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PubMed1995

Positional behavior in five sympatric Old World monkeys.

Observations of positional behavior and habitat use were recorded on focal individuals of five species of Old World monkeys at Kibale Forest, Uganda, through the dry season of 1990 and 1991. Cercopithecus ascanius, Cercopithecus mitis, Cercocebus albigena, Colobus badius, and Colobus guereza commonly utilize five similar types of positional behavior (i.e., quadrupedalism, leaping, climbing, sitting, and standing), but in varying frequencies and situations. As a group, colobines use oblique supports and leap more often, and cover greater linear distances during leaps than do cercopithecines. Colobines also prefer to sit (about 90% of all postures), while cercopithecines stand more frequently. Body size differences between the sexes of a species are not reflected in positional behavior. The two small-bodied species climb more and leap less often than the three larger species, which is the reverse of what we would expect. Leaping is the most common method of crossing open spaces within the canopy; but most spatial gaps and leaps are over short distances, usually one meter or less. All five species, regardless of body size or the availability of forest supports, prefer medium-sized supports. Incorporating our work from Uganda with previous investigations of positional behavior reveals few consistent trends with respect to body size or habitat use across primates.

Animals↗
PubMed2005

Comparative postcranial body shape and locomotion in Chlorocebus aethiops and Cercopithecus mitis.

Body weight and length, chest girth, and seven postcranial limb segment lengths are compared between two guenon species, Chlorocebus (Cercopithecus) aethiops (vervets) and Cercopithecus mitis (blue monkeys), exhibiting different habitual locomotor preferences. The subjects, all adults, were wild caught for a non-related research project (Turner et al. [1986] Genetic and morphological studies on two species of Kenyan monkeys, C. aethiops and C. mitis. In: Else JG, Lee PC, editors. Primate evolution, proceedings of the Xth International Congress of Primatology, Cambridge. London). The morphological results are interpreted within the context of previously published observations of primate locomotion and social organization. The sample is unique in that the body weight of each individual is known, allowing the effects of body-size scaling to be assessed in interspecific and intersexual comparisons. C. mitis has a significantly (P < 0.05) greater body weight and trunk length than C. aethiops. A shorter trunk may function to reduce spinal flexibility for ground-running in the latter. Proximal limb segments (arm and thigh) are significantly greater in C. mitis, reflecting known adaptations to committed arboreal quadrupedal locomotion. By contrast, relative distal limb segments (forearm, crus, and foot) are significantly longer in C. aethiops, concordant with a locomotor repertoire that includes substantial terrestrial quadrupedalism, in addition to arboreal agility, and also the requisite transition between ground and canopy. Although normally associated with arboreal monkeys, greater relative tail length occurs in the more terrestrial vervets. However, because vervets exploit both arboreal and terrestrial habitats, a longer tail may compensate for diminished balance during arboreal quadrupedalism resulting from the greater "brachial" and "crural" indices that enhance their ground quadrupedalism. Most interspecific differences in body proportions are explicable by differences in locomotor modalities. Some results, however, contradict commonly held "tenets" that relate body size and morphology exclusively to locomotion. Generally associated with terrestriality, sexual dimorphism (male/female) is greater in the more arboreal blue monkeys. A more intense, seasonal mating competition may account for this incongruity.

Animals↗
PubMed1978

Golgi studies of the neurons in layer II of the dorsal horn of the medulla (trigeminal nucleus caudalis).

The translucent band which lies just beneath the spinal V tract at the lower end of the spinal trigeminal nucleus (nucleus caudalis) can be divided into three layers. These three layers are distinguished by textural differences in their neuropil and by the morphology and laminar distribution of the axons and dendrites of their neurons. Layer II contains four different kinds of interneurons. Stalked cells are named after their short, stalk-like branches. Their cell bodies are found in greatest numbers in the outer half of layer II. Their coneshaped dendritic arbors extend medially across layers II and III and sometimes extend into layer IV. Their axons form extensive, canopy-like arborizations in layer I. Stalked cells are considered to be excitatory interneurons receiving input on their dendritic spines from primary axonal endings in the layers II and III glomeruli and transferring it to the dendrites of the layer I projection neurons. Layer II contains three kinds of Golgi type II inteneurons, i.e, neurons whose axons branch repeatedly within the confimes of their dendritic arbors. Islet cells similar to those found in layer III (Gobel), '75a), are found in small clusters in layer II. Their dendrites and axons are largely confined in layer II. The dendrites of the arboreal cell burst, in tree-like fashion, into highly focal dendritic arbors confined largely in layer II while the extensive rostral and caudal dendritic arbors of the II-III border cell lie largely in layers II and III with a few branches extending into layer I. The axons of both of these interneurons arborize in layers II and III with a few collaterals extending into layer I. Islet cells, arboreal cells and II-III border cells are considered to be inhibitory interneurons. They are strategically situated to interrupt transmission between primary axonal endings in layers II and III and the layer I projection neurons by altering the output of the stalked cells.

Animals↗
PubMed2001

Acute panic inventory symptoms during CO(2) inhalation and room-air hyperventilation among panic disorder patients and normal controls.

There is scant literature on anxiety symptoms induced during respiratory challenges developed to induce panic symptoms and attacks. Here we report on the prevalence of Acute Panic Inventory (API) symptoms during three consecutive respiratory challenges to patients with panic disorder (PD) and normal controls (NC). The challenges performed using a closed canopy system included voluntary room air hyperventilation (RAH), inhalation of 5% CO(2), and 7% CO(2)-enriched air. The PD patients were 41 men and 53 women whose mean age was 33.4 (SD = 8.55). The normal comparison group consisted of 35 men and 27 women with a mean age of 31.3 (SD = 9.21). The diagnosis of panic disorder was made using the Structured Clinical Interview for DSM-III-R. All potential normal controls underwent structured clinical interview using the Schedule for Affective Disorders and Schizophrenia-Lifetime Version Modified for the Study of Anxiety Disorders (SADS-LA), and must have been free of a lifetime history of anxiety disorders, affective disorders, substance use disorders, and schizophrenia. All participants also had a complete medical evaluation and were in good health. The experiment consisted of seven experimental epochs: three baseline/recovery periods each followed by a respiratory challenge, and then a final recovery epoch. The API was administered at the end of each epoch. Clinical staff trained and experienced in rating panic attacks rated participants' response during each challenge as panic or no panic. Three groups were defined for analysis: PD patients who panicked, PD patients who did not panic, and NC who did not panic. Staff ratings indicated that the 7% CO(2) challenge was the most panicogenic, followed by the 5% CO(2), and the RAH challenges. Conventional statistics (analysis of variance and partial correlations) indicated that many baseline symptoms as well as symptom increments differed across groups, and were associated with the outcome of panic/no panic during each challenge. However, logistic regression analysis indicated that only a few symptoms independently predicted the panic/no panic outcome because many symptoms were redundant. The symptom cluster of fear in general, dizziness, difficulties with concentrating, and doing one's job predicted panic to RAH. The cluster of fear in general, confusion, dyspnea, and twitching/trembling predicted the response to 5% CO(2). Finally, fear in general, confusion, twitching/ trembling and dizziness predicted the response to 7% CO(2). While univariate analyses indicated that many symptoms distinguished between panic and no panic outcome, logistic regression revealed that group differences were subsumed under a few prominent symptoms, namely, fear in general, confusion, dizziness, twitching/trembling, and dyspnea. The results are discussed in the context of patient (having a diagnosis of PD) and panic effects (rated as panicking to a challenge).

Acute Disease↗
PubMed2001

Respiratory variability in panic disorder.

Disordered breathing may play an important role in the pathophysiology of panic disorder. Several studies have now indicated that panic disorder patients have greater respiratory variability than normal controls. In this study, we examine baseline respiratory measures in four diagnostic groups to determine whether greater respiratory variability is specific to panic disorder and whether effective anti-panic treatment alters respiratory variability. Patients with panic disorder, major depression, or premenstrual dysphoric disorder, and normal control subjects underwent two respiratory exposures (5% and 7% CO(2) inhalation), while in a canopy system. Panic disorder patients returned after 12 weeks of either anti-panic medication or cognitive behavioral therapy, and were retested. Normal control subjects were also retested after a period of 12 weeks. Panic disorder patients had significantly greater respiratory variability at baseline than normal control subjects and patients with major depression. The premenstrual dysphoric patients also had greater variability than the normal control group. Panic disorder patients who panicked to 7% CO(2) inhalation had significantly greater baseline variability than panic disorder patients who did not panic. Anti-panic treatment did not significantly alter baseline respiratory variability. Our data suggest that increased respiratory variability may be an important trait feature for some panic disorder patients and may make them more vulnerable to CO(2)-induced panic.

Adult↗
PubMed2005

Temperamental development in the rat: the first year.

Behavioral continuity and change was studied in 32 (16 male) Wistar rats observed in the hole board and canopy tests, considered to measure exploration and anxiety, respectively. Subjects were tested at 6, 11, 16, 21, 37, and 52 weeks of age. In comparison to 16-week-old rats (the standard age of rats in many experiments), juveniles seemed more anxious and exploratory, whereas mature rats were more anxious and less exploratory. There was substantial behavioral consistency between week 6 and 52, the correlations being especially high between weeks 11 and 52. Principal components analyses revealed one temperamental dimension reflecting harm avoidance in juvenile and mature rats, whereas adult rats were characterized by a further dimension, reflecting novelty seeking.

Age Factors↗
PubMed2001

Limb and tail lengths in relation to substrate usage in Tropidurus lizards.

A close relationship between morphology and habitat is well documented for anoline lizards. To test the generality of this relationship in lizards, snout-vent, tail, and limb lengths of 18 species of Tropidurus (Tropiduridae) were measured and comparisons made between body proportions and substrate usage. Phylogenetic analysis of covariance by computer simulation suggests that the three species inhabiting sandy soils have relatively longer feet than do other species. Phylogenetic ANCOVA also demonstrates that the three species inhabiting tree canopies and locomoting on small branches have short tails and hind limbs. These three species constitute a single subclade within the overall Tropidurus phylogeny and analyses with independent contrasts indicate that divergence in relative tail and hind limb length has been rapid since they split from their sister clade. Being restricted to a single subclade, the difference in body proportions could logically be interpreted as either an adaptation to the clade's lifestyle or simply a nonadaptive synapomorphy for this lineage. Nevertheless, previous comparative studies of another clade of lizards (Anolis) as well as experimental studies of Sceloporus lizards sprinting on rods of different diameters support the adaptive interpretation.

Animals↗
PubMed1988

Morphology and locomotor adaptations of the bovid femur in relation to habitat.

Extant bovids inhabit a wide diversity of environments that range from forest to savanna and display locomotor patterns that are habitat specific. I report here on an investigation of the linkage between these locomotor patterns and habitat based on a study of the morphology of the bovid femur. Femoral head shape, shaft dimensions, and knee structure are examined and support a statistically significant separation of the different morphological complexes present in bovids from forest, broken cover, and savanna habitats. Morphological differences are primarily related to locomotor patterns as reflected in the degree of cursoriality displayed by bovids in different habitats. Cursorial bovids from savanna environments have laterally expanded femoral heads that act to limit the degree of abduction and axial rotation at the hip, and elliptically shaped distal femora that increase the moment arm of the extensor muscles that cross the knee. Forest bovids have spherically shaped femoral heads. This morphology permits a much higher degree of abduction and axial rotation at the hip and appears to provide greater maneuverability in a vegetationally complex habitat. Bovids living in broken cover environments that fall between the extremes of closed canopy forest and savanna display an intermediate set of femoral characters. This approach to the relationship between habitat and locomotion offers a potentially powerful means with which to examine the interplay between structural form and function in bovid evolution.

Adaptation, Physiological↗
PubMed2004

Comparing greenhouse sprayers: the dose-transfer process.

Three sprayers were evaluated for their affect on retention and efficacy: a carbon dioxide powered high-volume sprayer, a DRAMM coldfogger, and an Electrostatic Spraying Systems (ESS) sprayer with air-assistance. The active ingredients used were spinosad and azadirachtin. The plant canopy was constructed in the greenhouse using potted soybeans (Glycine max (L) Merrill cr Pioneer 9392). Application efficacy with spinosad was assessed using thrips [Western flower thrips, Frankliniella occidentalis (Pergande)] and mite (two-spotted spider mite, Tetranychus urticae Koch) abundance on shoots and leaves. Application efficacy with azadirachtin was assessed using thrips and aphid (soybean aphid, Aphis glycines Matsumura) abundance on shoots and leaves. The atomization characteristics of each sprayer were measured using an Aerometrics phase/Doppler particle analyzer (PDPA) 100-1D. The results of four tests are presented. Two tests used each sprayer according to manufacturer recommendations. These are 'recommended volume' tests that confound differences in toxicant distribution caused by the sprayer with differences caused by changes in application volume. The other two tests were 'constant volume' tests in which all three sprayers were used to deliver the same application volume. Both types of test gave differences between sprayers in retention of toxicant, but only the recommended volume tests showed significant effects of the sprayers on pest abundance. We attribute this difference to the role played by changing application volumes in the dose-transfer process. The constant-volume tests showed that application equipment influences efficacy.

Aerosols↗
PubMed2005

Managing Eastern tent caterpillars Malacosoma americanum (F) on horse farms to reduce risk of mare reproductive loss syndrome.

An equine disease now known as mare reproductive loss syndrome (MRLS) struck the Ohio Valley in 2001-2002 causing thousands of foal abortions and enormous economic loss. Evidence that pregnant mares' exposure to Eastern tent caterpillars Malacosoma americanum (F) induces MRLS created an urgent call for control measures suitable for use on horse farms. We surveyed egg mass distribution and monitored emergence in wild cherry trees, and evaluated reduced-risk treatment strategies including foliage sprays, trunk injections, winter egg mass treatments and barrier sprays to intercept larvae entering pastures. Egg masses were concentrated in the lower canopy, on exposed sides of trees. Larval emergence began in mid-March. Emergence was prolonged (3-4 weeks) in 2002, a typically cool spring, but more synchronized in warmer 2003. Winter treatment of egg masses with bifenthrin or permethrin in a penetrating solvent prevented emergence, but 3% horticultural oil was ineffective for that purpose. Insecticidal soap or oil sprayed directly on neonates gave relatively poor control. Bifenthrin and spinosad were effective as foliage sprays against all instars, their field-weathered residues active for at least 7 days. Bacillus thuringiensis Berliner var kurstaki controlled neonates within 3 days but was less active against late instars, with shorter residual action than bifenthrin or spinosad. Larvae did not avoid insecticide-treated leaves. Trunk microinjection of cherry trees with dicrotophos was effective against all instars, whereas microinjection with milbemectin or abamectin gave poor or inconsistent control. Trunk injection with emamectin benzoate also was effective. Dry permethrin residues controlled late instars crawling in pasture grass for at least 7 days. Factors complicating M americanum management on horse farms are discussed.

Abortion, Veterinary↗
PubMed1998

Effects of avian mobbing on roost use and diet of powerful owls, Ninox strenua

We observed the species and numbers of mobbing birds and their effects on a large, nocturnal, bird-eating predator, the powerful owl, together with the pattern of owl predation on mobbing and non-mobbing species. Owls were mobbed on 35 occasions by seven of 44 species of forest birds at a site composed of open forest (88% by area) and rainforest (12%). The majority of bouts involved individuals of a single species, although mixed groups were observed on nine occasions. Regular mobbers were between 4 and 26% of the owls' body weight. Owls abandoned their daytime roosts during 20% of bouts and responded by calling or actively monitoring mobbers during 54% of bouts. Mobbing appeared to explain why owls roosted in rainforest significantly more often than expected by its availability, mobbing being significantly less frequent in rainforest than in open forest. Only one mobbing species regularly occupied rainforest and the canopy of roosts in rainforest was denser than that in open forest, thus reducing the chances of an owl being detected by potential mobbers. Twelve species of forest birds were within the range of prey size of the powerful owl (75-800 g): six were mobbers and six non-mobbers. The frequency of owl predation on non-mobbers was 8.75 times that on mobbers. The species in this study took a high risk by mobbing a very large predator, but benefited by greatly reducing their chances of predation.Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1993

Permanent gases inside healthy and microbially infected cotton fruit during development.

Permanent gases inside developing cotton fruit (Gossypium hirsutum L.) were, by weight, 46% nitrogen, 29% oxygen, 4% argon and 20% carbon dioxide, whereas plant canopy air assayed at 73% nitrogen, 25% oxygen, 2% argon and 0.3% carbon dioxide. Light exposure, fruit age, and mild infection (Erwinia) had no compositional effect but aggressive infection (Aspergillus) raised carbon dioxide content to 31% by weight and correspondingly lowered oxygen to 17%. Respiration with oxygen replenishment except during aggressive infection accounted for the fruit gas compositions.

Fruit↗
PubMed1996

Hyperthermostable surface layer protein tetrabrachion from the archaebacterium Staphylothermus marinus: evidence for the presence of a right-handed coiled coil derived from the primary structure.

The scaffold of the surface layer covering the hyperthermophilic archaebacterium Staphylothermus marinus is formed by an extended filiform glycoprotein complex, tetrabrachion, which is anchored in the cell membrane at one end of a 70 nm stalk and branches at the other end into four arms of 24 nm length. The arms from a canopy-like meshwork by end-to-end contacts, enclosing a "quasi-periplasmic space". The primary structure of the complex, obtained by an approach based entirely on the polymerase chain reaction, shows that the light and the heavy chains are encoded in this order in a single gene and are generated by internal proteolytic cleavage. One light chain associates with the N-terminal part of a heavy chain to form one of the four arms of the complex, comprising about 1000 residues. Following a glycine-rich linker of about ten residues, the C-terminal 500 residues of the four heavy chains converge to form a four-stranded parallel coiled coil, which ends in a transmembrane segment. The sequence of the coiled coil is exceptional in that the heptad repeat of hydrophobic residues typical for left-handed coiled coils shifts to an undecad repeat after an internal proline residue, indicating that the C-terminal part of the sequence forms a right-handed coiled coil. Such a periodicity has not been detected in coiled coils to date. The almost flawless pattern of aliphatic residues, mainly leucine and isoleucine, throughout the hydrophobic core of the stalk provide one explanation for its exceptional stability.

Archaea↗
PubMed1999

Bet-hedging when targets may disappear: optimal mate-seeking or prey-catching trajectories and the stability of leks and herds

When a female frog moves towards a calling male, the male may suddenly stop calling and the female have to switch to another male. Analogous situations where "hunters" move towards "targets" that can disappear unpredictably include predators stalking prey and plants growing towards gaps in the canopy. I use dynamic programming to show that when the hunter has a choice of such targets it is optimal to take a curved bet-hedging trajectory, initially heading between two targets so that if one target disappears the other is closer. Also hunters should prefer groups of targets, even if a solitary target is somewhat closer, because it is unlikely that all targets in a group will disappear. Assuming that hunters follow these optimal trajectories I then ask whether it will pay targets to form herds or leks. The extra attractiveness of groups in this model turns out not to be sufficient to outweigh the advantages of herding, but the net benefits of herding are considerably reduced. Copyright 1999 Academic Press

Journal Article↗
PubMed2003

Development of a mathematical method for classifying and comparing tree architecture using parameters from a topological model of a trifurcating botanical tree.

This paper describes a model for the topological mapping of trifurcating botanical trees. The model was based on a system of modular units that represented the interconnectivity of shoot meristems (terminal segments) and internodes (internal segments) within whole plant canopies, organized with increasing centrifugal ordering. The model was capable of describing the dynamics of plant growth as expressed by changes in topological parameters over time. Preliminary calculations for experimental trees indicated that the model represents growth in a biologically sound manner. Methods are described for the calculation of the architecture parameters size, size-complexity, structural complexity, and tree asymmetry index (TAI). Parameter calculations were based on the mathematical principles developed for the classification of bifurcating dendrite trees, and were designed to both extract structural information, and to enable statistical comparison between trees of different size. Parameters were mathematically adjusted for trifurcation, and appeared to be able to represent quantitatively the architectural properties of tree structures. In addition to the calculation of the TAI for trifurcating trees, new methods were developed to enable comparisons to be made of the architectural complexity of trifurcating trees of differing size. These were based on the principle of the pair-wise comparison of the mean centrifugal order number (MCON) with respect to segments against highest order number. We argue and illustrate that this principle can be more informative than that of pair-wise comparison of the MCON against tree degree (topological size). Further improvements to this method were made by examining branching points (vertices) rather than segments (links) to calculate the MCON.

Models, Biological↗
PubMed2000

Natural variation in phytochrome signaling.

The phytochromes, photoreceptors sensitive to red and far-red light, are critical for sensing foliage shade, canopy breaks, and neighbor proximity. A combination of molecular genetic, evolutionary, and ecological techniques are being used to understand how phytochromes function in the natural environment. We discuss studies on the adaptive value of phytochrome mediated plasticity, as well as the role that variation in phytochrome expression and function might play in allowing plants to adapt to unique light environments. Continued study of phytochrome signaling variation may reveal how natural selection acts at the molecular level.

Adaptation, Physiological↗
PubMed1992

An interlaboratory comparison of data on brain cholinesterase activity in forest songbirds exposed to aerial application of Zectran.

Zectran (4-dimethylamino-3,5-xylyl N-methyl-carbamate), a carbamate insecticide (active ingredient [AI] mexacarbate), was aerially applied to two 300 ha plots of coniferous forest at dosage rates of 70 and 140 g AI/ha, respectively. The brains of 288 birds collected from the treated areas and 84 birds from untreated areas were sagittally sectioned into approximately equal halves. Each of the laboratories participating in the study, the Forest Pest Management Institute (FPMI) and the Canadian Wildlife Service, Atlantic Region (CWS), assayed one half of each brain for cholinesterase (ChE) activity and the results were compared. The ChE estimates of the two laboratories on half brains from the same birds were poorly correlated (R = 0.136, P less than 0.05) and differed significantly (P less than 0.00005). The reasons for this are uncertain. Despite the discrepancy in ChE estimates, however, separate statistical analysis of each data set produced the same general conclusion: the ChE response to Zectran exposure was statistically significant but biologically unimportant. In both data sets, statistically significant ChE responses by niche and time since spraying were found. The dosage rate emitted from the airplane was a better predictor of ChE activity in the canopy niches than was volume deposited at ground level, but volume deposited was a more useful predictor for ground birds in most situations. These results are discussed in the context of a proposal to develop a reference file of normal brain ChE activities of common wildlife species.

Acetylthiocholine↗
PubMed1992

A dose-effect relationship for the effect of deltamethrin on a linyphiid spider population in winter wheat.

The relationship between application rate and effect of deltamethrin (Decis) on a linyphiid spider population was studied in relation to ambient physical factors. A field experiment using five application rates and a control was conducted in winter wheat plots. The aim was to determine application rates that allowed for determination of negative as well as positive effects of physical factors on arthropod toxicity using pitfall traps. Several physical variables were measured in the crop canopy and deltamethrin deposition was determined at ground level. The use of Before-After-Control-Impact design (BACI) time series analysis for characterization of instantaneous pesticide effects and velocity of recovery, relative to the application rate sprayed was evaluated. An initial reduction in spider catches ranging from 58% to 85% percent for sprayed concentrations of 0.25 to 4 g active ingredient per hectare (ai ha-1) was observed, followed by exponential recovery with a half-life time of 2.8 days for all treatments. The effects observed in this study were relatively mild compared to other field-experiments. It was concluded that an application rate near 0.25 g ai ha-1 deltamethrin (i.e., one twentieth of the recommended rate) would be sufficient to study the relationship between physical factors and the effects of deltamethrin. BACI time series analysis was shown to be a useful technique for characterizing short-term pesticide effects.

Animals↗