Alpine Entomology

Journal: Alpine Entomology

Publisher

Pensoft

ISSN

2535-0889

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Publications 1 - 8 of 8

A new osmiine bee with a spectacular geographic disjunction: Hoplitis (Hoplitis) onosmaevae sp. nov. (Hymenoptera, Anthophila, Megachilidae)
Aubert, Matthieu; Müller, Andreas; Praz, Christophe (2024)
Alpine Entomology
A new osmiine bee species, Hoplitis (Hoplitis) onosmaevae sp. nov. (Megachilidae), is described. So far, this species is exclusively known from the Mercantour National Park in the southwestern French Alps and from mountainous ranges in Turkey and northern Iraq, two areas separated by at least 2000 km. Phylogenetic analyses based on mitochondrial and nuclear genes revealed that H. onosmaevae is closely related to H. adunca (Panzer, 1798), H. benoisti (Alfken, 1935) and H. manicata (Morice, 1901). Hoplitis onosmaevae is presumably narrowly oligolectic and harvests pollen only on flowers of Onosma L. (Boraginaceae). It has a particularly long proboscis, which is probably an adaptation to collect nectar from the long -tubed flowers of this plant genus. The females collect pollen by buzzing the Onosma flowers, a rare behavior in megachilid bees. The species nests in insect burrows in dead wood, similar to H. adunca and H. manicata but unlike other closely related representatives of the subgenus Hoplitis, suggesting a single origin of nesting in dead wood and hollow stems in this lineage. In France, H. onosmaevae inhabits alpine steppe -like habitats close to forests and appears to be extremely local, since only two populations are currently known. The conservation status of this extremely rare bee species in Europe is discussed.
On the occurrence of relict populations of Pytho abieticola J. R. Sahlberg, 1875 in Switzerland (Coleoptera, Pythidae)
Chittaro, Yannick; Sanchez, Andreas; Szallies, Alexander; et al. (2023)
Alpine Entomology
Several adults and larvae of Pytho abieticola were discovered in 2021 and 2022 at three different localities in two regions of Switzerland, the Jura mountains and the Swiss National Park in the Eastern Alps. This very rare saproxylic beetle has not been detected in Switzerland so far. Considered a relict of primeval forests, it is in strong decline or has already disappeared from large areas of Central Europe. The isolated Swiss populations are the westernmost in its distributional range. Information on the ecology and distribution of P. abieticola in Switzerland and Europe is provided and criteria to distinguish P. abieticola from the congeneric and syntopic P. depressus are defined.
A threefold plant specialist – distribution, habitat requirements and nesting biology of the rare leafcutter bee Megachile genalis in the eastern Swiss Alps (Hymenoptera, Megachilidae)
Müller, Andreas; Weibel, Urs; Lenz, Regina (2024)
Alpine Entomology
The leafcutter bee Megachile genalis Morawitz, which nests in thick, erect and usually hollow plant stems, is rare and endangered throughout Europe. In Switzerland, it was recorded only six times in the Grisons between 1932 and 2019. In order to create the necessary basis for the conservation of this rare bee, its distribution, habitat requirements and nesting biology were investigated in the eastern Swiss Alps by systematically searching for its nests, by DNA metabarcoding of the cell-building material, by analysing the pollen contained in abandoned brood cells and larval faeces, and by deducing aspects of the species’ nesting biology from collected old nests. A total of 141 new and 64 old nests were discovered at elevations between 600 m and 1270 m in – with decreasing frequency – the Albula Valley, the Lower Engadine, the Domleschg and the Ruinaulta. The nests were exclusively built in living stems of Peucedanum verticillare (Apiaceae), an up to 2–3 m tall umbellifer that grew on fallow land, road and railway embankments, scree slopes, ruderal areas and forest clearings. The leaf fragments used by the females of M. genalis to construct the brood cells in 20 selected nests were largely from shrubs and trees of the Rosaceae (e.g. Rosa, Rubus, Prunus, Sorbus), rarely also from Corylus (Betulaceae). The pollen in 65 brood cells was exclusively collected on thistles (e.g. Arctium, Carduus, Cirsium) and other Asteraceae. The nests were characterised by a surprisingly high variability in their architecture. They consisted of i) an approximately 6 mm x 9 mm large nest opening gnawed by the female bee at a height of 22–217 cm above ground with her mandibles, which are well adapted to penetrate the hard stem walls due to their enlarged base indicating strong adductor muscles and the short and chisel-like shape; ii) a 5–25 mm thick nest plug built 1.5–45 cm below the nest opening from pith particles, leaf fragments and/or grass fibers; iii) 1–14 brood cells usually arranged in one cigar-like series and lying 11–99 cm below the nest opening; and iv) a facultative 4–40 mm thick basal plug consisting of pith particles and/or leaf fragments. Brood mortality was high: at least 56% of 284 brood cells were unsuccessful due to parasites, mould or unknown reasons, and reproduction completely failed in almost half of 46 nests. The most harmful brood parasite was Melittobia acasta Walker (Hymenoptera, Eulophidae), which infested 19% of the brood cells and 28% of the nests. Measures to conserve the population of M. genalis in the eastern Swiss Alps should focus on the conservation and propagation of suitable habitats for P. verticillare in close vicinity to Asteraceae-rich areas and on the promotion of thistles.
Annotated checklist of the Swiss bees (Hymenoptera, Apoidea, Anthophila): hotspots of diversity in the xeric inner Alpine valleys
Praz, Christophe; Müller, Andreas; Bénon, Dmitri; et al. (2023)
Alpine Entomology
We present a checklist of the Swiss bees and provide information on the distribution of every bee species in all 26 Swiss cantons. 632 species are reported, including the European honeybee Apis mellifera Linnaeus, 1758 and the exotic species Megachile sculpturalis Smith, 1853. Species richness in each canton was correlated with the canton area, with the four largest cantons hosting the highest number of species. Bee diversity hotspots were located in some Alpine inner valleys characterized by a dry and warm climate due to the rain shadow effects of surrounding mountains. These hotspots are mostly located in the steppe-like habitats of the Valais and Graubünden cantons. They host diverse wild bee communities which include a unique assemblage of submediterranean faunal elements and subalpine species. In addition, these habitats host rare species with strongly disjunct distributions in Europe, further stressing the conservation priority of these habitats for wild bee conservation. Intensive faunistic surveys performed in the last 20 years have revealed that about 20 bee species, either previously unknown for Switzerland or which had disappeared from the country for several decades, have colonised areas close to the borders of France and Italy. Most of these new or reappeared species were observed in the warmest area of the country and presumably colonized or recolonized the country from neighbouring regions following global warming. Lastly, DNA barcodes are presented for 394 specimens, including for many species so far not represented in the BOLD database. The taxonomic status of numerous unclear taxa is briefly discussed based on combined genetic and morphological analyses.
Five years of Alpine Entomology, the international journal on mountain insects
Lachat, Thibault; Martin, Oliver Y. (2021)
Alpine Entomology
First observation of an ant colony of Formica fuscocinerea Forel, 1874 invaded by the social parasite F. truncorum Fabricius, 1804 (Hymenoptera, Formicidae)
Neumeyer, Rainer; Sommerhalder, Jürg; Ungricht, Stefan (2021)
Alpine Entomology
In the northern Alps of Switzerland we observed a mixed ant colony of Formica truncorum Fabricius, 1804 and F. fuscocinerea Forel, 1874 at the foot of a schoolhouse wall in the built-up centre of the small town of Nafels (canton of Glarus). Based on the fact that the habitat is favorable only for F. fuscocinerea and that F. truncorum is a notorious temporary social parasite, we conclude that in this case a colony of F. fuscocinerea must have been usurped by F. truncorum. This is remarkable, as it is the first reported case where a colony of F. fuscocinerea has been taken over by a social parasite. We consider the observed unusually small workers of F. truncorum to be a starvation form. This is probably due to the suboptimal urban nest site, as this species typically occurs along the edge of forests or in clearings.
The hidden diet-examination of crop content reveals distinct patterns of pollen host use by Central European bees of the genus Hylaeus (Hymenoptera, Colletidae)
Müller, Andreas (2023)
Alpine Entomology
Masked or yellow-faced bees of the genus Hylaeus (Colletidae) differ in their mode of pollen transportation from most other bees in that they ingest the pollen directly on the flowers and carry it back to the nest inside the crop located in the anterior half of the metasoma. Due to this hidden mode of pollen transportation, the examination of pollen collected by Hylaeus females requires the dissection of the metasoma. Although this method has never been applied in Europe, the great majority of the Central European Hylaeus species were supposed to be pollen generalists based on observations of flower visits. The microscopical analysis of pollen removed from 30 crops each of 36 Central European Hylaeus species revealed that the proportion of species exhibiting an exclusive or strong preference for pollen from a single plant taxon is much higher than hitherto assumed and that the current assumption of the genus Hylaeus to largely consist of pollen generalists is wrong. Nineteen of the 36 species examined are strictly or largely dependent on a single plant taxon for collecting pollen, such as Apiaceae (n = 11 species), Rosaceae (n = 3), Reseda (Resedaceae) (n = 2), Allium (Amaryllidaceae) (n = 1), Asteraceae (n = 1) and Melilotus (Fabaceae) (n = 1). The 36 Hylaeus species examined collected pollen from the flowers of 31 plant families, of which the Apiaceae and Rosaceae (particularly Potentilla and Rubus) were by far the most important contributing almost 60% to the pollen host spectrum of the entire genus. The comparison between pollen host spectrum and flower visiting records showed that the pollen generalists use the flowers of the Asteraceae as nectar rather than pollen sources, corroborating earlier findings that the digestion of Asteraceae pollen requires physiological adaptations to cope with its unfavourable or protective properties. In summary, the patterns of pollen host use by bees of the genus Hylaeus do not substantially differ from those of other Palaearctic bee taxa despite the masked bees' unusual habit to ingest the pollen directly on the flowers and to transport it inside their body back to the nest.
Unique nesting biology of Osmia ( Melanosmia) uncinata, a Palaearctic osmiine bee specialized on thick-barked conifers (Hymenoptera, Megachilidae)
Müller, Andreas; Prosi, Rainer; Taylor, Stewart; et al. (2020)
Alpine Entomology
Osmia (Melanosmia) uncinata Gerstäcker is a Palaearctic megachilid bee distributed from temperate and northern Europe eastwards to the Russian Far East. The discovery of over 80 nests in Switzerland, southern Germany and Scotland enabled for the first time a closer investigation of its nesting biology and prompted the assessment of the species’ phenology, distribution and habitat. O. uncinata nested in self-excavated burrows inside the bark of both living trunks and dead stumps of Pinus sylvestris. The nests were excavated at a height of 10–220 cm above ground either on the underside of prominences of longitudinal bark ribs or inside beetle borings and extended more or less vertically upwards. They consisted of a single straight to slightly curved burrow with rarely one to three side burrows, had a total length of 1.2–12.0 cm and contained 1–6 brood cells. The brood cells, which faced downwards with the larval provisions being located in the upper cell half, were separated from each other by one-layered walls of chewed leaves (“leaf pulp”). The nests were sealed with a plug of 2–4 closely adjacent walls of leaf pulp. DNA metabarcoding of cell and plug walls revealed that Potentilla and Fragaria (Rosaceae) served as leaf pulp sources. Pre-imaginal mortality amounted to 77%, partly caused by brood parasites such as Sapyga similis (Sapygidae) and Cacoxenus indagator (Drosophilidae) or predators such as snakeflies (Raphidioptera). At low elevations, O. uncinata needs one year for its development and overwinters as imago inside the nest, whereas in the subalpine zone of the Alps it has a two-year cycle passing the first winter as prepupa and the second winter as imago. O. uncinata starts to emerge between the end of March at low elevations and the end of May at higher elevations qualifying as an early flying bee like the other European O. (Melanosmia) species. The distribution of O. uncinata in Central Europe and Scotland largely coincides with the occurrence of P. sylvestris. As in the pine, it extends over a wide altitudinal range from below 100 m up to 1900 m a.s.l. and encompasses dry and wet as well as warm and cold habitats including open pine forests, inner and outer forest edges dominated by pine and isolated pine groups. At a few locations in the subalpine zone of the Alps, O. uncinata occurs in the absence of P. sylvestris; here, the thick bark of Larix decidua serves as a substitute nesting substrate.

Publications 1 - 8 of 8

Journal: Alpine Entomology

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