Sexual differences in auditory sensitivity: mismatch of hearing threshold and call frequency in a tettigoniid (orthoptera,tettigoniidae: Zaprochilinae)

Summary Sexual dimorphism of the ear of an undescribed species of zaprochiline tettigoniid is described. The internal trachea, dedicated to hearing in other tettigoniids, is unmodified in the male but fully developed in the female. The external auditory spiracle is also lost in the male. In contrast, there is no difference between the sexes in the number of sensilla within the hearing organ. The male is 10 dB less sensitive than the female. The characteristic frequency of the hearing organ at 35 kHz does not match the carrier frequency of the male's call at 51 kHz. As a result of this mismatch the female is remarkably insensitive to the male's call (threshold at 75 dB SPL), and the male is even less sensitive (thresholds80 dB SPL). In nature this provides a maximum hearing range of the male of less than 50 cm.     

The course control system of beetles walking in an air-current field

The wind-orientated walk of carrion beetles Necrophorus humator F. was analysed under closed-loop conditions with a walking compensator and under openloop conditions with a paired tread wheel (Fig. 1).

Serum protein polymorphisms (HP,GC, PI) in Muslims and Bodhs of Jammu and Kashmir,India

Two population groups of Jammu and Kashmir (India) — Muslims and Bodhs-have been typed for haptoglobin and for CG and PI subtype polymorphisms. The allele frequencies do not show significant differences between these two populations. HP and GC allele frequencies of Bodhs and Muslims differ considerably from with that observed in other North Indian populations. The PI allele frequencies of Bohds and Muslims differ considerably from those found in other Indian populations and are more similar to Mongoloid ones.     

Phosphorus in sediments — speciation and analysis

Characterization of sediment phosphorus is commonly based on sequential chemical extractions, in which phosphorus is supposed to be selectively removed from different compounds in the sediments. The first extraction schemes were designed to quantify discrete chemical or mineralogical compounds. As extraction schemes have been tested on different sediments, several systematic errors have been detected and the schemes have been modified and simplified accordingly. Other chemical extractions or treatments have attempted to determine phosphorus bound to particles with a certain strength or binding energy, the purpose being to determine the labile, loosely bound, exchangeable, mobile or algal-available fraction of sediment phosphorus. All extraction procedures yield operationally defined fractions and cannot be used for identification of discrete phosphorus compounds. The many methodological modifications make it necessary to be cautious when comparing results from the literature in this field.     

Demonstration of correlations between the 8 and 10 kHz atmospherics and the inflammatory reaction of rats after carrageenan injection

Between the mean daily density of 28 kHz atmospherics and the onset of epileptic fits there is a highly significant correlation coefficient (r) of 0.30; there is a negative coefficient of –0.20 between the fits and the mean daily density of 10 kHz atmospherics. The onset of heart infarction is correlated with 28 kHz atmospherics (r=0.15). Furthermore, we have discovered that sudden deafness is also correlated with certain configurations of atmospherics. In this paper we report the following correlation coefficients between the inflammatory reaction of rats to a carrageenan injection (rci) into a hind paw and the mean daily pulse rate of atmospherics of the same day:r=0.49 for the 8 kHz atmospherics (P<0.02) andr=0.44 for the 10 kHz atmospherics (P<0.04). The correlations between rci reaction and other atmospherics (12 and 28 kHz) are smaller and not significant. By the method of multiple linear regression we found a multipleR=0.54 between rci reaction and the 8 and 10 kHz atmospherics (the regression function for the rci reaction is 0.15+0.004×8 kHz+0.002×10 kHz,P<0.05).     

Proline accumulation induced by weak acids and IAA in coleoptiles of wheat seedlings

Proline accumulation in coleoptiles of wheat seedlings or in excised coleoptile segments incubated under shaking for a 24 h period was studied. There was no increase of proline content of coleoptiles after incubation of the seedlings in 5 mM citric acid (a relatively strong and slowly penetrating organic acid) in a pH range from 4.5 to 7.0 and only a slight increase of proline content after incubation in phosphate buffer at pH 7.0 to 7.5 duo to the higher osmotic concentration of phosphate buffer in this pH range. Quite different results were obtained with seedlings incubated in 10 mM acetic acid, a weak and easily penetrating organic acid. With increasing proton concentrations, proline accumulation increased. Application of 400 mM mannitol or higher concentrations of IAA (more than 10⁻⁵M) additionally increased proline accumulation in the presence of 10 mM acetic acid in the pH range from 6.0 to 7.5 in which acetic acid alone was loss effective. It is suggested that a decrease of cytosolic pH causes stress—induced proline accumulation.     

Effects of gravel size and peat material concentrations on embryo survival and alevin emergence of brown trout,Salmo trutta L.

Embryo survival and alevin emergence pattern of brown trout were studied in simulated redds with different homogeneous gravel sizes and different concentrations of peat material. Optimal survival (95%) occurred in 18 mm gravel and survival decreased with decreasing gravel size. High concentrations (40%) of peat material resulted in low survival (65%). The proportion of premature emerging alevins increased in finer gravels and at high peat concentrations. Premature alevins had a large yolk sac and are probably very vulnerable to predators.     

Behaviour of drifting insect larvae

The larval drift behaviour of 23 species representing Ephemeroptera, Plecoptera and Trichoptera was investigated in the laboratory using different current regimes. Mayfly nymphs often performed swimming, while caddis larvae were reluctant to do so. Stonefly nymphs were intermediate. In mayflies swimming seemed to be used to reach the substrate as soon as possible. In contrast most stonefly nymphs by swimming prolonged the time spent in the water column. Modes of swimming and sinking posture differed markedly between the orders. Living passively sinking animals often reached bottom faster than dead control specimens, so consequently behaviour did not always express itself in activity. Some caddis larvae spun adherent anchor lines. Differences among taxa seemed more important in explaining swimming activity compared to preferred habitats (as stream, river and lake) in each species. However, observed differences among closely related species indicated subtle differences related to microhabitat to be of profound importance in explaining the alternative behavioural strategies used.     

Effect of Monochromatic Light on Proton Efflux of the Blue-Green Alga Anabaena variabilis

Light-induced proton efflux of Anabaena variabilis was found to be biphasic, the second phase being inhibited by the ATPase inhibitor nitrofen (2,4-dichloro-1-[4-nitrophenoxy]benzene). The first, fast phase was triggered by monochromatic light of 707 nanometers, whereas the second, slower phase was not. With 707 nanometers, light, respiratory O₂ uptake was inhibited. Using light composed of two wavelengths (616 and 707 nanometers) a marked enhancement of both O₂ evolution as well as the second phase of proton efflux was observed. The first phase was not enhanced. Thus, phase II is driven by both photosystems. As concluded from the action spectrum phase I is markedly determined by photosystem-I activity. Altogether the data show that two different mechanisms of light-induced proton efflux exist on the cytoplasmic membrane of Anabaena, the slower one being dependent on ATP and linear photosynthetic electron flow.     

Recognition of peat-forming plant communities from their peat deposits in two south Swedish bog complexes

Peat samples, 3 015 from 103 boring points, on two mires (Åkhult mire, Store Mosse mire) south Sweden, have been subjected to macrofossil analysis. Based on plant remains, 9 peat groups were distinguished in the field. A further classification using phytosociological methods revealed 29 peat types. The affinities between the peat types were determined from TABORD classification and a Reciprocal Averaging ordination. The primary floristic differentiation is correlated with a gradient from treeless-to wooded stands, which coincides largely with the mire expanse-mire margin gradient. The poor-rich gradient seems to parallel the treeless-wooded gradient as well and may reflect the natural conditions in this mire before it was affected by man. The hummock-mud-bottom gradient is easy to distinguish in peat, formed by bog communities, but is not distinct in peat formed by fen communities and impossible to detect in peat dominated by wood remains. The amount of identifiable remains depends on the decomposition, which is determined by (1) the period of time the plant litter stays in the acrotelm, and (2) the nutrient status. The decomposition is greatest in fen-peat with abundant wood remains. This probably depends on a good supply of oxygen caused by greater horizontal water movements and better nutrient status.