Species range expansions are crucial for understanding niche formation and the interaction with the environment. Here, we studied the bumblebee Bombus haematurus Kriechbaumer, 1870, a species historically distributed from northern Serbia through northern Iran which has very recently started expanding northwestward into Central Europe without human-mediated dispersal (i.e., it is a natural spread). After updating the global distribution of this species, we investigated if niche shifts took place during this range expansion between newly colonized and historical areas. In addition, we have explored which climatic factors may have favored the natural range expansion of the species. Our results indicated that Bombus haematurus has colonized large territories in 7 European countries outside the historical area in the period from the 1980s to 2018, a natural expansion over an area that equals 20% of the historical distribution. In addition, this bumblebee performs generalism in flower visitation and it occurs in different habitats, although a preference for forested areas clearly emerges. The land-use associated with the species in the colonized areas is similar to the historical distribution, indicating that no major niche shifts occurred during the spread. Furthermore, in recently colonized localities, the range expansion was associated with warming temperatures during the winter and also during both queen overwintering and emergence phases. These findings document a case of natural range expansion due to environmental change rather than due to niche shifts, and specifically they suggest that warmer winters could be linked to the process of natural colonization of new areas.

Threatened bee species of Europe in Slovenia Three Endangered, seven Vulnerable and 40 Near Threatened species from the European Red List of Bees were recorded in Slovenia. Their distribution in Slovenia is overviewed and the importance of local populations for their survival in Europe is evaluated. Among the Endangered species the Slovenian population of Colletes graeffei is important. The species has also its locus typicus in Slovenia. Interesting is the case of Epeolus cruciger which is very numerous in Slovenia due to transition to a secondary host, Colletes hederae. Its other host, Colletes succinctus, is endangered in Slovenia.

Range expansions of naturally spreading species are crucial for understanding how species interact with the environment and build their niche. Here, we studied the bumblebee Bombus haematurus Kriechbaumer, 1870, a species historically distributed in the eastern Mediterranean area which has very recently started expanding northwards into Central Europe. After updating the global distribution of this species, we investigated if niche shifts took place during this range expansion between colonized and historical areas. In addition, we have explored which climatic factors have favoured the natural range expansion of the species. Our results indicated that Bombus haematurus has colonized large territories in 7 European countries outside the historical area in the period from the 1980s to 2018, a natural expansion over an area that equals the 20% of the historical distribution. In addition, this bumblebee performs generalism in flower visitation and habitat use, although a preference for forested areas emerges. The land-use associated with the species in the colonized areas is similar to the historical distribution, indicating that no major niche shifts occurred during the spread. Furthermore, the component of climate change that favoured this colonization is the warming of winter temperatures and similar warming rates took place during both overwintering and queen’s emergence phases. These findings document a case of natural range expansion due to environmental change rather than due to niche shifts, and specifically they indicate that warmer winters are playing a major role in the process of natural colonization of new areas.

Vloga reber pri nastanku in napredovanju idiopatske skoliozeRole of the ribs in the onset and progression of idiopathic scoliosis andrej gogala IzvlečekPatogeneza idiopatske skolioze je še vedno predmet razprave, saj skupni vzrok ni bil odkrit. A pri njenem nastanku in napredovanju obstaja nekaj osnovnih načel. Krivino hrbtenice vedno spremlja zasukanost vretenc in prsnega koša. Če želimo razložiti načela, po katerih se ravna nastanek in napredovanje skolioze, moramo odgovoriti na nekaj vprašanj: 1. Zakaj stransko ukrivljenost hrbtenice vedno spremlja sukanje prsnega koša in vretenc, da so najbolj zasukana vretenca pri vrhu krivine; 2. Ali strukturno skoliozo določa primarna rast kosti v rastnih ploskvah vretenc ali kostno preoblikovanje, s katerim se kosti prilagajajo zunanjim obremenitvam; 3. Zakaj je večina prsnih krivin usmerjenih v desno; in 4. Kaj vodi v napredovanje skolioze? V tukaj predstavljeni teoriji je pozornost namenjena vlogi reber. Someren prsni koš drži vretenca v središčni osi telesa in preprečuje obračanje vretenc z dvojnimi sklepnimi površinami na vsaki strani vretenca. Rebra so povezana z medrebrnimi mišicami in se ne morejo razmakniti na izbočeni strani, ko se hrbtenica upogne. Krivina hrbtenice v prsnem predelu ni možna brez obračanja vretenc in deformacije reber. Rebra pri vrhu krivine povleče navznoter proti vretencem, ker so premaknjena dlje od sredine kot druga rebra. Z obračanjem vretenc pri vrhu krivine, ki jih rebra stiskajo, se prsni obseg zmanjša in napetost v steni popusti. Deformacija postane nepovratna, če nova rast ali razgradnja in preoblikovanje kosti spremenijo obliko reber in vretenc ali če vezi niso dovolj čvrste. Pri utrjevanju strukturne skolioze je preoblikovanje kosti verjetno pomembnejše kot primarna rast kosti. Ko prsni koš in vretenca postanejo strukturno zasukani, vretenca izgubijo ravnovesno podporo reber z obeh strani. Strižne sile reber dodatno obračajo vretenca in potiskajo telesa vretenc na izbočeno stran. Neprenehno napredovanje skolioze se začne. AbstractThe pathogenesis of idiopathic scoliosis is still a matter of debate as its common cause has not been found. But some basic principles of its onset and progression do exist. The curvature of the spine is always accompanied by rotation of the vertebrae and rib cage. If we want to explain the principles governing scoliosis onset and progression, we should answer some questions. First, why is side curvature of the spine always accompanied by rotation of the rib cage and vertebrae and vertebral rotation is maximal at the curve apex? Second, is structural scoliosis fixed by primary bone growth in growth plates of the vertebrae or by bone remodeling by which bones adapt to external loads? Third, why most of the curvatures are right thoracic? And fourth, what drives the progression of scoliosis? In the theory presented here, attention is given to the role of the ribs. Symmetrical rib cage fixes vertebrae in the midline of the body and prevents rotation of the vertebrae with dual articulating surfaces on each side ...

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