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Several Nests (several + nest)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Spatial patterns, temporal variability, and the role of multi-nest colonies in a monogynous Spanish desert ant

ECOLOGICAL ENTOMOLOGY, Issue 1 2002
Xim Cerdá
Abstract 1.,The colonies of the Spanish desert ant Cataglyphis iberica are polydomous. This study describes the temporal and spatial patterns of the polydomy in this species at two different sites, and presents analyses of its role in reducing the attacks of the queen over sexual brood, and in allowing better habitat exploitation. 2. The spatial distribution of nests was clumped while colonies were distributed randomly. Mean nearest neighbour distance ranged from 3.4 to 7.0 m for nests and from 12.3 to 14.1 m for colonies. Distance of foragers searching for food varied among nests: mean values were between 6.1 and 12.6 m. 3. At both sites, the maximum number of nests per colony occurred in summer, during the maximum activity period of the species. Colonies regrouped at the end of this period but overwintered in several nests. 4. Nest renewal in C. iberica colonies was high and showed great temporal variability: nests changed (open, close, re-open) continuously through the activity season and/or among years. The lifetime of up to 55% of nests was only 1,3 months. 5. Polydomy in C. iberica might decrease the interactions between the queen and the sexual brood. In all colonies excavated just before the mating period, the nest containing the queen did not contain any virgin female. Females were in the queenless nests of the colony. 6. The results also suggest that polydomous C. iberica colonies may enhance habitat exploitation because foraging activity per colony increases with nest number. The relationship between total prey input and foraging efficiency and number of nests per colony attains a plateau or even decreases after a certain colony size (four to six nests). This value agrees with the observed mean number of nests per colony in C. iberica. [source]

Recurring main-chain anion-binding motifs in short polypeptides: nests

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2004
E. James Milner-White
A novel tripeptide motif called a nest has recently been described in proteins with the function of binding anionic, or partially anionic, atoms such as carbonyl O atoms. In the present work, a search for nests in small polypeptides stored in the Cambridge Structural Database is reported. 37 unique examples were found: over half form part of hydrogen-bond arrangements resembling those in proteins, such as Schellman/paperclip loop motifs, various types of ,-turn and Asx-turns or Ser/Thr-turns, while a third are in novel situations, some involving binding to anionic groups from other molecules within the crystal complex. An example is the antibiotic vancomycin, which incorporates a prominent nest forming part of a peptide-binding site. This nest binds the carboxylate of the C-terminal d -alanine of the bacterial cell-wall precursor peptide, thereby inhibiting the final step of bacterial cell-wall synthesis. As in proteins, a number of nests occur in short peptides with an alternating glycine/l -amino-acid sequence but, uniquely to non-ribosomally synthesized short peptides, several nests within them are constructed from alternating d - and l -amino acids, and such sequences seem to specially favour nests. [source]

Spatial distribution of communal nests in a colonial breeding bird: benefits without costs?

AUSTRAL ECOLOGY, Issue 5 2008
URS CHRISTIAN GIEßELMANN
Abstract The spatial organization of individuals, or groups of individuals, within a population can provide valuable information about social organization and population dynamics. We analysed the spatial distribution of nests of the sociable weaver (Philetairus socius) on two farms in the Kalahari. Sociable weavers build large communal nests on big savannah trees, forming a pattern of trees with and without nests. We used two spatial statistics, Ripley's K and the pair correlation function, to describe characteristics of the point patterns over a range of distances. (i) At distances of 200 and 300 m, communal nests were clustered. (ii) At distances greater than 1000 m, communal nests were regularly distributed. These findings are independent of the spatial distribution of trees. Furthermore, we used Moran's I to analyse spatial autocorrelation of nest sizes. We expected negative autocorrelation because of competition between nests. But on both farms there was no significant autocorrelation of nest sizes for any distance class. The regular distribution observed at larger distances may indicate competition and/or territoriality among different nests, but the lack of spatial autocorrelation between nest sizes suggests that these interactions may happen between nest clusters rather than between single nests. This was confirmed by significant clustering of nests on small scales. We thus suggest, that colonies of P. socius consist of several nests on adjacent trees forming a cluster of subcolonies. The question why sociable weavers establish subcolonies instead of adding more chambers to the natal nest, could not simply be answered by limitation of nesting space. We suggest a strategy to avoid costs due to increasing colony size. [source]

Speckled lentiginous naevus: which of the two disorders do you mean?

CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 2 2009
R. Happle
Summary Speckled lentiginous naevus (synonym: naevus spilus) no longer represents one clinical entity, but rather, two different disorders can be distinguished. Naevus spilus maculosus is consistently found in phacomatosis spilorosea, whereas naevus spilus papulosus represents a hallmark of phacomatosis pigmentokeratotica. The macular type is characterized by dark speckles that are completely flat and rather evenly distributed on a light brown background, resembling a polka-dot pattern. In contrast, naevus spilus papulosus is defined by dark papules that are of different sizes and rather unevenly distributed, reminiscent of a star map. Histopathologically, the dark spots of naevus spilus maculosus show a ,jentigo' pattern and several nests of melanocytes involving the dermoepidermal junction at the tips of the papillae, whereas most of the dark speckles of naevus spilus papulosus are found to be dermal or compound melanocytic naevi. The propensity to develop Spitz naevi appears to be the same in both types of speckled lentiginous naevus, whereas development of malignant melanoma has been reported far more commonly in naevus spilus maculosus. [source]