Teodora Ivanova

Ground gleaning in horseshoe bats: comparative evidence from Rhinolophus blasii, R. euryale and R. mehelyi

The 71 species of horseshoe bat (genus Rhinolophus) use echolocation calls with long constant-frequency (CF) components to detect and localize fluttering insects which they seize in aerial captures or glean from foliage. Here we describe ground-gleaning as an additional prey-capture strategy for horseshoe bats. This study presents the first record and experimental evidence for ground-gleaning in the little-studied Blasius’ horseshoe bat (Rhinolophus blasii). The gleaning bouts in a flight tent included landing, quadrupedal walking and take-off from the ground. The bats emitted echolocation calls continuously during all phases of prey capture. Both spontaneously and in a choice experiment, all six individuals attacked only fluttering insects and never motionless prey. These data suggest that R. blasii performs ground-gleaning largely by relying on the same prey-detection strategy and echolocation behaviour that it and other horseshoe bats use for aerial hawking.We also studied the Mediterranean horseshoe bat (R. euryale) in the flight tent. All four individuals never gleaned prey from the ground, though they appeared to be well able to detect fluttering moths on the ground. It is not known yet whether ground-gleaning plays a role in Mehely’s horseshoe bat (R. mehelyi). In a performance test, we measured the ability of these three European species of “middle-sized” horseshoe bats (R. euryale, R. mehelyi and R. blasii) to take-off from the ground. All were able to take flight even in a confined space; i.e. the willingness to ground-glean in R. blasii is not related to a superior take-off performance. In contrast to ground-gleaning bats of other phylogenetic lineages, R. blasii appears not to be a specialist, but rather shows a remarkable behavioural flexibility in prey-capture strategies and abilities. We suggest that the key innovation of CF echolocation paired with behavioural flexibility in foraging strategies might explain the evolutionary success of Rhinolophus as the second largest genus of bat.

Isoenzyme variation and genetic affinities among four species of the genus Festuca L. (Poaceae)

Abstract Festuca L. is one of the most complicated genera in Poaceae. Polyacrylamide gel electrophoresis was used to study the isoenzyme variation of glutamate-oxaloacetate transaminase, malate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase in natural populations of F. valesiaca Schleich. ex Gaud., F. rupicola Heuff., F. dalmatica (Hack.) K. Richt. and F. stojanovii (Acht.) Kozuharov ex Foggi & Petrova. The aim of the present study was to assess isoenzyme variation and genetic affinities among the four species of the genus Festuca. Genetic identities (I) and distances (D) were calculated to evaluate qualitative genetic affinities and systematic relationships among the species. Considering the patterns of isoenzyme variation in the studied group, it is evident that F. dalmatica and F. stojanovii are closely related species. The species F. valesiaca and F. rupicola are isoenzymatically well characterized as distinct genetic entities. The obtained results generally support recent narrow species concept in the genus Festuca.

Ex situ conservation of Ruscus aculeatus L. - ruscogenin biosynthesis, genome-size stability and propagation traits of tissue-cultured clones.

Ruscus aculeatus L. is a perennial semi-shrub with distinctive leaf-like branches (cladodes). Rhizomes and roots contain steroidal saponins (ruscogenins) that are used in medicine and cosmetics for their anti-inflammatory, venotonic and antihaemorroidal activity. Problematic cultivation of the species causes in many countries unsustainable over-collection from the wild. Tissue culture propagation of R. aculeatus was carried out for conservation and propagation purposes. The impact of the clonal origin (genotype) on the ruscogenin biosynthesis, genome-size stability and propagation traits and morpho-physiological response to long-term cultivation in vitro was studied. Production of ruscogenins in fully developed regenerants was quantified by high-performance liquid chromatography (HPLC). Genome-size stability of the clones was assessed by flow cytometry. Slow growth and prolonged lag-phase were characteristic for the whole propagation cycle. Produced plantlets with well-defined organs were suitable for direct ex vitro planting. Genome DNA content of all clones was stable and comparable to native plants. Ruscogenin biosynthesis was clone-specific, presenting distinctive profiles of the cultures. Our results imply that clone origin and culture type might influence saponin biosynthesis in Ruscus. These traits should be considered in the ex situ conservation of the genetic diversity of this species and by production of planting material as well.

Effect of the Administration of PGF2α Analogue to Extended Boar Semen on Sperm Motility, Morphology and Kinematic Parameters

Abstract The addition of prostaglandin F2α (PGF2α) to boar semen prior to insemination improves the conception and farrowing rates in sows. It is accepted that this is due to increased myometrial contractility, which improves the spermatozoa movement. However, there are limited data about the effect of the exogenous PGF2α analogs on sperm motility parameters and morphology. The aim of the current study was to define if there are changes in motility, morphology and kinematic parameters of spermatozoa on 1st and 24th hour after addition of PGF2α analogue to extended boar semen. A total of 18 ejaculates, obtained from clinically healthy boars were diluted 1:3 in semen extender, and each of them was separate into four aliquots, 50 ml each. PGF2α was added to 3 of them in concentrations of 6, 12 and 25 μg/ml, and the fourth served as untreated control. The motility, kinematic parameters and morphology of spermatozoa were evaluated on 1st and 24th hours after addition of PGF2α. There was no significant difference in sperm morphology, total and progressive motility between the untreated and treated groups. There was however a significant decrease in the rapid velocity and some of the kinematic parameters (VCL, VSL and VAP) in the group treated with 25 μg/ml compared to the control at the 1st hour after PGF2α treatment, which (except for the rapid velocity) persisted to the 24th hour. The results indicate that addition of Oestrophan (Bioveta, CZ) to the extended boar semen did not improve the sperm motility, morphology and kinematic parameters of the spermatozoa.