The diet of the European Ground Squirrel (Spermophilus citellus L. 1766) in Serbia

Ishrana je jedan od osnovnih životnih procesa koji životinjama obezbeđuje energiju i hranljive materije za rast i normalno funkcionisanje organizma. Optimalnost ishrane umnogome zavisi od dostupnosti hranidbenih resursa. Ovo  je naročito važno za hibernatore, kojima preživljavanje perioda hibernacije i reproduktivni uspeh direktno zavise od masnih naslaga nakupljenih tokom skraćene sezone aktivnosti. Tekunica, ugroženi predstavnik faune travnatih ekositema centralne i južne Evrope, nije izuzetak. Zbog gubitka velikih površina travnatih staništa usled razvoja poljoprivrede i napuštanja tradicionalnih oblika stočarstva, ova vrsta je izgubila najveći deo svog nekadašnjeg areala. Smatra se da je najveći broj staništa tekunice suboptimalnog karaktera. U studiji je, u cilju procene pogodnosti naseljenih staništa u Srbiji, izvedena analiza ishrane vrste na slatinskim i stepskim pašnjacima u Vojvodini te na visokoplaninskim livadama jugoistočne Srbije. U cilju procene dostupnih hranidbenih resursa, određen je diverzitet vegetacijskog pokrivača na istraživanim tipovima staništa. U proceni ishrane korištena je neinvazivna metoda mikrohistološke analize izmeta. Diverzitet vegetacije (hranidbene baze za tekunicu) značajno se razlikuje između  stanišnih tipova. U ishrani tekunice učestvuje veliki broj kategorija hrane biljnog i, značajno manje, životinjskog porekla. Ipak, kao najznačajnije izdvajaju se:  Achillea millefolium, mahunarke i trave. Dokazano je sezonsko variranje ishrane, kao i razlike u ishrani na različitim staništima. U studiji su, takođe, prikazane razlike u ishrani na nivou jedinki, čime se stiče uvid u različite strategije ishrane na različitim staništima. Rezultati ove studije nedvosmisleno ukazuju na postojanje selekcije ka određenom broju taksona u ishrani tekunice i naročito su značajni za izradu planova upravljanja vrstom i njenim staništima.Feeding is among the basic life history processes enabling animals to obtain energy and nutrients for the growth and normal functioning of their organisms. The optimality of diet depends a great deal upon the availability of feeding resources. This is especially important for hibernators, whose survival of the hibernation period and subsequent reproductive success depend directly on the fat reserves accumulated during the shortened active period. The European ground squirrel, an endangered representative of Central-  and South-European grasslands, is no exception. Due to a loss of vast areas of grasslands following agriculture development and the abandonment of traditional grazing practices, the specieslost the majority of its historical distribution. Most European ground  squirrel habitats are considered suboptimal. In this study, to evaluate the suitability of the occupied species’ habitats in Serbia, the diet analysis of the species was performed on steppe and saline pastures in Vojvodina and alpine meadows in southeastern Serbia. To gauge the availability of dietary resources, the diversity of the studied habitat types was assess. For diet estimation, the non-invasive method of microhistological analysis of feces was employed. The diversity of vegetation (the trophic base  for the ground squirrel) differs among the habitat types. A number of diet categories are present in the species’ diet. However,  Achillea  millefolium, legumes, and grasses were proven to be the most important ones. The study showed a seasonal variability of diet and variation among different habitats. Furthermore, a difference in diet among individuals is shown, giving insight into different feeding strategies on different  habitats. Results of this study unequivocally show a selection of few taxa in the diet  of the European ground squirrel  and  are especially important when developing species-and habitat management plans

The diet of the European Ground Squirrel (Spermophilus citellus L. 1766) in Serbia

Ishrana je jedan od osnovnih životnih procesa koji životinjama obezbeđuje energiju i hranljive materije za rast i normalno funkcionisanje organizma. Optimalnost ishrane umnogome zavisi od dostupnosti hranidbenih resursa. Ovo  je naročito važno za hibernatore, kojima preživljavanje perioda hibernacije i reproduktivni uspeh direktno zavise od masnih naslaga nakupljenih tokom skraćene sezone aktivnosti. Tekunica, ugroženi predstavnik faune travnatih ekositema centralne i južne Evrope, nije izuzetak. Zbog gubitka velikih površina travnatih staništa usled razvoja poljoprivrede i napuštanja tradicionalnih oblika stočarstva, ova vrsta je izgubila najveći deo svog nekadašnjeg areala. Smatra se da je najveći broj staništa tekunice suboptimalnog karaktera. U studiji je, u cilju procene pogodnosti naseljenih staništa u Srbiji, izvedena analiza ishrane vrste na slatinskim i stepskim pašnjacima u Vojvodini te na visokoplaninskim livadama jugoistočne Srbije. U cilju procene dostupnih hranidbenih resursa, određen je diverzitet vegetacijskog pokrivača na istraživanim tipovima staništa. U proceni ishrane korištena je neinvazivna metoda mikrohistološke analize izmeta. Diverzitet vegetacije (hranidbene baze za tekunicu) značajno se razlikuje između  stanišnih tipova. U ishrani tekunice učestvuje veliki broj kategorija hrane biljnog i, značajno manje, životinjskog porekla. Ipak, kao najznačajnije izdvajaju se:  Achillea millefolium, mahunarke i trave. Dokazano je sezonsko variranje ishrane, kao i razlike u ishrani na različitim staništima. U studiji su, takođe, prikazane razlike u ishrani na nivou jedinki, čime se stiče uvid u različite strategije ishrane na različitim staništima. Rezultati ove studije nedvosmisleno ukazuju na postojanje selekcije ka određenom broju taksona u ishrani tekunice i naročito su značajni za izradu planova upravljanja vrstom i njenim staništima.Feeding is among the basic life history processes enabling animals to obtain energy and nutrients for the growth and normal functioning of their organisms. The optimality of diet depends a great deal upon the availability of feeding resources. This is especially important for hibernators, whose survival of the hibernation period and subsequent reproductive success depend directly on the fat reserves accumulated during the shortened active period. The European ground squirrel, an endangered representative of Central-  and South-European grasslands, is no exception. Due to a loss of vast areas of grasslands following agriculture development and the abandonment of traditional grazing practices, the specieslost the majority of its historical distribution. Most European ground  squirrel habitats are considered suboptimal. In this study, to evaluate the suitability of the occupied species’ habitats in Serbia, the diet analysis of the species was performed on steppe and saline pastures in Vojvodina and alpine meadows in southeastern Serbia. To gauge the availability of dietary resources, the diversity of the studied habitat types was assess. For diet estimation, the non-invasive method of microhistological analysis of feces was employed. The diversity of vegetation (the trophic base  for the ground squirrel) differs among the habitat types. A number of diet categories are present in the species’ diet. However,  Achillea  millefolium, legumes, and grasses were proven to be the most important ones. The study showed a seasonal variability of diet and variation among different habitats. Furthermore, a difference in diet among individuals is shown, giving insight into different feeding strategies on different  habitats. Results of this study unequivocally show a selection of few taxa in the diet  of the European ground squirrel  and  are especially important when developing species-and habitat management plans

Endangered species’ trait responses to environmental variability in agricultural settings

Understanding the spatial and temporal effects of variable environmental conditions on demographic characteristics is important in order to stop the decline of endangered-species populations. To capture interactions between a species and its environment, in this work the demographic traits of the European ground squirrel (EGS), Spermophilus citellus, were modeled as a function of agricultural landscape structure. The habitat suitability index was determined for 20 localities within the study area based on habitat use, management and type. After mapping the habitat patch occupancy in the field, crop cover maps, the average normalized difference vegetation index (NDVI) and automated water extraction index (AWEI) were obtained from satellite images covering the period 2013-2015. This data was used to develop population-level generalized linear models (GLMs) and individual-level conditional mixed-effects models (GLMMs) in R package Ime4, focusing on the key demographic traits of the EGS. The land composition and patch carrying capacity (PCC) are the key determinants of the endangered EGS population size, while system productivity is the main factor influencing individuals’ body condition after monitoring for variations across sampling years and age classes. The proposed landscape structural models show that human activities and abiotic factors shape the demographic rates of the EGS. Thus, to conserve threatened species, an appropriate focus on the spatial adaptation strategies should be employed

MERODON NATANS AND M. PULVERIS (DIPTERA: SYRPHIDAE): DELIMITATING CRYPTIC HOVERFLY SPECIES USING THE GEOMETRIC MORPHOMETRIC METHOD

A landmark-based geometric morphometric method was employed to delimitate two morphologically closely-related species of the hoverfly Merodon natans species group based on wing parameters. The studied species, Merodon natans and M. pulveris, were successfully determined using this method. Analyses revealed a significant difference in wing size and shape between individuals of the two species, thereby proving that these are two distinct species, even though, morphologically very similar. Discriminant and cluster analyses also uncovered a subtle difference in wing shape between M. pulveris populations, indicating intraspecific differentiation with potential conservation implications. The results of the morphological study were supplemented with known distribution data of the investigated species

Review of the Merodon natans group with description of a new species, a key to the adults of known species of the natans lineage and first descriptions of some preimaginal stages

Merodon natans group (Diptera, Syrphidae) taxa are reviewed using an integrative taxonomic approach combining morphological, morphometric and molecular techniques. The approach substantiates recognition of the three species: M. calcaratus (Fabricius, 1794), M. natans (Fabricius, 1794) and M. pulveris Vujić & Radenković in Radenković et al. 2011, and reveals the existence of a new species, M. makrisi Vujić, Radenković & Tot sp. nov., which is described. It also highlights the existence of a series of natans group populations, especially on some of the Mediterranean islands, in the Levant and in the Afrotropical Region, for which more comprehensive data are required to clarify their status. A key is provided to the natans lineage species currently recognised, and preimaginal stages of some natans-group species are described for the first time. Redescriptions for M. calcaratus and M. natans are provided. A neotype is selected for M. natans. Lectotypes are designated for M. annulatus (Fabricius, 1794) and M. melancholicus (Fabricius, 1794). Merodon annulatus is recognised as a synonym of M. natans.The authors acknowledge financial support of the Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant No. 451-03-9/2021-14/200125 and Grant No. 451-03-9/2021-14/200358). André van Eck was financially supported for research in Cyprus by the Dutch Uyttenboogaart-Eliasen Foundation (UES), with grant nrs. SUB.2016.12.12 and SUB.2018.12.03

The Extraordinary Diversity of <i>Merodon avidus</i> Complex (Diptera: Syrphidae)—Adding New Areas, New Species and a New Molecular Marker

In this paper, the Merodon avidus (Diptera, Syrphidae) species complex was revised, whereupon we discovered and described four new species for science: Merodon atroavidus Vujić, Radenković et Likov sp. nov., M. magnus Vujić, Kočiš Tubić et Ačanski sp. nov., M. nigroscutum Vujić, Radenković et Likov sp. nov. and M. pseudomoenium Vujić, Kočiš Tubić et Ačanski sp. nov. An integrative taxonomy approach was used to delimit species boundaries. Two molecular markers (the mitochondrial COI gene and nuclear 28S rRNA gene—newly analysed marker for the complex) and geometric morphometry of the wing shape, together with morphological data and distribution, successfully separated all species from the complex. The morphological variability of the analysed species is described and discussed and an illustrated diagnostic key for typical morpho-forms of species from the M. avidus complex is presented. A distribution map of all investigated species from the complex is provided. The level of endemicity of the M. avidus complex was discussed