Druh

Liparus dirus (Herbst, 1795)
Jako hostitele uvádějí někteří autoři hladýš rodu Laserpitium z čeledi miříkovitých (Apiaceae) bez uvedení konkrétního druhu [Hoffmann 1954, Kippenberg 1983]. Smreczyński [Smreczyński 1968] a Strejček [Strejček 1965] uvádějí hladýš širolistý (Laserpitium latifolium) jako jedinou živnou rostlinu tohoto nosatce.
V Národním parku Podyjí jsem (= první autor) tento druh nacházel opakovaně na smldníku jelením (Peucedanum cervaria) z téže rostlinné čeledi. Bylo to na lokalitě “Hraběcí hora” poblíž obce Hnanice (8 km západně od města Znojma na jižní Moravě) ve velmi dobře zachovalém ekotonovém společenstvu dubového lesa asociace Sorbo torminalis-Quercetum. Většina exemplářů byla nacházena na biotopu trávníků asociace Peucedanetum cervariae navazujícím na lesní okraj. Imaga byla pozorována sedící v těsné blízkosti lodyh (v přízemní listové růžici) a nebo dokonce v krátké chodbě vyhrabané směrem ke kořeni smldníku. Moje domněnka, že se jedná o živnou rostlinu tohoto nosatce na této lokalitě, je podpořena faktem, že dosud známý hostitel – Laserpitium latifolium – se na lokalitě ani v jejím okolí nevyskytuje (nejbližší naleziště se nacházejí asi 10 km západně v Dolních Rakousech). Pokusy o nalezení larev v kořenech smldníku jeleního a na lokalitě rovněž rostoucí žebřice pyrenejské (Libanotis pyrenaica) byly neúspěšné.

Aphytobius sphaerion (Boheman, 1845)
Tento druh je znám jako oligofág čeledi hvozdíkovité (Caryophyllaceae). Smreczyński [Smreczyński 1974] uvádí tyto hostitele: Silene nutans, Silene gallica, Silene vulgaris subsp. vulgaris (syn. Silene inflata), Silene latifolia subsp. alba (syn. Melandrium album) a Arenaria montana.
Na Moravě byl tento druh recentně nalezen pouze v Národním parku Podyjí [Stejskal 2005] a v blízkém údolí řeky Jihlavy [Jiří Krátký, Hradec Králové, unpublished data]. Zatímco první nález z Podyjí byl publikován bez uvedení konkrétních okolností nálezu, další exkurze na lokalitě ”Ledové sluje” poblíž Vranova nad Dyjí ukázaly, že druh zde žije pravděpodobně na smolničce obecné (Lychnis viscaris, syn. Steris viscaria, Viscaria vulgaris), dosud neuváděné hostitelské rostlině. Výskyt tohoto bezkřídlého nosatce v Národním parku Podyjí se zdá být omezen pouze na lokalitu Ledové sluje, i když smolnička obecná se zde vyskytuje velmi hojně po celém území parku. Na lokalitě Ledové sluje je druh zjišťován metodou prosevů detritu v porostech smolničky rostoucí ve světlých a suchých porostech s převahou dubu. Brouci zřejmě upřednostňují místa s dobrými světelnými poměry společenstva Sorbo torminalis-Quercetum.
Na druhé moravské lokalitě nad řekou Jihlavou byl druh sbírán stejnými metodami na velmi podobném biotopu, ale pod silenkou nící (Silene nutans). Podařilo se zde zjistit také živný žír larev, kuklení v zemi a úživný žír dospělců. Larva 3. instaru je beznohá, bílá, délky cca. 2 mm.

1. Introduction

In literature, information of different precision on weevil host plants can be found). There are still a number of weevils with completely unknown host plant associations or life histories in Central Europe. While studying weevils, every "weevil-collector" should record all new or unusual bionomical observations and share them through an information exchange with other entomologists – by publishing the observations in printed media or ideally in the Internet. It is very important to record new weevil-plant associations, both natural and "strange" ones, and hereby to improve our current knowledge of weevil biology. A good example is the compilation by [Colonnelli & Osella 1998]. In these authors` opinions, in recent years it has become more and more evident that the knowledge of weevil biology is of paramount importance in understanding relationships among the different lineages of Curculionoidea.
    In some cases, newly recorded host plants of either adults or larvae (see [Nota1]) are only those that were just omitted by entomologists due to their insufficient examination of plants growing in a locality. We mean, sometimes we rely too much on literature data instead of direct checking on what plant species we collected our specimen as a feeding/ovipositing adult or as a larva. This may result in repeating the same - but not always reliable - information by more authors. So we always should pay attention to plant examination even by using botanical keys or cooperating with botanists if necessary. In case of the "aggregate-plant taxa" (e.g. Arabis hirsuta agg.), it is highly worth trying to find out which of the "microspecies" serve as host/refuge plants and which are neglected.
    On the other hand, some new weevil-host associations may signify a host shift, which means a (recent) colonization of a new host plant by a weevil. The colonization may be only of a temporary character. Repeated field recording can show whether the colonized plant is a true host or not. The question that follows is: "What mediated this colonization?"
    Here we bring new information on new host plants of two weevils taken from field observations mostly in the Podyjí National Park (Czech Republic, southern Moravia). We repeatedly found the below discussed species associated with plants outside their known host range.
    All photos by R. Stejskal or from archive of the Podyjí National Park Administration (Czech Republic, Znojmo) if not mentioned.

2. Comments on the species

Liparus dirus (Herbst, 1795) [Data]
    Regarding the host preference of this weevil, some authors [Hoffmann 1954], [Kippenberg 1983] give only "Laserpitium” from the family Apiaceae as its host without specifying a concrete species. Smreczyński [Smreczyński 1968] and Strejček [Strejček 1965] give Laserpitium latifolium L. as the only host of Liparus dirus.
    I (= the first author) found this rare weevil surprisingly on another plant from the Apiaceae family – Peucedanum cervaria (L.) Lapeyr., which seems to be its new host plant.
Since 2004, I have studied the weevil in a very small locality called ”Hraběcí hora hill” near Hnanice [Fig. W36_1] (8 km west of Znojmo, southern Moravia, Czech Republic) in a well-developed forest margin. This locality is the only one known so far from the Podyjí National Park and from southwestern Moravia. Currently, this weevil is known from very few areas in northern Bohemia (České Středohoří Mts.) and southeastern Moravia (Hustopečská pahorkatina Hilly Area, Bílé Karpaty Mts.).
    In the locality ”Hraběcí hora hill”, most specimens were found outside the forest in a grassland identified as Peucedanetum cervariae Kaiser, 1926 [Fig. W36_2] [Fig. W36_3] [Plant_list]. Single beetles also occurred in the forest margin under oak trees. Living beetles were observed only in months May and June. The surrounding forest belongs to the association Sorbo torminalis-Quercetum Svoboda ex Blažková, 1962. The altitude is about 320 m. The bedrock consists of granodiorite covered with sediments (calcareous sand and clay). The soil is deep and nutrient-rich.
    Several specimens of the weevil were observed sitting close to stem or leaf rosette of Peucedanum cervaria, and some of them even burying a tunnel to the plant root [Fig. W36_4]. My observation may show that Peucedanum cervaria is most likely the host plant of Liparus dirus in this locality. This hypothesis is supported by the fact that the so far known Central-European host – Laserpitium latifolium – does not occur in the locality, neither in the area of the whole Podyjí National Park including its buffer zone. The closest localities of Laserpitium latifolium are found some 10 km west of here in Lower Austria.
    I kept a specimen of Liparus dirus in a laboratory for two days in a simple plastic box with a leaf of Peucedanum cervaria. The beetle fed on the leaf margin both days and then it was released in the place of capture. I have not tested its feeding on other plants from the locality. My attempt to find a larva or a pupa of the weevil inside roots of Peucedanum cervaria and Libanotis pyrenaica (L.) Bourgeau, which both grow together in the locality, has not been successful. Nevertheless, I tested only about 15-20 plants of Peucedanum cervaria and the same number of Libanotis pyrenaica to avoid damaging the locality.
    In my opinion, there are two explanations concerning the new host plant Peucedanum cervaria – (1) it has been omitted by entomologists so far, and the weevil is thus not a strict specialist of Laserpitium latifolium, or (2) it is a surrogate host only in the locality ”Hraběcí hora” after the original host has become extinct here. This can be cleared only by more observations in other localities.

Aphytobius sphaerion (Boheman, 1845) [Data] [Fig. W36_9]
This weevil is known as an oligophagous species associated with members of the family Caryophyllaceae. Smreczyński [Smreczyński 1974] gives the following hosts: Silene nutans L., Silene gallica L., Silene vulgaris subsp. vulgaris (Moench) Garcke (syn. Silene inflata Sm.), Silene latifolia subsp. alba (Mill.) Greuter et Burdet (syn. Melandrium album (Mill.) Garcke) and Arenaria montana L.
    In Bohemia, this rare weevil was collected in the Labe River valley in a secondary habitat (river embankment) on Silene vulgaris subsp. vulgaris and Silene latifolia subsp. alba [Strejček 1993], [Strejček 1996]. In Moravia, the species was found only recently in the Podyjí National Park [Stejskal 2005] [Fig. W36_5] and in the near Jihlava River valley [Jiří Krátký, Hradec Králové, unpublished data]. The first finding of this weevil from the Podyjí National Park was without exact finding circumstances. During several excursions to its locality - Ledové sluje (Ice Caves) near Vranov nad Dyjí [Fig. W36_5] - in the Podyjí National Park in April and May 2005, we and our colleague Václav Křivan (the Czech Republic, Štěměchy) found more specimens under Lychnis viscaria L. (syn. Steris viscaria (L.) Raf., Viscaria vulgaris Bernh., family Caryophyllaceae) [Fig. W36_6] not reported as its host so far. Unlike this very common plant, the occurrence of this wingless weevil in the Podyjí National Park seems to be restricted to a small area in the western part of the national park. This might be a good evidence of its relic occurrence in the locality Ledové sluje (Ice Caves). Ledové sluje is one of the richest botanical localities of the Podyjí National Park hosting some 500 plant species in an area of 1 km². The weevil was collected by sifting (one specimen also by sweeping) under polycormons of Lychnis viscaria in a light and dry forest dominated by oak [Fig. W36_7] [Fig. W36_8]. The forest belongs to three associations: Melampyro nemorosi-Carpinetum Passarge, 1957, Sorbo torminalis-Quercetum and Luzulo albidae-Quercetum petraeae Zólyomi et al. ex Soó, 1963. The weevil obviously prefers sites with good light conditions of the Sorbo torminalis-Quercetum.
    In 2006, a new Moravian locality of this weevil was discovered by Jiří Krátký in the Jihlava River valley (Moravia mer., Dukovany – Dukovanský mlýn Nature Monument). In this locality, the weevil was collected with the same collecting methods, but under Silene nutans. Feeding marks of both, larvae [Fig. W36_10] and adults, were found in leaves, and pupae were found in the soil. Larva of the 3^rd instar is legless, white and about 2 mm long [Fig. W36_10].

3. References

Colonnelli E. & Osella G. (1998): Host and refuge plants of weevils (Coleoptera: Curculionoidea). Mus. reg. sci. nat. Torino, p. 191-216.
Hoffmann A. (1954): Coléoptères Curculionides. - Faune de France, vol. 59. Lechevalier, Paris.
Kippenberg H. (1983): Unterfamilie Hylobinae, p. 121-154. - In: Freude H., Harde K. W. & Lohse G. A.: Die Käfer Mitteleuropas. Vol. 11. Goecke and Evers. Krefeld, 11, 342 pp.
Skuhrovec J. (2005): Živné rostliny nosatců rodu Hypera (Coleoptera: Curculionidae) vyskytujících se na území České republiky (Host plants of weevils of the genus Hypera (Coleoptera: Curculionidae) occurring in the Czech Republic). - Klapalekiana. Praha, 41, p. 215-255.
Smreczyński S. (1968): Podrodziny Tanymecinae, Cleoninae, Tanyrhnychinae, Hylobiinae. Klucze do oznaczania owadów Polski; Cz. XIX: Coleoptera. Zeszyt 98c: Curculionidae. - PWN. Warszawa, 106 pp.
Smreczyński S. (1974): Podrodziny Curculioninae. Klucze do oznaczania owadów Polski; Cz. XIX: Coleoptera. Zeszyt 98e: Curculionidae. - PWN. Warszawa, 180 pp.
Stejskal R. (2005): New weevil species (Coleoptera, Curculionidae) for the Czech Republic. (Nové druhy nosatců (Coleoptera, Curculionidae) pro Českou republiku). Weevil News, 26, 5 pp.
Strejček J. (1965): Příspěvek k poznání fauny brouků Československa z čeledi Curculionidae. - Zprávy Čs. spol. entomolog. při ČSAV. Praha, 1(4), p. 1-6.
Strejček J. (1993): Faunistic records from the Czech Republic - 9. - Klapalekiana. Praha, 29, p.169-171.
Strejček J. (1996): Příspěvek k poznání fytofágních brouků z čeledí Chrysomelidae s. lat., Bruchidae, Urodontidae, Anthribidae a Curculionidae s. lat. v údolí Vltavy v okolí obce Veltrusy ve středních Čechách (Beitrag zur Kenntnis der phytophagen Käferfamilien (Chrysomelidae, Bruchidae, Urodontidae, Anthribidae und Curculionidae s. lat.) im Vltava-Tal (Mittelböhmen: Veltrusy). - Klapalekiana. Praha, 32, p. 247-266.

Adresses of the authors:
Robert Stejskal
Smetanova 3
CZ - 669 02 Znojmo

Jiří Krátký
Třebechovická 821
CZ - 500 03 Hradec Králové

Weevil News	http://www.curci.de/Inhalt.html	No. 36	5 pp.	28^th June 2007	ISSN 1615-3472
Stejskal, R. & J. Krátký (2007): Notes to host plants of the weevils Liparus dirus (Herbst, 1795) and Aphytobius sphaerion (Boheman, 1845) (Coleoptera, Curculionidae). - Weevil News: http://www.curci.de/Inhalt.html, No. 36: 5 pp., CURCULIO-Institute: Mönchengladbach. (ISSN 1615-3472).