Journal of Comparative Physiology A-Neuroethology Sensory Neural and Behavioral Physiology最新文献

In mammals, especially rodents, social behaviours, such as parenting, territoriality or mate attraction, are largely based on olfactory communication through chemosignals. These behaviours are mediated by species-specific chemosignals, including small organic molecules and proteins that are secreted in the urine or in various fluids from exocrine glands. Chemosignal detection is mainly ensured by olfactory neurons in two specific sensory organs, the vomeronasal organ (VNO) and the main olfactory epithelium (MOE). This study aimed to characterise the olfactory communication in the fossorial ecotype of the water voles, Arvicola terrestris. We first measured the olfactory investigation of urine and lateral scent gland secretions from conspecifics. Our results showed that water voles can discriminate the sex of conspecifics based on the smell of urine, and that urinary male odour is attractive for female voles. Then, we demonstrated the ability of the VNO and MOE to detect volatile organic compounds (VOCs) found in water vole secretions using live-cell calcium imaging in dissociated cells. Finally, we evaluated the attractiveness of two mixtures of VOCs from urine or lateral scent glands in the field during a cyclical outbreak of vole populations.

The spatial position of individuals within a social group, which provides the group members with benefits and costs, is determined by several physical and physiological factors. Lateralization (left and right asymmetry of morphology and behavior) could also be factors determining the individual's positions within a group. However, this possibility has been documented in some fish species, but never in an invertebrate species. This study investigates the association between spatial positions and lateralization in oval squid, Sepioteuthis lessoniana, which displays social behavior, such as schooling and lateralization for eye use (visual lateralization). The direction and strength of visual lateralization were determined for single squid by observing which eye was used to detect the prey, predators, and conspecifics. The spatial positions of individuals were determined by identifying whether the squids were in the left or right side from the center of the school. When the prey was presented to schooling squids, strongly lateralized squids against prey positioned themselves on the right side, whereas weakly lateralized squids positioned themselves on the left side. When the predator was presented to squids, the strongly lateralized squids against the conspecifics positioned themselves on the right side, and the weakly lateralized squids positioned themselves on the left side. When no targets were presented, the strongly lateralized squids against the predator positioned themselves on the right side, whereas the weakly lateralized squids positioned themselves on the left side. The strength of visual lateralization of oval squid could offer the defensive and offensive functions of schools with specific individual positions.

Two auditory neurons, TN-1 and ON-1, in the bush-cricket, Mecopoda elongata, have large dendritic arborisations which receive excitatory synaptic inputs from tonotopically organised axonal terminals of auditory afferents in the prothoracic ganglion. By combining intracellular microelectrode recording with calcium imaging we demonstrate that the dendrites of both neurons show a clear Ca²⁺ signal in response to broad-frequency species-specific chirps. Due to the organisation of the afferents frequency specific auditory activation should lead to local Ca²⁺ increases in their dendrites. In response to 20 ms sound pulses the dendrites of both neurons showed tonotopically organised Ca²⁺ increases. In ON-1 we found no evidence for a tonotopic organisation of the Ca²⁺ signal related to axonal spike activity or for a Ca²⁺ response related to contralateral inhibition. The tonotopic organisation of the afferents may facilitate frequency-specific adaptation in these auditory neurons through localised Ca²⁺ increases in their dendrites. By combining 10 and 40 kHz test pulses and adaptation series, we provide evidence for frequency-specific adaptation in TN-1 and ON-1. By reversible deactivating of the auditory afferents and removing contralateral inhibition, we show that in ON-1 spike activity and Ca²⁺ responses increased but frequency-specific adaptation was not evident.

Signal analysis plays a preeminent role in neuroethological research. Traditionally, signal identification has been based on pre-defined signal (sub-)types, thus being subject to the investigator's bias. To address this deficiency, we have developed a supervised learning algorithm for the detection of subtypes of chirps-frequency/amplitude modulations of the electric organ discharge that are generated predominantly during electric interactions of individuals of the weakly electric fish Apteronotus leptorhynchus. This machine learning paradigm can learn, from a 'ground truth' data set, a function that assigns proper outputs (here: time instances of chirps and associated chirp types) to inputs (here: time-series frequency and amplitude data). By employing this artificial intelligence approach, we have validated previous classifications of chirps into different types and shown that further differentiation into subtypes is possible. This demonstration of its superiority compared to traditional methods might serve as proof-of-principle of the suitability of the supervised machine learning paradigm for a broad range of signals to be analyzed in neuroethology.

Light is the most important environmental cue for the circadian system of most organisms to stay synchronized to daily environmental changes. Like many other insects, the wasp Nasonia vitripennis has trichromatic compound eye-based colour vision and is sensitive to the light spectrum ranging from UV to green. We recently described a red-sensitive, ocelli-based photoreceptor, but its contribution to circadian entrainment remains unclear. In this study, we investigated the possibility of Nasonia circadian light entrainment under long-wavelength red LED light-dark cycles and characterized the strength of red light as a potential Zeitgeber. Additionally, we measured the possibility of entrainment under various light intensities (from 5·10¹² to 4·10¹⁵ photons·cm^-2·s^-1) and a broader range of wavelengths (455-656 nm) to construct corresponding action spectra for characterizing all circadian photoreceptors involved in photic entrainment. We also conducted electroretinogram (ERG) recordings for each wavelength in the compound eyes. Our findings demonstrate that Nasonia can entrain under red light dark cycles, and the sensory pathway underlying the red-light Zeitgeber response may reside in the ocelli. Combined with findings from previous research, we pose that blue- and green-sensitive rhodopsin photoreceptor cells function as the major circadian photoreceptors in both circadian entrainment by light-dark cycles and circadian phase shifts by light pulses, whereas the red-sensitive photoreceptor cell requires higher light intensity for its role in circadian entrainment by light-dark cycles.

Maternal signals shape embryonic development, and in turn post-natal phenotypes. RNA deposition is one such method of maternal signalling and circadian rhythms are one trait thought to be maternally inherited, through this mechanism. These maternal circadian gene transcripts aid development of a functioning circadian system. There is increasing evidence that maternal signals can be modified, depending on prevailing environmental conditions to optimise offspring fitness. However, currently, it is unknown if maternal circadian gene transcripts, and consequently early embryonic gene transcription, are altered by maternal developmental conditions. Here, using avian mothers who experienced either pre-natal corticosterone exposure, and/or post-natal stress as juveniles we were able to determine the effects of the timing of stress on downstream circadian RNA deposition in offspring. We demonstrated that maternal developmental history does indeed affect transfer of offspring circadian genes, but the timing of stress was important. Avian mothers who experienced stress during the first 2 weeks of post-natal life increased maternally deposited transcript levels of two core circadian clock genes, BMAL1 and PER2. These differences in transcript levels were transient and disappeared at the point of embryonic genome transcription. Pre-natal maternal stress alone was found to elicit delayed changes in circadian gene expression. After activation of the embryonic genome, both BMAL1 and PER2 expression were significantly decreased. If both pre-natal and post-natal stress occurred, then initial maternal transcript levels of BMAL1 were significantly increased. Taken together, these results suggest that developmental stress differentially produces persistent transgenerational effects on offspring circadian genes.

Butterflies often have conspicuously patterned wings, due to pigmentary and/or structurally wing scales that cover the wing membrane. The wing membrane of several butterfly species is also pigmentary coloured, notably by the bile pigments pterobilin, pharcobilin and sarpedobilin. The absorption spectra of the bilins have bands in the ultraviolet and red wavelength range, resulting in blue-cyan colours. Here, a survey of papilionoid and nymphalid butterflies reveals that several species with wings containing bile pigments combine them with carotenoids and other short-wavelength absorbing pigments, e.g., papiliochrome II, ommochromes and flavonoids, which creates green-coloured patterns. Various uncharacterized, long-wavelength absorbing wing pigments were encountered, particularly in heliconiines. The wings thus exhibit quite variable reflectance spectra, extending the enormous pigmentary and structural colouration richness of butterflies.

The Editors' and Readers' Choice Awards were established in 2022 to celebrate some of the outstanding articles published every year in the Journal of Comparative Physiology A. The recipients of the 2024 Editors' Choice Awards were selected based on votes cast by the Editorial Board on articles published in 2023. In the category Original Paper, this distinction goes to 'Views from 'crabworld': the spatial distribution of light in a tropical mudflat' by Jochen Zeil (J Comp Physiol A 209:859-876, 2023); and in the category Review Article to 'Olfactory navigation in arthropods' by Theresa J. Steele and colleagues (J Comp Physiol A 209:467-488, 2023). The winners of the 2024 Readers' Choice Awards were determined by the number of online accesses of articles published in 2022. In the category Original Paper, the winner is 'Broadband 75-85 MHz radiofrequency fields disrupt magnetic compass orientation in night‑migratory songbirds consistent with a flavin‑based radical pair magnetoreceptor' by Bo Leberecht and colleagues (J Comp Physiol A 208:97-106, 2022). In the category Review Article, the winner is 'Magnetic maps in animal navigation' by Kenneth J. Lohmann and colleagues (J Comp Physiol A 208:41-67, 2022), which already won the Editors' Choice Award in 2023.

Duets are one of the most fascinating displays in animal vocal communication, where two animals fine-tune the timing of their emissions to create a coordinated signal. Duetting behavior is widespread in the animal kingdom and is present in insects, birds, and mammals. Duets are essential to regulate activities within and between social units. Few studies assessed the functions of these vocal emissions experimentally, and for many species, there is still no consensus on what duets are used for. Here, we reviewed the literature on the function of duets in non-human primates, investigating a possible link between the social organization of the species and the function of its duetting behavior. In primates and birds, social conditions characterized by higher promiscuity might relate to the emergence of duetting behavior. We considered both quantitative and qualitative studies, which led us to hypothesize that the shift in the social organization from pair living to a mixed social organization might have led to the emergence of mate defense and mate guarding as critical functions of duetting behavior. Territory/resource ownership and defense functions are more critical in obligate pair-living species. Finally, we encourage future experimental research on this topic to allow the formulation of empirically testable predictions.

This paper is not meant to be a review article. Instead, it gives an overview of the major research projects that the author, together with his students, colleagues and collaborators, has worked on. Although the main focus of the author's work has always been the fish lateral line, this paper is mainly about all the other research projects he did or that were done in his laboratory. These include studies on fishing spiders, weakly electric fish, seals, water rats, bottom dwelling sharks, freshwater rays, venomous snakes, birds of prey, fire loving beetles and backswimmers. The reasons for this diversity of research projects? Simple. The authors's lifelong enthusiasm for animals, and nature's ingenuity in inventing new biological solutions. Indeed, this most certainly was a principal reason why Karl von Frisch and Alfred Kühn founded the Zeitschrift für vergleichende Physiologie (now Journal of Comparative Physiology A) 100 years ago.