Conservation and the cricket culture in China

Several species of Tettigoniidae and Grylloidea are collected and traded as singing or fighting insects in China. There is anecdotal evidence that this trade is causing a reduction in the ranges and populations of some species. However, before any conservation status can be assigned to any species reliably, it will be necessary to reconcile the long-established traditional classification system of singing and fighting insects with scientific classification, determine the ranges and monitor the populations of selected species of commonly traded species, and initiate an educational programme for invertebrate conservation using these crickets as flagship taxa.     

Processing of calling songs by an L-shaped neuron in the prothoracic ganglion of the female cricket, Acheta domesticus

ABSTRACT. An L-shaped auditory intemeuron (LI) has been recorded from extracellularly and intracellularly, and identified morphologically (by Lucifer yellow or cobalt injection) in the prothoracic ganglion of mature female Acheta domesticus. The morphology of the LI is very similar to ascending, prothoracic acoustic interneurons that are most sensitive to higher carrier frequencies in both A. domesticus and other gryllid species. Its terminations in the brain are similar to ascending acoustic interneurons found in other gryllids. The LI neuron is most sensitive to 4–5 kHz model calling songs (CSs), the main carrier frequency of the natural call. Thresholds to high frequencies (8–15 kHz) are 15–20 dB higher. Increasing CS intensities of up to 15 dB above threshold at 4–5 kHz result in increased firing rates by the LI. More than 15 dB increase in intensity causes saturation with little increase in spiking rate until the intensity surpasses 80 dB. In response to 70 dB or higher stimulus intensities, the LI responds to the second and third CS syllables with one or two spikes, pauses, and then produces a burst of nerve impulses with the same or greater latency than for lower intensity stimuli. In response to CS syllables of changing duration (10–30 ms) this neuron responds with a rather constant duration burst of impulses. Syllable periods of the CS stimuli were accurately encoded by the LI. Progressively stronger injection of hyperpolarizing current reduces, and ultimately stops spiking of the LI in response to CS stimuli. More intense stimulation with reduced hyperpolarization shows an initial spike, pause and burst of spikes. Intracellular recording from axonal regions of the neuron shows large spikes, small EPSPs and a developing hyperpolarization through the response to a CS chirp. Inhibitory input to the LI is demonstrated at 4.5, 8 and 16 kHz. This probably explains the specialized response characteristics of the LI which enhanced its encoding of CS syllable period.     

Courtship role reversal in bush crickets: another role for parasites?

The last decade has seen an increasing body of evidence in supportof the idea that parasites can play a role in sexual selection.Parasites have been shown to influence mate choice and matingcompetition. Here I demonstrate a further role for parasitesin that they can determine the courtship roles of males andfemales and thus the sex on which sexual selection acts. Malebush crickets, Requena verticalis, feed their mates during inseminationwith a nutritious meal, the spermatophylax, that increases femalefecundity. I show how the ability of males to donate nutrientswas reduced by increased intensities of infection of a protozoangut parasite. Further, increased intensity of infection reducedfemale fecundity. Mating trials showed that when females wereuninfected the typical courtship roles prevailed; females werethe coy, discriminating sex. However, when infected with gutparasites, females attempted to mate more often and males adoptedthe coy discriminative role in courtship. Thus it appeared thatmale donations were of greater importance for reproductivelyconstrained, infected females. The infection status of the malehad no influence on courtship role reversal supporting the ideathat proximate cues in female behavior determine the courtshiprole adopted by males. It is argued that parasites will be animportant determinant f courtship role reversal in any specieswhere male gifts influence female fecundity, and parasites constrainhost reproduction, because of the opposing way in which reproductiveconstraints will influence male and female mating frequency.     

Abigaille-Ⅲ： A Versatile,Bioinspired Hexapod for Scaling Smooth Vertical Surfaces

This paper presents a novel, legged robot, Abigaille-Ⅲ, which is a hexapod actuated by 24 miniature gear motors. This robot uses dual-layer dry adhesives to climb smooth, vertical surfaces. Because dry adhesives are passive and stick to various surfaces, they have advantages over mechanisms such as suction, claws and magnets. The mechanical design and posture of Abigaille-Ⅲ were optimized to reduce pitchback forces during vertical climbing. The robot＇s electronics were designed around a Field Programmable Gate Array, producing a versatile computing architecture. The robot was reconfigured for vertical climbing with both 5 and 6 legs, and with 3 or 4 motors per leg, without changes to the electronic hardware. Abigaille-Ⅲ demonstrated dexterity through vertical climbing on uneven surfaces, and by transferring between horizontal and vertical sur- faces. In endurance tests, Abigaille-Ⅲ completed nearly 4 hours of continuous climbing and over 7 hours of loitering, showing that dry adhesive climbing systems can be used for extended missions.     

动物尿液化学通讯的研究进展

动物通讯是动物个体通过不同的信息交流方式实现信息传递及共享的过程。尿液是动物化学通讯中传递和分享信息的重要信号来源,尿液化学通讯是动物种内乃至种间信息交流的重要途径之一。本文阐述了不同物种之间信息交流和相同物种不同个体之间的尿液化学通讯,对于了解动物个体尿液化学成分组成、繁殖、行为以及社会识别等具有重要的生物学意义。     

Do Wolbachia infections play a role in unidirectional incompatibilities in a field cricket hybrid zone?

Two closely related field crickets, Gryllus firmus and G. pennsylvanicus, hybridize along an extensive north-south zone in the eastern United States. Crosses between G. firmus males and G. pennsylvanicus females produce viable and fertile F1, but the reciprocal cross consistently fails to produce offspring. Wolbachia, a bacterial parasite of arthropods that causes unidirectional incompatibilities in a variety of insect species, has been suggested as the cause of the observed incompatibility between G. pennsylvanicus and G. firmus. We examine the presence/absence of Wolbachia strains, defined by sequencing the ftsZ gene, in four cricket populations from the north-eastern United States. Most G. firmus individuals are infected (100% in Guilford, Connecticut; 65% in Seaside Park, New Jersey) and > 95% of those infected harbour a single strain of Wolbachia. All individuals in G. pennsylvanicus populations (Ithaca, New York; Sharon, Connecticut) are infected; the majority of individuals carry a second strain of Wolbachia, but a significant fraction carry the same strain found commonly in G. firmus. The presence of an apparently identical Wolbachia strain in crickets of both species means that some crosses between G. pennsylvanicus males and G. firmus females should be compatible. We have no evidence of such compatibility. Furthermore, if Wolbachia infections are responsible for the observed incompatibility between species, then incompatibilities must also exist within G. pennsylvanicus, because this species harbours both Wolbachia strains. Although some single pair crosses within G. pennsylvanicus do fail to produce offspring, the proportion is lower than expected if Wolbachia were responsible. Therefore, Wolbachia is unlikely to be involved in reproductive isolation between the two cricket species.     

Effect of temperature on auditory receptor functions in crickets (Orthoptera,Tettigoniodea)

By electrophysiological methods, effect of temperature on cricket tympanal organ functions was studied. Activity of auditory receptors was recorded intracellularly in the 5th nerve of I thoracic ganglion in Tettigonia cantans, Metrioptera roeselii, M. bicolor, Platycleis albopunctata, Pholidoptera griseoaptera, and Phaneroptera falcata. The temperature was changed in the range from 17 to 34° C. Heating of the tympanal organ to 30–32°C led to a decrease of impulse amplitude, shortening of their duration, an increase of sensitivity, of the burst instantaneous frequency, and of the number of impulses in the responses as well as to a decrease of latent periods (LP) of receptor reaction. The optimal frequency in all studied cells did not change, although the range of perceived frequencies was enlarged. The frequency threshold curve of receptor either was shifted down along the ordinate scale without changes of its shape or the thresholds at various frequencies decreased non-uniformly. Thus, the obtained data indicate the absence of changes in the frequency tuning of the auditory receptors with changes of temperature.     

The physiological costs of flight capability in wing-dimorphic crickets

Nutritional indices, triglyceride levels and flight muscle developmental profiles were compared between long-winged (LW) and short-winged (SW; flightless) morphs of the cricketsGryllus rubens Scudder andG. firmus Scudder. This was done to identify potential physiological costs of flight capability in adults. The LW morph of each species converted a lower proportion of assimilated nutrients into biomass (reduced ECD) than did the SW morph. This documents increased respiratory metabolism in the LW morph. Triglyceride concentration was higher in LW vs. SW adults. This suggests that the elevated respiration in the LW morph may be at least partially due to the increased biosynthesis of this high energy substance. Preliminary data indicate higher respiration rates of LW functional vs. SW vestigial flight muscles. Collectively, these data suggest that the energetic cost of flight capability in adults results from biosynthesis of triglyceride flight fuel and flight muscle maintenance but not flight muscle growth. No flight muscle growth was observed in adults.