nils-herrmann/clean_scirepeval huggingface dataset:
Economics of comb wax salvage by the red dwarf honeybee, Apis florea
Venue: Journal of Comparative Physiology B

Colonies of Apis florea, which only abscond a short distance, usually return to salvage old nest wax; but, those colonies, and all other honeybee species which go considerably further, do not. Wax salvage would clearly be counter-productive unless the energy input/energy yield threshold was a profitable one. There are two possible trade-offs in this scenario, the trade-off between the energy expended to recover the wax (recovering hypothesis) as against that of replacing the wax by new secretion (replacing hypothesis). In order to compare the two hypotheses, the fuel costs involved in salvaging wax on one return trip, the average flower handling time, flight time and relative values for substituting the salvaged wax with nectar were calculated. Moreover, the energy value of the wax was determined. Net energy gains for salvaged wax were calculated. The energy value of the salvaged wax was 42.7 J/mg, thus too high to be the limiting factor since salvaging costs are only 642.76 mJ/mg (recovering hypothesis). The recovery costs (642.76 mJ/mg) only fall below the replacement costs for absconding distance below 115 m thus supporting the replacing hypothesis. This energetic trade-off between replacing and recycling plus the small absconding range of A.florea might explain why A.florea is probably the only honeybee species known to salvage wax and it parsimoniously explains the underlying reasons why A.florea only salvages wax from the old nest if the new nesting site is less than 100–200 m away—energetically, it pays off to recycle.
Quantitative magnetic resonance analysis and a morphometric predictive model reveal lean body mass changes in migrating Nearctic–Neotropical passerines
Venue: Journal of Comparative Physiology B

Most studies of lean mass dynamics in free-living passerine birds have focused on Old World species at geographical barriers where they are challenged to make the longest non-stop flight of their migration. We examined lean mass variation in New World passerines in an area where the distribution of stopover habitat does not require flights to exceed more than a few hours and most migrants stop flying well before fat stores near exhaustion. We used either quantitative magnetic resonance (QMR) analysis or a morphometric model to measure or estimate, respectively, the fat and lean body mass of migrants during stopovers in New York, USA. With these data, we examined (1) variance in total body mass explained by lean body mass, (2) hourly rates of fat and lean body mass change in single-capture birds, and (3) net changes in fat and lean mass in recaptured birds. Lean mass contributed to 50% of the variation in total body mass among white-throated sparrows Zonotrichia albicollis and hermit thrushes Catharus guttatus. Lean mass of refueling gray catbirds Dumetella carolinensis and white-throated sparrows, respectively, increased 1.123 and 0.320 g h−1. Lean mass of ovenbirds Seiurus aurocapillus accounted for an estimated 33–40% of hourly gains in total body mass. On average 35% of the total mass gained among recaptured birds was lean mass. Substantial changes in passerine lean mass are not limited to times when birds are forced to make long, non-stop flights across barriers. Protein usage during migration is common across broad taxonomic groups, migration systems, and migration strategies.
Bats and frogs and animals in between: evidence for a common central timing mechanism to extract periodicity pitch
Venue: Journal of Comparative Physiology A

Widely divergent vertebrates share a common central temporal mechanism for representing periodicities of acoustic waveform events. In the auditory nerve, periodicities corresponding to frequencies or rates from about 10 Hz to over 1,000 Hz are extracted from pure tones, from low-frequency complex sounds (e.g., 1st harmonic in bullfrog calls), from mid-frequency sounds with low-frequency modulations (e.g., amplitude modulation rates in cat vocalizations), and from time intervals between high-frequency transients (e.g., pulse-echo delay in bat sonar). Time locking of neuronal responses to periodicities from about 50 ms down to 4 ms or less (about 20–300 Hz) is preserved in the auditory midbrain, where responses are dispersed across many neurons with different onset latencies from 4–5 to 20–50 ms. Midbrain latency distributions are wide enough to encompass two or more repetitions of successive acoustic events, so that responses to multiple, successive periods are ongoing simultaneously in different midbrain neurons. These latencies have a previously unnoticed periodic temporal pattern that determines the specific times for the dispersed on-responses.
Energetics in Liolaemini lizards: implications of a small body size and ecological conservatism
Venue: Journal of Comparative Physiology B

Liolaemini lizards occur in southern South America in a variety of dietary habits across a broad latitudinal and altitudinal distribution. We studied standard metabolic rates of 19 Liolaemini species and analyzed these data using both conventional and phylogenetically informed statistics. Oxygen consumption showed a significant and positive relationship with body mass (SMR = 0.109 × body mass0.876±0.023), with a higher slope than that expected on the basis of the three-quarter power law model. After phylogenetically informed and conventional analyses, no significant differences in metabolic rates were found to be related to diet or elevation. We hypothesize that small body size, ecological conservatism and physiological compensation may explain the lack of differences in metabolic rates observed among these lizards.
Neuronal precision and the limits for acoustic signal recognition in a small neuronal network
Venue: Journal of Comparative Physiology A

Recognition of acoustic signals may be impeded by two factors: extrinsic noise, which degrades sounds before they arrive at the receiver’s ears, and intrinsic neuronal noise, which reveals itself in the trial-to-trial variability of the responses to identical sounds. Here we analyzed how these two noise sources affect the recognition of acoustic signals from potential mates in grasshoppers. By progressively corrupting the envelope of a female song, we determined the critical degradation level at which males failed to recognize a courtship call in behavioral experiments. Using the same stimuli, we recorded intracellularly from auditory neurons at three different processing levels, and quantified the corresponding changes in spike train patterns by a spike train metric, which assigns a distance between spike trains. Unexpectedly, for most neurons, intrinsic variability accounted for the main part of the metric distance between spike trains, even at the strongest degradation levels. At consecutive levels of processing, intrinsic variability increased, while the sensitivity to external noise decreased. We followed two approaches to determine critical degradation levels from spike train dissimilarities, and compared the results with the limits of signal recognition measured in behaving animals.
The physiological response of larval Chironomus riparius (Meigen) to abrupt brackish water exposure
Venue: Journal of Comparative Physiology B

The physiological response of larval Chironomus riparius was examined following direct transfer from freshwater (FW) to brackish water (BW; 20% seawater). Endpoints of hydromineral status (hemolymph Na+, Cl−, and K+ levels, hemolymph pH, body water content, and whole body Na+/K+-ATPase and V-type H+-ATPase activity) were examined 1, 3, 5, 12 and 24 h following BW transfer. Larvae transferred from FW to FW served as a control. Hemolymph Na+ and Cl− levels increased following BW transfer. Hemolymph pH was initially regulated, but significantly decreased after 24 h in BW. Changes in hemolymph ions were not caused by osmotic loss of water from the hemolymph, since larvae tightly regulated total body moisture content. Furthermore, salinity did not affect hemolymph K+. When larvae were transferred to BW, Na+/K+-ATPase (NKA) activity did not significantly alter relative to FW control animals. In contrast, V-type H+-ATPase (VA) activity in C. riparius significantly decreased in BW. In FW-reared C. riparius, whole body NKA and VA activities were equivalent. However, in the isolated gut with intact Malpighian tubules of FW-reared C. riparius, VA activity was significantly greater than whole body while NKA activity was equivalent. This suggested that gut and/or Malpighian tubule VA activity contributes significantly to whole body VA activity and that a decline in whole body VA activity in BW may be closely linked to alterations in the physiology of gut and Malpighian tubule tissue. Taken together, data indicate that VA is important for ion uptake in FW and that the NKA does not play a major role in regulating ion homeostasis when larvae are acutely exposed to BW.
Role of the left aortic arch and blood flows in embryonic American alligator (Alligator mississippiensis)
Venue: Journal of Comparative Physiology B

All embryonic and fetal amniotes possess a ductus(i) arteriosus(i) that allows blood to bypass the pulmonary circulation and the non-functional lungs. The central hemodynamic of embryonic reptiles are unique, given the additional systemic aorta that allows pulmonary circulatory bypass, the left aorta (LAo). The LAo exits in the right ventricle or ‘pulmonary side’ of reptilian hearts in both embryos and adults, but its functional significance in ovo is unknown. This study investigated the role of the LAo in embryonic American alligators by surgically occluding the LAo and measuring oxygen consumption and, in addition, measured hemodynamic responses to hypoxia in embryonic alligators. We measured systemic cardiac output and primary chorioallantoic membrane (CAM) artery blood flow for normoxic and hypoxic-incubated (10% O2) American alligator embryos (Alligator mississippiensis). Chronic blood flow (1–124 h) in the primary CAM artery for hypoxic-incubated embryos (92 ± 26 ml min−1 kg−1) was elevated when compared with normoxic-incubated embryos (29 ± 14 ml min−1 kg−1, N = 6; P = 0.039). For hypoxic-incubated embryos, acute LAo blood flow (49.6 ± 24.4 ml min−1 kg−1) was equivalent to the combined flow of the three systemic great vessels that arise from the left ventricle, the right aorta, common carotid and subclavian arteries (43.6 ± 21.5 ml min−1 kg−1, N = 5). Similarly, for normoxic-incubated embryos, LAo blood flow (27.3 ± 6.6 ml min−1 kg−1) did not statistically differ from the other three vessels (18.4 ± 4.9 ml min−1 kg−1, N = 5). This study contains the first direct test of LAo function and the first measurements of blood flow in an embryonic reptile. These data support the hypotheses that embryonic alligators utilize the LAo to divert a significant amount of right ventricular blood into the systemic circulation, and that CAM blood flow increases following chronic hypoxic conditions. However, surgical occlusion of the LAo did not affect egg $$ \dot{V}_{{\text{O}}_{2}},$$ supporting the hypothesis that the LAo of reptiles is not critical to maintain in ovo oxygen consumption.
Otoacoustic emissions in bushcricket ears: general characteristics and the influence of the neuroactive insecticide pymetrozine
Venue: Journal of Comparative Physiology A

The tympanal organ of the bushcricket Mecopoda elongata emits pronounced distortion-product otoacoustic emissions (DPOAEs). Their characteristics are comparable to those measured in other insects, such as locusts and moths, with the 2f1–f2 emission being the most prominent one. Yet the site of their generation is still unclear. The spatial separation between the sound receiving spiracle and the hearing organ in this species allows manipulations of the sensory cells without interfering with the acoustical measurements. We tried to interfere with the DPOAE generation by pharmacologically influencing the tympanal organ using the insecticide pymetrozine. The compound appears to act selectively on scolopidia, i.e., the mechanosensor type characteristically constituting tympanal organs. Pymetrozine solutions were applied as closely as possible to the scolopidia via a cuticle opening in the tibia, distally to the organ. Applications of pymetrozine at concentrations between 10−3 and 10−7 M to the tympanal organ led to a pronounced and irreversible decrease of the DPOAE amplitudes.
Morphological correlates of echolocation frequency in the endemic Cape horseshoe bat, Rhinolophus capensis (Chiroptera: Rhinolophidae)
Venue: Journal of Comparative Physiology A

We investigated intraspecific variation in echolocation calls of the Cape horseshoe bat, Rhinolophus capensis, by comparing echolocation and associated morphological parameters among individuals from three populations of this species. The populations were situated in the center and at the western and eastern limits of the distribution of R. capensis. The latter two populations were situated in ecotones between vegetation biomes. Ecotone populations deviated slightly from the allometric relationship between body size and peak frequency for the genus, and there was no relationship between these variables within R. capensis. Nasal chamber length was the best predictor of peak frequency but not correlated with body size. The evolution of echolocation thus appears to have been uncoupled from body size in R. capensis. Furthermore, females used higher frequencies than males, which imply a potential social role for peak frequency. The differences in peak frequency may have originated from random founder effects and then compounded by genetic drift and/or natural selection. The latter may have acted directly on peak frequency altering skull parameters involved in echolocation independently of body size, resulting in the evolution of local acoustic signatures.
A central pacemaker that underlies the production of seasonal and sexually dimorphic social signals: functional aspects revealed by glutamate stimulation
Venue: Journal of Comparative Physiology A

The cyclic enrichment of behavioral repertoires is a common event in seasonal breeders. Breeding males Brachyhypopomus gauderio produce electric organ discharge (EOD) rate modulations called chirps while females respond with interruptions. The electromotor system is commanded by a pacemaker nucleus (PN) which sets the basal rate and produces the rate modulations. We focused on identifying functional, seasonal and sexual differences in this nucleus in correlation to these differences in behavior. The in vivo response to glutamate injection in the PN was seasonal, sexually dimorphic and site specific. Non-breeding adults and breeding females injected in dorsal and ventral sites generated EOD rate increases and interruptions, respectively. Reproductive males added a conspicuous communication signal to this repertoire. They chirped repetitively when we injected glutamate in a very restricted area of the ventral–rostral nucleus, surprisingly one with a low number of relay cell somata. This study shows that the PN is functionally organized in regions in a caudal–rostral axis, besides the previously documented dorsal–ventral division. Functional regions are revealed by seasonal changes that annually provide this nucleus with the cellular mechanisms that allow the bursting activity underlying chirp production, only in males.
Stingless bees (Scaptotrigona pectoralis) learn foreign trail pheromones and use them to find food
Venue: Journal of Comparative Physiology A

Foragers of several species of stingless bees (Hymenoptera, Apidae and Meliponini) deposit pheromone marks in the vegetation to guide nestmates to new food sources. These pheromones are produced in the labial glands and are nest and species specific. Thus, an important question is how recruited foragers recognize their nestmates’ pheromone in the field. We tested whether naïve workers learn a specific trail pheromone composition while being recruited by nestmates inside the hive in the species Scaptotrigona pectoralis. We installed artificial scent trails branching off from trails deposited by recruiting foragers and registered whether newly recruited bees follow these trails. The artificial trails were baited with trail pheromones of workers collected from foreign S. pectoralis colonies. When the same foreign trail pheromone was presented inside the experimental hives while recruitment took place a significant higher number of bees followed the artificial trails than in experiments without intranidal presentation. Our results demonstrate that recruits of S. pectoralis can learn the composition of specific trail pheromone bouquets inside the nest and subsequently follow this pheromone in the field. We, therefore, suggest that trail pheromone recognition in S. pectoralis is based on a flexible learning process rather than being a genetically fixed behaviour.
Is tissue maturation necessary for flight? Changes in body composition during postnatal development in the big brown bat
Venue: Journal of Comparative Physiology B

Patterns of offspring development reflect the availability of energy and nutrients, limitations on an individual’s capacity to use available resources, and tradeoffs between the use of nutrients to support current metabolic demands and tissue growth. To determine if the long period of offspring dependency in bats is associated with the need for an advanced state of tissue maturation prior to flight, we examined body composition during postnatal growth in the big brown bat, Eptesicus fuscus. Despite their large size at birth (22% of maternal mass), newborn bats are relatively immature, containing 82% body water in fat-free mass. However, the total body water content of newborn bat pups decreases to near-adult levels in advance of weaning, while concentrations of total body fat and protein exceed adult values. In contrast to many other mammals, postnatal growth of bat pups was characterized by relatively stable concentrations of calcium and phosphorus, but declining concentrations of magnesium. These levels remained stable or rebounded in late postnatal development. This casts doubt on the hypothesis that low rates of mineral transfer necessitate an extended lactation period in bats. However, our finding of near-adult body composition at weaning is consistent with the hypothesis that extended lactation in bats is necessary for the young to achieve sufficient tissue maturity to undertake the active flight necessary for independent feeding. In this respect, bats differ from most other mammals but resemble birds that must engage in active flight to achieve nutritional independence.
Striped mullet (Mugil cephalus) hemoglobin system: multiplicity and functional properties
Venue: Journal of Comparative Physiology B

The most frequent (90%) phenotype of the hemoglobin system of M. cephalus presented two major hemoglobins, the more anodal HbI accounting for approximately 70% of the total. The two hemoglobin components separated by ion-exchange chromatography were analyzed by reverse-phase HPLC and electrospray ionization-mass spectrometry which revealed a more complex pattern: HbI consists in four different globins, two β (named β1 and β3) and two co-eluting α chains (α1 and α2); HbII consists in three globins, one β chain (named β2) and the same α1 and α2 present in HbI. The oxygen-binding properties of both hemoglobin components purified by DEAE cellulose were almost identical to those of the hemolysate: stripped hemoglobin showed a large Bohr effect which was enhanced by chloride ions and, at a larger extent, by organic phosphates which, at acidic pH values gave rise to the Root effect. A series of oxygen-binding experiments at increasing GTP concentrations was carried out in order to compare GTP-binding activities in the absence and presence of physiological amounts of chloride. The results indicated that hemoglobin do have two sites for GTP binding. In the absence of chloride, the two sites cannot be discriminated, whereas in the presence of chloride, a competition between the two anions occurred for both GTP-binding sites. The presence of multiple hemoglobin components with identical properties confirms that hemoglobin heterogeneity that often occurs in fish cannot be only explained as an evolutionary response to the physiological and/or environmental needs of the species.
Discriminating among complex signals: the roles of inhibition for creating response selectivities
Venue: Journal of Comparative Physiology A

The review deals largely with studies from my laboratory that were prompted by conversations I had with Gerhard Neuweiler more than 15 years ago. The studies were conducted on bats and dealt with mechanisms that enable the population of neurons in the inferior colliculus (IC) to respond selectively to the variety of signals bats emit for both communication and echolocation. The first section is concerned with how neurons in the dorsal nucleus of the lateral lemniscus (DNLL), the nucleus ventral to the IC, respond to species-specific signals and how they compare to responses of IC neurons evoked by the same signals. Those studies showed that DNLL neurons have no sideband inhibition and their responses are determined by excitation. In contrast, inhibition dominates in the IC where it carves out highly selective discharge properties. Those studies, in turn, raised questions about the quantitative features of inhibition that could only be answered with more sophisticated techniques. In the second section, results from analyses with spectrotemporal receptive fields (STRFs) are presented, and in the final section I show data derived from in vivo whole cell recordings that illustrate how features of inhibition interact with excitation to generate directionality selective responses in the IC.
Metarhodopsin control by arrestin, light-filtering screening pigments, and visual pigment turnover in invertebrate microvillar photoreceptors
Venue: Journal of Comparative Physiology A

The visual pigments of most invertebrate photoreceptors have two thermostable photo-interconvertible states, the ground state rhodopsin and photo-activated metarhodopsin, which triggers the phototransduction cascade until it binds arrestin. The ratio of the two states in photoequilibrium is determined by their absorbance spectra and the effective spectral distribution of illumination. Calculations indicate that metarhodopsin levels in fly photoreceptors are maintained below ~35% in normal diurnal environments, due to the combination of a blue-green rhodopsin, an orange-absorbing metarhodopsin and red transparent screening pigments. Slow metarhodopsin degradation and rhodopsin regeneration processes further subserve visual pigment maintenance. In most insect eyes, where the majority of photoreceptors have green-absorbing rhodopsins and blue-absorbing metarhodopsins, natural illuminants are predicted to create metarhodopsin levels greater than 60% at high intensities. However, fast metarhodopsin decay and rhodopsin regeneration also play an important role in controlling metarhodopsin in green receptors, resulting in a high rhodopsin content at low light intensities and a reduced overall visual pigment content in bright light. A simple model for the visual pigment–arrestin cycle is used to illustrate the dependence of the visual pigment population states on light intensity, arrestin levels and pigment turnover.