Studia Universitatis Babeş-Bolyai Biologia

Population dynamics of Euphyllura olivina Costa, 1857 (Psyllidae: Hemiptera) in olive trees in the semi-arid region of Djelfa (Algeria)

Nassima Chaabane — 2023-12-27

We studied the population dynamics of the olive psyllid Euphyllura olivina Costa, 1857 in a semi-arid region (Djelfa, central Algeria) during a year, from December 2017 to November 2018. The visual control approach and the striking method were used to monitor the different stages of this pest. The species had two generations per year: a spring generation from March to June and a fall generation from September to November. The first generation of eggs is laid in March and continues through May. The second generation begins in late August and early September and continues through November. The statistical study of the impact of the researched climatic factors (minimum, maximum, and average temperatures; precipitation and frost) on the various stages differs from one stage to the next.

First notes on plant diversity, finding sites and sex ratio in natural populations of Thrips tabaci Lindeman (Thysanoptera: Thripidae) in Algeria (Biskra province)

Rima Rechid — 2023-12-27

Thrips tabaci Lindeman (Thysanoptera: Thripidae), commonly known as onion thrips, is a serious global pest of commercial onion, causing direct and indirect important damages. This survey carried out in natural areas of Biskra province (Algeria) during two periods, 2008/2009 and 2011/2012, aims to review the plant species harbouring T. tabaci in this region.

Algerian and Spanish researchers confirmed twenty-three thrips species. T. tabaci is the most abundant and polyphagous. Studies have indicated that it settled in fifty one plant species belonging to nineteen botanical families. The most important are Asteraceae, Brassicaceae, Fabaceae, and Amaranthaceae. In Biskra, T. tabaci was found in sites between -32 m and 1000 m of sea level. The results also indicate the presence of sexual and asexual populations.

This study shows that T. tabaci is ubiquitous in the natural habitat of Biskra province. Further research is needed to confirm its host plants and the most common mode of reproduction in this region by studying the largest number of plants in various environments and demonstrating the sex ratio over a broad survey spectrum.

Good news from newts: distribution, population size, and dynamics of two protected newt species in the Jiu Gorge National Park, Romania

Severus-Daniel Covaciu-Marcov — 2023-12-27

Long-time monitoring studies recently indicated that newts are in decline in many regions. Motivated by the above-mentioned, in the year 2019, we started monitoring the newt populations from the Jiu Gorge National Park (JGNP) in the Romanian Carpathians, 10 years after the previous study on the same topic. Compared with other areas where newts are in decline, we identified new distribution locations of the two newt species which are present in the park. Also, the previously known populations have greatly increased. Thus, the Lissotriton vulgaris population increased 2.58 times in 10 years, and the Triturus cristatus increased 1.80 times in 10 years. At the same time, in areas from JGNP affected by human activities in the past (abandoned quarry and areas adjacent to the railway), the newts extended their range in the last years and occupied artificial aquatic habitats. In the case of the populations from the natural habitat, the temporal dynamics and the ratio between sexes and species followed the same evolution as in the case of other populations from Romania. The increase of newt populations from JGNP in the last 10 years was most probably a consequence of the reduced human pressure, corroborated with the large surface occupied by native forests in the park. Thus, in natural areas, probably the best management measures for both newt species are not represented by direct (invasive) human interventions but by the conservation of the natural habitats used by the newts. A protected area should maintain the conservation status at least at the present level, and if the region is natural, this fact will maintain and also increase the newt and probably other amphibian populations.

Dual resistance to heavy metals and antibiotics of Aeromonas hydrophila isolated from Carassius carassius (Linnaeus, 1758) in Lake Tonga, Algeria

Lamia Benhalima — 2023-12-27

Aeromonas hydrophila, a bacterium with significant virulence potential, is the predominant pathogenic bacteria naturally infecting fish. This study aims to identify the antibiogram and heavy metal resistance pattern of Aeromonas hydrophila obtained from both Carassius carassius fish and their surrounding water environment in Lake Tonga, Algeria. A total of 59 strains of Aeromonas hydrophila were isolated from 168 Carassius carassius samples and 144 waters samples of Lake Tonga. All the strains were tested for resistance to 13 antibiotics and three types of heavy metals (Cobalt, copper and cadmium) using disk diffusion and two-fold agar dilution method, respectively. Clinical macroscopic examination of the fish was also carried out. More than 14% of the examined fishes showed the characteristic clinical signs. Drug screening showed high levels of resistance to β-lactam antibiotics, 100% of the strains were resistant to ampicillin followed by cefalotin (91.53%) and ticarcillin (88.14%). More than 40% of the strains exhibited resistance against gentamicin, amikacin and chloramphenicol. The multiple antibiotic resistance (MAR) indexing of A. hydrophila strains showed that all of them originated from high-risk sources. Among tested heavy metals, bacterial isolates exhibited resistant pattern of Co>Cu >Cd. A positive correlation was observed between antimicrobial resistance and metal tolerance (Odds Ratio>0.1). These resistant profiles could be useful information to avoid unnecessary use of chemical and antimicrobial products in the aquatic environment and to provide a novel approach to manage bacterial infection in fish.

Abstracts of The Annual International Conference of the Romanian Society of Biochemistry and Molecular Biology, September 13-15, 2023, Cluj-Napoca, Romania

2023-12-27

The issue contains the abstracts presented at The Annual International Conference of the Romanian Society of Biochemistry and Molecular Biology, September 13-15, 2023, Cluj-Napoca, Romania.