Jumping Apparatus Research Articles

On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in Collembola

BackgroundSpringtails have the ability to jump using morphological structures consisting of a catapult, the furca, and a latching system constructed with interaction of the retinaculum and the dens lock. The retinaculum engages in the furca at the dens lock in order to form a spring mechanism. They exhibit diversified morphological traits that serve as adaptations to a variety of terrestrial strata and aquatic surface environments. This comparative morphofunctional study centered on the retinaculum and the furcular region of the dens lock aims to describe the morphological variation between taxa and provide insights into the functional dynamics of the latching mechanism at work in the jumping apparatus. Using SEM, µCT and cLSM, we compared representatives of Collembola taxa, Poduromorpha (Neanura muscorum and Podura aquatica), Symphypleona (Dicyrtomina ornata) and Neelipleona (Megalothorax minimus), and examined extracts of the environment in which they were collected.ResultsA retinaculum is absent in N. muscorum, although vestigial muscles were found. Abdominal musculature varies significantly, being more abundant in springtails with clear segmentation (N. muscorum and P. aquatica), and reduced in springtails with fused segmentation (D. ornata and M. minimus). The M.a-ret varies as regards architecture and point of connection with the ramus, which is lateral in P. aquatica and median in the other species studied. The number of teeth in the retinaculum ramus also varies between three in M. minimus and four in the other species. The dens lock of all species studied has two locks and two furrows.ConclusionsThe retinaculum and dens lock interact in a key-lock relationship. The latching and unlatching mechanism from the retinaculum and dens lock appear to be similar in all the taxa examined, occurring by muscle force. This leads us to question the hypothesis that hemolymph pressure may be a force generator in jumping. We offer a reconstruction of the ground pattern of the retinaculum and dens lock and, in addition, an explanation of their functioning and the interaction between them. Finally, we frame the interaction between the retinaculum and the dens lock as a latch in a biological system, a mechanism which functions by force of physical contact.

On springtails (Hexapoda: Collembola): a morphofunctional study of the jumping apparatus

BackgroundSpringtails (Hexapoda: Collembola) are tiny organisms that lead a hidden life, mostly occuring deep in the soil and on leaf litter. They have a variety of interesting body morphology patterns, the most famous of which is the catapult-like structure that enables them to jump and flee from predators. This highly specialized jumping apparatus consists of a mobile furca, which when at rest fits into a trigger, "the retinaculum" on the ventral side of the abdomen. Despite the many studies that have attempted to investigate the jumping apparatus, the actual mechanisms involved in the jump, for example the way in which the furca is released by the retinaculum, how and where the mechanisms of spring and hydrostatic pressure originate, are still not properly understood. The morphology of the jumping apparatus of Orchesella cincta was investigated in detail using confocal laser scanning microscopy and MicroCT techniques for 3D reconstruction.ResultsThe morphology of O. cincta with both flexed and extended furca is analysed and described. The abdominal musculature involved in the jumping mechanism and relevant structures of the exoskeleton of retinaculum and furca are described in detail. With the data obtained in this study, hypotheses can be made about (1) where and how the spring and hydrostatic pressure mechanisms originate; (2) which muscles act on the extension and flexion of the furca; (3) which muscles act on the retinaculum and (4) how the retinaculum is released from the furca.ConclusionsThe comparative morphological study proved informative, and shows how springtail jumping involves mechanisms unique to this taxon. Hydrostatic pressure regulation possibly varies between animals with distinct segmentation, and those with fused segmentation. Interesting cuticular characters were revealed, such as basal plates and sclerites related to the construction of the spring mechanism. The present study establishes itself as a model option for future morphofunctional studies on springtail’s jumping. Analysis of videos and images using a high speed camera will be useful for understanding how the jump develops through take-off, aerial and landing phases.

Jumping mechanisms and performance in beetles. II. Weevils (Coleoptera: Curculionidae: Rhamphini)

We describe the kinematics and performance of the natural jump in the weevil Orchestes fagi (Fabricius, 1801) (Coleoptera: Curculionidae) and its jumping apparatus with underlying anatomy and functional morphology. In weevils, jumping is performed by the hind legs and involves the extension of the hind tibia. The principal structural elements of the jumping apparatus are (1) the femoro-tibial joint, (2) the metafemoral extensor tendon, (3) the extensor ligament, (4) the flexor ligament, (5) the tibial flexor sclerite and (6) the extensor and flexor muscles. The kinematic parameters of the jump (from minimum to maximum) are 530–1965 m s−2 (acceleration), 0.7–2.0 m s−1 (velocity), 1.5–3.0 ms (time to take-off), 0.3–4.4 μJ (kinetic energy) and 54–200 (g-force). The specific joint power as calculated for the femoro-tibial joint during the jumping movement is 0.97 W g−1. The full extension of the hind tibia during the jump was reached within up to 1.8–2.5 ms. The kinematic parameters, the specific joint power and the time for the full extension of the hind tibia suggest that the jump is performed via a catapult mechanism with an input of elastic strain energy. A resilin-bearing elastic extensor ligament that connects the extensor tendon and the tibial base is considered to be the structure that accumulates the elastic strain energy for the jump. According to our functional model, the extensor ligament is loaded by the contraction of the extensor muscle, while the co-contraction of the antagonistic extensor and flexor muscles prevents the early extension of the tibia. This is attributable to the leverage factors of the femoro-tibial joint providing a mechanical advantage for the flexor muscles over the extensor muscles in the fully flexed position. The release of the accumulated energy is performed by the rapid relaxation of the flexor muscles resulting in the fast extension of the hind tibia propelling the body into air.

The phylogeny of Galerucinae (Coleoptera: Chrysomelidae) and the performance of mitochondrial genomes in phylogenetic inference compared to nuclear rRNA genes.

With efficient sequencing techniques, full mitochondrial genomes are rapidly replacing other widely used markers, such as the nuclear rRNA genes, for phylogenetic analysis but their power to resolve deep levels of the tree remains controversial. We studied phylogenetic relationships of leaf beetles (Chrysomelidae) in the tribes Galerucini and Alticini (root worms and flea beetles) based on full mitochondrial genomes (103 newly sequenced), and compared their performance to the widely sequenced nuclear rRNA genes (full 18S, partial 28S). Our results show that: (i) the mitogenome is phylogenetically informative from subtribe to family level, and the per-nucleotide contribution to nodal support is higher than that of rRNA genes, (ii) the Galerucini and Alticini are reciprocally monophyletic sister groups, if the classification is adjusted to accommodate several 'problematic genera' that do not fit the dichotomy of lineages based on the presence (Alticini) or absence (Galerucini) of the jumping apparatus, and (iii) the phylogenetic results suggest a new classification system of Galerucini with eight subtribes: Oidina, Galerucina, Hylaspina, Metacyclina, Luperina, Aulacophorina, Diabroticina and Monoleptina.

Jumping mechanisms and performance in beetles. I. Flea beetles (Coleoptera: Chrysomelidae: Alticini).

The present study analyses the anatomy, mechanics and functional morphology of the jumping apparatus, the performance and the kinematics of the natural jump of flea beetles (Coleoptera: Chrysomelidae: Galerucinae: Alticini). The kinematic parameters of the initial phase of the jump were calculated for five species from five genera (average values from minimum to maximum): acceleration 0.91-2.25 (×10(3))ms(-2), velocity 1.48-2.80ms(-1), time to take-off 1.35-2.25 ms, kinetic energy 2.43-16.5 µJ, G: -force 93-230. The jumping apparatus is localized in the hind legs and formed by the femur, tibia, femoro-tibial joint, modified metafemoral extensor tendon, extensor ligament, tibial flexor sclerite, and extensor and flexor muscles. The primary role of the metafemoral extensor tendon is seen in the formation of an increased attachment site for the extensor muscles. The rubber-like protein resilin was detected in the extensor ligament, i.e. a short, elastic element connecting the extensor tendon with the tibial base. The calculated specific joint power (max. 0.714 W g(-1)) of the femoro-tibial joint during the jumping movement and the fast full extension of the hind tibia (1-3 ms) suggest that jumping is performed via a catapult mechanism releasing energy that has beforehand been stored in the extensor ligament during its stretching by the extensor muscles. In addition, the morphology of the femoro-tibial joint suggests that the co-contraction of the flexor and the extensor muscles in the femur of the jumping leg is involved in this process.

Anti-predator defence drives parallel morphological evolution in flea beetles.

Complex morphological or functional traits are frequently considered evolutionarily unique and hence useful for taxonomic classification. Flea beetles (Alticinae) are characterized by an extraordinary jumping apparatus in the usually greatly expanded femur of their hind legs that separates them from the related Galerucinae. Here, we examine the evolution of this trait using phylogenetic analysis and a time-calibrated tree from mitochondrial (rrnL and cox1) and nuclear (small subunits and large subunits) genes, as well as morphometrics of femora using elliptic Fourier analysis. The phylogeny strongly supports multiple independent origins of the metafemoral spring and therefore rejects the monophyly of Alticinae, as defined by this trait. Geometric outline analysis of femora shows the great plasticity of this structure and its correlation with the type and diversity of the metafemoral springs. The recognition of convergence in jumping apparatus now resolves the long-standing difficulties of Galerucinae-Alticinae classification, and cautions against the value of trait complexity as a measure of taxonomic significance. The lineage also shows accelerated species diversification rates relative to other leaf beetles, which may be promoted by the same ecological factors that also favour the repeated evolution of jumping as an anti-predation mechanism.

Decreased biodiversity in soil springtail communities: the importance of dispersal and landuse history in heterogeneous landscapes

In previously published papers it had been demonstrated that at the local level the species richness of soil springtail communities was negatively influenced by landuse diversity. When the dispersal rate of soil animals was taken into account, quite opposite trends were displayed by species having poor or high dispersal capabilities. At the local level, species with short legs, non functional jumping apparatus and reduction of visual organs were distinguished against by landuse diversity, while species with long legs, functional jumping apparatus (furcula) and complete eyes, thus able to disperse at the soil surface, were not. It was verified, through aerial photographs taken 50 years ago, that landuse changes, expected to be more frequent in heterogeneous landscapes, may contribute to explain this phenomenon.

Function of the Y optic nerve fibres in the cat: do they contribute to acuity and ability to discriminate fast motion?

1. A controlled pressure block has been applied to the optic nerve of the cat, sufficient to bring about degeneration of the axons of the large (Y) nerve fibres caudal to the block site. This degeneration has been monitored by means of implanted electrodes in optic nerve and tract which have shown a loss of the short-latency (t1) response 4-6 days after the block, and also by histological examination of the optic nerve. 2. Cats with one optic nerve blocked in this way have been used in behavioural experiments, one or other eye being covered during the tests. Tested via the blocked nerve, all cats with loss of only Y fibres could perform certain tests: the visual placing reaction, the blink reflex, the pupillary (light) reflex and simple manoeuvres such as walking a plank and jumping from table to floor. 3. When acuity was tested by means of the Mitchell jumping apparatus, cats with loss of only Y fibres showed the same acuity using either eye. This was true also of one cat in which many X fibres had also degenerated, as evidenced by a 55% loss of the medium-latency (t2) response, but in another cat with 90% loss of the t2 response acuity was reduced to about half-normal. 4. Ability to discriminate fast motion was tested by a modification of the Mitchell apparatus. All cats were able to discriminate the motion of an 11.5 deg spot up to a velocity of 6260 deg/s, whether using their normal eye or their affected eye. However, the loss of the Y fibres reduced the ability to discriminate fast motion, so that for any given level of contrast the velocity which could be discriminated was about two-thirds of the velocity discriminated using the normal eye. The ability of the cat to discriminate fast motion seems to be similar to that of the human. 5. These results suggest that there is no sharp restriction of function between the Y and X systems but instead considerable overlap. However, each system possesses specialized features giving it superiority in certain conditions.

Depth perception by means of ambient sounds in a small mammal.

Golden hamsters placed on a jumping stand from which they can descend onto a shallow or deep landing platform prefer to descend on to the shallow platform, even when tested under IR-light without tactile cues. This preference disappears for subjects with plugged ears. The simultaneous recording of the animal's behaviour and possible emission of ultrasound as well as experiments in which the external acoustical conditions or the sound-reflecting properties of the jumping apparatus were altered suggest that the animals use certain parameters of the ambient sound field for depth perception.

Fixated behavior in rats induced by frontal lesions and conflict

Male albino rats were subjected to frontal lesions and/or a conflictful insoluble problem on a Lashley jumping apparatus. They were subsequently tested on a bright-dark discrimination problem and its reversal. Compared to non-lesioned non-conflicted controls, rats having only frontal lesions showed a slight, if any, deficit but rats having only the insoluble problem had a significant deficit in solving the discrimination. The rats having both treatments (lesion and insoluble problem) were inferior to all other groups in solving the discrimination problem. In the reversal problem animals that were only lesioned made more correct responses than non-lesioned animals but this did not lead to more solutions. Analysis of learning scores and latency data suggests that the lesioned rats had a learning deficit that was especially evident when they were formerly subjected to the insoluble problem, a problem in which the reward cue outcomes were not held constant. In contrast animals experiencing only an insoluble problem learn about reward cue outcomes during the soluble problem but cannot abandon the conflict-induced response.

Avoidance learning and retention as a function of type of apparatus and Cs Interval.

The avoidance behavior of rats was observed under the conditions of a jumping or a running apparatus paired with a 5- or a 10-sec. CS interval. It was determined that the latency of S's response late in acquisition was dependent on the duration of CS interval but independent of the type of apparatus. Trials to criterion of acquisition indicated that Ss in the running apparatus required more trials than those in the jumping apparatus. After 3 days, extinction trials to criterion indicated that more trials to criterion were required for Ss in the running apparatus and having the 10-sec. CS interval.

An attempt to modify the rewarding characteristics of hypothalamic stimulation.

7 rats with chronically implanted electrodes in the lateral hypothalamus were allowed to self-stimulate in a Skinner box until they stabilized. Ss were then given avoidance training in a jumping apparatus. The discriminative stimulus for avoidance was reinforcing brain stimulation. All Ss were returned to the Skinner box after avoidance training and were allowed to self-stimulate. No differences were found in lever-pressing as the result of previous avoidance training.

The depressive effect of chlordiazepoxide on a negative incentive.

A group of rats that received daily doses of chlordiazepoxide before testing on a discrimination problem on a Lashley jumping apparatus persisted longer in prelearning preferences, had higher learning scores, and produced more learning failures than a no-drug group. Since 93% of the no-drug group solved the problem, the fear engendered by responding to the incorrect (locked) window was not great enough to produce conflict and fixations, but since the performance of the chlordiazepoxide treated animals was inferior, it is suggested that the drug attenuated the incentive value of the negative reinforcement of incorrect responses.

Influence of Massage on Jumping Performance

Abstract Using a psychological control (placebo) and a balanced experimental design to secure unequivocal results, it was found that pre-exercise massage yielded 2.6 percent improvement in the vertical jumping performance of 36 college men. The amount of improvement was twice as large in the fifth and sixth trials as in the preceding jumps of the six-trial test series. The average jump (48.8 cm.) and the test-retest reliability (r = .94) agreed closely with previous studies using the Henry jumping apparatus. During the six jumps of the first day (without massage), the practice effect caused 3.6 percent improvement, but there was no significant practice effect during the second or third day of testing or between three successive days spaced one week apart.

The Effect of Psychological Stress Procedures on the Prothrombin Time of Rats

Abstract Forced jumping in the Lashley jumping apparatus, maintenance in cages with an electrified water source, transportation, sound-induced seizures, and electroconvulsive treatment were used in studying the effects of psychological stress on the prothrombin time of the albino rat. An increased prothrombin time occurred at certain times following forced jumping, sound-induced seizures, and electroshock. Frequently the altered coagulability was reflected in a greater heterogeneity of variance due to some animals having a longer prothrombin time and others shorter. The changes in the prothrombin time following stress were more pronounced when the prothrombopenic drug, Dicumarol, was administered. This was evident from two indices, prothrombin time and mortality.

シロネズミの反応固定現象

7. Abstract7. 1. Purpose : The present experiment was designed to consider what effect the number of inconsistent trials (the frequency of inconsistent rewards or punish-ments) exerts on the development and strength of response fixation. Some grades, therefore, were set up in an insoluble discrimination problem on the Lashley's jumping apparatus for certain length of time.7. 2. Results.7. 2. 1. First Experiment : Subjects showing random response entered, respectively, each insoluble problem situation. (Fig. 1) More subjects developed response-fixation in 1/2 insoluble problem situation than in 1/3 and 1/6 insoluble situations. Subjects which developed response-fixation in 1/2 insoluble situation continued to show the position response longer in test stage than others. (Table 1. & 2.)7. 2. 2. Second Experiment : Subjects showing discriminative response entered insoluble problem. (Fig. 2.) More subjects developed position response in 2/3 and 5/6 insoluble situations than in the 1/2 situation and they established this response in fewer trials than others. In the next stage of test subjects which fixated response in 2/3 and 5/6 situations continued to show longer response than those in 1/2 situation. (Table 3, 4, 5, 6, 7, 8.)7. 2. 3. Third Experiment : As the total number of trials in the insoluble situation was the same in each subject in the second experiment, the residual number of the trials after the establishment of position response became different in each subject. Then in this experiment the total number of trials was not the same, but that of the trials after the establishment of position response was the same. However, the result did not differ from that of the second experiment. (Table 9, 10.)7. 3. Conclusion.7. 3. 1. When subjects showing both random response and discriminative response entered the insoluble problems, the greater number of inconsistent trials were included in each insoluble problem, the more subjects established position response and the more promptly they established fixated response. (1/6 : 1/3 : 1/2, 1/2 : 2/3 : 5/6) In test stage the greater numbers of inconsistent trials were used in the insoluble problem, the more stronger were response fixations. (1/2 : 2/3 : 5/6).7. 3. 2. The latency in each subject does not differ from that in the ordinary learning. (Fig. 3. & 4.)