共查询到20条相似文献,搜索用时 453 毫秒
1.
The myrmicine ant Mayriella overbecki lays recruitment trails during foraging and nest emigrations. The trail pheromone originates from the poison gland. From
ten identified components of the poison gland secretions only methyl 6-methylsalicylate 1 elicited trail following behavior.
Received: 6 April 2000 / Accepted in revised form: 6 June 2000 相似文献
2.
The behavioral response of the obligate bamboo-nesting ant Cataulacus muticus to nest flooding was studied in a perhumid tropical rainforest in Malaysia and in the laboratory. The hollow internodes of
giant bamboo, in which C. muticus exclusively nests, are prone to flooding by heavy rains. The ants showed a two-graded response to flooding. During heavy
rain workers block the nest entrances with their heads to reduce water influx. However, rainwater may still intrude into the
nest chamber. The ants respond by drinking the water, leaving the nest and excreting water droplets on the outer stem surface.
This cooperative 'peeing' behavior is a new survival mechanism adaptive to the ants' nesting ecology. Laboratory experiments
conducted with two other Cataulacus species, C. catuvolcus colonizing small dead twigs and C. horridus inhabiting rotten wood, did not reveal any form of water-bailing behavior.
Received: 3 August 2000 / Accepted in revised form: 6 November 2000 相似文献
3.
A new ant species of Megalomyrmex conducts mass raids to usurp gardens of the fungus-growing ant Cyphomyrmex longiscapus, then lives in the gardens and consumes the cultivated fungus. Unlike attine ants, however, Megalomyrmex sp. does not forage for substrate to manure the gardens; therefore, when gardens become depleted, Megalomyrmex sp. must locate and usurp new gardens. Megalomyrmex sp. workers feed their larvae with attine brood, but only after removing the fungal mycelium that covers the attine larval integument,
suggesting that this fungal coat may provide partial protection against other predators. Unlike other known Megalomyrmex species, which coexist as social parasites in attine colonies, Megalomyrmex sp. expels its attine hosts during the garden raids. Megalomyrmex sp. thus maintains a unique agro-predatory lifestyle that is described here for the first time.
Received: 18 August 2000 / Accepted in revised form: 1 November 2000 相似文献
4.
Gries R Gries G Khaskin G King S Olfert O Kaminski LA Lamb R Bennett R 《Die Naturwissenschaften》2000,87(10):450-454
Pheromone extract of the female orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (SM) (Diptera: Cecidomyiidae), was analyzed by coupled gas chromatographic-electroantennographic detection (GC-EAD)
and GC-mass spectrometry (MS), employing fused silica columns coated with DB-5, DB-210, DB-23 or SP-1000. These analyses revealed
a single, EAD-active candidate pheromone which was identified as 2,7-nonanediyl dibutyrate. In experiments in wheat fields
in Saskatchewan, traps baited with (2S,7S)-2,7-nonanediyl dibutyrate attracted significant numbers of male SM. The presence of other stereoisomers did not adversely
affect trap captures. Facile synthesis of stereoisomeric 2,7-nonanediyl dibutyrate will facilitate the development of pheromone-based
monitoring or even control of SM populations.
Received: 2 March 2000 / Accepted in revised form: 18 August 2000 相似文献
5.
The ant Eutetramorium mocquerysi (Myrmicinae) is endemic to the island of Madagascar. During foraging and nest emigration the ants lay recruitment trails
with secretions from the poison gland. We identified three pyrazine compounds in the poison gland secretion: 2,3-dimethyl-5-(2-methylpropyl)pyrazine
1, 2,3-dimethyl-5-(3-methylbutyl)pyrazine 3, 2,3-dimethyl-5-(2-methylbutyl)pyrazine 4. Only the first component elicited trail-following behavior in the ants. We were unable to investigate whether the other
pyrazine components have a synergistic function.
Received: 21 February 2000 / Accepted in revised form: 27 June 2000 相似文献
6.
Hariyama T 《Die Naturwissenschaften》2000,87(7):327-330
This paper deals with the structure and function of the intracerebral ocelli in the caudal area of the brain of the Japanese
firefly. A pair of epilaterally placed specialized pigmented organs was found at the caudal ends of the brains of the fireflies
Luciola cruciata and L. lateralis. On the basis of light and transmission electron micrographs of both male and female individuals these organs seemed photoreceptive
in nature. Intracellular and extracellular recordings were obtained from the intracerebral ocelli of the fireflies with microelectrodes.
The physiological evidence revealed that the cells found in the brain were, indeed, photoreceptors.
Received: 7 April 2000 / Accepted in revised form: 16 June 2000 相似文献
7.
Flavonoid wing pigments increase attractiveness of female common blue (Polyommatus icarus) butterflies to mate-searching males 总被引:1,自引:0,他引:1
Common blue butterflies (Polyommatus icarus) sequester flavonoids from their larval host plants and allocate these UV-absorbing pigments to the wings. In field experiments
using dummies constructed from female butterflies, mate-searching males inspected flavonoid-rich dummies more intensively
than those with little or no flavonoids. Flavonoid content as signalled by UV-wing pattern may indicate ontogenetically determined
female quality or enhance detectability to males.
Received: 21 March 2000 / Accepted in revised form: 17 May 2000 相似文献
8.
Fossils from the central Transantarctic Mountains in Antarctica are referred to a new species of the Triassic genus Kombuisia, one of four dicynodont lineages known to survive the end-Permian mass extinction. The specimens show a unique combination
of characters only present in this genus, but the new species can be distinguished from the type species of the genus, Kombuisia frerensis, by the presence of a reduced but slit-like pineal foramen and the lack of contact between the postorbitals. Although incomplete,
the Antarctic specimens are significant because Kombuisia was previously known only from the South African Karoo Basin and the new specimens extend the taxon’s biogeographic range
to a wider portion of southern Pangaea. In addition, the new finds extend the known stratigraphic range of Kombuisia from the Middle Triassic subzone B of the Cynognathus Assemblage Zone into rocks that are equivalent in age to the Lower Triassic Lystrosaurus Assemblage Zone, shortening the proposed ghost lineage of this taxon. Most importantly, the occurrence of Kombuisia and Lystrosaurus mccaigi in the Lower Triassic of Antarctica suggests that this area served as a refuge from some of the effects of the end-Permian
extinction. The composition of the lower Fremouw Formation fauna implies a community structure similar to that of the ecologically
anomalous Lystrosaurus Assemblage Zone of South Africa, providing additional evidence for widespread ecological disturbance in the extinction’s
aftermath. 相似文献
9.
Volatiles from leaves or bark of nonhost birch (Betula pendula) and Norway spruce (Picea abies) dramatically reduced the attraction of the bark beetle, Pityogenes bidentatus (Coleoptera: Scolytidae), to their aggregation pheromone components (cis-verbenol and grandisol) in the field. In addition, odors from both the needles and bark of the host Scots pine (Pinus sylvestris) similarly inhibited attraction. Monoterpenes of pine and spruce (α-pinene, β-pinene, terpinolene, and 3-carene) as well
as ethanol, chalcogran and some nonhost green leaf alcohols [(Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, and 1-hexanol], also reduced catches. Collections of volatiles from the field-tested plant tissues indicated
they released monoterpenes in amounts similar to the synthetics that inhibited responses. The various plant and insect sources
of these inhibitory compounds indicate that P. bidentatus bark beetles have evolved several strategies to increase their fitness by avoiding nonhost and unsuitable host trees in a
complex olfactory landscape.
Received: 6 June 2000 / Accepted in revised form: 25 September 2000 相似文献
10.
Honeybees, Apis spp., maintain elevated temperatures inside their nests to accelerate brood development and to facilitate defense against predators.
We present an additional defensive function of elevating nest temperature: honeybees generate a brood-comb fever in response
to colonial infection by the heat-sensitive pathogen Ascosphaera apis. This response occurs before larvae are killed, suggesting that either honeybee workers detect the infection before symptoms
are visible, or that larvae communicate the ingestion of the pathogen. This response is a striking example of convergent evolution
between this "superorganism" and other fever-producing animals.
Received: 2 September 1999 / Accepted in revised form: 28 February 2000 相似文献
11.
The Australian buprestid beetle Merimna atrata (Coleoptera: Buprestidae) approaches forest fires because its larvae develop in freshly burnt wood. So far nothing is known
about possible sensory systems enabling the beetles to detect fires and to cope with the thermal environment close to the
flames. We found that M. atrata has two pairs of infrared (IR) organs on the ventrolateral sides of the abdomen. Each IR organ consists of a specialized
IR-absorbing area which is innervated by one thermosensitive multipolar neuron. The primary dendritic branches ramify into
more than 800 closely packed terminal endings which contain a large number of mitochondria. We called the special morphology
of the dendritic region a terminal dendritic mass. The type of IR receptor found in M. atrata is unique in insects and can best be compared with the IR organs of boid snakes.
Received: 14 August 2000 / Accepted in revised form: 18 October 2000 相似文献
12.
Reddy PS 《Die Naturwissenschaften》2000,87(12):535-538
The possible involvement of an endogenous opioid system in the regulation of ovarian development in the prawn Penaeus indicus was investigated. Injection of leucine-enkephalin significantly increased the ovarian index and oocyte diameter in a dose-dependent
manner. In contrast, injection of methionine-enkephalin significantly decreased the ovarian index and oocyte diameters. These
results provide evidence to support the hypothesis that an opioid system is involved in the regulation of reproduction in
crustaceans.
Received: 25 July 2000 / Accepted in revised form: 9 October 2000 相似文献
13.
Mycotoxin-producing fungi were isolated from contaminated grains of rice, pulses and oilseeds sold in the local markets of
Calcutta for human consumption. It was found that aflatoxin B1 was produced by Aspergillus flavus and Aspergillus parasiticus, aflatoxin G1 by A. flavus, ochratoxin by Aspergillus ochraceous, sterigmatocystin by Aspergillus japonicus and citrinin by Penicillium citrinum. Aflatoxin B1 (333–10416 μg/kg) was produced by Aspergillus spp. in rice, pulses and oilseeds.
Received: 11 May 1999 / Accepted in revised form: 10 April 2000 相似文献
14.
The Middle Pleistocene site at Bilzingsleben is being excavated by the Forschungsstelle Bilzingsleben, FSU Jena. It is a
living floor with structures of settlement and a great number of Lower Palaeolithic cultural remains. So far, 28 human skull
fragments have been discovered, which can be reconstructed into two individual skulls. Recently, the right mandible has also
been discovered (Bilzingsleben E7). Morphological comparisons indicate that there is a great similarity to the mandibles of
HI and BI of Sinanthropus. A strong likeness to Arago II and XIII was also discovered. There are various different archaic features which assign the
Bilzingsleben mandible and the two skulls to the advanced Homo erectus.
Received: 16 March 2000 / Accepted in revised form: 30 March 2000 相似文献
15.
We determined chitinase activity in leaves of four myrmecophytic and four non-myrmecophytic leguminous species at the plants'
natural growing sites in Mexico. Myrmecophytic plants (or 'ant plants') have obligate mutualisms with ants protecting them
against herbivores and pathogenic fungi. Plant chitinases can be considered a reliable measure of plant resistance to pathogenic
fungi. The myrmecophytic Acacia species, which were colonised by mutualistic ants, exhibited at least six-fold lower levels of chitinase activity compared
with the non-myrmecophytic Acacia farnesiana and three other non-myrmecophytes. Though belonging to different phylogenetic groups, the myrmecophytic Acacia species formed one distinct group in the data set, which was clearly separated from the non-myrmecophytic species. These
findings allowed for comparison between two recent hypotheses that attempt to explain low chitinase activity in ant plants.
Most probably, chitinases are reduced in myrmecophytic plant species because these are effectively defended indirectly due
to their symbiosis with mutualistic ants.
Received: 16 August 2000 / Accepted in revised form: 28 October 2000 相似文献
16.
Micrographs of retinas from the deep-sea fish Cataetyx laticeps revealed visual cells containing membranous whorls in the ellipsoids of the inner segments resulting from stretching and
modifications of the mitochondria membranes and their cristae. These pathological structures seem to be homologous to the
whorls observed in retinas of human carriers of Tay-Sachs disease. This disease, a genetic disorder, is found in humans and
some mammals. Our findings in fish suggest that the gene responsible can be found throughout the vertebrate evolutionary tree,
possibly dormant in most taxa.
Received: 20 April 2000 / Accepted in revised form: 16 June 2000 相似文献
17.
Queenless workers of the Cape honeybee (Apis mellifera capensis) can develop into reproductives termed pseudoqueens. Although they morphologically remain workers they become physiologically
queenlike, produce offspring, and secrete mandibular gland pheromones similar to those of true queens. However, after queen
loss only very few workers gain pseudoqueen status. A strong intracolonial selection governs which workers start oviposition
and which remain sterile. The “queen substance”, 9-keto-2(E)-decenoic acid (9-ODA), the dominant compound of the queen's mandibular
gland pheromones, suppresses the secretion of queenlike mandibular gland pheromones in workers. It may act as an important
signal in pseudoqueen selection. By analysing the mandibular gland pheromones of workers kept in pairs, we found that A. m. capensis workers compete to produce the strongest queen-like signal.
Received: 2 July 2000 / Accepted in revised form: 28 July 2000 相似文献
18.
To determine whether the harvester ant Messor barbarus acts as a seed disperser in Mediterranean grasslands, the accuracy level of seed processing was assessed in the field by
quantifying seed drops by loaded foragers. In the vicinity of exploited seed patches 3 times as many diaspores were found
as in controls due to seed losses by foragers. Over trails, up to 30% of harvested seeds were dropped, singly, by workers
but all were recovered by nestmates within 24 h. Seeds were also dropped within temporary caches with very few viable diaspores
being left per cache when ants no longer used the trail. Globally, ant-dispersed diaspores accounted for only 0.1% of seeds
harvested by M. barbarus. We discuss the possible significance for grassland vegetation of harvester-ant-mediated seed dispersal.
Received: 26 January 2000 / Accepted in revised form: 20 June 2000 相似文献
19.
Self-diffusion coefficients were studied for the highly polar liquid N-methylformamide at pressures up to 200 MPa between the melting pressure curves and 420 K by the spin-echo method. N-Methylformamide exists as a mixture of two conformers in the neat liquid. These conformers have large differences at lower
temperatures in their dynamic and structural properties. The self-diffusion coefficient of the cis-conformer being 17% lower than that of the trans-conformer at the same T and p. This is the first observation of such an effect. The experimental study is supported by Monte Carlo (MC) calculations which
show that the first neighbors around a cis conformer are arranged differently than in an all trans liquid. The difference leads in the simulations to a much lower dielectric constant for the trans-cis mixture and might also explain the retardation of diffusion for the cis conformer.
Received: 15 November 1999 / Accepted in revised form: 28 February 2000 相似文献
20.
A factor separation technique and an improved regional air quality model (RAQM) were applied to calculate synergistic contributions of anthropogenic volatile organic compounds (AVOCs),biogenic volatile organic compounds (BVOCs) and nitrogen oxides (NOx) to daily maximum surface O3(O3DM) concentrations in East Asia in summer (June to August 2000).The summer averaged synergistic impacts of AVOCs and NOx are dominant in most areas of North China,with a maximum of 60 ppbv,while those of BVOCs and NOx are notable only in some limited areas with high BVOC emissions in South China,with a maximum of 25 ppbv.This result implies that BVOCs contribute much less to summer averaged O3DM concentrations than AVOCs in most areas of East Asia at a coarse spatial resolution (1×1) although global emissions of BVOCs are much greater than those of AVOCs.Daily maximum total contributions of BVOCs can approach 20 ppbv in North China,but they can reach 40 ppbv in South China,approaching or exceeding those in some developed countries in Europe and North America.BVOC emissions in such special areas should be considered when O3 control measures are taken.Synergistic contributions among AVOCs,BVOCs and NOx significantly enhance O3 concentrations in the Beijing-Tianjin-Tangshan region and decrease them in some areas in South China.Thus,the total contributions of BVOCs to O3DM vary significantly from day to day and from location to location.This result suggests that O3 control measures obtained from episodic studies could be limited for long-term applications. 相似文献