Tremulation of firebags <Emphasis Type="Italic">Pyrrhocoris apterus</Emphasis> L. (Heteroptera,Pyrrhocoridae)

Tremulatory signals of firebugs Pyrrhocoris apterus L. are described. The oscillogram of the tremulatory signals is given.     

Acoustic repertoire of the singing cicada <Emphasis Type="Italic">Cicadetta cantilatrix</Emphasis> Sueur et Puissant, 2007 (Homoptera,Cicadidae) from Russia

The singing cicada Cicadetta cantilatrix Sueur et Puissant, 2007, only recently described from Western Europe, was found in Russia. The acoustic repertoire of this species is studied, oscillograms and sonograms of the signals emitted by individuals from the south of Moscow Province are provided for the first time.     

The possibility of computer analysis of the twilight soundscape of the orthopteran (Tettigoniidae,Gryllidae) community,by the example of an agrocenosis in Eastern Bulgaria

Computer analysis of the twilight soundscape with the sounds of grasshoppers (Tettigoniidae) and crickets (Gryllidae) recorded in an agrocenosis of Eastern Bulgaria was performed. Seven species were identified by the dynamic spectrograms. It is shown that analysis of the group stridulation spectrograms of Ensifera can be useful not only for solving ecological and faunistic problems but also for studying the acoustic interactions of conspecific and heterospecific individuals in the same biotope.     

Confirmation of the Subspecies Status of Dianemobius fascipes nigrofasciatus (Orthoptera,Gryllidae) Based on Bioacoustic and Morphological Data,with the Description of the Male Sounds from Southern Siberia

The taxonomic status of Dianemobius fascipes (Walker, 1869) from Nepal (Kathmandu) and D. nigrofasciatus (Matsumura, 1904) from Japan (Akiruno City near Tokyo), Korea (Incheon near Seoul), and Russia (Novosibirsk) is discussed based on comparison of acoustic calling signals. The sounds of D. nigrofasciatus are described for the first time from the northwesternmost locality of its range in southern Siberia, Russia. The signals of males from Russia, Japan, and Korea show no differences in their amplitude-time characteristics but they differ slightly from the signals of D. fascipes from Nepal. There are no morphological differences between these taxa except for the color of the hind tibia. The male genitalia are similar, slightly differing only in the degree of development of the ectoparamere lobe. Thus we suggest that D. fascipes should be considered a polytypic species with two subspecies: the southern nominotypical subspecies D. fascipes fascipes stat. resurr., common in the Oriental Region, and the northern subspecies D. fascipes nigrofasciatus stat. resurr., known from the eastern part of the Palaearctic Region.

     

Mitochondrial respiratory activity of the trematode Fasciola hepatica

Polarographic studies have been made on the respiratory activity of isolated mitochondria of the trematode F. hepatica. Respiratory chain transferring electrons to oxygen and which is sensitive to cyanide was found in the mitochondria. Certain coupling between respiration and phosphorylation was observed. Intact mitochondria of the trematode exhibit the respiratory control although its level is significantly lower than that in the mitochondria from rat liver. The existence of an alternative respiratory chain was demonstrated in which electron transport is not associated with ATP synthesis.     

Dogs are sensitive to small variations of the Earth’s magnetic field

Introduction

Several mammalian species spontaneously align their body axis with respect to the Earth’s magnetic field (MF) lines in diverse behavioral contexts. Magnetic alignment is a suitable paradigm to scan for the occurrence of magnetosensitivity across animal taxa with the heuristic potential to contribute to the understanding of the mechanism of magnetoreception and identify further functions of magnetosensation apart from navigation. With this in mind we searched for signs of magnetic alignment in dogs. We measured the direction of the body axis in 70 dogs of 37 breeds during defecation (1,893 observations) and urination (5,582 observations) over a two-year period. After complete sampling, we sorted the data according to the geomagnetic conditions prevailing during the respective sampling periods. Relative declination and intensity changes of the MF during the respective dog walks were calculated from daily magnetograms. Directional preferences of dogs under different MF conditions were analyzed and tested by means of circular statistics.

Results

Dogs preferred to excrete with the body being aligned along the North–South axis under calm MF conditions. This directional behavior was abolished under unstable MF. The best predictor of the behavioral switch was the rate of change in declination, i.e., polar orientation of the MF.

Conclusions

It is for the first time that (a) magnetic sensitivity was proved in dogs, (b) a measurable, predictable behavioral reaction upon natural MF fluctuations could be unambiguously proven in a mammal, and (c) high sensitivity to small changes in polarity, rather than in intensity, of MF was identified as biologically meaningful. Our findings open new horizons in magnetoreception research. Since the MF is calm in only about 20% of the daylight period, our findings might provide an explanation why many magnetoreception experiments were hardly replicable and why directional values of records in diverse observations are frequently compromised by scatter.

     

Vibration communication in orthopteroid insects (Orthoptera) from suborder Caelifera

A review of vibration communication in suborder Caelifera is made. The vibration communication channel is found in three superfamilies—Tetrigoidea, Eumastacoidea and Acridoidea. The presence of vibration communication in Pyrgomorphoidea and Tridactyloidea is suggested. The data on vibration signals in superfamilies Pneumoroidea, Tanaoceroidea and Trigonopterygoidea are not known.