Weevil News
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No. 24 |
3 pp. |
10th
January 2005 |
ISSN 1615-3472
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Gültekin, L. (2005): New ecological niche for weevils of the genus Lixus Fabricius and biology of Lixus obesus Petri (Coleoptera: Curculionidae, Lixinae) - Weevil News: http://www.curci.de/Inhalt.html, No. 24: 3 pp., CURCULIO-Institute: Mönchengladbach. (ISSN 1615-3472). |
New ecological niche for weevils of the genus Lixus Fabricius and biology of
Lixus obesus Petri
(Coleoptera: Curculionidae, Lixinae)
by
Levent Gültekin
Abstract
Lixus obesus Petri completes his
generation in seed capsules of Prangos
uloptera DC., a new ecological niche
for the genus Lixus Fabricius, that is
known to be stem-boring. Females open holes in
young seed capsules and lay single eggs or in groups of 3-4 eggs. Larvae are
feeding in seed capsules and pupate afterwards at the same place. The new
generation of adults migrates after emerging by flight to hibernation sites.
Thus, L. obesus produces one
generation per year in northeastern Anatolia.
Six parasitoid species, Bracon
urinator (F.), Exeristes roborator F., Scambus brevicornis
Gravenhorst, Pteromalus sp. aff. vibulenus Wlk., Pimpline
sp., and Mesopolobus sp., were reared from larval and pupal stages of
L. obesus.
Key Words
Lixus obesus
Petri, biology, host plant, new ecological niche for
Lixus
F., Curculionidae, Lixinae.
Özet
Lixus Fabricius cinsi için yeni ekolojik niş, ilk kez bu
araştırmada belirlenmiş ve Lixus obesus
Petri neslini, Prangos uloptera DC.
bitkisinin tohum kapsülü içerisinde tamamlamıştır. Dişiler, genç tohum kapsülü
üzerinde çukurcuk açarak yumurtalarını tek tek veya 3-4 tanesi yan yana olacak
şekilde dizmektedir. Larvalar kapsül içerisinde tohumla beslenmekte ve aynı
yerde pupa olmaktadır. Yeni nesil erginler, buradan çıkıp kışlamak için uçarak
göç etmektedirler. Böylece, L. obesus
Kuzeydoğu Anadolu Bölgesi’nde bir nesil vermektedir.
L. obesus’un larva ve pupa
dönemlerinden altı adet parazitoid; Bracon urinator (F.), Exeristes
roborator F., Scambus brevicornis Gravenhorst, Pteromalus sp.
aff. vibulenus Wlk., Pimpline sp., ve Mesopolobus sp. elde
edilmiştir.
Introduction
The genus
Lixus Fabricius 1802 has a nearly
worldwide distribution and comprises over 500 species, in the Palaearctic region
over 150 species (Csiki 1934; Ter-Minassian 1967) and is classified into 18
subgenera (Alonso-Zarazaga and Lyal 1999). Korotyaev and Gültekin (2003) argued
that the host range includes several families of higher plants, but many, if not
most, of the accepted subgenera are not known to be associated with a single
plant family. The majority of the comparatively well-known species develops or
at least feeds on species of several genera of a single plant family. With some
plant families, e.g. the Chenopodiaceae, Brassicaceae, and Apiaceae, species of
more than one subgenus of Lixus are associated, and it is not always clear if this reflects a
multiple transition of the genus to plants of these families or the broad
diversification of the phylogenetic lineages associated with the respective
plants families. Only Palaearctic species of
Lixus are known to develop on Brassicaceae; the majority belongs to
the subgenus Compsolixus Reitter,
1916, in which 17 species have been placed by Csiki (1934), although the type
species of this subgenus, L. junci
Boheman, 1835, develops on Chenopodiaceae.
Csiki (1934) placed five species
in the subgenus Callistolixus Reitter, 1916 and then Ter-Minassian (1967) combinated
Lixus obesus Petri, 1904,
Lixus furcatus Olivier, 1807 and
Lixus tschemkenticus Faust, 1883 in
this subgenus. L. obesus Petri is
closely related to Lixus hypocrita
Chevrolat, 1866 who should be transferred in this subgenus. In addition, it
might be very interesting to investigate the biology of
L. hypocrita Chevrolat which is
distributed in Spain for comparing with L.
obesus.
In spite of species-richness of the genus
Lixus, for most of them biology,
ecology, host plant and behavior are poorly known or unknown. In the present
study, host plant, biology and parasitoids of
Lixus obesus Petri, 1904 are
investigated.
Material and Methods
This study was carried
out in NE Anatolia in 2003. Biological observations were performed mainly in
Aras Valley, 14 km E of Karakurt, Kars Province at an altitude of 1400 m.
Observations were made in the field directly, some seed capsules were harvested,
dissected and reared to adult stage in the laboratory; for rearing parasitoids,
seed capsules were collected and cultured. To determine hibernation site
preferences, ten adults of the new generation were released in the field at
daytime, and their behaviour was observed.
Results
Biological notes. Adults [Fig. W24.1]
of
Lixus obesus Petri were seen on its host plant
Prangos uloptera DC.
(Apiaceae) on June 10th, 2002 and June 12th, 2003. Weevils
fed on leaves, flowers and some also ate young seed capsules. On these dates
mating and deposition of eggs was observed; both males and females mated several
times. Copulation lasted more than 30 minutes. Usually, two or three pairs were
observed per plant. Adult specimens have dust-like secretions on body as
camouflage (but perhaps there is also
another function), and it was not easy to detect this weevil on the host
plant. Females deposited eggs usually solitarily or in groups of 3-4 in one seed
capsule [Fig. W24.2],
making approximately 1 mm
deep holes. After deposition of eggs, females closed the holes with a yellowish
liquid, that hardened in time and turned to brown color acting as an opercula.
When adults fed on young seed capsules, this part turned to brown color and
abnormal shape. Newly hatched larvae (15 June 2003) bored directly into and fed
on seeds. More than one young larva can be found per seed capsule (probably 1st
and 2nd stage) [Fig.
W24.3],
but only one larva can
develop into adult stage in one seed capsule [Fig.
W24.4].
Most of larvae passed
into pupal stage in the third week of July (22 July 2003) at the same place [Fig. W24.5].
These results show that the genus Lixus
is able to extend its ecological niche by developing in seed capsules of an
Apiaceae plant species; all other species with known biology are stem borers.
Parasitoids.
Bracon
urinator (F.) (Hymenoptera: Braconidae), Exeristes
roborator F., Scambus brevicornis Gravenhorst, and Pimpline
sp. (Hymenoptera: Ichneumonidae), Pteromalus sp. aff. vibulenus
Wlk., and Mesopolobus sp. (Hymenoptera: Pteromalidae) were reared from
L. obesus larvae and pupae. Immature
stages of L. obesus have a rich parasitoid spectrum. A parasitoid larva
feeding on a dead larva of L. obesus
[Fig.
W24.6]
] and a parasitoid emerging hole on a seed capsule were observed [Fig.
W24.7].
Habitat and host plants.
Prangos
uloptera DC. [Fig.
W24.8]
along
Aras Valley and Çoruh Valley.
Following Ter-Minassian (1967), L.
obesus develops in the shoots of
Prangos ferulacea in Armenia. But this record is probably erroneous and
attributed to a confusion with the larva of
Lixus furcatus Olivier, 1807 whose
larvae develop in the stems of several
Prangos species in Turkey as my observations have shown.
Distribution.
Caucasus (Petri 1904/5: 33; Csiki 1934:
107; Ter-Minassian, 1967: 131), Lebanon, Turkey (Tatvan), Italy (Fremuth 1982:
249).
Examined material.
NE
Turkey. Ağrı Prov.: 42 km SE of Horasan, 2000 m, 31.VIII.2003 (L. Gültekin), 15
M, 26
F (reared) Erzurum Prov.: 10 km N of Tortum, 1350 m, 10 VI 2002 (L.
Gültekin), 3 M, 3
F; 1 IX 2002 (L. Gültekin) 1
M (reared); Kars Prov.: 31 km E of
Horasan, 1500 m, 18.VII.2002 (Ö. Çalmaşur), 1
M, 1 F; 14 km E of
Karakurt, 1400 m, 1.VI.2002 (L. Gültekin), 1
M, 1 F; 28-29.VII.2003
(L. Gültekin) 4 M, 3 ♀ (reared);
12.VI.2003 (L.Gültekin), 2 M, 3
F; 32-33 km W of Tuzluca, 1100 m,
2.VI.2002 (L. Gültekin), 1 F.
Armenia. Amberd, 3.VI.1986 (P. Kazaryan), 1
F.
Acknowledgements
I am
sincerely grateful to Dr. V. I. Dorofeyev (Botanical Institute, Russian Academy
of Sciences, St. Petersburg) for identification of the plant species, Dr. B. A.
Korotyaev for contribution and consultation at joint expedition during summer
2003 in Turkey, Dr. S. V. Belokobylskij
for identification of braconid wasps; Dr. D. R. Kasparyan for ichneumonid wasps;
Dr. K. Dzhanokmen for chalcid wasps (Zoological
Institute,
Russian Academy of Sciences, St. Petersburg). Also, I would like to express my cordial thanks to Dr. Peter Sprick
(Hannover, Germany) for linguistic revision and Dr. Peter Stüben
(Mönchengladbach, Germany) for re-arrangement of color pictures.
The study was supported by the Collaborative Linkage
Grant No. 978845 of the NATO Life Science and Technology Programme.
References
Csiki, E., (1934):
Curculionidae: subfam. Cleoninae. – 152 p. in Coleopterorum catalogus.
W. Junk, S. Schenkling, Berlin, 134.
Fremuth, J., (1982): Cleoninae
aus der Türkei und den angrenzenden Gebieten (Coleoptera, Curculionidae). Fragm.
Entomol. 16 (2). P. 239–258.
Petri K., (1904/1905):
Bestimmungs-Tabellen der europäischen Coleopteren, 55. Curculionoidea,
Lixus F. Paskau: 1–62.
Ter-Minassian, M. E., (1967): Weevils of the Subfamily Cleoninae in the Fauna of
the USSR. Tribe Lixini. Keys to the USSR fauna published by the Zoological
Institute, Academy of Sciences of the USSR, 95. Nauka Publishers, Leningrad
Branch, Leningrad, 1967. 166 pp.
Korotyaev, B.A. and L. Gültekin, (2003): Biology of two weevils,
Lixus ochraceus Boheman and
Melanobaris
gloriae sp. n. (Insecta: Coleoptera,
Curculionidae), associated with
Tchihatchewia isatidea Boissier, a cruciferous plant endemic of Turkey.
Entomologische Abhandlungen, 61(1): 93-99.
Author
Levent Gültekin
Atatürk University, Faculty of Agriculture, Plant
Protection Department, 25240,
Erzurum-TURKEY.
e-mail:
lgul@atauni.edu.tr
(Levent Gültekin is a member of the
CURCULIO-Institute: "www.curci.de")