Accumulating behavioural data indicate that aggregation pheromones may mediate formation and sustaining of swarms of mosquitoes. However, chemical cues possibly luring mosquitoes to swarms have not been adequately investigated and the likely molecular incitants of these complex reproductive behaviours remain unknown. Here we show that males of important malaria vector species Anopheles arabiensis and Anopheles gambiae produce and release aggregation pheromones that attract individuals to the swarm, and enhance mating success. We found that males of both species released significantly higher amounts of 3-hydroxi-2-butanon (acetoin), 6-methyl-5-hepten-2-one (sulcatone), octanal, nonanal, and decanal during swarming in the laboratory. Males fed with stable isotope-labelled glucose, revealed that these five compounds were produced by them. A blend composed of synthetic analogues to these swarming odours proved highly attractive to virgin males and females of both species under laboratory conditions and significantly increased mating in five African malaria vectors: An. gambiae, Anopheles coluzzii, An. arabiensis, Anopheles merus and Anopheles funestus in semi-field experiments. Our results not only narrow a conspicuous gap in understanding a vital aspect of the chemical ecology of male mosquitoes but also demonstrate fundamental roles of rhythmic and metabolic genes in the physiology and behavioural regulation of these vectors. These identified aggregation pheromones have great potential for exploitation against these highly dangerous insects. Anopheles males, as among many other mosquito species, form mating swarms 1 that vary in size and temporal stability [2][3][4] . Wild Anopheles males swarm during sunset 1,5-7 and are often found near contrasting shade ground features, presumably guided by that visual cue 1,4,5,8 . Factors and mechanisms of swarming initiation in mosquitoes are still debatable 9 . A few studies have shown that initiation of swarming in mosquitoes is governed by the inherent circadian clock 10,11 and fine-tuned by environmental conditions [12][13][14] . However, very little is known about chemical cues that may mediate the formation and maintenance of male swarms and attracting females to those swarms in order to copulate 15 .2,6,6-trimethylcyclohex-2-ene-1,4-dione was isolated from males and females of Aedes aegypti mosquitoes and stimulated swarming behaviour by increasing number of swarming males and extending activity in a dose depending manner 15 .Another study revealed that under laboratory conditions, swarming of Ae. aegypti males was triggered with a host odour at the onset of scotophase but chemical cues remain unknown 16 .Behavioural tests showed that volatiles released from alive or dead males of three Culex species attracted significantly more conspecific females than the control odour without males 17 pointing out that attraction of females to swarms may be mediated by a sex pheromone. 1-(4-Ethylphenyl) ethanone, produced by both sexes of Ae. aegypti mosquitoes, elicited attraction ...
Robertsonian translocations (RobTs) in the progeny of triticale (×Triticosecale Wittmack) plants with monosomic substitution of Aegilops kotschyi chromosome 2S k (2R) were investigated by fluorescence in-situ hybridization. Chromosome 2S k of Ae. kotschyi is reported to possess many valuable loci, such as Lr54 + Yr37 leaf and stripe (yellow) rust resistance genes. We used a standard procedure to produce RobTs, which consisted of self-pollination of monosomic triticale plants, carrying 2R and 2S k chromosomes in monosomic condition. This approach did not result in RobTs. Simultaneously, we succeeded in producing 11 plants carrying 2R.2S k compensatory RobTs using an alternative approach that utilized ditelosomic lines of triticale carrying 2RS (short arm) and 2RL (long arm) telosomic chromosomes. Identification of molecular markers linked to Lr54 + Yr37 genes in the translocation plants confirmed that these resources can be exploited in current triticale breeding programmes.Agronomy 2019, 9, 646 2 of 12 from wild relatives into the wheat genetic background [10]. Recently, several attempts were made to transfer rust resistance genes from Aegilops, Agropyron and Triticum species into triticale [11][12][13][14][15].Aegilops species are closely related to wheat (and triticale, per se) and carry a number of valuable traits, which have been effectively incorporated into wheat by developing wheat-Aegilops hybrids and deriving addition, substitution and translocation lines [16]. Aegilops kotschyi Boiss. (2n = 4x = 28 chromosomes, U-and S-genomes) is a wild tetraploid goatgrass native to Northern Africa, the Mid-East, and Western Asia. Ae. kotschyi germplasm is exploited in wheat breeding [17] as a source of high grain protein, iron and zinc [18]. Moreover, Antonov and Marais [19] observed leaf rust resistance that was effective against the infection of Puccinia triticina in Ae. kotschyi. Marais et al. [20] identified the Lr54 and Yr37 leaf rust and stripe rust resistance genes, and developed aT2DS.2S k L wheat-Ae. kotschyi translocation line. The first Lr54 + Yr37 marker was developed by Heyns et al. [21]. Moreover, translocation gene sequences were cloned and specific SSR markers were developed [22].Homoeologous recombination based engineering is the most common way for efficiently utilizing the wild relative gene pool for crop improvement [23]. The generation of translocation lines is the most promising pathway for the exploitation of alien germplasm in crop breeding [23]. In distant hybrids, unpaired chromosomes are present as univalents during meiosis. Monosomic chromosomes are prone to centric breaks at anaphase I of meiosis, which misdivide and the broken ends fuse during the interkinesis of meiosis II [24][25][26]. Fusion of the misdivided products may result in the formation of a Robertsonian translocation (RobT) [27].Several steps are required to generate RobTs (Figure 1a), with self-pollination of double-monosomic plants being the most common method used in the induction of RobTs [26]. Wheat breeders can use a l...
Recent evidence suggests that temporal expectation is beneficial to memory formation. Rhythmic presentation of stimuli during encoding enhances subsequent recognition and is associated with distinct neural activity compared with when stimuli are presented in an arrhythmic manner. However, no prior study has examined how temporal expectation interacts with another important form of facilitation—spatial attention—to affect memory. This study systematically manipulated temporal expectation and spatial attention during encoding to examine their combined effect on behavioral recognition and associated ERPs. Participants performed eight experimental blocks consisting of an encoding phase and recognition test, with EEG recorded throughout. During encoding, pairs of objects and checkerboards were presented and participants were cued to attend to the left or right stream and detect targets as quickly as possible. In four blocks, stimulus presentation followed a rhythmic (constant, predictable) temporal structure, and in the other four blocks, stimulus onset was arrhythmic (random, unpredictable). An interaction between temporal expectation and spatial attention emerged, with greater recognition in the rhythmic than the arrhythmic condition for spatially attended items. Analysis of memory-specific ERP components uncovered effects of spatial attention. There were late positive component and FN400 old/new effects in the attended condition for both rhythmic and arrhythmic items, whereas in the unattended condition, there was an FN400 old/new effect and no late positive component effect. The study provides new evidence that memory improvement as a function of temporal expectation is dependent upon spatial attention.
The aim of the article is to present an original model of developing refl exivity in reference to educational events. The Department of Didactics and Studies in the Culture of Education lends the model a practical dimension in working with early school education teachers-to-be during the Refl exive Teacher Workshops course. The inspiration for creating (and sustaining) the model is a carried out under the direction of prof. Ewa Filipiak, Ph.D and is a research project concerning refl ection in reference to educational events taken up by early school education teachers. The article indicates three concepts: (1) critical events in teaching by D. Tripp, (2) the refl exive practitioner by D.A. Schön and (3) mindfulness and mindlessness by E.J. Langer, all of which constitute a theoretical background for the model. The paper also presents an adopted understanding of refl exivity and refl ection. Moreover, the paper considers the motives for using the model while working with teachers-to-be. Therefore, it discusses the value of being and becoming a refl exive teacher, as well as characteristic features of a refl exive practitioner and their signifi cance for working with students.
Ultrasound imaging has more frequently been used in veterinary medicine of amphibians and reptiles. In this study, we have verified the usefulness of ultrasound imaging in pregnancy determination of the fire salamander Salamandra salamandra. We have also undertaken to estimate the number of larvae and their developmental stage directly in the oviducts. Three gravid females from Lower Silesia (southern Poland) were examined. Due to the small size of the scanned animals, and the particular arrangement of embryos in the oviducts and ultrasound beams dispersal, the method proved to be inaccurate. Therefore, the minimum number of well-visualized larvae was determined. The maximum number of larvae was established on the basis of the visible fragments of embryos. After birth, we found that the number of larvae born was included in the "min-max"range in only one case. In the remaining two salamanders the number of larvae was higher than estimated in 3 to 7 individuals. The results showed that ultrasound imaging allows the minimum number of larvae in salamander; oviducts to be specified. However, total length measurements were possible only for single and clearly visible embryos.
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