Elektronenmikroskopische Untersuchungen an der Perikaryenschicht der Corpora pedunculata der Waldameise (Formica lugubris Zett.) Mit besonderer Ber�cksichtigung der Neuron-Glia-Beziehung

1965 ◽  
Vol 66 (5) ◽  
pp. 701-736 ◽  
Author(s):  
Alex M. Landolt
Keyword(s):  
Corpora Pedunculata ◽  
Formica Lugubris

scholarly journals ELECTRON MICROSCOPE STUDIES ON SOMA-SOMATIC INTERNEURONAL JUNCTIONS IN THE CORPUS PEDUNCULATUM OF THE WOOD ANT (FORMICA LUGUBRIS ZETT.)

1966 ◽  
Vol 28 (2) ◽  
pp. 391-403 ◽  
Author(s):  
Alex M. Landolt ◽  
Hans Ris
Keyword(s):  
Dynamic Properties ◽  
Average Diameter ◽  
Striking Similarity ◽  
Close Proximity ◽  
Corpora Pedunculata ◽  
Average Surface Area ◽  
A Subunit ◽  
Transfer Of Information ◽  
Formica Lugubris ◽  
Neuron Pool

1. The corpora pedunculata of the wood ant (Formica lugubris Zett.) contain densely packed neuron perikarya which are separated by ultrathin glial sheaths. 2. These glial sheaths are occasionally interrupted by round holes with an average surface area of 2.64 µ2. The holes are designated glial windows since they represent intracellular gaps of glial cytoplasm. 3. The glial windows allow soma-somatic interneuronal junctions. Of all adjacent neurons in a selected neuron pool, only 42% were interconnected by such junctions. 4. The intercellular space at the soma-somatic junctions has an average diameter of 30 A; occasionally, it is collapsed and an external compound membrane ensues. The junctional membranes are characterized by the presence of a subunit pattern of cross-directional electron-opaque lines with a 50- to 70-A periodicity. 5. Morphological signs of chemical transmission are absent in these junctions. On the other hand, there is a striking similarity in structural organization between soma-somatic junctions and electrical synapses described in other species. Therefore, it is suggested that these cell contacts of the ant's "cerebral cortex" are another form of electrical junction. 6. The close proximity of the junctions to the cell nucleus is noted. Its significance could not be ascertained. 7. The suggestion is made that glial windows may have dynamic properties and may intervene in the regulation of interneuronal transfer of information.

Corpora Pedunculata

2008 ◽  
pp. 1074-1074
Author(s):  
Beata Gabrys ◽  
John L. Capinera ◽  
Jesusa C. Legaspi ◽  
Benjamin C. Legaspi ◽  
Lewis S. Long ◽  
...  
Keyword(s):  
Corpora Pedunculata

The distribution of wood-ants (Formica lugubris Zetterstedt) in a northern English forest

1977 ◽  
Vol 2 (4) ◽  
pp. 301-313 ◽  
Author(s):  
J. H. SUDD ◽  
J. M. DOUGLAS ◽  
T. GAYNARD ◽  
D. M. MURRAY ◽  
J. M. STOCKDALE
Keyword(s):  
Wood Ants ◽  
Formica Lugubris

Carbohydrates as Energy Source during the Flight of Sexuals of the Ant Formica lugubris (Hymenoptera: Formicidae)

1990 ◽  
Vol 15 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Luc Passera ◽  
Laurent Keller ◽  
Anne Grimal ◽  
Dominique Chautems ◽  
Daniel Cherix ◽  
...  
Keyword(s):  
Energy Source ◽  
Formica Lugubris

The anatomy of the nervous system in the genus Gerris (Hemiptera-Heteroptera)

1961 ◽  
Vol 244 (708) ◽  
pp. 65-102 ◽  
Keyword(s):  
Nervous System ◽  
Close Association ◽  
Muscle Fibres ◽  
Functional Regions ◽  
Corpora Pedunculata ◽  
Staining Methods ◽  
Degree Of Condensation ◽  
The Many ◽  
The One ◽  
Object Of Study

The most successful methods used in this study were Palmgren’s silver-on-the-slide technique, the rapid silver nitrate method of Golgi, and a method that has seldom been applied to insect material, the Golgi-Cox mercuric chloride method. A way of preparing sections of adult hardened insects by infiltrating with wax prior to softening with chlorinated acetic acid and nitric acid was also employed. The nervous system of Gerris shows a high degree of condensation in that all the segmental neuromeres are fused. This characteristic of the nervous system may be associated with the disposition of the one hundred and twenty-two pairs of muscles. The nerves of the head are specialized in association with the complex mouthparts. There are distinct stylet and labral ganglia, and peripheral interconnexions between some of the nerves. The posterior labral nerve was traced to the principal salivary gland. The reticulum described by Baptist (1941) as of a nervous nature was shown to consist of fine muscle fibres: the much finer nerve fibres were also stained in silver preparations. The many separate nerves of the prothorax reflect the unspecialized nature of this segment as compared with the meso- and metathorax in which most of the fibres are gathered into a few nerve trunks. The coalesced neuromeres of the abdominal region give rise to a pair of posterior nerve trunks connected with small ganglia or lateral bodies lying near the spiracles. These ganglia appear similar to the structures described by Landois & Thelen (1867), as controlling spiracular movements in Cossus . Rough estimates of the number of cells in different parts of the nervous system were correlated with the percentage success of staining methods, and specialization of the neuromeres. The form and arrangement of neurones within the optic and protocerebral centres of Gerris conforms for the most part to the patterns worked out in other insects, though there do not seem to be as many different types of internuncial neurone in the optic lobes of Gerris as exist in Apis or Calliphora (Cajal & Sanchez 1915). The corpora pedunculata are connected through a dorsal glomerulus with the deutocerebrum, the glomerulus having the form of a loose meshwork of fine fibres rather than of a distinct calyx. The deutocerebrum is indistinctly divided into anterior and posterior glomeruli, as described in Apis by Sanchez (1936). The form and size of the elements composing the somewhat enigmatic posterior glomerulus in Gerris supports the view that this is a motor centre. The close association between the maxillary and mandibular nerves is to some extent reflected in the internal organization of these neuromeres. Separate ventral areas could be distinguished, but ganglionic boundaries were indistinct. The large labral centre shows many of the features of a trunk ganglion. The pattern of neurones in the thoracic and abdominal centres could be compared in detail with the pattern described by Zawarzin (1924) in the larva of Aeschna . There are three unusually large internuncials with processes in this region, and cell bodies in the protocerebrum and suboesophageal centres. It is suggested that they form part of a dual physiological system controlling the motor centres of the thorax (Roeder 1953). The mesothoracic centre was made a special object of study as representative of the thoracic neuromeres. The fibre tracts are clearly marked and can be seen to correspond to functional regions within the centre. The alary nervous system of the mesothorax was investigated in some detail in both winged and wingless forms of Gerris . In the flying forms dorsal and ventral tracts can be distinguished, associated with motor and sensory regions of the mesothoracic neuropile respectively. In forms without wing muscles or fully developed wings the dorsal tract is absent or vestigial and the ventral tract is clearly reduced. The abdominal neuromeres are very closely compacted so that they tend to lose their identity. The ventral longitudinal tracts are unusually well developed and this may be correlated with the importance of the sensory areas.

The fate of an intentional introduction of Formica lugubris to North America from Europe

2008 ◽  
Vol 132 (4) ◽  
pp. 276-280 ◽  
Author(s):  
A. J. Storer ◽  
M. F. Jurgensen ◽  
A. C. Risch ◽  
J. Delisle ◽  
M. D. Hyslop
Keyword(s):  
North America ◽  
Formica Lugubris ◽  
Intentional Introduction

Bears and ants: myrmecophagy by brown bears in central Scandinavia

1999 ◽  
Vol 77 (4) ◽  
pp. 551-561 ◽  
Author(s):  
Jon E Swenson ◽  
Anna Jansson ◽  
Raili Riig ◽  
Finn Sandegren
Keyword(s):  
Ursus Arctos ◽  
Important Food ◽  
Brown Bears ◽  
Plant Foods ◽  
Clear Cutting ◽  
Carpenter Ants ◽  
Formica Aquilonia ◽  
Formica Lugubris ◽  
Selection Of

To determine general patterns of myrmecophagy in bears, we tested hypotheses regarding selection of ant species, factors important to bears when selecting ant species, factors influencing seasonal use of ants, and foraging behavior of brown bears (Ursus arctos) in central Sweden. Ants were an important food for these bears, constituting 12, 16, and 4% of fecal volume in spring, summer, and autumn, respectively. Ants were abundant, 30.5-38.5 tonnes per bear, and bears excavated 8-33% (mean 23%) of the mounds of red forest ants annually. Carpenter ants (Camponotus herculeanus) were highly preferred. Among mound-building red forest ants, the Formica aquilonia/polyctena complex was preferred over Formica exsecta and Formica lugubris. The ants selected by bears had high digestible energy and low formic acid content and behaved passively when the colony was disturbed. Colony size and density may also have influenced the selection of ants. Seasonal use of ants was related not to the availability of pupae or the quality of plant foods but probably to the availability of other foods. Bears consumed only a small proportion of the ants, 4000-5000, each time they opened a mound, probably because of rapidly increasing difficulty in capturing them after the colony was attacked. Eurasian brown bears feed more on ants than North American bears do, perhaps because of greater availability of large colonies of red forest ants. Carpenter ants may have been especially available in our study area following intensive clear-cutting.

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