 2 | 1 | 3 | 2 | |
Ventral | ? | ? | ? | ? | ? | 1 | ? | 2 | |
Frontal | 6 | 5 | 2 | 7 | 5 | 5 | 4 | 6 | |
Clypeal | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | |
Labral | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | |
Mandibular | 2 | 2 | 2 | 0 | 2 | 2 | 0 | 2 | |
|
Anterolateral | 2 | 3 | 4 | 4 | 4 | 5 | 3 | 4 |
Anteromedial | ? | 2 | 2 | 3 | 4 | 2 | 2 | 3 | |
Medial | ? | 0 | 2 |
|
0 |
|
2 | 2 | |
|
Lacinia (dorsal) | 7 | 9 | 8 | 9 | 8 | 10 | 8 | 9 |
Lacinia (ventral) | 3 | 5 | 6 | 3 | 4 | 4 | 4 | 5 | |
Palpal |
|
|
|
|
|
|
|
|
|
Stipital | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 2 | |
Palpiferal | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | |
|
Postlabial | 5 | ? | 3 | 5 | 3 | 3 | 3 | 4 |
Prelabial | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
Ligular |
|
|
|
|
|
|
|
|
Pupal setal index of selected
Part of body | a | b | c | d | e | f | g | h | |
---|---|---|---|---|---|---|---|---|---|
|
vertical s. | - | 1 | 1 | 1 | 2 | 1 | - | 1 |
super orbital s. | 1 | 2 | 2 | 3 | 2 | 2 | 1 | 2 | |
orbital s. | 2 | 1 | 1 | 1 | 1 | 1 | 2 | 1 | |
post antennal s. | 5 | 4 | 4 | 4 | 4 | 4 | 3 | 3 | |
|
rostral s. | 3 | 2 | 1 | 8 | 5 | 4 | 1 | 1 |
epistomal s. | 2 | 1 | 0 | 1 | 1 | 1 | 1 | 2 | |
|
superapical s. | 1 | 1 | Σ | 1 | 1 | 1 | 1 | - |
apical s. | 0 | 0 | Σ | 0 | 0 | 0 | 2 | 2 | |
lateral s. | ~14 | 5 | Σ | 10 | 5 | 6 | 5 | 5 | |
superlateral s. | 5 | 1 | Σ | 4 | 1 | 2 | - | 2 | |
discal s. | 2 | 2 | Σ | 3 | 2 | 2 | 1 | 3 | |
posterolateral s. | 19 | 4 | Σ | 21 | 4 | 4 | 3 | 6 | |
|
6 | 12 | 6 | Σ | 16 | 6 | 6 | ~14 | |
|
6 | 12 | 6 | Σ | 16 | 6 | 6 | ~14 | |
|
dorsal | ~20 | 9 | Σ | ~40 | 9 | 9 | 8 | ~25 |
ventral | 3 | 3 | 3 | 3 | 3 | 3 | 4 | 3 | |
lateral | ~20 | 4 | 7 | ~20 | 4 | 4 | 2 | 3 | |
|
dorsal | 8 | 9 | Σ | ~10 | 8 | 8 | 8 | ~10 |
ventral | 3 | 3 | Σ | 3 | 3 | 3 | 4 | 4 | |
lateral | ~10 | 4 | 7 | ~20 | 4 | 4 | 2 | 3 | |
|
ventral | ? | 2 | 3 | 5 | 4 | 4 | ? | ? |
dorsal | ? | 1 | 2 | Σ | 1 | 3 | ? | ? | |
|
3 | 3 | 3 | 6 | 3 | 3 | 3 | 3(4) |
The following key is based on the larvae of
1 | Body with high count of setae; pronotum with more than 25 setae, postdorsum on meso- and metathorax and also on abdominal segments I–VII with more than 12 setae |
|
– | Body with usual count of setae; pronotum with less than 15 setae, postdorsum on meso- and metathorax and also on abdominal segments I–VII with fewer than 10(12) setae |
|
2 | Frons with 6 or 7 |
|
– | Frons with 4 or 5 |
|
3 | Postepicranial setae |
|
– | Postepicranial seta |
|
4 | Postlabium with 5 setae. Meso- and metathorax with 4 |
|
– | Postlabium with 4 setae. Meso- and metathorax with 6–7 |
|
5 | Frons with 5 setae. Endocarina either very thin and short (less than 1/3 of the length of frons) or absent. Prodorsum on metathorax with more than 5 |
|
– | Frons with 4 setae. Endocarina distinct, length of approximately 1/3 of the length of frons. Prodorsum on metathorax with 4 |
|
6 | Endocarina very thin, length of less than 1/3 of the length of frons. Epipharynx with 3 |
|
– | Endocarina absent. Epipharynx with 5 |
|
7 | Abdominal segments I–VII with more than 1 |
|
– | Abdominal segments I–VII without |
|
8 | Frons with 5 |
|
– | Frons with 2 |
|
9 | Meso- and metathorax with 5 |
|
– | Meso- and metathorax with 4 |
|
10 | Head with wide, bright stripes on sides. Abdominal segments I–VII with 1 |
|
– | Head with barely noticeable bright stripes on sides. Abdominal segments I–VII with 2 |
|
11 | Abdominal segments I–VII with 2 |
|
– | Abdominal segments I–VII with 1 |
|
12 | Stipes with 1 long |
|
– | Stipes with 2 long |
The following key is based on the pupa of
1 | Pronotum with 25 or even more setae. |
|
– | Pronotum with fewer than 20 setae. |
|
2 | Setae on pronotum form a regular pattern, which consists of lines and groups of setae (counting of setae possible) |
|
– | Pronotum densely covered by very long setae (counting of setae impossible) |
|
3 | Cuticle around setae not more pigmented than rest of pronotum. Rostrum with 3 or 4 |
|
– | Cuticle around setae dark-pigmented, visible spots formed. Rostrum with 3 |
|
4 | Head with 1 |
|
– | Head with 3 |
|
5 | Body rather elongated. Urogomphi distinct |
|
– | Body rather stout. Urogomphi very short, almost not visible |
|
6 | Body length over 10 mm. |
|
– | Body length under 8 mm. |
|
7 | Head with 2 |
|
– | Head with 1 |
Habitat, life cycle, and immature stages of
Female
Later, after hatching of larva, the oviposition site became a visible, brownish tiny spot (Fig.
After emergence, adults remained in the dry inflorescence for 5–7 days until fully sclerotised (Fig.
Hatching, pupal cells, and adults of
Abundance of
Count of larvae in one flower head | 0 | 1 | 2 | 3 | 4 | 5 |
Count of the inflorescences with specific count of larvae | 13 | 58 | 1 | 4 | – | 1 |
The inner surface of the wall was denser than that of the external item and was bright red-brown with yellowish spots and veins, glossy, and 0.8–1.0 mm thick. The inner surface was also smooth and appeared varnished and polished, similar to inner surface of the wall of the usual pupa chamber of
The absence of preimaginal development outside of flower heads is a characteristic of not only
Two important moments in the life cycle of
Pupal chamber outside inflorescence and habitat in 2006.
We are sincerely grateful to Dr VP Kolomiychuk (AV Fomin Botanical Garden, Taras Shevchenko National University of Kyiv) for identification of plant species and to Dr AG Radchenko (Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, Kyiv) for ant identifications. We thank RV Sklyarov (Chief State Sanitary Physician of Melitopol) for providing sufficient support and Anna Pitishkina for technical assistance. The author (JS) of the study was supported by a grant from the Czech Ministry of Agriculture (Mze ČR) RO0416. The manuscript was edited for English language by American Journal Experts.