A General Odorant Background Affects the Coding of Pheromone Stimulus Intermittency in Specialist Olfactory Receptor Neurones

In nature the aerial trace of pheromone used by male moths to find a female appears as a train of discontinuous pulses separated by gaps among a complex odorant background constituted of plant volatiles. We investigated the effect of such background odor on behavior and coding of temporal parameters of pheromone pulse trains in the pheromone olfactory receptor neurons of Spodoptera littoralis. Effects of linalool background were tested by measuring walking behavior towards a source of pheromone. While velocity and orientation index did drop when linalool was turned on, both parameters recovered back to pre-background values after 40 s with linalool still present. Photo-ionization detector was used to characterize pulse delivery by our stimulator. The photo-ionization detector signal reached 71% of maximum amplitude at 50 ms pulses and followed the stimulus period at repetition rates up to 10 pulses/s. However, at high pulse rates the concentration of the odorant did not return to base level during inter-pulse intervals. Linalool decreased the intensity and shortened the response of receptor neurons to pulses. High contrast (>10 dB) in firing rate between pulses and inter-pulse intervals was observed for 1 and 4 pulses/s, both with and without background. Significantly more neurons followed the 4 pulses/s pattern when delivered over linalool; at the same time the information content was preserved almost to the control values. Rapid recovery of behavior shows that change of perceived intensity is more important than absolute stimulus intensity. While decreasing the response intensity, background odor preserved the temporal parameters of the specific signal

Effects on Some Therapeutical, Biochemical, and Immunological Parameters of Honey Bee (Apis mellifera) Exposed to Probiotic Treatments, in Field and Laboratory Conditions

Several negative factors contribute to a decline in the number of insect pollinators. As a novel approach in therapy, we hypothesize that the EM® for bees could potentially have an important therapeutic and immunomodulatory e ect on honey bee colonies. The aim of our study was to evaluate its impact on honey bees at the individual and colony level. This is the first appliance of the commercial probiotic mix EM® PROBIOTIC FOR BEES in honey bees as economically important social insects. The sugar syrup with 10% of probiotic was administered by spraying or feeding the honey bee colonies in the field conditions, in order to evaluate the infection levels with spores of Nosema spp. and colonies’ strength. Moreover, in laboratory-controlled conditions, in the hoarding cages, adult workers have been fed with sugar syrup supplemented with 2.5, 5, and 10% of EM® for bees for biochemical and immunological analyses of hemolymph, and with 5 and 10% for measuring the size of hypopharyngeal glands. It was found that following the EM® for bees administration the Nosema spp. spore counts in colonies were significantly reduced, and colonies’ strength was increased. The results at the individual level showed significant positive physiological changes in treated groups of adult bees, revealing at the same time a higher mortality rate when feeding sugar syrup supplemented with the probiotic

Census of the Ural owl Strix uralensis macroura at Javorniki in central Slovenia

In the year 2000, a census of the Ural Owl Strix uralensis was carried out in selected areas of the Javorniki Mountains. The census was performed three times between April and the end of June by means of the playback method. The established density of 5,1 pairs/10 km2 corresponds to the highest Ural Owl densiry in Slovenia. During the census, altitudinal belrs from 600 to 1100 meters above sea level were surveyed. It was established that the highest UralOwl density was in the altitudinal belt stretching from 900 to 990 meters above sea leve(, which fully corresponds to the results obtained by previous researches

Impact of forest structure on honey harvest in Slovenia

V lesni zalogi sestojev smo proučili vpliv količine medonosnih drevesnih vrst na donos medu. Za 70 čebeljih družin v Sloveniji smo uporabili podatke o donosih medu za posamezne drevesne vrste glede na čebelarsko najugodnejša leta in v radiju treh kilometrov od panja in izračunali: a) število čebeljih družin (n), b) gozdnatost (%) ter c) skupno lesno zalogo medonosnih drevesnih vrst (m3 ). Vpliva števila družin na donos medu v panj v večini primerov nismo potrdili (p > 0,05), statistično značilno pa vpliva na donos gozdnega in smrekovega medu. Delež gozda je v pozitivni korelaciji (r > 0,84p 0,05). The proportion of forest is in positive correlation (r > 0, p < 0,05) with the intake of forest honey in a beehive, same as the proportion of forest and spruce honey. For other species, the proportion of forest doesn%t affect honey income. According to the curves for tree species, we can predict honey income for forest stands in Slovenia