| 1. |
- Tullberg, Birgitta S., et al.
(författare)
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A model of actions and norms : An integrated evolutionary perspective on normative ethics and human behavior
- 2011
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Ingår i: Biology and Politics. - : Emerald Group Publishing Limited. - 9780857245793 ; , s. 29-51
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Bokkapitel (refereegranskat)abstract
- One fundamental question in normative ethics concerns how norms influence human behavior and discussions within normative ethics would be facilitated by a classification that treats human actions/behavior and moral norms within the same functional framework. Based on evolutionary analysis of benefits and costs, we distinguish five categories of human action. Four of these – self-interest, kin selection, group egoism, and cooperation – are basically results of gene selection, benefit the individual's genetic interest and may be described as “broad self-interest.” In contrast, the fifth category, unselfishness, is more likely a result of cultural influences. All the five categories of action are influenced by three broad moral spheres, each of which represents many norms that have a common denominator. Thus, a sphere of integrity concerns the individual's right to act in his/her interest and against those of other individuals. A sphere of reciprocal morality deals with rules for various forms of cooperation. An altruistic sphere has to do with the obligations to generate advantages for others. Ethics can be viewed as a dynamic conflict among various norms within and between these spheres. The classical conflict is that between the integrity and altruistic spheres. However, we argue that the prime antagonism may be that between the altruistic and reciprocal spheres; the main impact of altruistic ideals may not be the reputed one of counteracting egoism, but subversively thwarting reciprocal morality.
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| 2. |
- Tullberg, Birgitta S., et al.
(författare)
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Proportionalism or liberalism-Two ideas of social justice
- 2006
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Ingår i: Politikon. - : Routledge. - 1470-1014 .- 0258-9346. ; 33:2, s. 147-161
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Tidskriftsartikel (refereegranskat)abstract
- Proportionalism' refers to the general idea that, in a well ordered society, people sharing different socio-demographic background variables such as sex, race or class should have a proportional representation in either advantageous or disadvantageous groups. If this is not the case, discrimination is indicated. The central proposition of proportionalism is that direct discrimination can be justified as a counter-measure against indirect or structural discrimination. Liberalism opposes direct individual discrimination, whether positive or negative, but then has to justify aspects of measured differences at the group level. To examine and penetrate whether taken positions represent special interests or perceptions of justice, certain reverse cases are discussed. Should we take actions that promote white basketball players or reduce male over-representation in prisons? The central argument in this article is that the liberal position is less dependent on the equality assumption, the cornerstone of proportionalism. Once the difference between groups is overlapping and not categorical, a case can be made for the liberal approach. The natural equilibrium might be equality, but this is not necessarily the case. Even when an average difference between two groups exists, a skilled individual should not be dismissed because of her group average, nor should a less capable individual gain credit based on the average of his group. To a high degree, proportionalism is a transfer of credit based on group characteristics to some individuals, and often touted from positions of under-representation. The justice of this is discussed. Proportionalism is often considered a just goal, but unfortunately, it is burdened with methodological problems that even its proponents find dubious. Further, the basic intentions of proportionalism may be questioned. We conclude that the liberal view evokes a more trenchant solution.
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| 3. |
- Ah-King, Malin, 1973-, et al.
(författare)
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Phylogenetic analysis of twinning in Callitrichinae
- 2000
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Ingår i: American Journal of Primatology. - 0275-2565 .- 1098-2345. ; 51:2, s. 135-146
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Tidskriftsartikel (refereegranskat)abstract
- The callitrichines are known for twinning and for a communal rearingsystem in which all or most group members help care for the offspring.The origin of twinning has been the subject of much speculation. In thisstudy predictions from earlier hypotheses are tested on the basis of twoalternative phylogenetic trees. From this analysis we infer that helpingbehavior and male care preceded the origin of twinning, and that thesetraits did not coevolve with, but might have been important prerequisitesfor twinning in callitrichines. Small body size does not necessarilyresult in twinning, although it might still have been a prerequisite forits evolution. Gum feeding was an ecological change which evolved alongwith twinning. If nutrition was a limiting factor in the number of offspringproduced, then the use of a new feeding resource could have beencrucial for the origin of twinning in callitrichines. According to one of thetwo alternative solutions inferred by the total evidence tree, and in accordancewith the morphological tree, semi-annual breeding appears inthe marmosets together with specialization in gum feeding. The fact thatgums are available for these monkeys all year may have facilitated semiannualbreeding. We suggest that the exploitation of gums as a feedingresource could have been the decisive factor in the increase of the reproductiverate by twinning and by semi-annual breeding.
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| 4. |
- Ah-King, Malin, 1973-, et al.
(författare)
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The influence of territoriality and mating system for the evolution of male care, a phylogenetic study on fish
- 2005
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Ingår i: Journal of Evolutionary Biology. - 1010-061X .- 1420-9101.
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Tidskriftsartikel (refereegranskat)abstract
- Evolution of male care is still poorly understood. Using phylogeneticallymatched-pairs comparisons we tested for effects of territoriality and matingsystem on male care evolution in fish. All origins of male care were found inpair-spawning species (with or without additional males such as sneakers) andnone were found in group-spawning species. However, excluding groupspawners, male care originated equally often in pair-spawning species withadditional males as in strict pair-spawning species. Evolution of male care wasalso significantly related to territoriality. Yet, most pair-spawning taxa withmale care are also territorial, making their relative influence difficult toseparate. Furthermore, territoriality also occurs in group-spawning species.Hence, territoriality is not sufficient for male care to evolve. Rather, we arguethat it is the combination of territoriality and pair spawning with sequentialpolygyny that favours the evolution of male care, and we discuss our results inrelation to paternity assurance and sexual selection.
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| 5. |
- Balogh, Alexandra C.V., et al.
(författare)
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Feature theory and the two-step hypothesis of Müllerian mimicry evolution
- 2010
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 64:3, s. 810-822
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Tidskriftsartikel (refereegranskat)abstract
- The two-step hypothesis of Müllerian mimicry evolution states that mimicry starts with a major mutational leap between adaptive peaks, followed by gradual fine-tuning. The hypothesis was suggested to solve the problem of apostatic selection producing a valley between adaptive peaks, and appears reasonable for a one-dimensional phenotype. Extending the hypothesis to the realistic scenario of multidimensional phenotypes controlled by multiple genetic loci can be problematic, because it is unlikely that major mutational leaps occur simultaneously in several traits. Here we consider the implications of predator psychology on the evolutionary process. According to feature theory, single prey traits may be used by predators as features to classify prey into discrete categories. A mutational leap in such a trait could initiate mimicry evolution. We conducted individual-based evolutionary simulations in which virtual predators both categorize prey according to features and generalize over total appearances. We found that an initial mutational leap towards feature similarity in one dimension facilitates mimicry evolution of multidimensional traits. We suggest that feature-based predator categorization together with predator generalization over total appearances solves the problem of applying the two-step hypothesis to complex phenotypes, and provides a basis for a theory of the evolution of mimicry rings.
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| 6. |
- Bohlin, Titti, et al.
(författare)
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The detectability of the colour pattern in the aposematic firebug, Pyrrhocoris apterus : an image-based experiment with human 'predators'
- 2012
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 105:4, s. 806-816
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Tidskriftsartikel (refereegranskat)abstract
- Crypsis and aposematism are often regarded as two opposite protective strategies. However, there is large variation in prey appearance within both strategies. In this article, we investigated the conspicuousness of the aposematic red-and-black firebug, Pyrrhocoris apterus, by presenting images of natural and digitally manipulated phenotypes in their natural habitat on a computer screen to human predators, and comparing the detection times. We asked whether the natural colour pattern can be made more or less conspicuous by rearranging the spatial distribution of colour elements. Hence, we created a phenotype in which the black colour elements were moved to the body outline to test for a possible disruptive effect. In the black and red manipulations, we removed one of the two colours, creating two uniform colour variants. We found that some of our manipulations increased, but none reduced, the detection time significantly; this indicates that the naturally coloured firebug is highly conspicuous. The detection time varied among backgrounds and there was a significant relationship between detection time and chromatic similarity between the bug and the background for the natural and black phenotypes. Although background colour composition has an important effect on the signal, we argue that the coloration of P. apterus has evolved for high conspicuousness.
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| 7. |
- Bohlin, Titti, et al.
(författare)
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The effect of signal appearance and distance on detection risk in an aposematic butterfly larva (Parnassius apollo)
- 2008
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472. ; 76, s. 577-584
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Tidskriftsartikel (refereegranskat)abstract
- Aposematic coloration commonly involves patterns with contrasting colours. The early larva of Parnassius apollo is uniformly black, but the later instars develop two rows of dorsal orange spots. We tested the effect of these orange markings on the conspicuousness of the last-instar larva, by manipulating larval coloration in photographs from a natural habitat and measuring how fast human subjects could discover the larva on a touch screen. In the first experiment we compared the detectability of the natural phenotype with that of manipulated uniformly black and uniformly orange variants at different distances. In the second experiment with another set of photographs we added manipulations involving enlarged and reduced spot sizes. Generally, detection time increased with distance, and decreased with the proportion of orange in the coloration. The uniformly black larvae were surprisingly hard to detect even at the closest distances, suggesting that the young black instar has an efficient camouflage. Furthermore, even a small amount of orange colour increased the conspicuousness of the larva considerably, indicating that the orange markings are costly in terms of detectability. Importantly, as the increase in detection time over distances was larger for the natural coloration than for the orange coloration, we suggest that the natural coloration may involve a distance-dependent switch from conspicuousness to camouflage with increasing distance. Thus, even though the orange markings most probably have a signalling function, the coloration is not maximized for either crypsis or conspicuousness.
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| 8. |
- Gamberale-Stille, Gabriella, 1969-, et al.
(författare)
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Change in protective coloration in the striated shieldbug Graphosoma lineatum (Heteroptera: Pentatomidae) : predator avoidance and generalization among different life stages
- 2010
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Ingår i: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 24:2, s. 423-432
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Tidskriftsartikel (refereegranskat)abstract
- There are two major forms of protective coloration, camouflage and warning coloration, which often entail different colour pattern characteristics. Some species change strategy between or within life stages and one such example is the striated shieldbug, Graphosoma lineatum. The larvae and the pale brownish-and-black striated pre-diapause adults are more cryptic in the late summer environment than is the red-and black striation that the adults change to after diapause in spring. Here we investigate if the more cryptic pre-diapause adult and larval coloration may affect the aposematic function of the coloration as compared to the red adult form. In a series of trials we presented fifth instar larvae, pale or red adults to shieldbug-naïve domestic chicks, Gallus gallus domesticus, to investigate the birds’ initial wariness, avoidance learning, and generalization between the three prey types. The naïve chicks found the red adults most aversive followed by pale adults, and they found the larvae the least aversive. The birds did not find the larvae unpalatable and did not learn to avoid them, while they learned to avoid the two adult forms and then to a similar degree. Birds generalized asymmetrically between life stages, positively from larvae to adults and negatively from adults to larvae. We conclude that the lower conspicuousness in the pale forms of G. lineatum may entail a reduced aposematic function, namely a reduced initial wariness in inexperienced birds. The maintenance of the colour polymorphism is discussed
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| 9. |
- Gamberale-Stille, Gabriella, et al.
(författare)
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FEATURE SALTATION AND THE EVOLUTION OF MIMICRY
- 2012
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 66:3, s. 807-817
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Tidskriftsartikel (refereegranskat)abstract
- In Batesian mimicry, a harmless prey species imitates the warning coloration of an unpalatable model species. A traditional suggestion is that mimicry evolves in a two-step process, in which a large mutation first achieves approximate similarity to the model, after which smaller changes improve the likeness. However, it is not known which aspects of predator psychology cause the initial mutant to be perceived by predators as being similar to the model, leaving open the question of how the crucial first step of mimicry evolution occurs. Using theoretical evolutionary simulations and reconstruction of examples of mimicry evolution, we show that the evolution of Batesian mimicry can be initiated by a mutation that causes prey to acquire a trait that is used by predators as a feature to categorize potential prey as unsuitable. The theory that species gain entry to mimicry through feature saltation allows us to formulate scenarios of the sequence of events during mimicry evolution and to reconstruct an initial mimetic appearance for important examples of Batesian mimicry. Because feature-based categorization by predators entails a qualitative distinction between nonmimics and passable mimics, the theory can explain the occurrence of imperfect mimicry.
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| 10. |
- Gamberale-Stille, Gabriella, 1969-, et al.
(författare)
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Higher survival of aposematic prey in close encounters with predators – an experimental study of detection distance.
- 2009
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Ingår i: Animal Behaviour. - : elsevier. - 0003-3472 .- 1095-8282. ; 78, s. 111-116
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Tidskriftsartikel (refereegranskat)abstract
- Aposematic animals are often conspicuous. It has been hypothesized that one function of conspicuousness in such prey is to be detected from afar by potential predators: the ‘detection distance hypothesis’. The hypothesis states that predators are less prone to attack at long detection range because more time is allowed for making the ‘correct’ decision not to attack the unprofitable prey. The detection distance hypothesis has gained some experimental support in that time-limited predators make more mistakes. To investigate effects of prey presentation distance we performed two experiments. First, in experiment 1, we investigated at what distance chicks, Gallus gallus domesticus, could see the difference in colour between aposematic and plain mealworms. Birds chose the correct track in a two-way choice when prey were at 20, 40 and 60 cm distance but not at 80 cm. Second, in experiment 2, fifth-instar larvae of the aposematic bug Lygaeus equestris were presented to experienced chicks at 2, 20 or 60 cm distance. We found no difference in attack probability between distances. However, prey mortality was significantly lower for the shortest presentation distance. In conclusion, we found no support for the hypothesis that aposematic prey benefit from long-range detection; in fact they benefit from shortdistance detection. This result, and others, suggests that the conspicuousness of aposematic prey at a distance may simply be a by-product of an efficient signalling function after detection.
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