Involvement of the suboesophageal and thoracic ganglia in the control of antennal movements in crickets

In crickets (Gryllus campestris, Gryllus bimaculatus) the contribution of the suboesophageal ganglia (SOG) and thoracic ganglia to the generation of antennal movements during visual tracking, walking and flight was investigated by the transection of connectives. Transection of one circumoesophageal connective abolished the movements and postures of the antenna ipsilateral to the lesion, while the contralateral antenna behaved normally. Simple antennal reflexes remained. Transection of one neck connective reduced fast components of antennal movements during tracking and walking. During flight the ipsilateral antenna could not be maintained in a prolonged forward position. Antennal movements during tracking and walking appeared normal after transection of one connective between pro- and mesothoracic ganglia. However, the antennal flight posture required uninterrupted connections between brain and mesothoracic ganglion. The ablation of more posterior ganglia had no effect on the antennal behaviours investigated. Recordings from an antennal motor nerve revealed a unilateral net excitation relayed via the SOG to the brain. Two ascending interneurones with activity closely correlated with antennal movements are candidates for such a relay function. The data show that the brain is not sufficient to generate antennal movements and postures as integral parts of several behaviours. The SOG and the thoracic ganglia are required in addition. Accepted: 12 March 1997     

The antennal motor system of the stick insect Carausius morosus: anatomy and antennal movement pattern during walking

The stick insect Carausius morosus continuously moves its antennae during locomotion. Active antennal movements may reflect employment of antennae as tactile probes. Therefore, this study treats two basic aspects of the antennal motor system: First, the anatomy of antennal joints, muscles, nerves and motoneurons is described and discussed in comparison with other species. Second, the typical movement pattern of the antennae is analysed, and its spatio-temporal coordination with leg movements described. Each antenna is moved by two single-axis hinge joints. The proximal head-scape joint is controlled by two levator muscles and a three-partite depressor muscle. The distal scape-pedicel joint is controlled by an antagonistic abductor/ adductor pair. Three nerves innervate the antennal musculature, containing axons of 14-17 motoneurons, including one common inhibitor. During walking, the pattern of antennal movement is rhythmic and spatiotemporally coupled with leg movements. The antennal abduction/adduction cycle leads the protraction/retraction cycle of the ipsilateral front leg with a stable phase shift. During one abduction/adduction cycle there are typically two levation/depression cycles, however, with less strict temporal coupling than the horizontal component. Predictions of antennal contacts with square obstacles to occur before leg contacts match behavioural performance, indicating a potential role of active antennal movements in obstacle detection.     

The control of antennal movements by leg proprioceptors in the rock lobster,Palinurus vulgaris

Summary The antennae of the rock lobster,Palinurus vulgaris, show systematic responses to movements of the legs on a tilting footboard. Myographic recordings in muscles of the first antennal segment have been used in an analysis of the sensory basis of these reactions. Antennal posture is modified in the experimental apparatus, although its relation to the change in loading conditions of the legs is uncertain. The motor control of the antennal equilibrium responses involves a complete reciprocation between both excitatory and inhibitory motoneurones to the antagonist muscle groups in the two antennae. Sensory inputs from single legs produce movements of both antennae, but a stronger drive ipsilaterally. Leg receptor inputs also modulate antennal resistance reflexes in a systematic manner, providing a sensitive test for the involvement of particular receptor organs in the leg. Movement at the coxo-basal leg joint is a major source of sensory input, and ablation/ stimulation experiments have established that stimulation of the CB chordotonal organ is a necessary but not sufficient condition to produce the antennal equilibrium reactions. The possibility is discussed that other receptors at the coxo-basal joint are also involved.D.M.N. was supported by a grant from The Max-Planck Institut to Professor H. Schöne.     

The dynamics of sleep-like behaviour in honey bees

At night, honey bees pass through a physiological state that is similar to mammalian sleep. Like sleep in mammals, sleep-like behaviour in honey bees is an active process. This is expressed most clearly in these insects by spontaneous antennal movements which appear at irregular intervals throughout the night and interrupt episodes of antennal immobility. Here we present a newly developed video technique for the continuous recording of the position and movements of the bee's antennae. The same technique was used to record head inclination and ventilatory movements. Despite the constancy of the ambient temperature, the magnitudes of antennae-related parameters, as well as head inclination and ventilatory cycle duration, displayed dynamic unimodal time-courses which exhibited a high degree of temporal covariance. The similarity between these time-courses and the nightly time-course of the reaction threshold for a sensory stimulus, investigated previously, indicates that, in honey bees, deepest "sleep" and least ventilatory activity occur at the same time (in the 7th hour of the rest phase).Abbreviations DD continuous darkness - EMG electromyogram - LD periodic alternation between light (L) and darkness (D) - MEST Middle European Summer Time (UTC+2 h); - UV ultraviolet This paper is dedicated to Professor Martin Lindauer, who—to our knowledge—was the first to meticulously record the nightly behaviour of honey bees (Lindauer 1952) and who also inspired one of us (W.K.) to investigate antennal motility during nightly rest in these animals.     

The functions of antennal mechanoreceptors and antennal joints in tactile discrimination of the honeybee (<Emphasis Type="Italic">Apis mellifera</Emphasis> L.)

Honeybees learn and discriminate excellently between different surface structures and different forms of objects, which they scan with their antennae. The sensory plate on the antennal tip plays a key role in the perception of mechanosensory and gustatory information. It is densely covered with small tactile hairs and carries a few large taste hairs. Both types of sensilla contain a mechanoreceptor, which is involved in the antennal scanning of an object. Our experiments test the roles of the mechanoreceptors on the antennal tip in tactile antennal learning and discrimination. Joints between head capsule and scapus and between scapus and pedicellus enable the bee to perform three-dimensional movements when they scan an object. The role of these joints in tactile antennal learning and discrimination is studied in separate experiments. The mechanoreceptors on the antennal tip were decisive for surface discrimination, but not for tactile acquisition or discrimination of shapes. When the scapus–pedicellus joint or the headcapsule–scapus joint was fixed on both antennae, tactile learning was still apparent but surface discrimination was abolished. Fixing both scapi to the head capsule reduced tactile acquisition.     

Antennal motor activity induced by pilocarpine in the American cockroach

The antennal motor system is activated by the muscarinic agonist pilocarpine in the American cockroach Periplaneta americana, and its output patterns were examined both in restrained intact animals and in isolated CNS preparations. The three-dimensional antennal movements induced by the hemocoelic drug injection were analyzed in in vivo preparations. Pilocarpine effectively induced prolonged rhythmic movements of both antennae. The antennae tended to describe a spatially patterned trajectory, forming loops or the symbol of infinity (∞). Such spatial regularity is comparable to that during spontaneous tethered-walking. Rhythmic bursting activities of the antennal motor nerves in in vitro preparations were also elicited by bath application of pilocarpine. Cross-correlation analyses of the bursting spike activities revealed significant couplings among certain motor units, implying the spatial regularity of the antennal trajectory. The pilocarpine-induced rhythmic activity of antennal motor nerves was effectively suppressed by the muscarinic antagonist atropine. These results indicate that the activation of the antennal motor system is mediated by muscarinic receptors.     

Active tactile exploration for adaptive locomotion in the stick insect

Insects carry a pair of actively movable feelers that supply the animal with a range of multimodal information. The antennae of the stick insect Carausius morosus are straight and of nearly the same length as the legs, making them ideal probes for near-range exploration. Indeed, stick insects, like many other insects, use antennal contact information for the adaptive control of locomotion, for example, in climbing. Moreover, the active exploratory movement pattern of the antennae is context-dependent. The first objective of the present study is to reveal the significance of antennal contact information for the efficient initiation of climbing. This is done by means of kinematic analysis of freely walking animals as they undergo a tactually elicited transition from walking to climbing. The main findings are that fast, tactually elicited re-targeting movements may occur during an ongoing swing movement, and that the height of the last antennal contact prior to leg contact largely predicts the height of the first leg contact. The second objective is to understand the context-dependent adaptation of the antennal movement pattern in response to tactile contact. We show that the cycle frequency of both antennal joints increases after obstacle contact. Furthermore, inter-joint coupling switches distinctly upon tactile contact, revealing a simple mechanism for context-dependent adaptation.     

The antennal motor system of crickets: modulation of muscle contractions by a common inhibitor,DUM neurons,and proctolin

In the crickets Gryllus bimaculatus and Gryllus campestris, the two intrinsic antennal muscles in the scape (first antennal segment) control antennal movements in the horizontal plane. Of the 17 excitatory antennal motoneurons, three motoneurons, two fast and one slow, can be stimulated selectively and their effect on muscle contraction, i.e. antennal movement, measured. Simultaneously, either a common inhibitor (CI) neuron or two DUM neurons can be stimulated and the effect on the slow and/or fast muscle contraction measured. The activity of the common inhibitor affected only slow muscle contractions. It decreased contraction rate, increased relaxation rate and suppressed prolonged muscle tension. This effect was blocked by picrotoxin. DUM neuron stimulation affected both slow and fast contractions. It reduced slow and enhanced fast contractions but in only 10% of the experiments could this effect be detected. DUM neuron activity could be mimicked by octopamine application. Proctolin application enhanced both slow and fast contractions but did not increase muscle tension in the absence of motoneuron activity. The results are discussed in relation to the large variability of possible antennal movements during behaviors.Abbreviations CI common inhibitor neuron - DUM dorsal unpaired median neuron     

Antennal muscles and fast antennal movements in ants

The antennal movements of eight ant species (subfamilies Ponerinae, Myrmicinae, and Formicinae) are examined by high-frequency videography. They show a wide range of antennal velocities which is generated by antennal muscles composed of particularly diverse muscle fibers. Fiber diameter, sarcomere length and histochemically assessed myosin ATPase activity suggest that some thin fibers are fairly slow, while the bulk of antennal muscle fibers show intermediate or fast properties. These morphological properties correlate with the antennal movement velocities measured for the respective species. Based on their morphology, the fibers that generate the fast antennal retraction in some trap-jaw ants appear particularly fast and comprise the shortest sarcomeres yet described (1.1 μm). Accepted: 2 January 1997     

Muscular anatomy and aspects of the structure of the antennae of Anthosoma crassum (Dichelesthiidae: Siphonostomatoidae: Copepoda)

The muscular anatomy and fine structure of the antennae of adult Anthosoma crassum are described from specimens collected from jaws of shortfin makos. Casual observations of live parasites showed that embedded adult A. crassum can move toward or away from the host by shortening or lengthening the antennae, respectively. These movements were controlled by antennal retractor muscles. Microprotuberances located on the distal antennal segments may increase friction between these copepods and their hosts, thus strengthening parasite attachment.     

Bewegungsmechanismus und gelenkrezeptoren der Antennen von Locusta migratoria L. (Insecta,orthoptera)

The morphological arrangement of the antennal joints and their significance for the complex antennal movements are investigated. Particular value is attached to the mechanoreceptors of the 2. segment because of their importance for the function of the antennae as air current sense organs.     

六斑月瓢虫触角及感觉器扫描电镜观察

[目的] 明确六斑月瓢虫雌雄成虫触角感觉器种类、分布及形态特征。[方法] 利用扫描电子显微镜对六斑月瓢虫雌、雄成虫触角形态及触角感受器超微结构进行观察。[结果] 六斑月瓢虫成虫触角由柄节、梗节和鞭节组成,柄节长度与宽度显著大于梗节长度与宽度;鞭节分为9个亚节,末端3节横向膨大呈锤状。雌雄成虫触角上共有8种感觉器:刺形感觉器(SC)、毛形感觉器(ST)、锥形感觉器(SB)、腔形感觉器(CaS)、钟形感觉器(CS)、哑铃形感觉器(DS)、香肠形感觉器(SS)及B?hm氏鬃毛感觉器(BB)。以毛形感觉器和刺形感觉器分布最广,遍布触角;B?hm氏鬃毛仅存在于触角柄节与梗节;触角鞭节第9亚节顶端密布7种触角感觉器。六斑月瓢虫雌雄成虫触角长度、触角感觉器类型及分布无显著差异。[结论] 六斑月瓢虫成虫触角上共有8种感觉器,其触角可能具有感知机械刺激、识别化学信息素及感受温湿度变化的作用。本研究为进一步了解六斑月瓢虫触角与其行为间的关系提供基础资料。     

Antennal movements induced by odour and central projection of the antennal neurones in the honey-bee

Movements of the antennae induced by odour were investigated. Odour presented to the antenna of one side induced both antennae to move to that side. The EMGs recorded from the flexor muscles of both scapes showed that the latency of the movement of the ipsilateral flagellum when induced by odour was about 71 msec shorter than that of the contralateral flagellum. Recording electrical activities from the antennal nerve showed that there are more than 14 neurones in the antenno-motor externus.The distribution of the antennal nerve in the brain was investigated histologically by the injection of fluorescent dye. Antennal sensory neurones terminated at the glomeruli in the antennal lobe, in the dorsal lobe, in the protocerebrum, and in the commissural part of the suboesophageal ganglion. Injection of the fluorescent dye into the antennal nerve after degeneration of the antennal sensory neurones showed that the antennal motoneurones run in the ventral side of the antennal and dorsal lobes, and terminate in the marginal region of the ipsilateral oesophageal connective.The difference in latency of odour-induced flagellar movements is discussed in relation to the histological results and the unitary responses in the brain reported previously.     

A preliminary note on a new optomotor response in crickets: Antennal tracking of moving targets

Summary Black disks moving horizontally in the visual field of a cricket (Gryllus campestris) induce an antennal tracking response. It consists of movements of the ipsilateral antenna following the target in a saccade-like fashion.This work was supported by a grant from the Deutsche Forschungsgemeinschaft Ho 463/12.     

Mechanosensory control of antennal movement by the scapal hair plate in the American cockroach

The voluntary movement of antennae of blinded cockroaches was examined in the tethered-walking condition. An object of metal plate was presented to a tip of a single antenna in order to induce tactile orientation behavior. Horizontal movements of the antenna before and during the object presentation were analyzed both before and after ablation of a mechanosensory organ, the scapal hair plate (S-HP), at the base of antenna. The resting antennal position shifted outwardly by about 20 degrees after the S-HP ablation. Spontaneous antennal movements in ablated animals became stiff and wider ranged. The tactile object was set at two different horizontal positions, 45 degrees and 90 degrees clockwise to the head, for the right side antenna. The number of contacts in a constant test period was significantly decreased in the tests at 45 degrees after ablation. Trajectories of antennal movements before and after contacts were categorized into four patterns. In the case that an antenna made contact with the object during its abduction (outward) movement, it then passed the object outwardly or withdrew inwardly. These were termed "outward-pass (O-P)" and "outward-withdrawal (O-W)" patterns, respectively. Similarly, contacts during the adduction (inward) movement were divided into "inward-pass (I-P)" or "inward-withdrawal (I-W)" pattern. Significant effects of the S-HP ablation appeared in the tests at 90 degrees : the I-P pattern mostly disappeared and was replaced by the I-W pattern. The results strongly suggest that the S-HP has crucial roles for controlling both spontaneous and stimulated movements of the cockroach antenna.     

七星瓢虫触角转录组及嗅觉相关基因分析

【目的】瓢虫科食性高度分化。本研究旨在通过建立七星瓢虫Coccinella septempunctata触角转录组数据库,探讨其触角嗅觉相关基因与食性分化的关系。【方法】采用Illumina HiSeq 4000高通量测序平台对七星瓢虫成虫触角转录组进行测序、组装、注释,挖掘嗅觉相关基因,并与已发表的茄二十八星瓢虫Henosepilachna viginyioctopunctata转录组进行比较。【结果】共获得七星瓢虫触角转录组31 775条unigenes,其中69.71%的序列得以注释,NR数据库中注释最多,为20 539条。据注释信息,挖掘到27个嗅觉相关基因,包括1个气味结合蛋白(odorant binding protein, OBP)基因,13个化学感受蛋白(chemosensory protein, CSP)基因,4个气味受体(odorant receptor, OR)基因,7个味觉受体(gustatory receptor, GR)基因和2个感觉神经元膜蛋白(sensory neuron membrane protein, SNMP)基因。相对应地,在植食性茄二十八星瓢虫转录组中鉴定到38个嗅觉相关基因,包括七星瓢虫中未发现的1个离子型受体(ionotropic receptor, IR)基因。在各类型嗅觉相关基因中,茄二十八星瓢虫转录组的OBP基因比例(13.16%)高于七星瓢虫触角转录组的(3.70%),而七星瓢虫触角转录组的GR基因比例(25.93%)则高于茄二十八星瓢虫转录组的(13.16%)。【结论】触角嗅觉相关基因数目不是昆虫食性分化的主因。本研究获得了七星瓢虫触角转录组学资源,初步探讨了嗅觉相关基因同瓢虫食性分化的关系,为了解瓢虫乃至昆虫食性分化的分子基础提供了信息。     

Retinal scanning and visual inputs in freely walking crickets

ABSTRACT. Freely walking crickets were filmed from above during their visual orientation towards a black stripe. A frame-by-frame analysis enabled head and body movements to be recorded. The animals walk in 200ms bouts (runs) separated by pauses of similar duration. During each run, rotations of the body axis are observed and some corrections of the course direction occur between successive runs. Generally, the crickets do not walk straight ahead but slightly sideways. Because no lateral head movements were observed during visually orientated locomotion, retinal scanning results from both rotations of the body axis and translation of the head. While walking, one of the target edges is maintained by the cricket on a relatively limited area of the retina, generally between 10 and 25 laterally. Thus, the cricket often records three pieces of information about each edge: one in the monocular visual field, and two in the binocular visual field. Nevertheless, between two pauses, the images of each edge shift asymmetrically on the retinae. Such movement could prevent receptor adaptation by modulation of the ommatidial excitation, or by stimulation of the neighbouring ommatidia. It is also suggested that antennal movements are influenced by the positions of the visually fixated target edges.     

Tactile motor learning in the antennal system of the honeybee (Apis mellifera L.)

Honeybees fixed in small tubes scan an object within the range of the antennae by touching it briefly and frequently. In our experiments the animals were able to scan an object for several minutes with the antennae. After moving the object out of the range of the antennae, the animals showed antennal movements for several minutes that were correlated with the position of the removed object. These changes of antennal movements are called “behavioural plasticity” and are interpreted as a form of motor learning. Bees showed behavioural plasticity only for objects with relatively large surfaces. Plasticity was more pronounced in bees whose compound eyes were occluded. Behavioural plasticity was related to the duration of object presentation. Repeated presentations of the object increased the degree of plasticity. After presentation durations of 30 min the animals showed a significant increase of antennal positions related to the surface of the object and avoidance of areas corresponding to the edges. Behavioural plasticity was compared with reward-dependent learning by conditioning bees to objects. The results of motor learning and reward-dependent conditioning suggest that bees have tactile spatial memory. Accepted: 13 May 1997     

An informational analysis of antennal communication during trophallaxis in the ant Myrmica Rubra L.

Trophallaxis by ants is accompanied by antennal movements which have an informational value. The succession of contacts permits the transmission of information for triggering, maintaining or stopping the exchange. The use of information theory indicates that antennal contacts during trophallaxis quantitatively transmit much less information than some other systems used by social insects (i.e. the dance of the bees or trails of Solenopsis). The information transferred by the signal is never more than 20%; the system is not appropriate to conduct important messages but belongs to a modulatory communication system.     

Mechanisms of stick insect locomotion in a gap-crossing paradigm

Locomotion of stick insects climbing over gaps of more than twice their step length has proved to be a useful paradigm to investigate how locomotor behaviour is adapted to external conditions. In this study, swing amplitudes and extreme positions of single steps from gap-crossing sequences have been analysed and compared to corresponding parameters of undisturbed walking. We show that adaptations of the basic mechanisms concern movements of single legs as well as the coordination between the legs. Slowing down of stance velocity, searching movements of legs in protraction and the generation of short steps are crucial prerequisites in the gap-crossing task. The rules of leg coordination described for stick insect walking seem to be modified, and load on the supporting legs is assumed to have a major effect on coordination especially in slow walking. Stepping into the gap with a front leg and antennal contact with the far edge of the gap provide information, as both events influence the following leg movements, whereas antennal non-contact seems not to contain information. Integration of these results into the model of the walking controller can improve our understanding of insect locomotion in highly irregular environments.Abbreviations AEP anterior extreme position - fAEP fictive anterior extreme position - PEP posterior extreme position - TOT treading-on-tarsus