| 1. |
- Aronsson, Marianne, 1978-, et al.
(författare)
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Colour and pattern similarity in mimicry : evidence for a hierarchical discriminative learning of different components
- 2012
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 84:4, s. 881-887
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Tidskriftsartikel (refereegranskat)abstract
- Many aposematic species combine their bright colours with a black pattern that produces internal contrasts. Studies have shown that birds often pay attention to some parts of a signalling pattern and disregard others, which could be of importance in Batesian mimicry, where a palatable species copies the visual appearance of a distasteful model in order to deceive predators. We used domestic chicks, Gallus gallus domesticus, and artificial prey signals to investigate whether predators use different warning colour components for discrimination depending on the degree of information about prey quality they convey. This study supports earlier findings of the importance of colour for discrimination among prey but also provides evidence that other less associable signal properties such as internal patterning, when holding valuable discriminatory information, can be used to assess prey quality in a hierarchical manner. The results also suggest that, in certain circumstances, the presence of a palatable mimic can have positive effects on learning, resulting in 'super-Mullerian' effects. We propose that the degree of selection for perfect mimicry may be dependent on the proportion of well-educated predators in the population.
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| 2. |
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| 3. |
- Aronsson, Marianne, 1978-
(författare)
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Colour patterns in warning displays
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In aposematism a prey species use bright colours, often combined with a black contrasting pattern, to signal unprofitability as prey to potential predators. Although there are several different hypotheses about the presence of these internally contrasting patterns, there is little experimental evidence of any beneficial effects. In this thesis I have used bird predators and artificial prey signals to investigate if the contrasting internal patterns in warning displays may have evolved to increase signal efficacy, especially regarding the speed of avoidance learning. In paper I the relative importance of colour and pattern in avoidance learning was studied. The conclusion was that birds primarily attend to colour, not pattern, when learning the discrimination, which was further supported by the results in paper II-IV, all suggesting a secondary role of patterns. In paper II I show that predators may to some degree use patterns for discrimination, if they convey important information about prey quality. The predators showed a hierarchical way of learning warning colour components, where colour is learned to a higher degree than pattern. In paper III I investigate if internal contrasting patterns promote avoidance learning by increasing conspicuousness as prey-to-background contrast does. The study did not support this idea, as the presence of internal black patterns did not improve avoidance learning on a colour matching background. In paper IV, however, I show that the presence of many internal colour boundaries resulted in faster avoidance learning on a multi-coloured background, and predator generalization favoured more internal boundaries, while there was no effect of pattern regularity. From these studies I conclude that internal pattern contrasts may function to increase the efficacy of the warning colour, its salience, and as a means for aposematic prey to be discriminated from harmful mimics. However, the major finding is the importance of colour over pattern.
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| 4. |
- Aronsson, Marianne, et al.
(författare)
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Domestic chicks primarily attend to colour, not pattern, when learning an aposematic coloration
- 2008
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 75, s. 417-423
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Tidskriftsartikel (refereegranskat)abstract
- Aposematic conspicuous coloration consists of one or a few bright colours, often in combination with a black defined internal pattern. The function of conspicuousness in aposematism has been ascribed to signal efficacy, based on experimental evidence involving prey items with uniform colour that contrast with the background. Although there are several hypotheses about the existence of internal contrasts within warning coloration, little experimental evidence has been presented. Here we used domestic chicks, Gallus gallus domesticus, to investigate the relative importance of colour and pattern in avoidance learning. Birds in two groups were first trained to discriminate between a grey positive stimulus and a cyan negative stimulus with either black dots or stripes. Pieces of mealworms, untreated and palatable or made unpalatable by soaking in quinine were used as reinforcers. Secondly, to determine what birds had attended to when learning the discrimination, colour and/or pattern, we compared how they generalized their avoidance of the ‘training stimulus’ to either a ‘colour only’ or ‘pattern only’ stimulus. The chicks learned to avoid the unpalatable prey items but showed no difference in behaviour depending on the type of pattern presented. The generalization test showed that birds avoided the novel ‘colour only’ stimulus at least as much as the ‘training stimulus’, and did not generalize their avoidance to the ‘pattern only’ stimulus. We conclude that birds do not necessarily attend to complex patterns when learning a warning signal, and domestic chicks primarily learn a bright colour rather than an equally novel conspicuous black pattern.
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| 5. |
- Aronsson, Marianne, et al.
(författare)
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Evidence of signaling benefits to contrasting internal color boundaries in warning coloration
- 2013
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 24:2, s. 349-354
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Tidskriftsartikel (refereegranskat)abstract
- It has been suggested that the common existence of regular patterning in aposematic prey animals makes them stand out from the background, improving detection and recognition. Another suggestion is that internal patterns could have a similar positive effect on predator aversion learning as prey-to-background contrast. We used wild caught blue tits (Cyanistes caeruleus) and artificial prey signals to investigate if internal color boundaries, pattern regularity and pattern symmetry affect learning. Birds in different treatments were trained, on a complex background, to discriminate between artificial prey with different nonrewarding color stimuli with a black pattern and rewarding stimuli without a black pattern, followed by a generalization test. This study provides evidence of learning benefits to internally contrasting patterns as the striped prey stimuli were learned faster than the unstriped. Also, we found no beneficial effects of pattern regularity and symmetry. The birds generalized more between prey with different black patterns than to the profitable prey, suggesting that color is of foremost importance. The generalization test also showed a greater avoidance of striped than that of unstriped prey, suggesting some attention on patterns. Thus, internal patterning may affect signal salience and in some circumstances benefit prey due to both a faster avoidance learning and generalization behavior.
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| 6. |
- Aronsson, Marianne, et al.
(författare)
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Importance of internal pattern contrast and contrast against the background in aposematic signals.
- 2009
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 20:6, s. 1356-1362
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Tidskriftsartikel (refereegranskat)abstract
- Aposematic color patterns that signal prey unprofitability are suggested to work best when there is high contrast within the animal color pattern or between the animal and its background. Studies show that prey contrast against the background increases the signal efficiency. This has occasionally been extended to also explain the presence of internal patterns. We used domestic chicks, Gallus gallus domesticus, to investigate the relative importance for avoidance learning of within-prey pattern contrast and prey contrast against the background. In a series of trials, birds were first trained to avoid artificially made aposematic mealworms that were plain red or red with black stripes, and to discriminate them from palatable brown mealworms, on either a red or a brown background. Second, we investigated how the birds generalized between striped and nonstriped prey. The chicks showed faster avoidance learning when the basic color of the aposematic prey (red) contrasted with the background color (brown). However, there was no similar effect of internal pattern contrast. The generalization test showed a complete generalization between the nonstriped and the striped prey. We conclude that contrasting internal patterns do not necessarily affect predator avoidance learning the same way as shown for prey-to-background contrast in aposematic prey.
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| 7. |
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| 8. |
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| 9. |
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Barn i tid och rum
- 1984
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- En antologi med 10 artiklar av författare från olika discipliner. Utifrån teoretiker som Ariès, Bourdieu, Berger och Luckmann, Freud, Mead, Piaget m.fl. belyser författarna barns villkor förr och nu och där arbete och fritid flyter samman.
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| 10. |
- Brooks, Samantha J, et al.
(författare)
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Obsessive-compulsivity and working memory are associated with differential prefrontal cortex and insula activation in adolescents with a recent diagnosis of an eating disorder
- 2014
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Ingår i: Psychiatry Research. - : Elsevier BV. - 0165-1781 .- 1872-7123 .- 0925-4927. ; 224:3, s. 246-253
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Tidskriftsartikel (refereegranskat)abstract
- The role of rumination at the beginning of eating disorder (ED) is not well understood. We hypothesised that impulsivity, rumination and restriction could be associated with neural activity in response to food stimuli in young individuals with eating disorders (ED). We measured neural responses with functional magnetic resonance imaging (fMRI), tested working memory (WM) and administered the eating disorders examination questionnaire (EDE-Q), Barratt impulsivity scale (BIS-11) and obsessive-compulsive inventory (OCI-R) in 15 adolescent females with eating disorder not otherwise specified (EDNOS) (mean age 15 years) and 20 age-matched healthy control females. We found that EDNOS subjects had significantly higher scores on the BIS 11, EDE-Q and OCI-R scales. Significantly increased neural responses to food images in the EDNOS group were observed in the prefrontal circuitry. OCI-R scores in the EDNOS group also significantly correlated with activity in the prefrontal circuitry and the cerebellum. Significantly slower WM responses negatively correlated with bilateral superior frontal gyrus activity in the EDNOS group. We conclude that ruminations, linked to WM, are present in adolescent females newly diagnosed with EDNOS. These may be risk factors for the development of an eating disorder and may be detectable before disease onset.
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| 11. |
- Egelkraut, Dagmar, 1989-, et al.
(författare)
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Multiple feedbacks contribute to a centennial legacy of reindeer on tundra vegetation
- 2018
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Ingår i: Ecosystems (New York. Print). - : Springer. - 1432-9840 .- 1435-0629. ; 21:8, s. 1545-1563
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Tidskriftsartikel (refereegranskat)abstract
- Historical contingency is the impact of past events, like the timing and order of species arrival, on community assembly, and can sometimes result in alternative stable states of ecological communities. Large herbivores, wild and domestic, can cause profound changes in the structure and functioning of plant communities and therefore probably influence historical contingency; however, little empirical data on the stability of such shifts or subsequent drivers of stability are available. We studied the centennial legacy of reindeer (Rangifer tarandus) pressure on arctic tundra vegetation by considering historical milking grounds (HMGs): graminoid- and forb-dominated patches amid shrub-dominated tundra, formed by historical Sami reindeer herding practices that ended approximately 100 years ago. Our results show that the core areas of all studied HMGs remained strikingly stable, being hardly invaded by surrounding shrubs. Soil nitrogen concentrations were comparable to heavily grazed areas. However, the HMGs are slowly being reinvaded by vegetative growth of shrubs at the edges, and the rate of ingrowth increased with higher mineral N availability. Furthermore, our data indicate that several biotic feedbacks contribute to the stability of the HMGs: increased nutrient turnover supporting herbaceous vegetation, strong interspecific competition preventing invasion and herbivore damage to invading shrubs. In particular, voles and lemmings appear to be important, selectively damaging shrubs in the HMGs. We concluded that HMGs provide clear evidence for historical contingency of herbivore effects in arctic ecosystems. We showed that several biotic feedbacks can contribute to subsequent vegetation stability, but their relative importance will vary in time and space.
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| 12. |
- Gerdin, Elisabeth Warnberg, et al.
(författare)
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Dental caries and body mass index by socio-economic status in Swedish children
- 2008
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Ingår i: Community Dentistry and Oral Epidemiology. - : Wiley. - 0301-5661 .- 1600-0528. ; 36:5, s. 459-465
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of the present study was to evaluate the association between dental caries, childhood body mass index (BMI), and socioeconomic status in Swedish children. Methods: The study cohort consisted of 2303 10-year-old children with data on socioeconomic status, BMI at 4, 5, 7 and 10 years of age, and caries at 6, 10 and 12 years of age. Anthropometric measures were carried out by trained nurses according to standardized routines. The occurrence of caries was registered from county records, and the children were classified into one of five socioeconomic clusters based on their census registration address. Results: Caries prevalence decreased with increasing socioeconomic status at all ages, whereas childhood BMI and proportion of overweight/obese children were unrelated to socioeconomic status. Obese, but not overweight, children had more caries affected teeth than non-obese, and BMI had an independent, though weak, effect on caries variation in multiple regression. Interestingly, overweight/obese 4-year-olds, who had normal body weight at 5, 7 and 10 years of age, had significantly less caries than children who had normal body weight from 4 to 10 years of age. Conclusions: Overweight and caries prevalence are significantly associated in Swedish children. However, the association is weak. Nevertheless, the concept that child dental services and child welfare services can benefit from joint programs is supported.
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| 13. |
- Sharpley, Andrew N., et al.
(författare)
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Future agriculture with minimized phosphorus losses to waters: Research needs and direction
- 2015
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Ingår i: Ambio. - : Springer Verlag (Germany). - 0044-7447 .- 1654-7209. ; 44, s. S163-S179
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Tidskriftsartikel (refereegranskat)abstract
- The series of papers in this issue of AMBIO represent technical presentations made at the 7th International Phosphorus Workshop (IPW7), held in September, 2013 in Uppsala, Sweden. At that meeting, the 150 delegates were involved in round table discussions on major, predetermined themes facing the management of agricultural phosphorus (P) for optimum production goals with minimal water quality impairment. The six themes were (1) P management in a changing world; (2) transport pathways of P from soil to water; (3) monitoring, modeling, and communication; (4) importance of manure and agricultural production systems for P management; (5) identification of appropriate mitigation measures for reduction of P loss; and (6) implementation of mitigation strategies to reduce P loss. This paper details the major challenges and research needs that were identified for each theme and identifies a future roadmap for catchment management that cost-effectively minimizes P loss from agricultural activities.
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| 14. |
- Solstrand Dahlberg, Linda, 1988-, et al.
(författare)
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Adolescents Newly Diagnosed with Eating Disorders have Structural Differences in Brain Regions linked with Eating Disorder Symptoms
- 2017
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Ingår i: Nordic Journal of Psychiatry. - : Taylor & Francis. - 0803-9488 .- 1502-4725. ; 71:3, s. 188-196
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Tidskriftsartikel (refereegranskat)abstract
- Background: Adults with eating disorders (ED) show brain volume reductions in the frontal, insular, cingulate, and parietal cortices, as well as differences in subcortical regions associated with reward processing. However, little is known about the structural differences in adolescents with behavioural indications of early stage ED.Aim: This is the first study to investigate structural brain changes in adolescents newly diagnosed with ED compared to healthy controls (HC), and to study whether ED cognitions correlate with structural changes in adolescents with ED of short duration.Methods: Fifteen adolescent females recently diagnosed with ED, and 28 age-matched HC individuals, were scanned with structural magnetic resonance imaging (MRI). Whole-brain and region-of-interest analyses were conducted using voxel-based morphometry (VBM). ED cognitions were measured with self-report questionnaires and working memory performance was measured with a neuropsychological computerized test.Results and conclusions: The left superior temporal gyrus had a smaller volume in adolescents with ED than in HC, which correlated with ED cognitions (concerns about eating, weight, and shape). Working memory reaction time correlated positively with insula volumes in ED participants, but not HC. In ED, measurements of restraint and obsession was negatively correlated with temporal gyrus volumes, and positively correlated with cerebellar and striatal volumes. Thus, adolescents with a recent diagnosis of ED had volumetric variations in brain areas linked to ED cognitions, obsessions, and working memory. The findings emphasize the importance of early identification of illness, before potential long-term effects on structure and behaviour occur.
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