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Oviposition preferences of the alcon large blue phengaris alcon (Lepidoptera: Lycaenidae) at a seasonal lake in Southwestern Slovenia

Jugovic Jure, Kostadinovski Luka, Kopač Klara

Polish Journal of Ecology

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2023

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Vol. 71, nr 1

15--25

EN

We investigated the oviposition preferences of Phengaris alcon in relation to the height of the host plant (Gentiana pneumonanthe), the number of flowers, and the choice of microsite for oviposition (part of the host plant, height of oviposition) in a local population of this species in SW Slovenia at a depression of a seasonal lake Petelinje. P. alcon prefers the tallest (most conspicuous) host plants and plants with a larger number of flowers (i.e., more than 90% of all eggs were deposited on 12% of the tallest plants ≥ 30 cm), where eggs are deposited in the upper quarter of the plant height, usually on calyx (66.1%) and corolla (29.9%), and rarely on leaves or stems. Eggs are mostly deposited singly or in groups of two (> 50%) on a single plant, and eggs were found only on less than 3% of examined plants. Butterfly density was estimated at about 60 individuals per hectare. Obtained results indicate that preferences for oviposition sites are not random, and monitoring population density may provide important insight into the future population status of P. alcon.

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The effect of neighboring plant height, disturbance level and gap size on spontaneous recruitment of large-seeded and small-seeded species in Molinietum caeruleae meadows

Kostrakiewicz-Gierałt K.

Polish Journal of Ecology

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2014

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Vol. 62, nr 2

289--306

EN

The seed size is considered as a key feature, which effects both: colonizing and competitive abilities of species. The disturbance dependent small-seeded taxa are regarded as superior colonists, whereas the large-seeded taxa are considered as best competitors able to survive the competition from adjacent plants and negative effect of litter. The impact of character of standing vegetation, disturbance level and size of gaps on spontaneous recruitment of seedlings of selected light-seeded species (Gentiana pneumonanthe L., Dianthus superbus L.) and heavy-seeded taxa (Serratula tinctoria L., Gladiolus imbricatus L.) were conducted. The investigations were carried out in two areas (A and B). Both of them were consisted of three adjacent patches of Molinietum caeruleae: dominated by small meadow species (labeled MC), prevailed by large-tussocks grasses (labeled GR), and overgrown by willows (labeled SA). In the year 2007, in all patches, ten permanent experimental plots were randomly arranged. In Area A, plots were divided in four square-shaped, neighboring subplots subjected to: no treatment; the removal of litter and moss layers; the removal of litter, bryophytes, and above-ground parts of plants; the removal of litter, moss and the plants, as well as top soil stripping. In the Area B, plots were divided into four subplots measuring from 0.16 m2 to 0.01 m2. In each of them the litter and above-ground part of plant biomass were clipped and removed. The recruitment of seedlings was monitored from 2007 through 2010. In both studied areas, regardless of seed mass, the greatest abundance of seedlings were found in patches MC, and decreased gradually in sites GR and SA. Irrespective of seed size, in subplots where plant cover and litter stayed intact no new genets was noted, moderate appearance of seedlings was observed in subplots without plant necromass, whereas the greatest number of generative progeny was found in subplots without necromass and aboveground parts of plants. The lower abundance of seedlings in subplots without litter, plants and topsoil might have been caused by depletion of seed bank reserves. Moreover, in all patches the number of seedlings of small- and large-seeded taxa increased significantly with augmentation of gap size. In light of performed studies it might be concluded, that the disturbances might play very important role in active protection of studied taxa. The positive impact of disruption diminishes with increasing of plant canopy height. The removal of plant cover and litter contributes to the greatest seedling recruitment but its beneficial effect diminishes with decreasing of opening size.

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The effect of vegetation character on abundance and structure of subpopulations of rare herb species Gentiana pneumonanthe L.

Kostrakiewicz-Gierałt K.

Polish Journal of Ecology

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2013

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Vol. 61, nr 1

35--46

EN

During the 20th century in Central and Eastern Europe, traditional agricultural management was either heavily intensified or abandoned due to socio-economic reasons. The land abandonment led to subsequent secondary succession reverted many wet meadows into Phragmites swamps, Salix or Alnus thickets, as well as woodlands. Therefore, the understanding of changes in abundance and structure of populations in the process of succession has become very important especially for rare and endangered species. In Poland one of strictly protected plant is Gentiana pneumonanthe L. It is a nonclonal, long-lived, iteroparous plant consisted of numerous vegetative and generative stems, bearing 1–25 flowers per year. The investigations of abundance and structure of subpopulations of Gentiana pneumonanthe were conducted in the years 2009–2011 in abandoned Molinietum caeruleae meadows dominated by low-stature species (Patch I), prevailed by tall grasses (Patch II), willows (Patch III), as well as partly overgrown by shrubs and trees (Patch IV). The average height of vegetation cover achieved from 65.3 cm (Patch I), via 85.8 cm (Patch II) and 94.0 cm (Patch III), to 142.7 cm (Patch IV). The gradually decline of abundance of Gentiana pneumonathe subpopulations and increased trend toward their senilization along the gradient of vegetation height might be due to successional closure of plant cover, preventing seedling recruitment. The total number of stems per individual and length of vegetative stems decreased with augmentation of neighbouring plants dimensions, whereas the height of generative stems, as well as flower and fruit production presented inversed trend. The greatest dimensions of capsules found in patch dominated by small meadow species might be due to greater availability of solar radiation. The conditions of studied subpopulations decrease gradually from patch dominated by small meadow species, via sites prevailed by grasses and willows, to place overgrown by shrubs and trees. Although obvious differences in abundance and structure of individuals, the prospects of all observed populations are poor, especially that patches are not subjected active protection.

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Oviposition patterns in the myrmecophilous butterfly Maculinea alcon denis & schiffermüller (Lepidoptera: Lycaenidae) in relation to characteristics of foodplants and presence of ant hosts

Nowicki P., Witek M., Skórka P., Woyciechowski M.

Polish Journal of Ecology

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2005

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Vol. 53, nr 3

409-417

EN

To test the hypothesis of random oviposition by Maculinea butterflies we investigated the oviposition patterns of M. alcon Denis & Schiffermüller in wet meadows in the Vistula valley, southern Poland, in relation to the stem length and flower number of Gentiana pneumonanthe Linnaeus foodplants as well as to their spatial distribution, the height of the surrounding vegetation and the presence of potential ant hosts. Analysis conducted for 403 gentians recorded within the 0.96 ha study plot indicated that plants with M. alcon eggs present were significantly higher and had more flowers. On the other hand, neither the local density of gentians nor the presence of ant hosts had any apparent effect on oviposition preferences of M. alcon. Our conclusion is that females of the butterfly select visually conspicuous plants as the oviposition sites regardless of their clumping or ant presence. As a consequence, the two factors do not need to be included in computer models developed to study the population dynamics of the species and its trophic interactions with foodplants and ant hosts.