An Opposite Pattern to the Conventional Thermal Hypothesis: Temperature-Dependent Variation in Coloration of Adults of Saccharosydne procerus (Homoptera: Delphacidae)

Melanism is a common polymorphism in many insect species that also influences immune function. According to the thermal melanin hypothesis, ectothermic individuals from cooler environments have darker cuticles and higher polyphenol oxidase (PO) levels, which represent a better immunocompetence. In this study, the links among environmental temperature, melanism, and PO activity of Saccharosydne procerus (Matsumura) were examined. Most S. procerus have a black spot on their forewings at high temperatures in the field and in the laboratory. In PO activity assay, a positive association between PO level and temperature was found. Our results showed that a diversification of melanism occurred under different temperatures and that melanism in S. procerus presented an opposite pattern to the one proposed by the thermal hypothesis.     

记陕西洛南张坪洞穴群中更新世绒(鼠平)(Caryomys)

详细描述了陕西洛南张坪洞穴群中中更新世的洮州绒(鼠平)(Caryomys eva)和苛岚绒(鼠平) (C.inez),讨论了绒(鼠平)属的分类地位。分析显示,C.eva各齿测量的平均值小于C.inez;两种臼齿形态从约493 kaBP以来无显著变化,显示出该属的原始性质。     

A new species of Laranda Walker 1869 (Orthoptera: Grylloidea, Phalangopsidae) from remnant patches of the Brazilian Atlantic Forest

The genus Laranda has six described species and is confined to South and Southeast of Brazil. We describe a new species and discuss the biology and distribution of the genus. The new species can be distinguished from its known congeners by the following characteristics: absence of yellow spots on pronotum and base of posterior tibiae; female copulatory papilla: sclerotization in dorsal view forming opposing acute angles, apical lobes narrow and small; male genitalia: pseudepiphallic median process short and wide; pseudepiphallic paramere with apex incurved and ectophallic fold surpassing apex of the parameres. The genus is distributed within the Atlantic Forest biome; the new species is found on tree trunks, as well as on forest leaf litter.     

Comparative analysis of leaf angle and sclerophylly of Aspidosperma quebracho‐blanco on a water deficit gradient

Abstract Aspidosperma quebracho‐blanco is found throughout the Chaco (17°?33°S) in Argentina, and it is the dominant tree species in the arid Chaco. Under the hypothesis that morpho‐physiological features of A. quebracho‐blanco change as a function of its geographical position on a water deficit gradient, it was predicted that with increasing water stress, leaf angles (specifically horizontal) would be greater and mean values of the leaf mass per area would increase. These leaf characteristics were compared at three points on a water deficit gradient extending from the humid Chaco through semi‐arid Chaco to the arid Chaco of Argentina (south‐west to north‐east rainfall gradient, from 350 to 1200 mm annual mean precipitation). Twig and leaf positions were modified and water potentials were measured at the highest heating hour of the day at a site of the arid Chaco. Daily and seasonal water potential variations of untreated twigs were also observed. Leaf angle modification towards horizontal produced more negative twig water potentials with respect to those of leaves in non‐horizontal positions. The comparison of the three sites along the gradient showed contrasting patterns of leaf‐angle frequency distribution of adults. In Chancaní (mean annual temperature: 18–24°C, mean annual precipitation: 450 mm, arid) there was a higher frequency of angles near 90° for non‐pendulous and about 270° for pendulous trees. Leaf angles in Copo (semi‐arid) and Chaco National Park (mean annual temperature: 20–23°C, mean annual precipitation: 1300 mm humid) were widely distributed with higher frequency towards the angles near 0° and 180°. This sclerophyllous tree species showed plasticity in its leaf traits along the precipitation gradient. Plasticity in leaf mass per area and leaf position enables plants to develop efficiently in contrasting environmental conditions of humidity and aridity.     

Remarkable discovery in a cave of south west Morocco: Siagona taggadertensis n.sp. (Carabidae: Siagoninae)

Five species of the genus Siagona Latreille 1804 (Carabidae: Siagoninae) are known from Morocco. Siagona taggadertensis n. sp., a remarkable species of Carabidae from a Moroccan cave is described. This insect is spectacular by its large size (one of the largest species of the genus), its external morphology, which isolates it from all the north african representant of the genus, and for the conditions of its discovery: its only known from the remains of six specimens, all of them found in the cave of Taggadert, western Atlas. Hypotheses concerning the ecology of this species are discussed.     

Relevance of crustacean carapace wettability for fouling

Carapace wettability and density of fouling organisms (bacteria, diatoms, protozoa, fungi, macro-organisms) were investigated for 45 crustacean species (Hoplocarida, Decapoda) from 15 families in the Gulf of Thailand. The results show that crustaceans can create and maintain characteristic carapace wettabilities. About 21 species (47%) possess highly wettable carapaces with contact angles below 20°. Contact angles between 20° and 40° were recorded for four species (2%), angles between 40° and 60° for eight species (4%) and from 60° to 70° for 11 (24%) species. One species, Alpheus euphrosyne (Alpheidae, Decapoda), exhibited an extremely low surface wettability (contact angle: 91°). Densities of colonisers and contact angles did not correlate. Very low wettability by water ( > 90°) may only contribute little to fouling reduction in A. euphrosyne which showed the most hydrophobic carapace surface and was colonised by the lowest numbers of bacteria among all species and no other colonisers at all. We conclude that surface wettability is of little relevance for antifouling defence in crustaceans.     

Allochthonous resources are less important for faunal communities on highly productive,small tropical islands

Ecosystems are interconnected by energy fluxes that provide resources for the inhabiting organisms along the transition zone. Especially where in situ resources are scarce, ecosystems can become highly dependent on external resources. The dependency on external input becomes less pronounced in systems with elevated in situ production, where only consumer species close to the site of external input remain subsidized, whereas species distant to the input site rely on the in situ production of the ecosystem. It is largely unclear though if this pattern is consistent over different consumer species and trophic levels in one ecosystem, and whether consumer species that occur both proximate to and at a distance from the input site differ in their dependency on external resource inputs between sites. Using stable isotope analysis, we investigated the dependency on external marine input for common ground‐associated consumer taxa on small tropical islands with high in situ production. We show that marine input is only relevant for strict beach‐dwelling taxa, while the terrestrial vegetation is the main carbon source for inland‐dwelling taxa. Consumer species that occurred both close (beach) and distant (inland) to the site of marine input showed similar proportions of marine input in their diets. This supports earlier findings that the relevance of external resources becomes limited to species close to the input site in systems with sufficient in situ production. However, it also indicates that the relevance of external input is also species‐dependent, as consumers occurring close and distant to the input site depended equally strong or weak on marine input.     

The ontogeny of cranial base angulation in humans and chimpanzees and its implications for reconstructing pharyngeal dimensions

This paper examines differences in the processes by which the cranial base flexes in humans and extends in chimpanzees. In addition, we test the extent to which one can use comparisons of cranial base angles in humans and non-human primates to predict vocal tract dimensions. Four internal cranial base angles and one external cranial base angle were measured in a longitudinal sample of Homo sapiens and a cross-sectional sample of Pan troglodytes. These data show that the processes of cranial base angulation differ substantially in these species. While the human cranial base flexes postnatally in a rapid growth trajectory that is complete by two years, the cranial base in P. troglodytes extends postnatally in a more prolonged skeletal growth trajectory. These comparisons also demonstrate that the rate of cranial base angulation is comparable for different measures, but that angles which incorporate different anterior cranial base measurements correlate poorly. We also examined ontogenetic relationships between internal and external cranial base angles and vocal tract growth in humans to test the hypothesis that cranial base angulation influences pharyngeal dimensions and can, therefore, be used to estimate vocal tract proportions in fossil hominids. Our results indicate that internal and external cranial base angles are independent of the horizontal and vertical dimensions of the vocal tract. Instead, a combination of mandibular and palatal landmarks can be used to predict dimensions of the vocal tract in H. sapiens. The developmental contrasts in cranial base angulation between humans and non-human primates may have important implications for testing hypotheses about the relationship between cranial base flexion and other craniofacial dimensions in hominid evolution.     

Lateral wedges decrease biomechanical risk factors for knee osteoarthritis in obese women

Obesity is the primary risk factor for the development and progression of medial compartment knee osteoarthritis. Laterally wedged insoles can reduce many of the biomechanical risk factors for disease development in osteoarthritis patients and lean individuals but their efficacy is unknown for at-risk, obese women. The purpose was to determine how an 8° laterally wedged insole influenced kinetic and kinematic gait parameters in obese women. Gait analysis was performed on fourteen obese (average 29.3 years; BMI 37.2kg/m(2)) and 14 lean control women (average 26.1 years; BMI 22.4kg/m(2)) with and without a full-length, wedged insole. Peak joint angles, the external knee adduction moment and its angular impulse were calculated during preferred and standard 1.24m/s walking speeds. Statistical significance was assessed using a 2-way ANOVA (α=0.05). The insole significantly reduced the peak external knee adduction moment (mean decrease of 3.6±3.9Nm for obese and 1.9±1.8Nm for controls) and its angular impulse in both groups. The wedged insoles also produced small changes in ankle dorsiflexion (obese: 1.2±1.4° increase; control: 1.5±1.4° increase) and eversion range of motion (obese: 1.3±1.9° decrease; control: 1.5±1.2° decrease) but did not alter peak angles of superior joints. Although the majority of obese women may develop knee osteoarthritis during their lifetime, a prophylactic insole intervention could allow obese women with no severe knee malalignments to be active while preventing or delaying disease onset. However, the long-term effects of the insole have not yet been examined.     

The walk of the Silver gull (Larus novaehollandiae) and of other birds

A total of 317 steps of walking Silver gulls ( Larus novaehollandiiae ) and filmed sequences of 24 other species of medium-sized and large birds were analyzed. The angles made by the tibiotarsus-tarsometatarsus joint of each leg during walking were measured. These varied depending on the species. In the Silver gull, where the angles were correlated with speed, the leg bent more sharply the slower the step; otherwise the angles were not correlated with speed. In all but the four largest birds, as in man, the leg was more bent in the middle of its stance phase than it was at the beginning or end of this phase. Thejoint was never completely straight, or 180". In general the larger the bird, the slower was its step. The Silver gull and other birds do not bob their heads back-and-forth as they walk, but many birds do. It is not known why some birds bob their heads, although it may be correlated in part with a relative horizontal body posture, with seeing effectively, with balance during locomotion, or with habitat. The Silver gull does not hop, but some birds do, usually birds that live in the bush, or that are small.     

Gimbals in the insect leg

We studied the common kinematic features of the coxa and trochanter in cursorial and raptorial legs, which are the short size of the podomers, predominantly monoaxial joints, and the approximate orthogonality of adjacent joint axes. The chain coxa-trochanter with its short elements and serial orthogonality of joint axes resembles the gimbals which combine versatility and tolerance to external perturbations. The geometry of legs was studied in 23 insect species of 12 orders. Insects with monoaxial joints were selected. The joint between the trochanter and the femur (TFJ) is defined either by two vestigial condyles or by a straight anterior hinge. Direction of the joint axes in the two basal podomers was assessed by 3D measurements or by goniometry in two planes. Length of the coxa is <15% (mostly <8%) of the total length of the cursorial leg, that of the trochanter <10%. Angles between the proximal and distal joint axes in the middle coxa range from 124 to 84 degrees (mean 97+/-14 degrees ), in the trochanter (in all legs studied) from 125 to 72 degrees (mean 90+/-13 degrees ). Vectors of the distal axis in the coxa are concentrated about the normal to the plane defined by the proximal axis and the midpoint between the distal condyles. These vectors in the trochanter lie at various angles to the normal; angles are correlated with the direction of the TFJ relative to the femur. Range of reduction about the TFJ is over 60 degrees in the foreleg of Ranatra linearis, Mantispa lobata and the hind leg in Carabus coriaceus (confirming observations of previous authors), 40-60 degrees in the foreleg of Vespa crabro and in the middle one in Ammophila campestris, 10-30 degrees in other studied specimens. The special role of the trochanter in autotomy and in active propulsion in some insect groups is discussed. The majority of insects possess small trochanters and slightly movable TFJs with the joint axis laying in the femur-tibia plane. We pose the hypothesis that the TFJ damps external forces, the vectors of which lie off the femur-tibia plane, the reductor muscle acting as a spring. Thus the TFJ contributes to dynamic stability of legged locomotion.     

Trade-offs between light interception and leaf water shedding: a comparison of shade- and sun-adapted species in a subtropical rainforest

Species in high-rainfall regions have two major alternative approaches to quickly drain off water, i.e., increasing leaf inclination angles relative to the horizontal plane, or developing long leaf drip tips. We hypothesized that shade-adapted species will have more pronounced leaf drip tips but not greater inclination angles (which can reduce the ability to intercept light) compared to sun-adapted species and that length of leaf drip tips will be negatively correlated with photosynthetic capacity [characterized by light-saturated net photosynthetic rates (A _max), associated light compensation points (LCP), and light saturation points (LSP)]. We tested this hypothesis by measuring morphological and physiological traits that are associated with light-interception and water shedding for seven shade-adapted shrub species, ten sun-adapted understory shrub species, and 15 sun-adapted tree species in a subtropical Chinese rainforest, where mean annual precipitation is around 1,600 mm. Shade-adapted understory species had lower LMA, A _max, LSP, and LCP compared to understory or canopy sun-adapted species; their leaf and twig inclination angles were significantly smaller and leaf drip tips were significantly longer than those in sun-adapted species. This suggests that shade-adapted understory species tend to develop pronounced leaf drip tips but not large leaf inclination angles to shed water. The length of leaf drip tips was negatively correlated with leaf inclination angles and photosynthetic capacity. These relationships were consistent between ordinary regression and phylogenetic generalized least squares analyses. Our study illustrates the trade-offs between light interception and leaf water shedding and indicates that length of leaf drip tips can be used as an indicator of adaptation to shady conditions and overall photosynthetic performance of shrub species in subtropical rainforests.     

On conformations of the superhelix structure

The slight deformation of a helical macromolecule leading to the superhelical structure is considered. General equations which connect “internal” stereochemical parameters of the backbone of a helical macrcmolecule with “external” parameters of the superhelix are obtained; they are analogous to those of Shimanouchi and Mizushima. The case when the radius of the major helix is much greater than the radius of the minor helix is treated. Assuming that all conformational changes are due to small distortions of the rotation angles (bond angles and bond lengths are kept constant) the general equations reduce to a set of nonhomogeneous linear algebraic equations. Its solution (in the case of the DNA double-helix in B-form) shows that the DNA backbone can form a coiled-coil with parameters close to those estimated from experimental data on DNP in chromatine from nuclei of cells.     

Different adaptation to visual hunting in three ground beetle species of the same genus

Compound eyes and hunting behaviour of three species of the genus Asaphidion de Gozis 1886 (Coleoptera, Carabidae) have been investigated. All three have a fovea and binocular overlap in their frontal fields of vision. In the smallest species A. flavipes, the binocular overlap is largest and the foveal interommatidial angles are narrowest. All three species hunt by visual cues; A. flavipes is the most precise during the approach to the prey and during the attack. The mean size of its approach jerks and its critical distance prior to the attack are shorter than those of A. caraboides, and the scatter of these distances is much smaller. This leads to greater success in capturing fast fleeing prey (Collembola) on the soil surface.     

A new long-leaved species of <Emphasis Type="Italic">Asplundia</Emphasis> (Cyclanthaceae) from Colombia

A new species of Asplundia from the Cordillera Central in Colombia is described and illustrated. Asplundia callejasii is placed in A. subg. Asplundia, based on the morphology of the staminate flowers. The most distinctive characteristic of A. callejasii is its long leaves, with the blade unicostate, oblanceolate, shallowly divided, and very lustrous, with the plicate nerves forming roughly 45° angles with the midrib. These features give it a unique aspect that sets it apart from any other species within the family.     

Kulikovskiyia gen. nov. (Bacillariophyceae) from the lateritic rock pools of the Western Ghats,India and from Hainan Province,China

A new triundulate naviculoid diatom genus is described from the Western Ghats of Peninsular India and Hainan Province, China. The new taxon, Kulikovskiyia gen. nov. has robust conical spines along its margin and at the apices and the external valve face has longitudinally‐oriented siliceous slat system extending the length of the valve. The external distal raphe ends bifurcate and terminates on the valve face. There appear to be superficial similarities between this Asian genus and species and Playaensis, a genus comprised of two species found only in the western USA. The systematic position of Kulikovskiyia is discussed, and other than noting its similarities to other biraphid naviculoid diatoms due to symmetry features and the position of the raphe, we are uncertain about its systematic placement at finer levels of classification.     

A New Species of the Genus Xenophrys(Amphibia: Anura: Megophryidae) from Libo County,Guizhou, China

A new species of the genus Xenophrys is described from a karst cave environment of Libo County, Guizhou Province, Southern China. The new species, Xenophrys liboensis sp. nov., is distinguished from its congeners by a combination of the following characters: 1) tympanum distinct; 2) vomerine teeth present; 3) the length of lower arm and hand larger than the half of snout-vent; 4) heels overlapped slightly when the flexed legs are held at right angles to the body axis; 5) toe tips with rudimentary webs and without grooves; 6) dermal fringes moderate; 7) tubercles on the dorsum forming an X-shaped weak ridge; 8) horn-like tubercle at the edge of the upper eyelid distinct; 9) color of the iris in life is brown. In Bayesian phylogenetic analysis of 22 species of Xenophrys, all the individuals of X. liboensis sp. nov. clustered into a monophyletic clade with high posterior probabilities. In addition, the ranges of genetic divergences of X. liboensis sp. nov. with other species were interspecific rather than intraspecific. Based on the above evidences, we consider that X. liboensis sp. nov. is a valid species in Xenophrys.     

Epibiontic and endobiontic polychaetes of Geodia cydonium (Porifera,Demospongiae) from the Mediterranean Sea

Polychaete assemblages associated to the sponge Geodia cydonium were investigated at two sampling sites in the Mediterranean Sea: Porto Cesareo Basin (Apulia) and Marsala Lagoon (Sicily), both characterized by sheltered hydrodynamic conditions. Samples were seasonally performed during 1997, in order to compare the assemblages coming from the two localities studied, considering separately the internal and external tissues of the sponge, and with the aim of evaluating the influence of sponge size on polychaete colonization. The examined sponge is characterized by a peculiar stratification of its tissues: an external thick and hard layer, the cortex, and an internal softer one, the choanosome. Statistical analysis showed that this was the main factor controlling polychaete assemblage, with the internal tissue, less rich and diversified, appearing impoverished with respect to the external layer. A similarity in species composition was observed between sites, even though some differences were evidenced in the abundance of some species, mainly reflecting differences in local environmental conditions. Species richness and density increased with the increasing sponge size. Such a situation is particularly evident at Porto Cesareo, where sponges are covered by an algal layer which is particularly rich on the largest specimens, thus suggesting that most of the species of polychaetes were linked more to the neighbouring environment than to the sponge itself.     

DISSOCIATION OF THE CIRCADIAN SYSTEM OF OCTODON DEGUS BY T28 AND T21 LIGHT-DARK CYCLES

Octodon degus is a primarily diurnal rodent that presents great variation in its circadian chronotypes due to the interaction between two phase angles of entrainment, diurnal and nocturnal, and the graded masking effects of environmental light and temperature. The aim of this study was to test whether the circadian system of this diurnal rodent can be internally dissociated by imposing cycles shorter and longer than 24?h, and to determine the influence of degus chronotypes and wheel-running availability on such dissociation. To this end, wheel-running activity and body temperature rhythms were studied in degus subjected to symmetrical light-dark (LD) cycles of T28h and T21h. The results show that both T-cycles dissociate the degus circadian system in two different components: one light-dependent component (LDC) that is influenced by the presence of light, and a second non–light-dependent component (NLDC) that free-runs with a period different from the external lighting cycle. The LDC was more evident in the nocturnal than diurnal chronotype, and also when wheel running was available. Our results show that, in addition to rats and mice, degus must be added to the list of species that show an internal dissociation in their circadian rhythms when exposed to forced desynchronization protocols. The existence of a multioscillatory circadian system having two groups of oscillators with low coupling strength may explain the flexibility of degus chronotypes. (Author correspondence: angerol@um.es)