| 41. |
- Lind, Johan, et al.
(författare)
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Body-building and concurrent mass loss: flight adaptations in tree sparrows
- 2001
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 268:1479, s. 1915-1919
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Tidskriftsartikel (refereegranskat)abstract
- Environmental changes are responsible for the evolution of flexible physiology and the extent of phenotypic plasticity in the regulation of birds' organ size has not been appreciated until recently. Rapid reversible physiological changes during different life–history stages are virtually only known from long–distance migrants, and few studies have focused on less extreme aspects of organ flexibility. During moult, birds suffer from increased wing loading due to wing–area reductions, which may impair flight ability. A previous study found that tree sparrows' escape flight (Passer montanus) is unaffected during moult, suggesting compensatory aptness. We used non–invasive techniques to study physiological adaptations to increased wing loading in tree sparrows. As wing area was reduced during natural moult the ratio of pectoral–muscle size to body mass increased. When moult was completed this ratio decreased. We show experimentally a novel, strategic, organ–flexibility pattern. Unlike the general pattern, where body mass is positively coupled to pectoral–muscle size, tree sparrows responded within 7 days to reductions in wing area by reducing body mass concurrently with an increase in pectoral–muscle size. This rapid flexibility in a non–migratory species probably reflects the paramount importance and long history of flight in birds.
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| 42. |
- Lind, Johan, et al.
(författare)
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Detection distance influencing escape behaviour in two parids (Parus major and P. caeruleus)
- 2003
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Ingår i: Journal of Avian Biology. - 0908-8857 .- 1600-048X. ; 34:3, s. 233-236
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Tidskriftsartikel (refereegranskat)abstract
- When birds are attacked by aerial predators they should benefit by adjusting their escape to the prevailing attack situation. One important factor likely to affect escape decisions of prey, to our knowledge not previously studied, is the distance at which the attacking predator is detected. We investigated if great tits Parus major and blue tits P. caeruleus alter their escape behaviour to two different detection distances (2.3 m and 1m) by simulating surprise attacks using a predator model. Both species used the information about detection distance when escaping by increasing the escape angle at the shorter detection distance. In addition, blue tits adjusted to the shorter detection distance by dodging sideways more frequently. Great tits escaped initially steeper and faster than blue tits, whereas blue tits increased escape angle and speed more than great tits along the measured distance after taking wing
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| 43. |
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| 44. |
- Lind, Johan, et al.
(författare)
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Split-second escape decisions in blue tits (Parus caeruleus)
- 2002
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Ingår i: Die Naturwissenschaften. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 89:9, s. 420-423
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Tidskriftsartikel (refereegranskat)abstract
- Bird mortality is heavily affected by birds of prey. Under attack, take-off is crucial for survival and even minor mistakes in initial escape response can have devastating consequences. Birds may respond differently depending on the character of the predator's attack and these split-second decisions were studied using a model merlin (Falco columbarius) that attacked feeding blue tits (Parus caeruleus) from two different attack angles in two different speeds. When attacked from a low attack angle they took off more steeply than when attacked from a high angle. This is the first study to show that escape behaviour also depends on predator attack speed. The blue tits responded to a high-speed attack by dodging sideways more often than when attacked at a low speed. Escape speed was not significantly affected by the different treatments. Although they have only a split-second before escaping an attack, blue tits do adjust their escape strategy to the prevailing attack conditions.
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| 45. |
- Lindskog, Magnus, et al.
(författare)
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Overall survival in Swedish patients with renal cell carcinoma treated in the period 2002 to 2012: Update of the RENCOMP study with subgroup analysis of the synchronous metastatic and elderly populations
- 2017
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Ingår i: Urologic Oncology-Seminars and Original Investigations. - : Elsevier BV. - 1078-1439 .- 1873-2496. ; 35:9, s. 541.e15-541.e22
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Tidskriftsartikel (refereegranskat)abstract
- Background: This retrospective study investigated overall survival (OS) and factors influencing OS in Swedish patients with metastatic renal cell carcinoma (mRCC) during the pre- (2002-2005), early (2006-2008), and late (2009-2012) targeted therapy (TT) era. Methods: Three national Swedish registries identified patients with mRCC. Median OS was estimated using the Kaplan-Meier method. Multivariate analysis was performed using Cox proportional hazards regression. Subgroup analysis was conducted for patients with synchronous metastases (Ml) and the elderly (aged >= 75 y). Results: A total of 4,217 patients with mRCC were identified, including 1,533 patients with Ml and 1,275 elderly patients. For patients with mRCC diagnosed in 2002 to 2005, 2006 to 2008, and 2009 to 2012, median OS was 10.0, 13.0, and 18.0 months. Similarly, median OS improved in the M1 and elderly populations. Elderly patients were less likely to be prescribed TT (>= 75 vs. <75 y): 18.3 vs. 63.5% (in 2006-2008) and 28.6% vs. 55.9% (in 2009-2012). Diagnosis of mRCC in 2009 to 2012, nephrectomy and TT prescription were associated with improved OS in the total mRCC, Ml, and elderly populations. Conclusion: This real-world study showed continued significant improvement in mRCC OS during the late TT era, including in Ml and elderly populations. TT should be considered for all patients with mRCC based on tolerability, regardless of age. (C) 2017 Elsevier Inc. All rights reserved.
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| 46. |
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| 47. |
- Lisovski, Simeon, et al.
(författare)
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The Indo-European flyway : Opportunities and constraints reflected by Common Rosefinches breeding across Europe
- 2021
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Ingår i: Journal of Biogeography. - : Wiley. - 0305-0270 .- 1365-2699. ; 48:6, s. 1255-1266
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The configuration of the earth's landmasses influences global weather systems and spatiotemporal resource availability, thereby shaping biogeographical patterns and migratory routes of animals. Here, we aim to identify potential migratory barriers and corridors, as well as general migration strategies within the understudied Indo-European flyway. Location Europe, Central Asia. Major taxon studied Common rosefinches.Methods: We used a combination of theoretical optimization modelling and empirical tracking of Common Rosefinches (Carpodacus erythrinus) breeding across a large latitudinal gradient in Europe. First, we identified optimal migration routes driven by wind and resource availability along the Indo-European flyway. Second, we tracked rosefinches from five breeding populations using light-level geolocators. Finally, we compared to what extent empirical tracks overlapped with the modelled optimal routes.Results: In autumn, theoretical wind driven migration routes formed a broad-front corridor connecting Europe and the Indian Subcontinent while the theoretical resource driven routes formed a distinct north-south divide. The latter pattern also reflected the rosefinch tracks with all but the most southerly breeding birds making a northern detour towards non-breeding sites in Pakistan and India. In spring, the resource availability model predicted a similar migratory divide, however, the southern route seemed relatively more favourable and closely matched with the optimal wind driven migration routes. Spring tracking data showed larger overlap with the modelled wind driven migration routes compared to the resource driven routes.Main conclusions: Optimal wind and resource driven migration routes along the Indo-European flyway are seasonally specific and to a large extend do not overlap with one another. Under these conditions, migratory birds adopt seasonally distinct migration strategies following energy minimization strategy in autumn, driven by resource availability, and time minimizing strategy in spring, driven by wind conditions. Our optimal migration models can be applied worldwide and used to validate against empirical data to explain large-scale biogeographic pattern of migratory animals.
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| 48. |
- Løvlie, Hanne, 1977-
(författare)
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Pre- and post-copulatory sexual selection in the fowl, Gallus gallus
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The evolutionary goal of individuals is reproduction and sexual selection favours traits improving reproductive success. When males invest less than females in offspring, males have potentially a higher reproductive rate than females. This typically results in sex-specific reproductive strategies of male-male competition and female choice of mating partner. Under polyandry, sexual selection can continue after copulation as sperm competition and cryptic female choice. This thesis focuses on male and female pre- and post-copulatory reproductive strategies in the promiscuous red junglefowl, Gallus gallus ssp., and its domestic subspecies the domestic fowl, Gallus gallus domesticus. Males impose high re-mating rates on females, which triggers female resistance in copulations. In addition, when sexual harassment increases, females re-mate at times of day when male mating propensity is lower, to avoid intense sexual harassment. Males allocate sperm supplies differentially according to (i) variation in female polyandry and own competitive ability, (ii) earlier sperm investment in a female, and (iii) female reproductive quality, signalled by female comb size. Males also perform ‘aspermic’ copulations (i.e. copulations with no semen transfer), which inhibit polyandry and in turn reduce sperm competition. In mating opportunities with relatives, males do not avoid inbreeding. However, females avoid inbreeding before copulation through kin recognition and after copulation by selecting against related males’ sperm. These results show that selection on males to re-mate at higher rates than females and copulate indiscriminately according to partner relatedness, trigger counteracting female responses, creating the potential for sexual conflict over fertilisation. Teasing apart pre- and post-copulatory strategies and the contribution of each sex therefore becomes crucial in order to understand the evolution of reproductive strategies and the mechanisms affecting paternity.
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| 49. |
- Olofsson, Martin, et al.
(författare)
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Auditory defence in the peacock butterfly (Inachis io) against mice (Apodemus flavicollis and A. sylvaticus)
- 2012
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 66:2, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- Morphological and behavioural traits can serve as anti-predator defence either by reducing detection or recognition risks, or by thwarting initiated attacks. The latter defence is secondary and often involves a 'startle display' comprising a sudden release of signals targeting more than one sensory modality. A suggested candidate for employing a multimodal defence is the peacock butterfly, Inachis io, which, by wing-flicking suddenly, produces sonic and ultrasonic sounds and displays four large eyespots when attacked. The eyespots make small birds retreat, but whether the sounds produced thwart predator attacks is largely unknown. Peacocks hibernate as adults in dark wintering sites and employ their secondary defence upon encounter with small rodent predators during this period. In this study, we staged predator-prey encounters in complete darkness in the laboratory between wild mice, Apodemus flavicollis and Apodemus sylvaticus, and peacocks which had their sound production intact or disabled. Results show that mice were more likely to flee from sound-producing butterflies than from butterflies which had their sound production disabled. Our study presents experimental evidence that the peacock butterfly truly employs a multimodal defence with different traits targeting different predator groups; the eyespots target birds and the sound production targets small rodent predators.
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| 50. |
- Olofsson, Martin, 1980-, et al.
(författare)
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Bird attacks on a butterfly with marginal eyespots and the role of prey concealment against the background : Marginal eyespots can deflect bird attacks
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Small eyespots on butterflies have long been thought to deflect attacks and birds are presumptive drivers selecting for these patterns. However, evidence of this function is still ambiguous. Marginal eyespots typically consist of a UV-reflective white pupil, surrounded by one black and one yellowish ring. We have recently shown that blue tits attack such eyespots, but only under low light intensities with accentuated UV-levels. An increased salience of the eyespots relative to the rest of the butterfly probably explains this result. Possibly, a background against which the butterfly is concealed may deceive birds to making similar errors. We therefore presented speckled wood butterflies provided with eyespots (or controls without eyespots) to blue tits against two backgrounds, oak- and birch bark. Results show that (i) eyespots, independent of background, were effective in deflecting attacks, (ii) the time elapsed between a bird’s landing and attack was interactively dependent on background and whether the butterfly bore an eyespot and (iii) the speed at which a butterfly was attacked predicted the outcome, with faster birds being more prone to errors than slower birds. This underscores a speed-accuracy tradeoff in the predators and that background plays a role in the defensive qualities of marginal eyespots.
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