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1.
Social harmony often relies on ritualised dominance interactions between society members, particularly in queenless ant societies,
where colony members do not have developmentally predetermined castes but have to fight for their status in the reproductive
and work hierarchy. In this behavioural plasticity, their social organisation resembles more that of vertebrates than that
of the “classic” social insects. The present study investigates the neurochemistry of the queenless ant species, Streblognathus peetersi, to better understand the neural basis of the high behavioural plasticity observed in queenless ants. We report measurements
of brain biogenic amines [octopamine, dopamine, serotonin] of S. peetersi ants; they reveal a new set of biogenic amine influences on social organisation with no common features with other “primitively
organised societies” (bumble bees) and some common features with “highly eusocial” species (honey bees). This similarity to
honey bees may either confirm the heritage of queenless species from their probably highly eusocial ancestors or highlight
independent patterns of biogenic amine influences on the social organisation of these highly derived species. 相似文献
2.
Crickets in the genus Laupala (subfamily Trigonidiinae) have an elaborate courtship system, defined by a highly ritualized serial transfer of multiple
spermatophores. Males produce multiple “micro” spermatophores followed by a final “macro” spermatophore during a single mating
bout. Remarkably, the microspermatophores of L. cerasina, the first species whose mating system was studied in detail, were discovered to be spermless. However, in a study of another
species, L. pacifica, sperm transfer was reported after every copulation suggesting that L. pacifica microspermatophores contain sperm. The presence or absence of sperm in the microspermatophore has important implications
for the evolution of this exaggerated courtship system and the origin of nuptial gifts. In this study, we systematically examined
L. pacifica spermatophore contents for sperm using a fluorescent nuclear stain. We detected sperm only in macrospermatophores. This finding
suggests that spermless microspermatophores are typical for Laupala; thus, to determine the origin of this highly modified phenotype will require comparative analyses with closely related outgroups
that exhibit less exaggerated courtship systems. 相似文献
3.
4.
We report on a partial varanopid skull and mandible from the Pristerognathus Assemblage Zone of the Beaufort Group, in the South African Karoo Basin, which is probably latest Middle Permian (Capitanian)
in age. This mycterosaurine is not only the youngest known varanopid from the Southern Hemisphere, but it is also the youngest
known “pelycosaur” (i.e., non-therapsid synapsid). Like all other members of this clade of hypercarnivores, the teeth are
strongly flattened, recurved, and have finely serrated cutting edges. The anterior dentary teeth form a caniniform region,
and the splenial features a foramen intermandibularis oralis, the first ever to be described in a “pelycosaur.” The last varanopids
were the smallest carnivores of latest Middle Permian continental faunas. Occupation of the small carnivore guild appears
to have allowed varanopids to achieve a nearly cosmopolitan distribution throughout the Middle Permian, between the great
Early Permian radiation of basal synapsids and the spectacular diversification of therapsid synapsids in the Late Permian
and Early Triassic. 相似文献
5.
Kohko Tokushige Keigo Akimoto Toshimasa Tomoda 《Mitigation and Adaptation Strategies for Global Change》2007,12(7):1237-1251
CO2 geological storage will be one of the cost-effective options for global warming mitigation, and this technology is under
development widely in the world. However, the technology may face the challenge of public acceptance before its implementation.
In order to evaluate the public acceptance, questionnaire surveys were conducted among Japanese university students. A cognitive
map of geological storage, together with other major global warming mitigation options, everyday life activities, etc., was
constructed by means of a statistical analysis of the responses to the questionnaire. The risk-benefit cognitive map consists
of the following factors: “risk perception,” “benefit perception,” and “public acceptance.” The risk perception is further
disaggregated into “dread risk” and “unknown risk.” Additionally, a second survey was conducted after providing the students
with additional information on global warming and CO2 geological storage, and the effects of the information on their perceptions were evaluated. The effects of risk and benefit
perceptions on public acceptance were evaluated and discussed based on the cognitive maps representing the perceptions before
and after providing the information. The analyses revealed that the benefit perception was more influential than the risk
perception on the public acceptance of CO2 geological storage. The benefit perception increased greatly after providing the information; however, the unknown risk remained
considerably large. Further, RD&D relating unknown risk, for example, the monitoring technology for stored CO2 and the risk assessment of CO2 leakage, and the supply of related information to the public would be beneficial for increasing the public acceptance. 相似文献
6.
The evolution of winged stick insects (phasmids) from secondarily wingless ancestors was proposed in recent studies. We explored
the cuticle of flying phasmids for wind sensors that could be involved in their flight control, comparable to those known
for locusts. Surprisingly, wind-sensitive hairs (wsH) occur on the palps of mouthparts and on the antennae of the winged phasmid
Sipyloidea sipylus which can fly in tethered position only when air currents blow over the mouthparts. The present study describes the morphology
and major functional properties of these “new” wsH with soft and bulging hair bases which are different from the beaker-like
hair bases of the wsH on the cerci of phasmids and the wsH described in other insects. The most sensitive wsH of antennae
and palps respond with phasic-tonic afferents to air currents exceeding 0.2 ms−1. The fields of wsH on one side of the animal respond mainly to ventral, lateral, and frontal wind on the ipsilateral side
of the head. Afferent inputs from the wsH converge but also diverge to a group of specific interneurons at their branches
in the suboesophageal ganglion and can send their integrated input from wsH fields of the palps and antennae to the thoracic
central nervous system. Response types of individual wsH-interneurons are either phasic or phasic-tonic to air puffs or constant
air currents and also, the receptive fields of individual interneurons differ. We conclude that the “new” wsH system and its
interneurons mainly serve to maintain flight activity in airborne phasmids and also, the “new” wsH must have emerged together
with the integrating interneurons during the evolution from wingless to the recent winged forms of phasmids. 相似文献
7.
Xia Xinghui Meng Lihong Hu Lijuan 《Frontiers of Environmental Science & Engineering in China》2007,1(2):172-178
Experiments have been carried out to study the sorption of Benzo(a)pyrene(Bap) on sediment particles from the Yellow River
using a batch equilibration technique. Effects of particle size on the adsorption and partition of Bap were investigated with
the particle content of 3 g/L. Several significant results were obtained from the study. (1) Isotherms of Bap could be fitted
with the dual adsorption-partition model under different particle sizes, and the measured value of the adsorption and partition
was in agreement with the theoretical value of the dual adsorption-partition model. (2) When the particle diameter was d ⩾ 0.025 mm, the adsorption was predominant in the sorption of Bap, which accounted for 68.7%–82.4% of the sorption. For the
particles with the size of 0.007 mm⩽d<0.025 mm, the adsorption was predominant when the equilibrium concentration of Bap was 0–8.87 μg/L in the water phase; and
the partition was predominant when the equilibrium concentration of Bap was higher than 8.87 μg/L in the water phase. When
the particle diameter was d<0.007 mm, the partition was predominant. (3) On the point of particle size, the contribution of adsorption to sorption followed
the order: “d⩾0.025 mm”>“0.007 mm ⩽d<0.025 mm” >“d<0.007 mm”. (4) The partition coefficients of Bap in solids with different particle sizes were linearly correlated with the
organic content, and the K
oc of Bap was about 1.26 × 105 (L/kg).
Translated from Acta Scientiae Circumstantiae, 2006, 26(2): 269–274 [译自: 环境科学学报] 相似文献
8.
Sexually aberrant individuals, displaying both male and female characteristics, are rare in occurrence but are documented
throughout the animal kingdom. In parasitoid wasps of the genus Trichogramma, such individuals typically appear as a result of rearing Wolbachia-infected thelytokous wasps at high temperatures. Sexually aberrant Trichogramma have been referred to interchangeably in the literature as gynandromorphs, sexual mosaics and intersexes. However, accurately
used, the terms “gynandromorph” and “sexual mosaic” describe an individual composed of a mixture of genetically distinct tissues
corresponding to the sexual phenotypes observed, while “intersex” refers to an individual having a uniform genetic constitution
but with some tissues exhibiting sexual phenotypes conflicting with the associated genotype. Here, we investigate the heat-induced
production of sexually aberrant offspring by thelytokous Trichogramma kaykai. Aberrant individuals were rare, but each was characterized as one of 11 morphotypes ranging from very feminine to very masculine.
Overall, the production of aberrant individuals increased with time from the onset of maternal oviposition. However, while
the production of males also increased with time, the degree of masculinity of aberrant individuals did not; the different
morphotypes appeared to be produced haphazardly. We conclude that the aberrant individuals produced by T. kaykai are actually intersexes and not gynandromorphs. The wasp's close association with Wolbachia and the absence of intersexes in uninfected populations allow us to discuss a possible origin of the condition. 相似文献
9.
Several stages, from eggs to adults, of the water strider, Aquarius paludum (Fabricius), inhabiting fresh water are sometimes conveyed by heavy flow in the rainy or typhoon seasons in Japan to lotic
brackish water in the mouth of rivers. The water striders might then respond to salinity either by remaining to wait for extensive
rainfall to reduce osmotic pressure locally before reproducing (“breed here and later tactic”) or by flying away to reproduce
in fresh waters elsewhere (“breed elsewhere and later tactic”). All first instars died before the first molt when they were
exposed to 1.75 and 3.5% NaCl solutions in a laboratory experiment. Living on 0.5 and 0.9% solutions through larval and adult
stages slowed down larval growth and suppressed female reproduction. When exposed to the 0.5 and 0.9% solutions, 90 and 92%
of males, respectively, showed histolysis of their flight muscles. Therefore, in brackish natural habitats, larvae and adults
seem to follow the strategy “breed here and later.” When water striders were exposed to 0.9% solution either just after emergence
or 20 days later, females showed a higher flight propensity than those kept on fresh waters throughout, and they delayed the
deposition of eggs. Therefore, when conveyed to brackish water after emergence by stream flow after heavy rain, adults seem
to leave the area by flight, demonstrating the strategy “breed elsewhere and later” tactic. We conclude that water striders
use alternative tactics for responding to salinity, depending on the stage of exposure. 相似文献
10.
Kaatz FH 《Die Naturwissenschaften》2006,93(8):374-378
A method that explains how to quantify the amount of order in “ordered” and “highly ordered” porous arrays is derived. Ordered arrays from bee honeycomb and several from the general field of nanoscience are compared. Accurate measures of the order in porous arrays are made using the discrete radial distribution function (RDF). Nanoporous anodized aluminum oxide (AAO), hexagonal arrays from functional materials, hexagonal arrays from nanosphere lithography, and square arrays defined by interference lithography (all taken from the literature) are compared to two-dimensional model systems. These arrays have a range of pore diameters from ∼60 to 180 nm. An order parameter, OP
3
, is defined to evaluate the total order in a given array such that an ideal network has the value of 1. When we compare RDFs of man-made arrays with that of our honeycomb (pore diameter ∼5.89 mm), a locally grown version made by Apis
mellifera without the use of foundation comb, we find OP
3
=0.399 for the honeycomb and OP
3
=0.572 for man’s best hexagonal array. The nearest neighbor peaks range from 4.65 for the honeycomb to 5.77 for man’s best hexagonal array, while the ideal hexagonal array has an average of 5.93 nearest neighbors. Ordered arrays are now becoming quite common in nanostructured science, while bee honeycombs were studied for millennia. This paper describes the first method to quantify the order found in these arrays with a simple yet elegant procedure that provides a precise measurement of the order in one array compared to other arrays. 相似文献
11.
In an attempt to better understand the mechanism underlying lateral collision avoidance in flying insects, we trained honeybees
(Apis mellifera) to fly through a large (95-cm wide) flight tunnel. We found that, depending on the entrance and feeder positions, honeybees
would either center along the corridor midline or fly along one wall. Bees kept following one wall even when a major (150-cm
long) part of the opposite wall was removed. These findings cannot be accounted for by the “optic flow balance” hypothesis
that has been put forward to explain the typical bees’ “centering response” observed in narrower corridors. Both centering
and wall-following behaviors are well accounted for, however, by a control scheme called the lateral optic flow regulator, i.e., a feedback system that strives to maintain the unilateral optic flow constant. The power of this control scheme is
that it would allow the bee to guide itself visually in a corridor without having to measure its speed or distance from the
walls. 相似文献
12.
Male cockroaches of the species Elliptorhina chopardi expel air through a pair of modified abdominal spiracles during courtship. This air expulsion simultaneously produces air and substrate-borne vibrations. We described and compared in details these two types of vibrations. Our analysis of the air-borne signals shows that males can produce three categories of signals with distinct temporal and frequency parameters. “Pure whistles” consist of two independent harmonic series fast frequency modulated with independent harmonics that can cross each other. “Noisy whistles” also possess two independent voices but include a noisy broad-band frequency part in the middle. Hiss sounds are more noise-like, being made of a broad-band frequency spectrum. All three call types are unusually high in dominant frequency (>5 kHz) for cockroaches. The substrate-borne signals are categorised similarly. Some harmonics of the substrate-borne signals were filtered out, however, making the acoustic energy centered on fewer frequency bands. Our analysis shows that cockroach signals are complex, with fast frequency modulations and two distinct voices. These results also readdress the question of what system could potentially receive and decode the information contained within such complex sounds.Electronic supplementary material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
13.
Schröder HC Brandt D Schlossmacher U Wang X Tahir MN Tremel W Belikov SI Müller WE 《Die Naturwissenschaften》2007,94(5):339-359
Biomineralization, biosilicification in particular (i.e. the formation of biogenic silica, SiO2), has become an exciting source of inspiration for the development of novel bionic approaches following “nature as model”.
Siliceous sponges are unique among silica forming organisms in their ability to catalyze silica formation using a specific
enzyme termed silicatein. In this study, we review the present state of knowledge on silicatein-mediated “biosilica” formation
in marine sponges, the involvement of further molecules in silica metabolism and their potential application in nanobiotechnology
and medicine.
Werner E. G. Müller dedicated this study to Prof. Vera Gamulin (Rudjer Boskovic Institute, Zagreb, Croatia) in honour of her
unique contributions in molecular evolution. 相似文献
14.
Grohé C Chaimanee Y de Bonis L Yamee C Blondel C Jaeger JJ 《Die Naturwissenschaften》2010,97(11):1003-1015
We report new dental remains of Mustelidae from the late middle Miocene of Mae Moh Basin, northern Thailand, improving the
poor fossil record of the family in Southeast Asia. Siamogale thailandica is a poorly known mustelid, previously recorded from just a single tooth. Here we present over a hundred new specimens attributable
to this species. S. thailandica shows a combination of primitive and convergent features of the dentition that makes its original subfamilial assignment
to Lutrinae doubtful. Evidence from the dental morphology suggests that it belongs to a bunodont otter-like mustelid that
evolved in convergence with “true” otters (Lutrinae) toward a semi-aquatic way of life. Autapomorphic features such as the
height and the position of the m1 metaconid and the shape of the P4 lingual shelf make S. thailandica unique among Mustelidae. The morphology of this species is mostly similar to Mionictis species and Lartetictis dubia, reported in the Miocene of North America and Europe, respectively. These similarities could imply immigration events to
Thailand in the early or middle Miocene. Alternately, the lineage leading to Siamogale might have deeper origins from an endemic early Miocene Southeast Asian mustelid. 相似文献
15.
Wolfgang Wiltschko Lars Dehe Katrin Stapput Peter Thalau Roswitha Wiltschko 《Die Naturwissenschaften》2010,97(1):37-42
Under 502 nm turquoise light combined with 590 nm yellow light and in total darkness, European robins, Erithacus rubecula, no longer prefer their migratory direction, but exhibit so-called fixed direction responses that do not show the seasonal
change between spring and autumn. We tested robins under these light conditions in the local geomagnetic field of 46 μT, a
field of twice this intensity, 92 μT, and a field of three times this intensity, 138 μT. Under all three magnetic conditions,
the birds preferred the same easterly direction under turquoise-and-yellow light and the same northwesterly direction under
dark, while they were oriented in their seasonally appropriate direction under control conditions. “Fixed direction” responses
are thus not limited to a narrow intensity window as has been found for normal compass orientation. This can be attributed
to their origin in the magnetite-based receptor in the upper beak, which operates according to fundamentally different principles
than the radical pair mechanism in the retina mediating compass orientation. “Fixed direction” responses are possibly a relict
of a receptor mechanism that changed its function, now mainly providing information on magnetic intensity. 相似文献
16.
R. D. Lasco M. M. Cardinoza 《Mitigation and Adaptation Strategies for Global Change》2007,12(2):243-257
Climate change is one of the most pressing environmental problems humanity is facing today. Forest ecosystems serve as a source
or sink of greenhouse gases, primarily CO2. With support from the Canadian Climate Change Fund, the Community-based Natural Resource Management for Carbon Sequestration
project in East Timor (CBNRM-ET) was implemented to “maintain carbon (C) stocks and increase C sequestration through the development
of community-based resource management systems that will simultaneously improve livelihood security”. Project sites were in
the Laclubar and Remexio Sub-districts of the Laclo watershed. The objective of this study was to quantify baseline C stocks
and sequestration benefits of project components (reforestation with fast-growing species, primarily Casuarina equisetifolia, and agroforestry involving integration of Paraserianthes falcataria). Field measurements show that mature stands (≥30 years) of P. falcataria and C. equisetifolia contain up to 200 Mg C ha−1 in above ground biomass, indicating the vast potential of project sites to sequester carbon. Baseline C stocks in above ground
biomass were very low in both Laclubar (6.2 Mg C ha−1 for reforestation sites and 5.2 Mg C ha−1 for agroforestry sites and Remexio (3.0 Mg C ha−1 for reforestation and 2.5 Mg C ha−1 for agroforestry). Baseline soil organic C levels were much higher reaching up to 160 Mg C ha−1 in Laclubar and 70 Mg C ha−1 in Remexio. For the next 25 years, it is projected that 137 671 Mg C and 84 621 Mg C will be sequestered under high- and
low C stock scenarios, respectively. 相似文献
17.
The “Linh Duong” (Pseudonovibos spiralis), a newly described Vietnamese bovid, has been shown to be related to the Caprinae on the basis of the mitochondrial cytochrome
b gene sequencing from horn fragments. To integrate the greatest available biodiversity we performed a new phylogenetic analysis
including all genera of Caprinae. Unexpectedly, Pseudonovibos is found to be robustly associated with Rupicapra, and closer to the Alpine than to the Pyrenean chamois. Several clues led us to interpret this result as a carry-over DNA
contamination of Pseudonovibos by Rupicapra.
Received: 19 July 1999 / Accepted in revised form: 20 October 1999 相似文献
18.
Doug M. Boyer Guntupalli V. R. Prasad David W. Krause Marc Godinot Anjali Goswami Omkar Verma John J. Flynn 《Die Naturwissenschaften》2010,97(4):365-377
Extant species of the supraordinal mammal clade Euarchonta belong to the orders Primates, Scandentia, or Dermoptera. The fossil
record of euarchontans suggests that they underwent their initial radiation during the Paleocene (65–55 million years ago)
in North America, Eurasia, and Africa. The time and place of origin is poorly resolved due to lack of definitive fossils of
euarchontan stem taxa. We describe a fragmentary humerus and two fragmentary ulnae from the latest Cretaceous of India that
bear significantly on this issue. The fossils are tentatively referred to Deccanolestes cf. hislopi due to their small size and the fact that Deccanolestes is the only eutherian dental taxon to have been recovered from the same locality. The new fossils are used to evaluate the
existing behavioral hypothesis that Deccanolestes was arboreal, and the competing phylogenetic hypotheses that Deccanolestes is a stem eutherian versus a stem euarchontan. The humerus resembles those of euarchontans in possessing a laterally keeled
ulnar trochlea, a distinct zona conoidea, and a spherical capitulum. These features also suggest an arboreal lifestyle. The
ulnar morphology is consistent with that of the humerus in reflecting an arboreal/scansorial animal. Detailed quantitative
comparisons indicate that, despite morphological correlates to euarchontan-like arboreality, the humerus of Deccanolestes is morphologically intermediate between those of Cretaceous “condylarthran” mammals and definitive Cenozoic euarchontans.
Additionally, humeri attributed to adapisoriculids are morphologically intermediate between those of Deccanolestes and definitive euarchontans. If adapisoriculids are euarchontans, as recently proposed, our results suggest that Deccanolestes is more basal. The tentative identification of Deccanolestes as a basal stem euarchontan suggests that (1) Placentalia began to diversify and Euarchonta originated before the Cretaceous–Tertiary
boundary and (2) the Indian subcontinent, Eurasia, and Africa are more likely places of origin for Euarchonta than is North
America. 相似文献
19.
Wolfgang Priester (1924–2005) was one of Germany’s most versatile and quixotic astrophysicists, reinventing himself successively
as a radio astronomer, space physicist and cosmologist, and making a lasting impact on each field. We focus in this personal
account on his contributions to cosmology, where he will be most remembered for his association with quasars, his promotion
of the idea of a nonsingular “big bounce” at the beginning of the current expansionary phase, and his recognition of the importance
of dark energy (Einstein’s cosmological constant Λ) well before this became the standard paradigm in cosmology.
In memoriam Wolfgang Priester, 22 April 1924 – 9 July 2005 相似文献
20.
A new mass estimate for the dodo (Raphus cucullatus), based on the lengths of the femur, tibiotarsus and tarsometatarsus, is attempted. The obtained mean mass is 10.2 kg, which
is less than previous estimates based on other methods, which ranged from 10.6 to 21.1 kg, and much lower than the 50 lbs
reported by a seventeenth-century eyewitness. The new estimated mass, which is similar to that of a large wild turkey, seems
more realistic than previous ones and supports the hypothesis that contemporary illustrations of extremely fat dodos were
either exaggerations, or based on overfed specimens. Pictures of “fat” dodos may also have been based on individuals exhibiting
a display behaviour with puffed out feathers. 相似文献