Corresponding author: Rafał Gosik (
Academic editor: Harald Letsch
The larvae of
The short-nosed weevil genus
In this paper the L1 larvae of
The older larvae on which these descriptions are based on, were collected in the field or – in a few cases – bred in flower-pots. L1 larvae were obtained from adults kept in the laboratory. Larvae of the polyphagous species
Measurements of characteristic body parts of the
|
|
|||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
BW. | BW. | |||||||||||||||
min. | max. | min. | max. | min. | max. | min. | max. | min. | max. | min. | max. | min. | max. | min. | max. | |
|
0.19 | 0.20 | 0.16 | 0.17 | 1.00 | 1.10 | 0.23 | 0.28 | 0.80 | 0.90 | 0.70 | 0.75 | 5.2 | 6.0 | 1.5 | 1.8 |
|
0.21 | 0.23 | 0.19 | 0.20 | 0.87 | 1.03 | 0.22 | 0.26 | 0.90 | 1.00 | 0.80 | 0.90 | 5.0 | 6.5 | 1.5 | 2.0 |
|
0.23 | 0.24 | 0.22 | 0.23 | 0.95 | 1.11 | 0.28 | 0.31 | 0.57 | 0.65 | 0.75 | 0.80 | 3.50 | 5.0 | 1.1 | 1.8 |
Drawings were made using a drawing tube installed on a stereomicroscope and processed by computer programmes (Corel Photo-Paint X7, Corel Draw X7). Photos were made using an Olympus BX63 microscope and processed by Olympus
L1 larvae: 45 ex., 28.04.2012. Adults collected in Brelingen, north of Hannover (Germany), border of an oak forest, 80 m, 16.04.2012.
Mature larvae: 8 ex., 12.03.2016, Niedersachsen, Deister Mountains, Bredenbeck-Steinkrug, southwest of Hannover (Germany), 165 m (Fig.
L1 larvae: 80 ex., 10.06.2012. Adults collected in Brelingen from a row of old oak trees and from broom (
Mature larvae (9 ex.): 1 ex., 04.10.2013, climate chamber of the Julius-Kühn-Institute in Braunschweig, breeding in flower-pots with
L1 larvae: 6 exx., 23.05.2012. Adults collected in Berkhof, north of Hannover, heathland and light pine forest with
Old larvae (2 exx.): 1 ex., 25.07.2012, collected from under roots of
Rather elongate, white to yellowish, abdominal segment VIII dark yellow. Setae long to very short. Each side of prothorax (Fig.
Yellow, oval (Fig.
Rather stout, yellowish, abdominal segment VIII dark brown. Setae medium-length to very short. Each side of prothorax (Fig.
Dark brown, almost circular (Fig.
Elongated, yellowish, abdominal segment VIII dark yellow. Setae medium long to very short. Each side of prothorax (Fig.
Dark yellow to dark brown, slightly flattened bilaterally (Fig.
Sampling sites, host plants, larvae, teneral and mature adults.
The larva of
1 | Abdominal segment VIII with 4 |
|
– | Abdominal segment VIII with 3 |
|
1 | Stemmata absent; head capsule slightly flattened bilaterally; labral rods elongate |
|
– | Stemmata (two pairs) present; head capsule rounded; labral rods short |
|
1 | Pleural lobes of |
|
– | Pleural lobes of |
|
The data about the development of
Larvae then develop in soil and feed mainly on fine roots until the third or last (fourth) instar and overwinter. In the following year the larvae complete their development and pupate, mainly in August. Adults of the new generation emerge from September to November and single specimens also in spring of the succeeding year. Adults climb for maturation feeding in tree crowns in spring, late summer and early autumn. They also feed in the herb layer and in leaf litter.
According to
The breeding of
The larval development of any other
Some basic information regarding the morphology of the larva of
The presence of four ventral malar setae in larvae of the genus
Further information on the morphology of preimaginal stages of the genus
The differences in the number of setae and in the morphology of abdominal segments which are observed in the species treated in this paper (
Because of the morphology of the eighth abdominal segment, especially the sclerotization and the dark colour, larvae of the genus
Even if we do not know anything about the function of this conspicuous abdominal structure, the possibility that this is an adaptation to the environment has to be taken into account. It is found in a few genera of
We thank Andreas Marten from the National Park Harz for his support in collecting larvae inside the protected area and Dr. Martin Hommes (Braunschweig) for the chance to use a climate chamber in the rooms of the Julius-Kühn-Institute in Braunschweig. This study was in part supported by the Federal Institute for Agriculture and Nutrition (BLE, Bonn).
We would like to express our sincere thanks to Dr. Michael Morris (Natural History Museum, London) for his linguistic correction of the manuscript.