Biology subjects

Sima, P.

Publications and source records attributed to Sima, P..

3 recordsLinked to original sources

bioRxiv2025

Bombus terrestris Complementary Sex Determiner (BtCSD) is identified as a conserved hymenopteran sex determination region: evolution, breeding, and conservation implications

All Hymenoptera (bees, sawflies, ants, wasps) are haplodiploid. Haploid males develop from unfertilized eggs and diploid females from fertilized eggs. Many species also have single locus complementary sex determination (sl-CSD): hemizygosity of a CSD gene results in normal males and heterozygosity in normal females, but homozygosity typically yields sterile diploid males. Populations that lose CSD allelic diversity to critical level, increasingly produce detrimental diploid males. Emblematic of this problem are the bumblebees. Bumblebees are one of the fastest declining animal groups worldwide, with CSD diversity loss playing a likely role, especially in isolated populations. Presently utilized and potential future species in agriculture are also challenged by diploid males in production. Population management of both requires exact knowledge of the CSD locus. Here we report the identity of Bombus terrestris CSD, a bumblebee model that is also a major commercial pollinator. As CSD must be reciprocally homozygous in diploid males and heterozygous in diploid females, we whole-genome-sequenced these for four colonies. From this, we identified B. terrestris CSD (BtCSD) on Chromosome 2: a 26 Kb region with a long non-coding RNA region (lncRNA) and a proximate hypervariable region. Comparative analyses indicated conservation of this region across infraorder Aculeata, including other bumblebees, mason bees, and ants. This supports a deep-rooted ancestral origin for BtCSD despite a lack of homology with con-familial honey bee csd and rapid evolutionary divergence of insect sex determination cascades. Our analyses do not support the lncRNA region as functional CSD, as proposed for other taxa, because of inadequate variation to constitute distinct alleles. Rather, a downstream region is implicated for its massive structural variation and candidate coding genes including Creld and two copies of aCOP. We discuss how this identification of BtCSD has critical implications for hymenopteran evolution and bumblebee population management.

genomics↗

bioRxiv2024

First records of invasive Vespa velutina nigrithorax Buysson, 1905 (Hymenoptera: Vespidae) and Megachile sculpturalis Smith, 1853 (Hymenoptera: Megachilidae) in Slovakia

Biological invasions are an increasing threat to ecosystems; early identification of invasive species and rigorous monitoring are prerequisites to minimize environmental damage. Currently, two large hymenopterans of Asian origin are spreading across Europe: the yellow-legged hornet Vespa velutina nigrithorax Buysson, 1905 and the giant resin bee Megachile sculpturalis Smith, 1853, populations of which have been gradually being discovered across Europe since 2004 and 2008, respectively. Considering the current distribution of both species in Europe, further spread through Central Europe is expected in recent years. In July 2024, the first record of M. sculpturalis was documented in Slovakia, followed by more reports from 11 localities. Less than two months later, the second invasive hymenopteran, V. velutina nigrithorax, was also detected. Utilising multiple methods, their nest was discovered as well. On-site observations showed that the yellow-legged hornets (workers) were active almost two days after colony eradication. The finding of both species was accompanied by an intensive campaign using citizen science.

zoology↗

bioRxiv2020

The hotter, the better: warmer winters boost the natural spread of an eastern Mediterranean bumblebee (Hymenoptera: Apidae: Bombus haematurus)

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 queens 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.

ecology↗