| 1. |
- Lopez-Reyes, Karla, et al.
(författare)
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Colour vision in thrips (Thysanoptera)
- 2022
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Ingår i: Philosophical Transactions of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 377:1862
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Forskningsöversikt (refereegranskat)abstract
- Insects are an astonishingly successful and diverse group, occupying the gamut of habitats and lifestyle niches. They represent the vast majority of described species and total terrestrial animal biomass on the planet. Their success is in part owed to their sophisticated visual systems, including colour vision, which drive a variety of complex behaviours. However, the majority of research on insect vision has focused on only a few model organisms including flies, honeybees and butterflies. Especially understudied are phytophagous insects, such as diminutive thrips (Thysanoptera), in spite of their damage to agriculture. Thrips display robust yet variable colour-specific responses despite their miniaturized eyes, but little is known about the physiological and ecological basis of their visual systems. Here, we review the known visual behavioural information about thrips and the few physiological studies regarding their eyes. Eye structure, spectral sensitivity, opsin genes and the presence of putative colour filters in certain ommatidia strongly imply dynamic visual capabilities. Finally, we discuss the major gaps in knowledge that remain for a better understanding of the visual system of thrips and why bridging these gaps is important for expanding new possibilities for applied pest management strategies for these tiny insects. This article is part of the theme issue 'Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods'.
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| 2. |
- Nicolaï, Michaël P J, et al.
(författare)
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The function and consequences of fluorescence in tetrapods
- 2024
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 1091-6490. ; 121:24, s. 2318189121-2318189121
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Forskningsöversikt (refereegranskat)abstract
- Fluorescence, the optical phenomenon whereby short-wavelength light is absorbed and emitted at longer wavelengths, has been widely described in aquatic habitats, in both invertebrates and fish. Recent years have seen a stream of articles reporting fluorescence, ranging from frogs, platypus, to even fully terrestrial organisms such as flying squirrels, often explicitly or implicitly linking the presence of fluorescence with sexual selection and communication. However, many of these studies fail to consider the physiological requirements of evolutionary stable signaling systems, the environmental dependence of perception, or the possible adaptive role of fluorescent coloration in a noncommunicative context. More importantly, the idea that fluorescence may simply constitute an indirect by-product of selection on other traits is often not explored. This is especially true for terrestrial systems where environmental light conditions are often not amenable for fluorescent signaling in contrast to, for example, aquatic habitats in which spectral properties of water promote functional roles for fluorescence. Despite the appeal of previously unknown ways in which coloration may drive evolution, the investigation of a putative role of fluorescence in communication must be tempered by a realistic understanding of its limitations. Here, we not only highlight and discuss the key body of literature but also address the potential pitfalls when reporting fluorescence and how to solve them. In addition, we propose exciting different research avenues to advance the field of tetrapod fluorescence.
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| 3. |
- Bok, Michael J., et al.
(författare)
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High-resolution vision in pelagic polychaetes
- 2024
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Ingår i: Current Biology. - 0960-9822. ; 34:7, s. 269-270
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution object vision — the ability to separate, classify, and interact with specific objects in the environment against the visual background — has only been conclusively shown to have evolved in three of the thirty-five animal phyla: chordates, arthropods, and mollusks (cephalopods)1. However, alciopid polychaetes (Phyllodocidae, Alciopini), which possess a pair of bulbous camera-type eyes, have also been hypothesized to achieve high acuity. In this study, we examined three species of night-active pelagic alciopids from the Mediterranean Sea. Our optical, morphological, and electrophysiological investigations show that their eyes have high spatial acuity and temporal resolution, supporting the notion that they are capable of active, high-resolution object vision. These results encourage interesting hypotheses about the visual ecology of these enigmatic polychaetes.
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| 4. |
- Cork, Steven, et al.
(författare)
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Exploring Alternative Futures in the Anthropocene
- 2023
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Ingår i: Annual Review Environment and Resources. - 1543-5938 .- 1545-2050. ; 48, s. 25-54
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Forskningsöversikt (refereegranskat)abstract
- Many challenges posed by the current Anthropocene epoch require fundamental transformations to humanity's relationships with the rest of the planet. Achieving such transformations requires that humanity improve its understanding of the current situation and enhance its ability to imagine pathways toward alternative, preferable futures. We review advances in addressing these challenges that employ systematic and structured thinking about multiple possible futures (futures-thinking). Over seven decades, especially the past two, approaches to futures-thinking have helped people from diverse backgrounds reach a common understanding of important issues, underlying causes, and pathways toward optimistic futures. A recent focus has been the stimulation of imagination to produce new options. The roles of futures-thinking in breaking unhelpful social addictions and in conflict resolution are key emerging topics. We summarize cognitive, cultural, and institutional constraints on the societal uptake of futures-thinking, concluding that none are insurmountable once understood.
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| 5. |
- Cronin, Thomas W., et al.
(författare)
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Colour vision in stomatopod crustaceans
- 2022
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Ingår i: Philosophical Transactions of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 377:1862
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Forskningsöversikt (refereegranskat)abstract
- The stomatopod crustaceans, or mantis shrimps, are colourful marine invertebrate predators. Their unusual compound eyes have dorsal and ventral regions resembling typical crustacean apposition designs separated by a unique region called the midband that consists of from two to six parallel rows of ommatidia. In species with six-row midbands, the dorsal four rows are themselves uniquely specialized for colour analysis. Rhabdoms of ommatidia in these rows are longitudinally divided into three distinct regions: an apical ultraviolet (UV) receptor, a shorter-wavelength middle tier receptor and a longer-wavelength proximal tier receptor. Each of the total of 12 photoreceptors has a different spectral sensitivity, potentially contributing to a colour-vision system with 12 channels. Mantis shrimps can discriminate both human-visible and UV colours, but with limited precision compared to other colour-vision systems. Here, we review the structure and function of stomatopod colour vision, examining the types of receptors present in a species, the spectral tuning of photoreceptors both within and across species, the neural analysis of colour and the genetics underlying the multiple visual pigments used for colour vision. Even today, after many decades of research into the colour vision of stomatopods, much of its operation and its use in nature remain a mystery. This article is part of the theme issue 'Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods'.
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| 6. |
- Gühmann, Martin, et al.
(författare)
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The Gluopsins : Opsins without the Retinal Binding Lysine
- 2022
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Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 11:15
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Tidskriftsartikel (refereegranskat)abstract
- Opsins allow us to see. They are G-protein-coupled receptors and bind as ligand retinal, which is bound covalently to a lysine in the seventh transmembrane domain. This makes opsins light-sensitive. The lysine is so conserved that it is used to define a sequence as an opsin and thus phylogenetic opsin reconstructions discard any sequence without it. However, recently, opsins were found that function not only as photoreceptors but also as chemoreceptors. For chemoreception, the lysine is not needed. Therefore, we wondered: Do opsins exists that have lost this lysine during evolution? To find such opsins, we built an automatic pipeline for reconstructing a large-scale opsin phylogeny. The pipeline compiles and aligns sequences from public sources, reconstructs the phylogeny, prunes rogue sequences, and visualizes the resulting tree. Our final opsin phylogeny is the largest to date with 4956 opsins. Among them is a clade of 33 opsins that have the lysine replaced by glutamic acid. Thus, we call them gluopsins. The gluopsins are mainly dragonfly and butterfly opsins, closely related to the RGR-opsins and the retinochromes. Like those, they have a derived NPxxY motif. However, what their particular function is, remains to be seen.
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| 7. |
- Jiang, Wei, et al.
(författare)
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Rapid manoeuvre of fan worms (Annelida: Sabellidae) through tubes
- 2023
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Ingår i: Journal of Experimental Biology. - 0022-0949. ; 226:9
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Tidskriftsartikel (refereegranskat)abstract
- Multiple variables determine the success of an escape response of an animal, and the rapidity of the escape manoeuvre is often the most important. Fan worms (Annelida: Sabellidae) can rapidly withdraw their tentacles, which are covered in heavily ciliated ramifications called pinnules, into their tubes to protect them from approaching threats. Here, we explore the dynamic and mechanistic features behind this escape manoeuvre. The escape responses of fan worms were recorded by high-speed videography and quantified by computerized motion analysis, showing an ultrahigh retraction speed of 272 ±135 mm s−1 (8±4 body lengths s−1). We found that fan worms possess powerful muscle-driven systems, which can generate contractive forces up to 36 times their body weight. In order to achieve these rapid, forceful movements through seawater without damaging their tentacles, fan worms have developed functional morphological adaptations to reduce fluidic drag, including the flattening of their radiolar pinnules and the deformation of bodily segmental ridges. Our hydrodynamic models indicate that these mechanical processes can decrease fluidic drag by 47%, trapped mass by 75% and friction coefficient by 89%. These strategies allow fan worms to execute rapid escape responses and could inspire the design of fast in-pipe robots.
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| 8. |
- Mäthger, Lydia M., et al.
(författare)
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Pupil dilation and constriction in the skate Leucoraja erinacea in a simulated natural light field
- 2022
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 225:4
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Tidskriftsartikel (refereegranskat)abstract
- The skate Leucoraja erinacea has an elaborately shaped pupil, whose characteristics and functions have received little attention. The goal of our study was to investigate the pupil response in relation to natural ambient light intensities. First, we took a recently developed sensory-ecological approach, which gave us a tool for creating a controlled light environment for behavioural work: During a field survey, we collected a series of calibrated natural habitat images from the perspective of the skates' eyes. From these images, we derived a vertical illumination profile using custom-written software for quantification of the environmental light field (ELF). After collecting and analysing these natural light field data, we created an illumination set-up in the laboratory, which closely simulated the natural vertical light gradient that skates experience in the wild and tested the light responsiveness - in particular the extent of dilation - of the skate pupil to controlled changes in this simulated light field. Additionally, we measured pupillary dilation and constriction speeds. Our results confirm that the skate pupil changes from nearly circular under low light to a series of small triangular apertures under bright light. A linear regression analysis showed a trend towards smaller skates having a smaller dynamic range of pupil area (dilation versus constriction ratio around 4-fold), and larger skates showing larger ranges (around 10- to 20-fold). Dilation took longer than constriction (between 30 and 45 min for dilation; less than 20 min for constriction), and there was considerable individual variation in dilation/constriction time. We discuss our findings in terms of the visual ecology of L. erinacea and consider the importance of accurately simulating natural light fields in the laboratory.
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| 9. |
- Niu, Mengyao, et al.
(författare)
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Fungal oxylipins direct programmed developmental switches in filamentous fungi
- 2020
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Ingår i: Nature Communications. - : NATURE RESEARCH. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Filamentous fungi differentiate along complex developmental programs directed by abiotic and biotic signals. Currently, intrinsic signals that govern fungal development remain largely unknown. Here we show that an endogenously produced and secreted fungal oxylipin, 5,8-diHODE, induces fungal cellular differentiation, including lateral branching in pathogenic Aspergillus fumigatus and Aspergillus flavus, and appressorium formation in the rice blast pathogen Magnaporthe grisea. The Aspergillus branching response is specific to a subset of oxylipins and is signaled through G-protein coupled receptors. RNA-Seq profiling shows differential expression of many transcription factors in response to 5,8-diHODE. Screening of null mutants of 33 of those transcription factors identifies three transcriptional regulators that appear to mediate the Aspergillus branching response; one of the mutants is locked in a hypo-branching phenotype, while the other two mutants display a hyper-branching phenotype. Our work reveals an endogenous signal that triggers crucial developmental processes in filamentous fungi, and opens new avenues for research on the morphogenesis of filamentous fungi.
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| 10. |
- Wang, Shih-Hao, et al.
(författare)
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TAROGE-M : radio antenna array on antarctic high mountain for detecting near-horizontal ultra-high energy air showers
- 2022
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The TAROGE-M radio observatory is a self-triggered antenna array on top of the similar to 2700m high Mt. Melbourne in Antarctica, designed to detect impulsive geomagnetic emission from extensive air showers induced by ultra-high energy (UHE) particles beyond 1017 eV, including cosmic rays, Earth-skimming tau neutrinos, and particularly, the "ANITA anomalous events" (AAE) from near and below the horizon. The six AAE discovered by the ANITA experiment have signal features similar to tau neutrinos but that hypothesis is in tension either with the interaction length predicted by Standard Model or with the flux limits set by other experiments. Their origin remains uncertain, requiring more experimental inputs for clarification. The detection concept of TAROGE-M takes advantage of a high altitude with synoptic view toward the horizon as an efficient signal collector, and the radio quietness as well as strong and near vertical geomagnetic field in Antarctica, enhancing the relative radio signal strength. This approach has a low energy threshold, high duty cycle, and is easy to extend for quickly enlarging statistics. Here we report experimental results from the first TAROGEM station deployed in January 2020, corresponding to approximately one month of livetime. The station consists of six receiving antennas operating at 180-450 MHz, and can reconstruct source directions of impulsive events with an angular resolution of similar to 0.3 ffi, calibrated in situ with a drone-borne pulser system. To demonstrate TAROGE-M's ability to detect UHE air showers, a search for cosmic ray signals in 25.3-days of data together with the detection simulation were conducted, resulting in seven identified candidates. The detected events have a mean reconstructed energy of 0.95+0.46 -0.31 EeV and zenith angles ranging from 25 ffi to 82 ffi, with both distributions agreeing with the simulations, indicating an energy threshold at about 0.3 EeV. The estimated cosmic ray flux at that energy is 1.2+0.7 -0.9x10(-16) eV(-1) km(-2) yr(-1) sr(-1), also consistent with results of other experiments. The TAROGE-M sensitivity to AAEs is approximated by the tau neutrino exposure with simulations, which suggests comparable sensitivity as ANITA's at around 1 EeV energy with a few station-years of operation. These first results verified the station design and performance in a polar and high-altitude environment, and are promising for further discovery of tau neutrinos and AAEs after an extension in the near future.
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