Research Article |
Corresponding author: Dóra Arnóczkyné Jakab ( jakidori6@gmail.com ) Academic editor: Christopher K. Starr
© 2023 Dóra Arnóczkyné Jakab, Miklós Tóth, István Szarukán, Szabolcs Szanyi, Zsolt Józan, Miklós Sárospataki, Antal Nagy.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Arnóczkyné Jakab D, Tóth M, Szarukán I, Szanyi S, Józan Z, Sárospataki M, Nagy A (2023) Long-term changes in the composition and distribution of the Hungarian bumble bee fauna (Hymenoptera, Apidae, Bombus). Journal of Hymenoptera Research 96: 207-237. https://doi.org/10.3897/jhr.96.99002
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One of the most important pollinator taxa is Bombus (Hymenoptera, Apidae), the genus of bumble bees, since they are important, often specialized, pollinators of many plants. As a result of climate change, warming winters and changes in landscape structure, the distribution and frequency of Bombus species is constantly changing. To develop appropriate protection strategies, it is essential to monitor them and update the occurrence and threat status of the species.
The last review of the distribution of Bombus species in Hungary was completed 20 years ago. Here we present updated distribution maps based on published data from the last 20 years together with unpublished data collected in 2018–2021. Based on the new data, we examine changes in the last two decades. In the case of 9 species further studies should be carried out to confirm the presence of stable populations, while 3 species are recommended for protection by law in Hungary. Seven species showed increasing frequency, B. argillaceus and B. haematurus.
bumble bee, climate change, distribution data, distribution map, pollination, threatened, UTM
Due to the intensification of agriculture and spreading urbanization, landscape diversity is decreasing with a parallel increase of air, water and soil pollution throughout Europe (
The intensity and success of pollination are negatively affected by the decrease in the diversity and abundance of wild bees (
The last overview of the Hungarian bumble bee fauna was published in 2003 (
The former distribution database of Hungarian bumble bee fauna used a 10×10 km UTM system (
In the case of data collected after 2003, transect counts and direct search are used. Data collected in 2018–2021 with volatile traps designed for noctua pests were also added by Dóra Arnóczkyné Jakab and Antal Nagy. For identification of the collected materials, the keys of
The database contains the following data by species: sampling site with GPS coordinates and/or locality name, sampling dates, and data source. In the original data set,
Bombus elegans is now recognized as a junior synonym of B. distinguendus (
The relative frequencies of the species (RF%) were calculated based on the formula of
This index was used for comparison of former and newly calculated values. The frequency categories of species were recalculated also using this index and the original categories of
Checklist of the Hungarian bumble bee fauna with the relative frequency (RF%) and frequency category of the species published by
RF% | Frequency categories | |||
---|---|---|---|---|
2003 | 2021 | 2003 | 2021 | |
B. (Megabombus) argillaceus* (Scopoli, 1763) | 7.06 | 15.44 | I | II |
B. (Psithyrus) barbutellus (Kirby, 1802) | 12.53 | 10.73 | II | II |
B. (Psithyrus) bohemicus (Seidl, 1838) | 4.33 | 3.58 | I | I-cn |
B. (Psithyrus) campestris (Panzer, 1801) | 4.78 | 6.21 | I | I |
B. (Bombias) confusus* (Schenck, 1861) | 12.98 | 10.92 | II | II-cn |
B. (Megabombus) consobrinus (Dahlbom 1832) | 0.23 | 0.19 | cn | |
B. (Bombus) cryptarum (Fabricius, 1775) | - | 0.19 | cn | |
B. (Subterraneobombus) distinguendus (Morawitz 1869) | 1.59 | 1.32 | E | |
B. (Subterraneobombus) fragrans* (Pallas, 1771) | 3.64 | 3.01 | I | I-cn |
B. (Pyrobombus) haematurus (Kriechbaumer, 1870) | 3.87 | 10.92 | I | II |
B. (Megabombus) hortorum (Linnaeus, 1761) | 37.13 | 42.94 | III | IV |
B. (Thoracobombus) humilis* (Illiger, 1806) | 36.90 | 35.59 | III | III |
B. (Pyrobombus) hypnorum (Linnaeus, 1758) | 6.38 | 9.42 | I | I |
B. (Thoracobombus) laesus* (Morawitz, 1875) | 8.66 | 6.21 | I | I-cn |
B. (Melanobombus) lapidarius (Linnaeus, 1758) | 57.63 | 59.13 | IV | IV |
B. (Bombus) lucorum (Linnaeus, 1761) | 12.53 | 14.69 | II | II |
B. (Thoracobombus) muscorum* (Linnaeus, 1758) | 19.59 | 18.46 | II | II |
B. (Bombias) paradoxus* (Bombus confusus paradoxus, Dalla Torre, 1882) | 3.87 | 3.39 | I | I-cn |
B. (Thoracobombus) pascuorum (Scopoli, 1763) | 47.38 | 51.79 | IV | IV |
B. (Thoracobombus) pomorum* (Panzer, 1805) | 10.48 | 10.17 | II | II |
B. (Pyrobombus) pratorum (Linnaeus, 1761) | 14.12 | 14.69 | II | II |
B. (Thoracobombus) ruderarius (Linnaeus, 1776) | 37.13 | 39.74 | III | III |
B. (Megabombus) ruderatus* (Fabricius, 1775) | 17.54 | 18.08 | II | II |
B. (Psithyrus) rupestris (Fabricius, 1793) | 17.77 | 14.69 | II | II |
B. (Cullumanobombus) cullumanus serrisquama (Kirby, 1802) | 0.46 | 0.38 | E | |
B. (Kallobombus) soroeensis* (Fabricius, 1776) | 1.37 | 1.69 | I | I |
B. (Subterraneobombus) subterraneus* (Linnaeus, 1758) | 9.11 | 7.53 | I | II-cn |
B. (Thoracobombus) sylvarum* (Linnaeus, 1761) | 40.77 | 42.75 | III | IV |
B. (Psithyrus) sylvestris (Lepeletier, 1832) | 1.14 | 0.94 | I | cn |
B. (Bombus) terrestris (Linnaeus, 1758) | 68.34 | 77.21 | IV | IV |
B. (Psithyrus) vestalis (Fourcroy, 1785) | 12.30 | 12.62 | II | II |
Since RF% considers the spatial distribution of the species based only on all occupied UTM cells, the other modified relative frequency value of species was calculated (RF'%) for all sampling periods. This modified value refers to both UTM-based distribution and sampling intensity as follows:
In this equation, only UTM-based distribution data could be used. Since we have numerous data without detailed locations, the fine-scale locality data cannot be calculated. Using it the bias caused by the different sampling intensity of the different periods of the study can be decreased and the changes of relative frequencies of the species can be more correctly evaluated.
In the case of the morphologically similar Bombus hortorum / B. ruderatus, and B. terrestris / B. lucorum species pairs, the calculated RF% and RF'% values were adjusted. The ratio of the two species was calculated for each sampling period based on valid data, and its minimum was chosen for both species. During the calculations of RF% and RF'% values, valid data and the ratio (equal to this minimum value) of the dubious data were taken into consideration.
The national territory of Hungary is divided into by 1052 10×10 km UTM cells, of which 531 contain 3716 bumble bee records (species/UTM cell/period). The first data were collected in 1953 (
The number of studied UTM cells, adjusted according to the length of the periods of data collection was nearly equal in all periods (Fig.
Data on 31 bumble bee species (6 of which are cuckoo bumble bees, subgenus Psithyrus) are presented. Two species (B. distinguendus and B. cullumanus serrisquama) have only archaic (at least 70 years old) data (Fig.
Among the listed species B. fragrans is strictly protected, while B. argillaceus, B. confusus, B. humilis, B. laesus, B. muscorum, B. paradoxus, B. pomorum, B. ruderatus, B. sylvarum, B. soroeensis and B. subterraneus are protected in Hungary (13/2001. (V. 9.) KöM decree) (Table
As seen in Fig.
In the last period of the studies, 835 data records of 21 species were collected from 259 UTM cells, while in the case of eight species we have no new data.
The only valid Hungarian data on B. consobrinus were collected from the Gál-rét, in the Börzsöny Mountains (UTM cell: CU51) after 1970, the exact date unknown (Fig.
Relative frequencies of B. humilis, B. muscorum and B. pomorum have continuously decreased (Figs
In contrast, the relative frequencies of 15 species have increased since the last review (Sárospataki 2003): B. argillaceus, B. campestris, B. haematurus, B. hortorum, B. hypnorum, B. lapidarius, B. lucorum, B. pascuorum, B. pratorum, B. ruderarius, B. ruderatus, B. soroeensis, B. sylvarum, B. terrestris and B. vestalis (Figs
Bumble bees present in Hungary (29 species) with their modified relative frequency (RF'%) calculated for consecutive periods of samplings based on the revised database and the trend of frequency changes till 2005 (based on
Species | Modified relative frequency (RF'%) | Trend | ||||
---|---|---|---|---|---|---|
–1953 | 1954–1970 | 1971–2000 | 2001–2021 | –2005 | 2005–2021 | |
B. argillaceus | 2.38 | 0.73 | 0.90 | 6.64 | - | + |
B. barbutellus | 0.79 | 0.85 | 2.95 | 0.24 | - | |
B. bohemicus | 0.00 | 1.09 | 1.09 | 0.00 | ND | |
B. campestris | 0.00 | 1.09 | 1.22 | 1.42 | + | |
B. confusus | 2.97 | 2.67 | 2.37 | 0.00 | - | - |
B. consobrinus | 0.00 | 0.00 | 0.06 | 0.00 | ND | ND |
B. cryptarum | ND | ND | ND | 0.12 | ND | ND |
B. fragrans | 2.97 | 0.12 | 0.06 | 0.00 | - | - |
B. haematurus | 0.00 | 0.00 | 1.03 | 5.34 | + | + |
B. hortorum | 4.75 | 8.13 | 8.34 | 8.19 | u | u |
B. humilis | 9.31 | 9.59 | 6.35 | 3.68 | - | - |
B. hypnorum | 0.20 | 0.12 | 1.67 | 2.85 | + | + |
B. laesus | 5.94 | 0.24 | 0.45 | 0.00 | - | - |
B. lapidarius | 10.10 | 9.10 | 13.09 | 11.39 | u | u |
B. lucorum | 1.98 | 4.37 | 1.35 | 3.32 | u | + |
B. muscorum | 6.34 | 3.64 | 2.82 | 1.78 | - | - |
B. paradoxus | 1.78 | 0.12 | 0.58 | 0.00 | - | - |
B. pascuorum | 9.90 | 11.29 | 9.37 | 11.86 | u | + |
B. pomorum | 4.55 | 1.46 | 1.54 | 0.83 | - | - |
B. pratorum | 2.18 | 1.94 | 3.08 | 2.02 | u | u |
B. ruderarius | 4.75 | 6.92 | 8.28 | 6.64 | u | u |
B. ruderatus | 5.94 | 3.76 | 1.86 | 2.14 | - | - |
B. rupestris | 0.40 | 5.70 | 3.40 | 0.12 | - | |
B. soroeensis | 0.20 | 0.00 | 0.32 | 0.36 | + | + |
B. subterraneus | 1.98 | 0.97 | 1.67 | 0.00 | u | - |
B. sylvarum | 8.51 | 10.19 | 6.74 | 7.59 | - | u |
B. sylvestris | 0.00 | 0.00 | 0.32 | 0.00 | ND | |
B. terrestris | 9.90 | 13.11 | 15.92 | 15.30 | u | u |
B. vestalis | 0.20 | 2.79 | 3.15 | 1.42 | u |
Considering the long-term trends of the changes in the relative frequencies, seven of the 15 mentioned species showed stable values (B. hortorum, B. lapidarius, B. pratorum, B. ruderarius, B. sylvarum, B. terrestris, B. vestalis), while the frequency of B. ruderatus slightly decreased (Table
New data redraw the area of many Bombus species. In the case of the East-Mediterranean B. argillaceus, the first protected Bombus species in Hungary, both the northern (Tiszatelek; cell EU64) and the eastern (Túristvándi; cell FU22) occurrences in Hungary were recorded after 2000. The relative frequency of the species had decreased between the 1950s and 2000, however, it has spread since 2000 and become widely distributed in the whole country (Table
The intensive spread of B. haematurus was also detected. The first data on the species were collected in the 1980s, but till 2003 it was only known from the central and southern parts of Transdanubia in western Hungary. After that, it appeared east from the Danube and the Tisza Rivers as well (Fig.
We had no data on B. hypnorum from Hungary after the 1990s. Before that it was known from the hilly areas of Transdanubia and northern Hungary. It newly appeared in Transdanubia in 2015 and has been collected several times since 2018 also in eastern Hungary (Fig.
The last review of the Hungarian bumble bee fauna was published in 2003 (
Bombus lucorum and Bombus cryptarum. B. cryptarum belongs to the B. lucorum species complex, with only one Hungarian data from YN21 UTM cell where B. lucorum have been not reported yet. Distribution maps of bumble bee species present in Hungary according to periods of data collection and/or publication. +: before 1954, ×: 1954–1970, empty circle: 1971–2000 and grey square: after 2000.
Confirming the result of
Most species have only a few and in many cases even only archaic records, that accounted for the reevaluation of their status and need of further targeted investigations. The occurrence of 9 species (B. bohemicus, B. confusus, B. consobrinus, B. cryptarum, B. fragrans, B. laesus, B. paradoxus (synonym B. confusus paradoxus), B. subterraneus, B. sylvestris) in Hungary needs verification. On the other hand, distribution of other seven species have become well known with more than 250 UTM data records that allow us to draw a more realistic picture on their distribution, vulnerability status and their role in ecosystem services.
The relative frequencies of the species were recalculated and decreasing of the relative frequency of 11 species were detected and four of them has no data from the last two decades.
Seven species showed constant distribution, while seven others had increasing relative frequencies. In the case of five species, the trend of relative frequency changed during the latest period of studies: the trend of B. sylvarum changed from decreasing to stable, while the trend of B. pascuorum and B. lucorum changed from stable to increasing, and the trend of B. argillaceus changed from decreasing to increasing.
Although members of subgenus Psithyrus were not studied previously (
The previously observed increasing relative frequency of B. hypnorum and B. soroeensis remain increasing also after 2000. The intensive increase of relative frequencies of B. haematurus and B. argillaceus showed continuous spread of these species in Hungary during the last two decades. It can be explained rather with natural expansion, than artificial spreading of managed colonies, since their use is not common in Hungary, however the greening programs and promotion of sustainable agricultural methods methods can also help their spread. Although the expansion of the area of B. haematurus to northwest in Central Europe was already known (
Twenty years ago, Bombus argillaceus was a rare species with a decreasing distribution and was classified as critically endangered according to the IUCN (
Climate change, warming winters and changes in landscape structure can significantly affect the distribution of bumble bee species in Hungary (
Regular monitoring of Bombus assemblages is recommended. The actualized distribution maps provide basis for both gap analysis and prioritization. The investigation of previously unexplored areas (white patches) and UTM cells containing only archaic data, as well as confirmation of the data of species with dubious data should be prioritized.
The authors thank Jenő Papp†, Balázs Károlyi and authors of izeltlabuak.hu web page for making their unpublished data available. Lenner Ádám, colleges of the Tiszatáj Foundation, Tímea Nagy-Szalárdi, Aletta Ősz, Arnold Szilágyi, Anikó Cserenyec, András Líbor, Tibor Venter, Fanni Béres, Barnabás Vasas, Anna Bába, Péter Vámos, Veronika Szentpéteri-Nagy, Krisztina Ary, Kinga Urbán, Bianka Karacs, Edina Török, Viktor Lutián, Gábor Németh, Péter Májer, Orsolya Szakács, Tamás Szilágyi, Edina Bánki, Kristóf Bene, Anna Mester, Krisztina Fruzsina Sinka, Tünde Gyöngyösi and Orsolya Rácz helped with fieldwork. Kálmán Szanyi proofread and improved the revised text. We also thank Jack Neff and an anonymous reviewer for useful criticism.
Miklós Sárospataki was supported by the H2020 Safeguard project funded by the EU (101003476).
Szabolcs Szanyi’s research was financed by the National Research Development and Innovation Office (NKFIH, grant PD 138329).