Twist and chew: three-dimensional tongue kinematics during chewing in macaque primates

Three-dimensional (3D) tongue movements are central to performance of feeding functions by mammals and other tetrapods, but 3D tongue kinematics during feeding are poorly understood. Tongue kinematics were recorded during grape chewing by macaque primates using biplanar videoradiography. Complex shape changes in the tongue during chewing are dominated by a combination of flexion in the tongue''s sagittal planes and roll about its long axis. As hypothesized for humans, in macaques during tongue retraction, the middle (molar region) of the tongue rolls to the chewing (working) side simultaneous with sagittal flexion, while the tongue tip flexes to the other (balancing) side. Twisting and flexion reach their maxima early in the fast close phase of chewing cycles, positioning the food bolus between the approaching teeth prior to the power stroke. Although 3D tongue kinematics undoubtedly vary with food type, the mechanical role of this movement—placing the food bolus on the post-canine teeth for breakdown—is likely to be a powerful constraint on tongue kinematics during this phase of the chewing cycle. The muscular drivers of these movements are likely to include a combination of intrinsic and extrinsic tongue muscles.     

A Comparative Study of Snake and Lizard Tongue-flicking,with an Evolutionary Hypothesis

Many lizards and all snakes flick their tongues. It is known that this unique behavioral pattern serves to collect airborne and substrate chemicals which give the animal information via Jacobson's Organ about the location of food, conspecifics, and possibly other environmental factors. However, a comparative topographic analysis of tongue movements in squamate reptiles is lacking, and it might shed light on the evolution of this behavior. In this study, a survey was made of the lizards and snakes which tongue-flick. Observations and films were made of 25 lizard species representing 10 families and 30 snake species representing 5 families. The information from observations and film analyses of representative species was used to hypothesize the steps of the evolution of tongue-flicking from the simple downward extensions of primitive lizards to the complex multiple oscillations of snakes.     

The scaling of tongue projection in the veiled chameleon,Chamaeleo calyptratus

Within a year of hatching, chameleons can grow by up to two orders of magnitude in body mass. Rapid growth of the feeding mechanism means that bones, muscles, and movements change as chameleons grow while needing to maintain function. A previous morphological study showed that the musculoskeletal components of the feeding apparatus grow with negative allometry relative to snout–vent length (SVL) in chameleons. Here, we investigate the scaling of prey capture kinematics and muscle physiological cross-sectional area in the veiled chameleon, Chamaeleo calyptratus. The chameleons used in this study varied in size from approximately 3 to 18 cm SVL (1–200 g). Feeding sequences of 12 chameleons of different sizes were filmed and the timing of movements and the displacements and velocities of the jaws, tongue, and the hyolingual apparatus were quantified. Our results show that most muscle cross-sectional areas as well as tongue and hyoid mass scaled with isometry relative to mandible length, yet with negative allometry relative to SVL. Durations of movement also scaled with negative allometry relative to SVL and mandible length. Distances and angles generally scaled as predicted under geometric similarity (slopes of 1 and 0, respectively), while velocities generally scaled with slopes greater than 0 relative to SVL and mandible length. These data indicate that the velocity of jaw and tongue movements is generally greater in adults compared to juveniles. The discrepancy between the scaling of cross-sectional areas versus movements suggests changes in the energy storage and release mechanisms implicated in tongue projection.     

Jaw and hyolingual movements during prey transport in varanid lizards: effects of prey type

The ability to modulate feeding kinematics in response to prey items with different functional properties is likely a prerequisite for most organisms that feed on a variety of food items. Variation in prey properties is expected to reveal variation in feeding function and the functional role of the different phases in a transport cycle. Here we describe the kinematics of prey transport of two varanid species, Varanus niloticus and Varanus ornatus. These species were selected for analysis because of their highly specialised hyolingual system and food transport mechanism (inertial food transport). In these animals, tongue and hyoid movements are expected to make no, or only a minor, contribution to prey transport. We observed statistically significant prey type effects that could be associated with prey properties such as mass, size and mobility. These data show that both species are capable of modulating the kinematics of food transport in response to different prey types. Moreover, not only the kinematics of the jaws were modulated in response to prey characteristics but also the anterior/posterior movements of the tongue and hyoid. This suggests a more important role of the tongue and hyolingual movements in these animals than previously suspected. In contrast, head movements were rather stereotyped and were not modulated in response to changes in prey type.     

Determinants of ingestion rates in filter-feeding larval blackflies (Diptera: Simuliidae)

SUMMARY 1. The functional response of the filter-feeding blackfly larva Frosimulium mixtum/fuscum was examined in laboratory experiments. We focused on the relationship between a component of the particle handling process (the cephalic fan flick rate) and ingestion rate, to determine whether ingestion rate is limited by handling-time. The influence of food deprivation on ingestion rate and feeding efficiency also was assessed. 2. Ingestion rate rose asymptotically with increasing food availability, leveling off at a concentration of about 100 mg1^?1. Satiation did not account for this plateau. Flick rate (the frequency with which larvae open and close their cephalic fans) increased in a similar fashion, though flick rate only accounted for about two-thirds of the variation in ingestion rate. 3. A simple equation describing the components of the feeding process in blackfly larvae was developed to investigate alternate flick rate ‘decision rules’ capable of predicting relationships between food concentration, flick rate and ingestion rate. The flick rate did not follow a fixed time rule, in which larvae allow particles to accumulate in the fan for a fixed amount of time prior to retraction. For most food densities, flick rate patterns more closely approximated a fixed number rule, in which fans are retracted after a fixed number of particles accumulate. 4. Flick rate rose with increasing food concentration even after the ingestion rate had levelled off, whereas several optimal filter-feeding models predict that filtering rate should decline as food concentration increases above this level. This predicted behavior was not observed because the number of particles ingested per flick failed to increase with increasing food concentration. 5. The efficiency of particle ingestion (number ingested × number available^?1× 100) was very low (<0.1%), and declined with increasing food concentration. 6. An increase in food deprivation time prior to a feeding trial produced a significant increase in flick rate, ingestion rate and feeding efficiency. This adjustment of feeding behaviour allowed animals to replace their gut contents more quickly following longer periods of food deprivation, which agrees with the qualitative predictions of optimal digestion-time models.     

Patterns of Sperm Transfer Behavior in a Pholcid Spider with Two Distinct Copulatory Phases

Sexual selection is the responsible force for the evolution and maintenance of genital diversity and function. This is the case for example, of genital movements performed by males during mating and copulation duration. Spiders perform ritualized copulations whereby males carry out different types of movements using their pedipalps with varying duration. The function and duration of these pedipalp movements is unclear. In the pholcid spider, Holocnemus pluchei males that copulate with virgin females perform two copulatory phases: phase I in which the pedipalps move and phase II in which pedipalps remain motionless. Using H. pluchei as a study species, our study aims were: 1) to assess if sperm transfer occurs when pedipalps move or are still and quantify the number of sperm in male bulbs and in the female uterus externus after copulation; and, 2) to determine if amount of sperm transferred to females is associated with duration of each copulatory phase. Two experimental groups (i. e. complete copulation and interrupted copulation) were established in which the amount of sperm remaining in the male bulbs and the amount of sperm stored by females were determined. Our results show that sperm transfer occurs during phase I, that males transfer almost all sperm from their bulbs while the females store only 20% of that male amount. There was no relation between the amount of sperm transferred or stored and the duration of the copulatory phases. These results support the hypothesis that while both phases may serve a copulatory courtship, only phase I (when pedipalps move) serves for sperm transfer.     

Remote sensing application for the study of rapid flushing to remediate eutrophication in shallow lagoons (Albufera of Valencia)

Albufera of Valencia shallow lagoon experiences water clarification about once a year. This study aimed to observe the timing of water clarity events and to detect the associated flow during these periods. Spatial variation in chlorophyll a along the Albufera was observed using remote sensing images. Due to the lagoon’s spatial complexity and the varying water qualities flowing in from more than 60 tributaries, remote sensing was the only approach that could obtain images simultaneously covering the entire lagoon. The data were used to explore the evolution, duration and intensity of the clear-water phase, and the lagoon’s subsequent re-eutrophication. The duration and intensity of the clear-water phase varied across the lagoon, but complete water quality renovation occurred in 1 week. Our analysis demonstrates that rapid flushing could remediate the lagoon eutrophication.

     

Variability in bumblebee pollination buzzes affects the quantity of pollen released from flowers

Buzz-pollination is a plant strategy that promotes gamete transfer by requiring a pollinator, typically bees (Hymenoptera: Apoidea), to vibrate a flower’s anthers in order to extract pollen. Although buzz-pollination is widespread in angiosperms with over 20,000 species using it, little is known about the functional connection between natural variation in buzzing vibrations and the amount of pollen that can be extracted from anthers. We characterized variability in the vibrations produced by Bombus terrestris bumblebees while collecting pollen from Solanum rostratum (Solanaceae), a buzz-pollinated plant. We found substantial variation in several buzzing properties both within and among workers from a single colony. As expected, some of this variation was predicted by the physical attributes of individual bumblebees: heavier workers produced buzzes of greater amplitude. We then constructed artificial “pollination buzzes” that varied in three parameters (peak frequency, peak amplitude, and duration), and stimulated S. rostratum flowers with these synthetic buzzes to quantify the relationship between buzz properties and pollen removal. We found that greater amplitude and longer duration buzzes ejected substantially more pollen, while frequency had no directional effect and only a weak quadratic effect on the amount of pollen removed. These findings suggest that foraging bumblebees may improve pollen collection by increasing the duration or amplitude of their buzzes. Moreover, given that amplitude is positively correlated with mass, preferential foraging by heavier workers is likely to result in the largest pollen yields per bee, and this could have significant consequences for the success of a colony foraging on buzz-pollinated flowers.     

The effect of photoperiod on the circadian rhythm of mating responsiveness in the fruit fly, Dacus tryoni

ABSTRACT. The daily fluctuation in mating responsiveness of Dacus tryoni was recorded through a range of light cycles. Evidence was obtained of strict control of the fluctuation by a circadian clock. The phase setting of the fluctuation in the different light cycles was in conformity with Aschoff's (1965) generalizations about circadian rhythms, and had no relationship to overt sexual behaviour occurring during the cycles. The amplitude of the fluctuation in mating responsiveness varied between cycles, suggesting possible variation in the amplitude of the oscillation of the circadian clock.     

Models of tongue movement in the walrus (Odobenus rosmarus)

Three hypothetical models of tongue movement of the walrus during suction feeding are examined. These models encompass the entire range of simple tongue retraction movements possible by examining 1) movement of the tongue directly to the rear following the curvature of the palate, 2) to the rear and ventrally in a straight line, and 3) ventrally in a straight line. The percent of muscular force available from the hyoglossus, genioglossus, and styloglossus that could be applied toward retraction as predicted by each model is calculated. The resistance that the tongue would provide during retraction is calculated using projected tongue areas and is combined with the above data from the muscles to provide an estimate of the percent of the total available force that is needed to retract the tongue for each model. A separate examination of the direction of tongue-induced wear striations on the palatal and lingual aspects of the teeth is used to help support or reject the three models. The model where the tongue is moved directly to the rear is supported by studies of both muscle force and tooth wear. In the mammalian groups that were compared to the walrus, there is a great deal of interspecific variation in movements of the tongue during suction feeding; no two groups can be considered to have identical stereotyped tongue movements.     

Cortical control of appropriate tongue protrusion during licking in cats—Increase in regional cerebral blood flow (rCBF) of the contralateral area P and in tongue protrusion after the unilateral area P lesion

Adequate tongue protrusion may be regulated by cat bilateral area P (the motor cortex for jaw and tongue movements) (Hiraba and Sato, Somatosens Mot Res 2005b;22:183–192). The ICMS (intracortical microstimulation) in the unilateral area P evoked motor effects of tongue protrusion without deviation (Hiraba and Sato, Somatosens Mot Res 2004;23:1–12), and cats with the unilateral lesion of area P showed abnormal tongue protrusion without deviation during licking (Hiraba and Sato, Somatosens Mot Res 2005b;22:183–192). Further, the measurements of the regional cerebral blood flow (rCBF) in the bilateral jaw and tongue motor cortical areas were shown to have the same activity rate during the lateral licking (Hiraba and Sato, Somatosens Mot Res 2005c;22:307–317). We assumed from these results that cortical control for tongue protrusion was executed by networks between the bilateral area P including inhibitory interneurons. We prepared the measurable cats of the rCBF in the contralateral side after the unilateral area P lesion. Changes in the rates of rCBF and tongue protrusion during licking were examined over a long time course of about 1–2 months after the unilateral area P lesion. All cats after the unilateral area P lesion showed increased rate (double or triple in comparison with the normal ones) of rCBF of the contralateral area P in the early (0–20 days) phase. On the other hand, increased rates of tongue protrusion were about 120% in the early phase, and about 180% in the middle (21–35 days) and late (36–last days) phases. The results support the organization of networks between bilateral area P including the inhibitory interneurons.     

Consequences of periodic augmented breaths on tongue muscle activities in hypoxic rats.

This study was designed to investigate the influence of hypoxia-evoked augmented breaths (ABs) on respiratory-related tongue protrudor and retractor muscle activities and inspiratory pump muscle output. Genioglossus (GG) and hyoglossus (HG) electromyogram (EMG) activities and respiratory-related tongue movements were compared with peak esophageal pressure (Pes; negative change in pressure during inspiration) and minute Pes (Pes x respiratory frequency = Pes/min) before and after ABs evoked by sustained poikilocapnic, isocapnic, and hypercapnic hypoxia in spontaneously breathing, anesthetized rats. ABs evoked by poikilocapnic and isocapnic hypoxia triggered long-lasting (duration at least 10 respiratory cycles) reductions in GG and HG EMG activities and tongue movements relative to pre-AB levels, but Pes was reduced transiently (duration of <10 respiratory cycles) after ABs. Adding 7% CO(2) to the hypoxic inspirate had no effect on the frequency of evoked ABs, but this prevented long-term declines in tongue muscle activities. Bilateral vagotomy abolished hypoxia-induced ABs and stabilized drive to the tongue muscles during each hypoxic condition. We conclude that, in the rat, hypoxia-evoked ABs 1) elicit long-lasting reductions in protrudor and retractor tongue muscle activities, 2) produce short-term declines in inspiratory pump muscle output, and 3) are mediated by vagal afferents. The more prolonged reductions in pharyngeal airway vs. pump muscle activities may lead to upper airway narrowing or collapse after spontaneous ABs.     

Deficits of masticatory movements caused by lesions in the orofacial somatosensory cortex of the awake cat

The purpose of this study was to determine the role of somatosensory cortex (SI) in the control of orofacial movements during eating.We identified perioral and tongue projection regions of the cat SI and destroyed cells in one region by injecting kainic acid. The effects on orofacial behavior were then studied over a period of 4-6 weeks. Cats with unilateral lesions in the perioral region (PL-cats) dropped food from the contralateral side of the mouth in the early phase. Failure in erection of the contralateral whisker hairs during masticatory movements and delay of the masticatory start were observed throughout the experimental period. Furthermore, in the late phase, PL-cats showed prolongations of the masticatory and food intake periods, which were accompanied by the increase in the number of swallows and chewing cycles. Cats with unilateral lesions in the tongue region (TL-cats) showed the prolongation of the masticatory period in the early phase, which was accompanied by the increase in the number of swallows and chewing cycles. TL-cats did not show the prolongation of the food intake period and failure in erection of the contralateral whisker hairs. In both PL- and TL-cats, masticatory and swallowing rhythms were normal.     

Deficits of masticatory movements caused by lesions in the orofacial somatosensory cortex of the awake cat

The purpose of this study was to determine the role of somatosensory cortex (SI) in the control of orofacial movements during eating. We identified perioral and tongue projection regions of the cat SI and destroyed cells in one region by injecting kainic acid. The effects on orofacial behavior were then studied over a period of 4-6 weeks. Cats with unilateral lesions in the perioral region (PL-cats) dropped food from the contralateral side of the mouth in the early phase. Failure in erection of the contralateral whisker hairs during masticatory movements and delay of the masticatory start were observed throughout the experimental period. Furthermore, in the late phase, PL-cats showed prolongations of the masticatory and food intake periods, which were accompanied by the increase in the number of swallows and chewing cycles. Cats with unilateral lesions in the tongue region (TL-cats) showed the prolongation of the masticatory period in the early phase, which was accompanied by the increase in the number of swallows and chewing cycles. TL-cats did not show the prolongation of the food intake period and failure in erection of the contralateral whisker hairs. In both PL- and TL-cats, masticatory and swallowing rhythms were normal.     

Inhibition of <Emphasis Type="SmallCaps">d</Emphasis>-Amino-Acid Oxidase Activity Induces Pain Relief in Mice

(1). We investigated the effects of inhibiting d-amino-acid oxidase (DAO) activity on nociceptive responses through the use of mutant ddY/DAO⁻ mice, which lack DAO activity, and through the application of a selective inhibitor of DAO, sodium benzoate, in the tail flick test, hot-plate test, formalin test, and acetic acid-induced writhing test. (2). Compared with normal ddY/DAO⁺ mice, ddY/DAO⁻ mice showed significantly prolonged tail withdrawal latency in the tail flick test and licking/jumping latency in the hot-plate test, as well as significantly reduced duration of licking/biting in the late phase of the formalin test and the number of abdominal writhing in the acetic acid-induced writhing test. (3). In addition, we investigated the effects of sodium benzoate in Kunming mice having normal DAO activity. (4). Intravenous administration of sodium benzoate (400 mg/kg) significantly inhibited pain responses of the late phase of the formalin test and abdominal writhing responses in the acetic acid-induced writhing test, with no effects on the early phase flinch responses in the formalin test, nociceptive responses in the tail flick test, or hot-plate test. (5). These results suggest that DAO acts as a pro-nociceptive factor in pain, particularly chronic pain, transmission and modulation, and may be a target for pain treatment.     

Floral plasticity in an iteroparous plant: the interactive effects of genotype, environment, and ontogeny in Campanula rapunculoides (Campanulaceae)

Phenotypic variation in 11 floral and reproductive traits was studied in cloned plants of Campanula rapunculoides replicated in three discrete environments. Using an ANOVA approach, we determined the relative influence of genotype (G), environment (E), G × E interaction, and ontogeny (position on the raceme) on the 11 traits. Two traits, duration of flowering and pollen size, showed no significant variation. All nine remaining traits had significant genotypic variation, accounting for 21-38% of the total phenotypic variation. Correlations among variant traits in seven genotypes were predominantly positive, but several significant correlations in one environment changed sign or were nonsignificant in another environment. Ovule number was negatively correlated with most male function traits: the negative correlation between ovule and pollen number was particularly strong and consistent across environments. Six traits varied significantly across environments, including number of flowers, number of ovules per flower, and duration of the male phase, but pollen traits did not show a significant environmental main effect. The G × E interaction was significant for flower number, corolla size, nectar quality, duration of the male phase, pollen viability, and ovule number. The contribution of interaction variance to the total phenotypic variation (5-14%) was comparable to that of the environment alone (7-21%). Ovule number decreased in flowers on the upper part of the raceme by nearly 25%, but other traits did not vary significantly by floral position. These results suggest that (1) pollen traits are buffered against environmental change more than ovule number or other floral characters, (2) a male-female trade-off exists and is complicated by ontogenic factors, (3) G × E interactions are common but may have small effects, and (4) specific correlation patterns among floral traits can be dependent upon the environment under which they develop.     

The effect of lateral illumination on growth oscillations of pine seedling hypocotyls (Pinus silvestris L.)

Phototropic sensitivity of forest wood seedlings to lateral illumination was proposed as an early assay for distinquishing various ecotypes of woody plants of the same species. Statistical analysis showed that results were significantly influenced by heterogenity of experimental material caused by an interference of phototropic movements and natural oscillations of hypocotyl. Both movements of pine seedlings (Pinus silvestris L.) were registered by phase photography and their mechanism was analyzed. The apical part of growing hypocotyl illuminated from above oscillates in a space spiral with frequency 3.3 h at mean growth rate 0.66 mm h^?1. The mean size of spiral amplitudes is 2.9 mm. The oscillation rhythm is disturbed after the lateral illumination and a phase shift was observed as a result. A new oscillation rhythm with frequency 3.9 h and mean growth rate 0.69 mm h^?1 was stabilized after a period of time equal to one nutation turn. Oscillation amplitudes were increased to 4.3 mm. In addition to the radiation intensity the appearance of the phototropic response to light pulse is first of all effected by the actual position of the apical part of hypocotyl in the course of endogenous circumnutations. A uniform plant material for the early assay may be obtained by selection of seedlings which are at the beginning of lateral illumination in the same phase of nutation rhythm. Under such conditions the deviations of longitudinal axis of oscillating spirals characterize the actual phototropic curvature.     

Cultural characteristics of the marine ciliated protozoan, Uronema marinum Dujardin

The marine hymenostome ciliate Uronema marinum Dujardin was isolated from sediment from Robin Hood's Bay, Yorkshire. Experiments on the growth of U. marinum were carried out in batch cultures in which the ciliate was maintained on a diet of Vibrio sp. The duration of the lag phase varied directly with the age of the inoculum. Factorially designed experiments were used to investigate the effects of salinity and temperature on the rate of logarithmic growth of the ciliate. A response surface analysis of the data indicated that there was interaction between salinity and temperature. Regression equations predicted a minimum doubling time of 2.5 h at 32‰ and 25 °C. The cell volume of U. marinum varied during growth; it reached a maximum at the end of the lag phase and decreased during the logarithmic phase to become minimal in the stationary phase.