Discrimination of inclined path segments by the desert ant Cataglyphis fortis

Desert ants (Cataglyphis fortis) navigate by means of path integration, and perform accurately even in undulating terrain. They are able to correctly calculate the ground distance between nest and feeder even if their foraging excursion leads them over corrugated surfaces. To compute the respective ground projection when walking over an inclined surface, ants must measure its slope with sufficient accuracy—but how they do so is still not understood. Using a new behavioural assay that included a negative reinforcement, we investigated how well different slopes are discriminated by the ants. Ants were trained to visit an elevated feeder, via a ramp of fixed inclination (five training inclinations were used: 0°, 15°, 30°, 45°, 60°). The ants discriminated a steeper test slope that differed from the training slope by 12.5°. This discrimination performance was found to be constant for training slopes between 0° and 45°. Ants trained on a 60° slope, however, did not discriminate all steeper slopes, up to a vertical ascent, from the 60° inclination. The consequences of this discrimination accuracy for errors in the path integration process are discussed.     

Effects of nursery table slope orientation on coral survival and growth

Transplanting nursery-reared corals is among one of the most common approaches to assist the recovery of degraded reefs. The nursery phase is considered essential for providing a favourable environment for coral fragments to grow into suitable sizes before transplantation to natural reef substrates. Several types of coral nursery designs have been used, but the effect of nursery table slope orientation on survival and growth of coral fragments has not been fully evaluated. Survival and growth of coral fragments from four species (Pectinia paeonia, Podabacia crustacea, Pocillopora acuta, Merulina ampliata) on three inclinations of nursery table top (horizontal (0°), diagonal (45°) and vertical (90°)) were monitored over six months. The effects of slope orientation on survival and growth of fragments were not significant among species except P. acuta, for which survivorship and growth decreased significantly only on vertical nursery tables. The conditions required for coral propagation, such as slope orientation of nursery tables and the initial size of fragments, clearly differ among species due to their inherent attributes and restoration success will greatly benefit from empirical studies derived from a wider range of species.     

Camillea (Xylariaceae, Ascomycota), including two new species, along a trans-Andean altitude gradient in Ecuador

Two new species of Camillea are described from localities on an east–west transect through Ecuador between the latitudes 1°00’N and 1°00’S. Camillea ovalispora was collected in San Vicente de Huaticocha, an area characterized as humid lowland rainforest and premontane cloud forest; C. unistoma was collected at Cuyabeno, a protected area with black water inundated forest and primary rainforest on terra firme. Further, C. heterostoma var. macrospora is elevated to full species status as C. macrospora. New country records of six Camillea species are annotated from the same east-west transect. These are C. flosculosa, C. fossulata, C. hainesii, C. macrospora, C. scriblita, and C. tinctor. Also, previously recorded species have been annotated with new specimens added. Additionally, six distinct taxa from the transect that appear to be undescribed were included in the analysis; one is partly described but not the others due to insufficient material. The data showed an obvious altitude influence on the distribution and frequency of Camillea species. The diversity of species is lower on the western part of the transect compared to the eastern side, probably due to multiple factors such as differences in search intensity between the two slopes, difference in annual rainfall, and possibly the availability of host plants. Camillea taxa were only found at altitudes below 2,000 m, with the highest diversity below 600 m. Palmae is reported as a new host for Camillea species.     

Stand structure and carbon metabolism of coppice forests at a heavy snowfall climate region of central Japan. I. Dynamics of stand structure during 14 years

The coppice stands under the climatic conditions of Warmth Index (WI)≧85°C·month, and Coldness Index (CI)≦−10°C·month could be classified into aQuercus serrata type andCarpinus types at a heavy snowfall climate region of central Japan. The latter types tended to be more distributed on steeper slopes rather than the former. An analysis of tree forms and growth rates of species could reveal the characteristic of this habitat and vegetation type. The growth rates of stem diameter of dominant species on a gentle slope were higher than ones on a steep slope. However, the dominant species on the steeper slope had plasticity to basal bend with sustentacular roots, which is one form of tolerance of heavy snowfall on steep slopes. Average mortality during 14 years was 26%, irrespective of the gradient of a slope. More than one-third of dead shoots were induced by direct damage, while cracked or broken pieces of a stem were from heavy snowfall. The shoot density at smaller diameter classes tended to be higher at a stand having high horizontal variance of canopy surface caused by basal bend of big shoots. A frequency distribution function of individual tree weight (w), f(w)=pw^−3/2, could be obtained at each coppice stand by statistical analysis. The value of a parameter p, a packing factor, tended to be higher at stands on steeper slopes consisting of largely bent shoots and was constant irrespective of the growth.     

A common strategy of cold hardiness in ants of the genus <Emphasis Type="Italic">Myrmica</Emphasis> (Formicidae,Hymenoptera) in Northeast Asia

The biotopic distribution, nest structure, wintering conditions, and cold hardiness of four ecologically contrasting ant species (Myrmica angulinodis, M. kamtschatica, M. bicolor, and M. transsibirica) are considered. The cold hardiness of these species is typical of the genus: the supercooling points vary from −28 to −31°C; cold hardiness levels (LT50%) are higher by 5°C. At this level of cold hardiness, ants can be practically ubiquitous across the whole Hypoarctic (Berman et al., 2007). However, the above Myrmica species are strictly segregated (M. kamtschatica occurs in moss bogs, M. angulinodis and M. transsibirica, on dry and warm south slopes, and M. bicolor, in sandy-gravel floodplains), probably due to different requirements for weather conditions in summer and depth of ground thawing. At present, the excess cold hardiness common to the species in question (exceeding the nest temperature by 5–10°C in different years) is not adaptive and may be considered as preadaptive. It could have been acquired during ancient cold epochs or inherited by the genus as a concomitant result of adaptation not to low temperatures but, for instance, to aridity. These Myrmica species do not undergo selection for resistance to negative temperatures since their current level of cold hardiness is excessive, considering the possible wintering temperatures.     

Hierarchy of sun,beach slope,and landmarks as cues for Y-axis orientation of the supratidal amphipod Talorchestia longicornis (Say)

The semi-terrestrial amphipod Talorchestia longicornis (Say) undergoes Y-axis orientation and has a hierarchy among orientation cues. A previous study found that they used sun compass orientation and moved in the onshore direction of the home beach in both air and water. The present study determined whether this species could also use local landmarks and beach slope as orientation cues. They oriented upslope in simulated darkness in the laboratory on both dry and wet sand with threshold slopes of 2° and 4°, respectively. When tested outside in an arena in air on wet sand, they were disoriented when sun, slope, and landmarks were absent as cues. If presented with single cues, they moved upslope, toward landmarks and in the up-beach direction of the home beach during sun compass orientation. Using paired cues, sun was dominant over slope and landmarks, while slope was dominant over landmarks. In the presence of all three cues, amphipods displayed sun compass orientation in all test combinations except when slope and landmarks were paired together against the sun, which evoked a bimodal response. Thus, the hierarchy of cues for up-beach movement of T. longicornis during Y-axis orientation is the sun, then the slope, and finally the landmarks.     

高寒草地不同坡向披针叶黄华蒸腾速率与叶性状的关系

植物蒸腾速率(Tr)与叶性状间的协同变异关系,对理解异质性生境下植物叶片形态构建模式及其生态适应性具有重要意义。利用ArcGIS建立研究区域的数字高程模型(DEM),并提取样地坡度数据,研究了祁连山高寒草地不同坡向披针叶黄华叶性状与Tr的关系。结果表明:随着坡向由北坡向东坡、西坡、南坡转变,草地群落的密度、高度和土壤含水量逐渐减小,披针叶黄华叶面积(LA)与Tr呈减小趋势,而叶厚度呈增大趋势;在南坡和北坡披针叶黄华的Tr与LA之间存在极显著正相关关系(P0.01),与叶厚度之间存在极显著负相关关系(P0.01),在东坡和西坡披针叶黄华的Tr与LA之间存在显著正相关关系(P0.05),与叶厚度之间存在显著负相关关系(P0.05)。生长在南坡的披针叶黄华选择了小而厚的叶片和低的Tr,生长在北坡的披针叶黄华选择了大而薄的叶片和高的Tr,体现了异质生境中植物通过叶片生物量分配机制实现资源有效利用的生存策略。     

Phylogenetic relationships between the slave‐making ants Rossomyrmex and their Proformica hosts in relation to other genera of the ant tribe Formicini (Hymenoptera: Formicidae)

The ant genus Proformica is very common to Eurasian semi‐deserts, and a few species are parasitized by the slave‐making ants Rossomyrmex. However, the phylogenetic relationship between Proformica (host) and Rossomyrmex (parasite) remains unclear as another closely related genus (Cataglyphis) could be a sister group of Rossomyrmex. This work has two main goals: (i) to study the phylogenetic relationships among Proformica, Rossomyrmex, and other genera of the tribe Formicini, with a special focus on the highly diverse genus Cataglyphis; and (ii) to reconstruct the biogeographical distribution of parasite and host genera. We perform a phylogenetic study for the first time including several species of the genera Rossomyrmex, Proformica, and Cataglyphis. Our results indicate that Proformica and Rossomyrmex are reciprocally monophyletic and that Rossomyrmex is nested within Cataglyphis, rendering the latter paraphyletic. Finally, the ancestral distribution range of the host genus could be situated in Central Asia and subsequently dispersed to Western Europe, whereas additional studies are required to clarify the range of the parasite.     

Chemotaxonomy of some Cataglyphis ants from Morocco and Burkina Faso

The taxonomy of Cataglyphis ants has many unsolved problems and chemotaxonomy can provide additional insight for their resolution. We describe here the chemical content of the postpharyngeal and Dufour glands of three Cataglyphis ant species: C. viaticus, C. mauritanicus from Morocco and for the first time a Sub-Saharan Cataglyphis, C. sp. (BF) from Burkina Faso. These three species are very distinct chemically with respect to both the postpharyngeal and Dufour glands. Methyl-alkenes, rare in ants, are characteristic of C. sp. (BF) postpharyngeal glands. A comparison with C. bicolor from Tunisia indicated that C. sp. (BF) can be included into the bicolor group with C. viaticus. We suggest that the content of the Dufour gland is a better phylogenetic indicator than the content of the postpharyngeal gland.     

Lycodes adolfi Nielsen and Foss?, 1993 (Teleostei: Zoarcidae) found in the Arctic Ocean

Adolf’s eelpout, Lycodes adolfi, was found at five bottom trawl stations in 2007–2009, on the slope towards the Sofia Deep north of Spitsbergen, at depths of 970–1,220 m and water temperatures below 0°C. Previously, the species has been known from cold and deep waters south of 74°N to both sides of Greenland and in the Norwegian Sea. The present material represents the first records from the Arctic Ocean and may indicate a wider arctic distribution of this species.     

微地形对大西沟新疆野杏萌发层土壤因子的影响

野杏是新疆野果林的主要建群种和种质资源树种。野杏在种子萌发成苗期,幼苗的根系主要分布在0—15 cm土层中。为了阐明坡向、坡位、坡度和坡形等微地形因子对野杏种子萌发层土壤特征和养分分布的影响,在新疆伊犁州霍城县大西沟的封育野果林内(44°26′01.09″—44°26′17.12″N,80°46′27.49″—80°47′03.26″E)设置样地,测定0—15 cm土层的土壤砾石、酸碱值、有机质和全氮、全磷、全钾、水解性氮、有效磷和速效钾含量,分析各土壤因子和地形因子的关系。结果表明:(1)东北坡土壤养分含量较高,其土壤砾石含量、酸碱值、有机质、全磷、水解性氮和速效钾含量与东南坡、南坡皆存在显著差异(P0.05),阴坡的土壤有机质、全氮、有效磷和速效钾含量都高于阳坡,不同坡向的土壤特征和养分分布存在显著差异(P0.05);(2)不同坡位的土壤有机质、全氮、全磷和有效磷含量均表现为中坡位下坡位上坡位,土壤砾石、全钾和速效钾含量均呈现上坡位中坡位下坡位,全钾、全磷和有效磷含量在同坡位分布较均匀,不同坡位的土壤特征和土壤养分分布无显著差异(P0.05);(3)不同坡度下的土壤水解性氮和有效磷含量是缓坡中坡缓中坡陡坡,土壤砾石、酸碱值、全氮、水解性氮、有效磷和速效钾含量有显著差异(P0.05),陡坡土壤有机质、全氮、水解性氮和有效磷含量均低于其他坡度,而土壤砾石、土壤酸碱值和全钾在陡坡土层中含量最高,缓坡与缓中坡的土壤养分含量丰富,陡坡较为贫瘠,坡度对土壤特征和土壤养分分布有显著影响(P0.05);(4)不同坡形下的土壤砾石、全钾、水解性氮、有效磷和速效钾含量是凸形坡凹形坡直线坡,不同坡形下的土壤特征和土壤养分(除全钾和速效钾)均存在显著差异性(P0.05)。野果林地形因子对野杏萌发层土壤特征和土壤养分分布有显著影响,东北坡、中坡位、缓坡和凸形坡土壤养分含量较为丰富,是适宜野杏萌发的地形。研究结果可为探究影响野杏种子萌发和生长的气候与土壤水热等因子奠定良好基础。     

Orientation of the sand-beach amphipod, Orchestoidea corniculata

Laboratory experiments demonstrated that Orchestoidea corniculata, a sand-beach amphipod, can orient to slopes of only 3°. Studies suggest they reach the upper interdial zone where they burrow by moving up a wet slope or down a dry slope. When they emerge from the sand at night, however, they either reverse this response or show no response to slope. This behaviour, enhanced by a preference for wet, surface sand, would account for the initial seaward movement observed in the field. Behavioural variations among differing segments of the population were investigated. Three additional beach inhabitants oriented to slope, thus indicating the mechanism of slope orientation as a possible generalization in the beach habitat.     

Structural transition temperature of hemoglobins correlates with species’ body temperature

Human red blood cells (RBCs) exhibit sudden changes in their biophysical properties at body temperature (T _B). RBCs were seen to undergo a spontaneous transition from blockage to passage at T _C = 36.4 ± 0.3°C, when the temperature dependency of RBC-passages through 1.3 μm narrow micropipettes was observed. Moreover, concentrated hemoglobin solutions (45 g/dl) showed a viscosity breakdown between 36 and 37°C. With human hemoglobin, a structural transition was observed at T _B as circular dichroism (CD) experiments revealed. This leads to the assumption that a species’ body temperature occupies a unique position on the temperature scale and may even be imprinted in the structure of certain proteins. In this study, it was investigated whether hemoglobins of species with a T _B different from those of human show temperature transitions and whether those were also linked to the species’ T _B. The main conclusion was drawn from dynamic light scattering (DLS) and CD experiments. It was observed that such structural temperature transitions did occur in hemoglobins from all studied species and were correlated linearly (slope 0.81, r = 0.95) with the species’ body temperature. We presumed that α-helices of hemoglobin were able to unfold more readily around T _B. α-helical unfolding would initiate molecular aggregation causing RBC passage and viscosity breakdown as mentioned above. Thus, structural molecular changes of hemoglobin could determine biophysical effects visible on a macroscopic scale. It is hypothesized that the species’ body temperature was imprinted into the structure of hemoglobins.     

Polarized skylight orientation in the desert antCataglyphis

Summary The desert antCataglyphis bicolor is able to use the pattern of polarized light in the sky as compass. By confronting the ant to single spots of artificially and naturally polarized light it is shown howCataglyphis uses the polarization pattern.When exposed to a horizontal e-vector,Cataglyphis was always oriented correctly. Orientation errors occurred, however, when other e-vector directions were presented. This indicates that the e-vector positions assumed by the ant do not coincide with the e-vector positions actually realized in the sky. From this it is concluded thatCataglyphis has no detailed knowledge of the actual azimuthal positions of the e-vectors. Instead, it is relying on a simplified celestial map of the polarization patterns in the sky (Fig. 7).Usually, the ant did not confuse celestial spots with identical e-vector directions. Even at sunset when the polarization pattern is completely ambiguous, correct orientation occurred. This suggests that the ant uses additional celestial cues such as the degree of polarization, the color or the intensity to find its way home when the sun is obscured.     

Group recruitment in a thermophilic desert ant, Ocymyrmex robustior

Thermophilic desert ants—Cataglyphis, Ocymyrmex, and Melophorus species inhabiting the arid zones of the Palaearctic region, southern Africa and central Australia, respectively—are solitary foragers, which have been considered to lack any kind of chemical recruitment. Here we show that besides mainly employing the solitary mode of food retrieval Ocymyrmex robustior regularly exhibits group recruitment to food patches that cannot be exploited individually. Running at high speed to recruitment sites that may be more than 60 m apart from the nest a leading ant, the recruiter, is followed by a loose and often quite dispersed group of usually 2–7 recruits, which often overtake the leader, or may lose contact, fall back and return to the nest. As video recordings show the leader, while continually keeping her gaster in a downward position, intermittently touches the surface of the ground with the tip of the gaster most likely depositing a volatile pheromone signal. These recruitment events occur during the entire diurnal activity period of the Ocymyrmex foragers, that is, even at surface temperatures of more than 60 °C. They may provide promising experimental paradigms for studying the interplay of orientation by chemical signals and path integration as well as other visual guidance routines.     

Morphological,cultural, and biodestructive peculiarities of <Emphasis Type="Italic">Chaetomium</Emphasis> species

Chaetomium is a fungus species that inhabits different cellulose substrates. Some species of this genus destroy books, textile, and wood. This genus is of particular interest due to its antagonistic and enzyme peculiarities. Studies on morphological and cultural features of Chaetomium species have both theoretical and practical output. Growth rates and development of C. globosum, C. funicola, C. elatum, and C. spirale were studied under different temperatures (17–20°C, 25°C, 27°C, 30°C, and 33–35°C) and carbon source media (glucose, saccharose, mannite, lactose, amylum, and cellulose). The optimal growth temperature was 25–27°C for all the studied species, while the temperature range of 33–35°C inhibited the colonies’ growth. Growth dynamics and colony shape and morphology, as well as development of overhead mycelium and ascocarps, varied greatly in different Chaetomium species in regard to the carbon source media. When comparing the destructive effect of four studied species and C. murorum on craft paper, the highest activity was registered for C. globosum, C. funicola, and C. elatum.     

The composition and distribution of pelagic ostracods (Ostracoda: Myodocopa) in antarctic waters adjacent to the d’Urville Sea

The faunistic composition of pelagic ostracods of regions situated to the north and northwest of the d’Urville Sea (60°–65°S, 148°–136° and 136°–113°E) is largely similar to that of the area adjacent to the Somov Sea at the same latitudes. Alacia hettacra is the most abundant species here; Austrinoecia isocheira, Boroecia antipoda, and Obtusoecia antarctica are common species. The maximum abundance of pelagic ostracods is observed in the 100–200 m depth range; the largest contribution to it is contributed by A. hettacra. The number of species increases with increasing depth. The 64°–65°S region between 148° and 113° E is regarded as the northern boundary of the “Polar Antarctic zone.”     

Patterns of host ant use by sympatric populations of <Emphasis Type="Italic">Maculinea alcon</Emphasis> and <Emphasis Type="Italic">M. ‘rebeli’</Emphasis> in the Carpathian Basin

Maculinea butterflies show social parasitism via obligatory myrmecophily as their larvae are adopted and raised to pupation by Myrmica ants. Suitable hosts differ for different Maculinea species, and host ant specificity can further differ at the population-level. Although early studies suggested single ant species as main hosts for each Maculinea species, it has recently become clear that their host ant specificity is more complex. Maculinea alcon and Maculinea ‘rebeli’ have variously been separated according to adult and larval morphology, phenology, and their use of different ecosystems, including host plant and host ant species. However, recent genetic evidence has questioned their separation as good species. Here we compare the use of host ants by M. alcon and M. ‘rebeli’ at the regional scale in NE-Hungary and Transylvania (Romania), where molecular studies have found no species-level separation between the two forms. We opened 778 nests of Myrmica ants and searched for Maculinea specimens (larvae, pupae and exuviae) shortly before imago emergence from the nest in seven M. alcon sites, six M. ‘rebeli’- sites and one site where both M. alcon and M. ‘rebeli’ are syntopic. In all, Maculinea caterpillars were found in the nests of seven different ant species (M. alcon was recorded mainly with Myrmica scabrinodis and occasionally with M. salina and M. vandeli; M. ‘rebeli’ used mainly M. scabrinodis, M. sabuleti and M. schencki and occasionally M. lonae and M. specioides). Myrmica scabrinodis was found to be a general host of both M. alcon and M. ‘rebeli’, which is the first record for a common host ant of these two closely related butterflies within the same region. However there were also differences in host ant use patterns between the sites occupied by the two Maculinea taxa, which reflect differences in Myrmica communities between the two types of habitat. Possible explanations for the similar but not identical host use patterns of M. alcon and M. ‘rebeli’, and their relevance for the question of whether they are separate species are discussed. Received 27 November 2007; revised 28 May 2008; accepted 11 June 2008.     

Energy, water balance and the roost microenvironment in three Australian cave-dwelling bats (Microchiroptera)

The ghost bat, Macroderma gigas, and the orange leaf-nosed bat, Rhinonycteris aurantius, occupy similar ranges across northern Australia and are often found in the same roost caves. Both species are considered rare and vulnerable to further population decline. A third small species, the large bent-wing bat, Miniopterus schreibersii, has a similar body mass to R. aurantius, but has one of the largest ranges of any Australian mammal. In the present study we examine the effect and sensitivity of the animals' roosting microclimates on their energy and water balance. M. schreibersii exhibits a basal metabolic rate about 40% greater than other bats of similar body mass, whereas the other two species are close to predicted levels. R. aurantius shows a decrease in body temperatures below thermoneutrality. R. aurantius has levels of pulmocutaneous water loss among the highest seen for a mammal, and calculations based on nasal tip temperatures suggest that most of this loss is across the skin. Calculated ambient temperatures at which metabolic water production is equal to pulmocutaneous water loss in dry air are −14.7 °C for R. aurantius, 9.8 °C for M. schreibersii and −0.3 °C for M. gigas. Exposing the animals to relative humidities of between 80% and 90% shifted these calculated temperatures to 5.6 °C, 25.2 °C, and 2.9 °C, respectively. For each species the ratio of metabolic water production to evaporative water loss has been treated as a joint function of humidity and ambient temperature. The resulting surface plot shows that under known roosting conditions in caves R. aurantius and M. schreibersii remain in positive water balance, whereas M. gigas does not. Accepted: 20 May 2000     

Wind tunnel assays of olfactory responses of femaleRhagoletis pomonella flies to apple volatiles: effect of wind speed and odour release rate

Little is known about how adults of the corn leafhopper,Dalbulus maidis (DeLong & Wolcott), and its congeners survive subfreezing temperatures at high elevations during the dry winter in Mexico. In the laboratory, duration of survival at −5°C was measured for four MexicanDalbulus species:D. maidis, D. elimatus (Ball),D. gelbus DeLong andD. quinquenotatus DeLong & Nault; and a closely related North American species,Baldulus tripsaci Kramer & Whitcomb. Adult leafhoppers reared under environmental conditions that simulated the beginning of the dry winter season during October in Mexico (‘October-reared’) were at least twice as tolerant of −5°C than adults reared under environmental conditions that simulated the beginning of the wet summer season during June (‘June-reared’).Dalbulus species found primarily at high elevations, such asD. elimatus, were seven times more tolerant of −5°C thanD. quinquenotatus, a species which overwinters at low to mid elevations on itsTripsacum hosts. October-rearedD. maidis adults survived relatively short periods at −5°C (LT₅₀=8.9h) compared to October-rearedD. elimatus adults (LT₅₀=42.3h). This suggests that in Mexico,D. maidis either overwinters in protected habitats at higher elevations or it migrates to lower, frost-free regions. October-rearedB. tripsaci adults, which overwinter in the egg stage, were intolerant of −5°C (LT₅₀=2.6h). A conditioning period for 1 h at +5°C before and after exposure to −5°C significantly improved survival forD. maidis. Supercooling points (SCPs) were between −23 and −20°C, indicating that mortality of these leafhoppers at −5°C was due to cold shock injury rather than internal ice formation.