| 1. |
- Andersson, Leif, et al.
(author)
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Afghanistans skenande folkökning är ohållbar
- 2021
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In: Expressen. ; :3 oktober
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Journal article (pop. science, debate, etc.)abstract
- Sverige har pausat det mycket stora biståndet till Afghanistan, ett land med snabbt ökande befolkning. Landet är nu på väg mot omfattande resursbrist, fattigdom och svält. En viktig del i fortsatt bistånd bör vara familjeplanering som minskar de problem den skenande folkökningen orsakar
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| 2. |
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| 3. |
- Andersson, Staffan, 1959, et al.
(author)
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Multiple receivers, multiple ornaments, and a trade-off between agonistic and epigamic signaling in a widowbird.
- 2002
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In: The American naturalist. - : University of Chicago Press. - 1537-5323 .- 0003-0147. ; 160:5, s. 683-91
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Journal article (peer-reviewed)abstract
- Sexual displays often involve several different ornamental traits. Yet most indicator models of sexual selection based on a single receiver (usually a choosy female) find that multiple handicap signals should be unstable. Here we study reasons for this contradiction, analyzing signal function, signal content, and trade-offs between signals in the polygynous red-collared widowbird Euplectes ardens. Males have both a long, graduated tail and a red carotenoid collar badge. Territory-holding "residents" have slightly shorter tails than the nonbreeding "floaters," but their carotenoid collars are 40% larger, and they have (on the basis of reflectance spectrometry and objective colorimetry) a 23-nm more long-wave ("redder") hue than floaters. This corroborates experimental evidence that the red collar is selected by male contest competition, whereas female choice is based almost exclusively on male tail length. Tail length is negatively correlated with the carotenoid signal, which together with body size and condition explains 55% of the variation in tail length. The trade-off in tail length and carotenoid investment is steeper among residents, suggesting an interaction with costs of territory defense. We propose that the "multiple receiver hypothesis" can explain the coexistence of multiple handicap signals. Furthermore, the trade-off between signal expressions might contribute to the inverse relation between nuptial tail elongation and coloration in the genus Euplectes (bishops and widowbirds).
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| 4. |
- Andersson, Malte, 1941
(author)
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Aposematism and crypsis in a rodent: antipredator defence of the Norwegian lemming
- 2015
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In: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 69:4, s. 571-581
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Journal article (peer-reviewed)abstract
- Aposematism is unusual in herbivorous mammals, and exceptions help clarify its ecology and evolution. The Norwegian lemming differs from other rodents in colouration and behaviour. One hypothesis is that its black, yellow and white colours, loud calls and ferocious defence reduce predation by conspicuous aposematism. Another hypothesis is that the colouration is cryptic. These alternatives are tested in a detectability experiment comparing lemmings and sympatric grey-sided voles. All 18 observers detected a higher proportion of the lemmings, corroborating conspicuousness. Unlike smaller rodents, Norwegian lemmings often call from a distance at predators. The aposematism hypothesis predicts that cryptically coloured Alaskan brown lemmings will not call. In the field, Norwegian lemmings gave antipredator calls at a human observer in 36 of 110 encounters, but brown lemmings did so in only 1 of 39 cases. Most Norwegian lemmings called if surprised within a few metres but froze or fled silently farther away, relying on crypsis against distant predators. Small juveniles called as often as adults, a possible case of auto-mimicry. In an earlier experiment, Norwegian lemmings, in contrast with grey-sided voles, aggressively resisted attacks by a major avian predator of rodents. The tests corroborate the hypotheses that (1) distinctive, contrast-rich colouration, antipredator calls and threat postures of the Norwegian lemming form a multimodal suit of aposematic traits, warning predators that this is a more dangerous prey than the smaller sympatric voles, and (2) discriminability from undefended species is an important adaptive reason for conspicuous distinctness of many aposematic signals.
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| 5. |
- Andersson, Malte, 1941
(author)
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Biologisk evolution
- 2009
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In: Djuren och människan. Om den moderna biologin och dess världsbild (LJ Erkell, red). - Lund : Studentlitteratur. - 9789144048888 ; , s. 103-125
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Book chapter (other academic/artistic)abstract
- Biologisk evolution sker genom selektion och neutral drift i populationer av individer. Detta är idag testat och belagt hos många arter, växter som djur. Darwins idéer om naturligt urval står sig. Selektionens mekanismer blir allt bättre kända, även för komplexa egenskaper som socialt beteende och djursamhällens evolution. Förståelsen av ärftlighet gör enorma framsteg, och evolutionsbiologin inriktas på allt djupare analys av växelspelet mellan genetiska mekanismer, miljö, funktion och selektion under individens utveckling. I naturen testas alla egenskaper slutligen via sina effekter på individens mer eller mindre framgångsrika beteenden, som även dessa under senare år börjat studeras ur genetisk synpunkt. Om förra seklets naturvetenskapliga forskning dominerades av fysik, så kommer kanske biologin att ta dess plats under 2000-talet, med evolution, genetik, uppväxtmiljö, ontogeni, ekologi och beteende som viktiga aspekter. Inte minst vid analys av smittsamma sjukdomar som HIV och influensa, och av motmedel som antibiotika. Selektion, evolution och beteende hos de inblandade organismerna reser ibland svåra stötestenarna för effektiv långsiktig behandling. Evolutionsbiologin är inte bara intellektuellt spännande, den får allt fler livsviktiga praktiska tillämpningar.
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| 6. |
- Andersson, Malte, 1941, et al.
(author)
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Biologisk mångfald föröds av jordens folkökning – nonchaleras av miljörörelser och media
- 2023
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In: Fauna och flora : populär tidskrift för biologi. - 0014-8903. ; 118:3, s. 28-36
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Journal article (other academic/artistic)abstract
- Världens ohållbara folkökning leder till miljöförstörelse och minskande biologisk mångfald. Vi har utplånat det mesta av jordens tidigare rika fauna av stora däggdjur. Idag är vår och tamdjurens biomassa 50 gånger större än för alla andra landdäggdjur tillsammans! Ändå har stora delar av miljö- rörelsen märkligt nog tystnat om världens snabba folkökning, som behöver hejdas snarast möjligt med de humanitära medel som står till buds.
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| 7. |
- Andersson, Malte, 1941, et al.
(author)
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Bromsa både folkökning och klimatändring
- 2021
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In: Svenska Dagbladet. ; :2 februari
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Journal article (pop. science, debate, etc.)abstract
- Många av dagens miljöproblem beror mer på folkökning än på klimatförändring. Svenskt bistånd skulle kunna göra stor skillnad
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| 8. |
- Andersson, Malte, 1941, et al.
(author)
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Brood parasitism, relatedness and sociality: a kinship role in female reproductive tactics
- 2019
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In: Biological Reviews. - : Wiley. - 1464-7931. ; 94:1, s. 307-327
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Journal article (peer-reviewed)abstract
- Conspecific brood parasitism (CBP) is a reproductive tactic in which parasitic females lay eggs in nests of other females of the same species that then raise the joint brood. Parasites benefit by increased reproduction, without costs of parental care for the parasitic eggs. CBP occurs in many egg-laying animals, among birds most often in species with large clutches and self-feeding young: two major factors facilitating successful parasitism. CBP is particularly common in waterfowl (Anatidae), a group with female-biased natal philopatry and locally related females. Theory suggests that relatedness between host and parasite can lead to inclusive fitness benefits for both, but if host costs are high, parasites should instead target unrelated females. Pairwise relatedness (r) in host-parasite (h-p) pairs of females has been estimated using molecular genetic methods in seven waterfowl (10 studies). In many h-p pairs, the two females were unrelated (with low r, near the local population mean). However, close relatives (r = 0.5) were over-represented in h-p pairs, which in all 10 studies had higher mean relatedness than other females. In one species where this was studied, h-p relatedness was higher than between nesting close neighbours, and hosts parasitized by non-relatives aggressively rejected other females. In another species, birth nest-mates (mother-daughters, sisters) associated in the breeding area as adults, and became h-p pairs more often than expected by chance. These and other results point to recognition of birth nest-mates and perhaps other close relatives. For small to medium host clutch sizes, addition of a few parasitic eggs need not reduce host offspring success. Estimates in two species suggest that hosts can then gain inclusive fitness if parasitized by relatives. Other evidence of female cooperation is incubation by old eider Somateria mollissima females of clutches laid by their relatives, and merging and joint care of broods of young. Merging females tended to be more closely related. Eiders associate with kin in many situations, and in some geese and swans, related females may associate over many years. Recent genetic evidence shows that also New World quails (Odontophoridae) have female-biased natal philopatry, CBP and brood merging, inviting further study and comparison with waterfowl. Kin-related parasitism also occurs in some insects, with revealing parallels and differences compared to birds. In hemipteran bugs, receiving extra eggs is beneficial for hosts by diluting offspring predation. In eggplant lace bugs Gargaphia solani, host and parasite are closely related, and kin selection favours egg donation to related females. Further studies of kinship in CBP, brood merging and other contexts can test if some of these species are socially more advanced than presently known.
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| 9. |
- Andersson, Malte, 1941
(author)
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Condition-dependent indicators in sexual selection: development of theory and tests
- 2006
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In: Essays in Animal Behaviour, celebrating 50 years of Animal Behaviour. - Burlington : Academic Press. - 9780123694997 ; , s. 255-269
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Book chapter (other academic/artistic)abstract
- Since ideas addressing sexual selection by condition-dependent indicators began to grow four decades ago there has been continuing progress, both in theoretical development and empirical testing. Mathematical models and empirical tests have led to indicator processes now being viewed as plausible, but their relative importance compared to Fisherian mating advantages (‘sexy sons’) and mate complementarity remains debated. There is much scope for imaginative empirical work to estimate the fitness consequences of mate choice and the relative strength of the different mechanisms. Measurements of mate choice costs may help determine the applicability of the models. Assumptions and predictions from indicator processes have been corroborated in many animals, but additional well-controlled studies of genetic aspects are needed, based for instance on maternal half-sib designs and artificial fertilization, also measuring fitness and offspring production over more than one generation if possible. This field is still full of open problems requiring a variety of empirical and theoretical approaches for their solution.
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| 10. |
- Andersson, Malte, 1941, et al.
(author)
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Don't Put All Your Eggs in One Nest: Spread Them and Cut Time at Risk
- 2012
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In: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 180:3, s. 354-363
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Journal article (peer-reviewed)abstract
- In many egg-laying animals, some females spread their clutch among several nests. The fitness effects of this reproductive tactic are obscure. Using mathematical modeling and field observations, we analyze an unexplored benefit of egg spreading in brood parasitic and other breeding systems: reduced time at risk for offspring. If a clutch takes many days to lay until incubation and embryo development starts after the last egg, by spreading her eggs a parasitic female can reduce offspring time in the vulnerable nest at risk of predation or other destruction. The model suggests that she can achieve much of this benefit by spreading her eggs among a few nests, even if her total clutch is large. Field data from goldeneye ducks Bucephala clangula show that egg spreading enables a fecund female to lay a clutch that is much larger than average without increasing offspring time at risk in a nest. This advantage increases with female condition (fecundity) and can markedly raise female reproductive success. These results help explain the puzzle of nesting parasites in some precocial birds, which lay eggs in the nests of other females before laying eggs in their own nest. Risk reduction by egg spreading may also play a role in the evolution of other breeding systems and taxa-for instance, polyandry with male parental care in some birds and fishes.
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