ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

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Electronic Resource

Tenascin-X deficiency mimics Ehlers-Danlos syndrome in mice through alteration of collagen deposition (2002)

Mao, Jau Ren ; Taylor, Glen ; Dean, Willow B. ; [et al.]

[s.l.] : Nature Publishing Group

Nature genetics 30 (2002), S. 421-425

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ISSN: 1546-1718

Source: Nature Archives 1869 - 2009

Topics: Biology , Medicine

Notes: [Auszug] Tenascin-X is a large extracellular matrix protein of unknown function. Tenascin-X deficiency in humans is associated with Ehlers–Danlos syndrome, a generalized connective tissue disorder resulting from altered metabolism of the fibrillar collagens. Because TNXB is the first ...

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1038/ng850

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2

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Colony age, neighborhood density and reproductive potential in harvester ants (1999)

Wagner, Diane ; Gordon, Deborah M.

Springer

Oecologia 119 (1999), S. 175-182

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ISSN: 1432-1939

Keywords: Key words Harvester ants ; Life history ; Intraspecific competition ; Body mass ; Body fat

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract At about age 5 years, colonies of the harvester ant, Pogonomyrmex barbatus, begin to produce winged, sexual forms (alates) that mate in large annual aggregations. We examined how colony age and neighborhood density affect the numbers, body mass, and body fat of alates produced by 172 colonies ranging in age from 4 to 17 years. Over one-third (36%) of all colonies produced no alates. Failure to reproduce was independent of colony age. Of those colonies that did produce alates, older colonies produced more alates than younger colonies. Older colonies produced lighter female alates (in dry mass), but the total biomass of additional alates produced by older colonies far outweighed the reduced allocation to female alate body mass. Body fat content was much higher in female alates (36.0% on average) than in males (3.7% on average). Alate body fat content was not related to colony age. The fitness of female alates may be related to their fresh body mass; that of females captured after mating and reared in the laboratory was positively correlated with egg-laying rate, although not with the total number of eggs in the first brood. Neighborhood density was not related to alate number, mass, or fat content, in contrast to the results of a 1995 study at the site, in which alate numbers were negatively related to neighborhood density. Thus the influence of crowding on reproductive output appears to vary from year to year, perhaps in response to variation in rainfall and food supply. Alate output by individual colonies was correlated among years. These results suggest that a few, older colonies dominate the pool of reproductives year after year.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004420050774

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3

Electronic Resource

Experimental tests of the mechanism for ant-enhanced growth in an ant-tended lycaenid butterfly (1997)

Wagner, Diane ; del Rio, Carlos Martínez

Springer

Oecologia 112 (1997), S. 424-429

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ISSN: 1432-1939

Keywords: Key words Ant tending ; Digestion ; Formica perpilosa ; Growth ; Hemiargus isola

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract In a previous laboratory study, larvae of the ant-tended lycaenid butterfly Hemiargus isola developed into larger adults when reared with the ant Formica perpilosa than when reared without ants. Ants neither fed butterfly larvae nor significantly delayed developmental duration. We investigated two non-exclusive hypotheses for the mechanism of this effect: larvae tended by F. perpilosa (1) consume more food, and (2) digest the food they consume more efficiently, than those reared without ants. Larvae reared in the laboratory with F. perpilosa ants became significantly heavier adults but produced a significantly lighter fecal mass than their untended counterparts, suggesting that greater food consumption was not the primary mechanism for the higher growth rates of ant-tended larvae. Tended and untended larvae were equally proficient at digesting the contents of pollen (a major natural food source) throughout the tended portion of the life cycle. Taken together, the results suggest that neither greater consumption nor higher assimilation accounts for the larger size of F. perpilosa-tended larvae. We propose that tended larvae may expend less energy than their untended counterparts.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004420050328

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4

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Neighborhood density and reproductive potential in harvester ants (1997)

Gordon, Deborah M. ; Wagner, Diane

Springer

Oecologia 109 (1997), S. 556-560

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ISSN: 1432-1939

Keywords: Key words Age-related effects ; Density ; Formicidae ; Reproductive success ; Spatial distribution

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract When neighbors compete for resources, the characteristics of a neighborhood may affect fitness. We examined the relationship between reproductive success and the density and size/age characteristics of neighbors in a population of the seed-eating ant, Pogonomyrmex barbatus, in which the ages of all colonies were known. Reproductive success was estimated by trapping and counting the number of alate, reproductive ants emerging from the nest for the annual mating flight. Alate production was negatively related to neighborhood density. Decreased production of alates by more crowded colonies may be due to competition for food with surrounding colonies. Neighbor size/age was unrelated to alate production. If alate production is correlated with lifetime reproductive success, these results suggest that selection favors colonies that monopolize more space, whatever the size of neighboring colonies.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004420050116

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5

Electronic Resource

Harvester ant nests, soil biota and soil chemistry (1997)

Wagner, Diane ; Brown, Mark J. F. ; Gordon, Deborah M.

Springer

Oecologia 112 (1997), S. 232-236

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ISSN: 1432-1939

Keywords: Key words Formicidae ; Pogonomyrmex ; Soil ; Community ; Spatial heterogeneity

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Many ant species accumulate organic debris in the vicinity of their nests. These organic materials should provide a rich resource base for the soil biota. We examined the effect of harvester ant nests (Pogonomyrmex barbatus) on the soil community and soil chemistry. Ant nest soils supported 30-fold higher densities of microarthropods and 5-fold higher densities of protozoa than surrounding, control soils. The relative abundances of the major groups of protozoa differed as well: amoebae and ciliates were relatively overrepresented, and flagellates underrepresented, in ant nest versus control soils. Densities of bacteria and fungi were similar in the two soil types. Concentrations of nitrate, ammonium, phosphorus, and potassium were significantly higher in ant nest soils, while concentrations of magnesium, calcium, and water were similar in nest and control soils. Ant nest soils were marginally more acidic than controls. The results demonstrate that P. barbatus nests constitute a significant source of spatial heterogeneity in soil biota and soil chemistry in arid grasslands.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004420050305

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6

Electronic Resource

Species-specific effects of tending ants on the development of lycaenid butterfly larvae (1993)

Wagner, Diane

Springer

Oecologia 96 (1993), S. 276-281

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ISSN: 1432-1939

Keywords: Hemiargus isola ; Lycaenidae ; Formicidae ; Development ; Mutualism

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The transfer of nutrients between organisms is a common feature of mutualism. The production of these food rewards is often assumed to be costly. Estimation of the costs of producing food rewards is important for understanding the overall effects of the interaction on fitness. When food rewards are harvested by several species differing in foraging behavior, costs to the producer may differ. The larvae of many species in the butterfly family Lycaenidae produce secretions consumed by tending ants. Here I report that three North American ant species, Formica perpilosa, Dorymyrmex sp. (smithi complex), and Forelius foetida, had no negative effect on the duration of development and adult size of the lycaenid Hemiargus isola. Moreover, tending by the ant Formica perpilosa significantly enhanced larval growth, resulting in butterflies that were 20% heavier than their untended counterparts. Tending by the ants Dorymyrmex sp. (smithi complex) and Forelius foetida had no effect on butterfly weight. Tended, nonfeeding larvae lost 69% more weight than untended, nonfeeding larvae. Taken together, the results suggest that, although ant tending imposes a physiological cost, H. isola larvae use behavioral or physiological mechanisms to compensate or overcompensate for nutrients lost to ants.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00317742

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7

Electronic Resource

Wagner, Diane ; Brown, Mark J. F. ; Broun, Pierre ; [et al.]

Springer

Journal of chemical ecology 24 (1998), S. 2021-2037

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ISSN: 1573-1561

Keywords: Cuticular hydrocarbons ; Formicidae ; Pogonomyrmex barbatus ; task allocation ; n-alkanes

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology

Notes: Abstract Colonies of the harvester ant, Pogonomyrmex barbatus, perform a variety of tasks. The behavior of an individual worker appears to depend on its recent history of brief contacts with ants of the same and other task groups. The purpose of this study was to determine whether task groups differ in cuticular hydrocarbon composition. We compared the cuticular hydrocarbon composition of ants collected under natural conditions as they performed one of three tasks: patrolling (locating food sources), foraging, or nest maintenance. Task groups differed significantly in the relative proportions of classes of hydrocarbon compounds, as well as in individual compounds. Relative to nest maintenance workers, foragers and patrollers had a higher proportion of straight-chain alkanes relative to monomethylalkanes, dimethylalkanes, and alkenes. There was no significant difference in the chain length of n-alkanes among the task groups. Foragers did not differ in hydrocarbon composition from patrollers. Colonies differed significantly from one another in hydrocarbon composition, but task groups differed in consistent ways from colony to colony, suggesting that the mechanism responsible for task-related hydrocarbon composition was the same in all colonies. P. barbatus workers switch tasks during their lifetimes, suggesting that cuticular hydrocarbon composition changes during adulthood as well. Nest maintenance workers are probably younger than foragers and patrollers and perform very little of their work outside of the nest. Task-related hydrocarbon differences detected here may be associated with worker age, and/or the abiotic characteristics (temperature, humidity, and ultraviolet light) of the interior and exterior work environments.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1020781508889

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8

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Harvester Ants Utilize Cuticular Hydrocarbons in Nestmate Recognition (2000)

Wagner, Diane ; Tissot, Madeleine ; Cuevas, William ; [et al.]

Springer

Journal of chemical ecology 26 (2000), S. 2245-2257

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ISSN: 1573-1561

Keywords: Cuticular hydrocarbons ; Formicidae ; Nestmate recognition ; Pogonomyrmex barbatus

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology

Notes: Abstract Cuticular hydrocarbons appear to play a role in ant nestmate recognition, but few studies have tested this hypothesis experimentally with purified hydrocarbon extracts. We exposed captive colonies of the harvester ant Pogonomyrmex barbatus to small glass blocks coated with whole cuticular lipid extracts and the purified hydrocarbon portion of extracts from nestmate and nonnestmate workers. As an estimate of agonistic behavior, we measured the proportion of ants in contact with blocks that flared their mandibles. Blocks coated with cuticular extracts from nonnestmates were contacted by more workers in one of two experiments and elicited higher levels of aggression in both experiments than blocks bearing extracts from nestmates. The cuticular hydrocarbon fraction of extracts alone was sufficient to elicit agonistic behavior toward nonnestmates. The results demonstrate that harvester ants can perceive differences in cuticular hydrocarbon composition, and can use those differences in nestmate recognition.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1005529224856

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Long-term impact of a leaf miner outbreak on the performance of quaking aspen (2013)

Wagner, Diane ; Doak, Patricia

Canadian Science Publishing

In: Canadian Journal of Forest Research. 2013; 43(6): 563-569. Published 2013 Jun 01. doi: 10.1139/cjfr-2012-0486.

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Publication Date: 2013-06-01

Description: The aspen leaf miner, Phyllocnistis populiella Cham., has caused widespread and severe damage to aspen in the boreal forests of western North America for over a decade. We suppressed P. populiella on individual small aspen ramets using insecticide at two sites near Fairbanks, Alaska, annually for 7 years and compared plant performance with controls. Insecticide treatment successfully reduced leaf damage by P. populiella during most years and had little effect on herbivory by externally feeding invertebrates. By the end of the study, control ramets had suffered a reduction in height and girth relative to treated ramets and to the original, pretreatment size. Control ramets produced smaller leaves during some years and, after 7 years, produced fewer total shoots and leaves than ramets sprayed with insecticide. Treatment did not affect mortality, but at the warmer of the two sites, ramets sustaining ambient levels of leaf mining were significantly more likely to die back to basal sprouts than those treated with insecticide. We conclude that a decade of P. populiella outbreak has caused strongly negative effects on aspen development and the production of aboveground tissues.

Print ISSN: 0045-5067

Electronic ISSN: 1208-6037

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition