| 1. |
- Balkenius, Anna, et al.
(författare)
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Colour preferences influences odour learning in the hawkmoth, Macroglossum stellatarum
- 2006
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Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904 .- 0028-1042. ; 93:5, s. 255-258
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Tidskriftsartikel (refereegranskat)abstract
- The hummingbird hawkmoth, Macroglossum stellatarum, learns colour fast and reliably. It has earlier been shown to spontaneously feed from odourless artificial flowers. Now, we have studied odour learning. The moths were trained to discriminate feeders of the same colour but marked with different odours. They did not learn to discriminate two natural flower odours when they were presented with the innately preferred colour blue, but they did learn this discrimination combined with yellow or green colours that are less attractive to the moth. The yellow colour could be trained to become as attractive as the innately preferred blue colour and the blue colour could be trained to become less attractive. This is the first proof of odour learning in a diurnal moth. The results show that M. stellatarum can use more than one modality in their foraging behaviour and that the system is plastic. By manipulating the preferences for the different colours, their influence on odour learning could be changed.
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| 2. |
- Dalsätt, Johan, 1969-, et al.
(författare)
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Food remains in Confuciusornis sanctus suggest a fish diet.
- 2006
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Ingår i: Die Naturwissenschaften. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 93:9, s. 444-6
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Tidskriftsartikel (refereegranskat)abstract
- Despite hundreds of excellent fossils of Confuciusornis, the most abundant group of birds in the Early Cretaceous, 'Jehol Biota' in China, there is yet no indication of the food choice of these birds. Here, we describe fish remains preserved in the alimentary system of a specimen of Confuciusornis sanctus from the Jiufotang Formation. This find is about five million years younger than all previously published confuciusornithid birds from the Yixian Formation. Although it is unknown how common fish was in the diet of Confuciusornis, the find does not support previous hypotheses that it fed on plants or grain.
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| 3. |
- Goyret, Joaquin, et al.
(författare)
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Why do Manduca sexta feed from white flowers? Innate and learnt colour preferences in a hawkmoth
- 2008
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Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904 .- 0028-1042. ; 95:6, s. 569-576
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Tidskriftsartikel (refereegranskat)abstract
- Flower colour is an important signal used by flowering plants to attract pollinators. Many anthophilous insects have an innate colour preference that is displayed during their first foraging bouts and which could help them locate their first nectar reward. Nevertheless, learning capabilities allow insects to switch their colour preferences with experience and thus, to track variation in floral nectar availability. Manduca sexta, a crepuscular hawkmoth widely studied as a model system for sensory physiology and behaviour, visits mostly white, night-blooming flowers lacking UV reflectance throughout its range in the Americas. Nevertheless, the spectral sensitivity of the feeding behaviour of naive moths shows a narrow peak around 450 nm wavelengths, suggesting an innate preference for the colour blue. Under more natural conditions (i.e. broader wavelength reflectance) than in previous studies, we used dual choice experiments with blue- and white-coloured feeders to investigate the innate preference of naive moths and trained different groups to each colour to evaluate their learning capabilities. We confirmed the innate preference of M. sexta for blue and found that these moths were able to switch colour preferences after training experience. These results unequivocally demonstrate that M. sexta moths innately prefer blue when presented against white flower models and offer novel experimental evidence supporting the hypothesis that learning capabilities could be involved in their foraging preferences, including their widely observed attraction to white flowers in nature.
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| 4. |
- Hettyey, Attila, et al.
(författare)
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Does testis weight decline towards the Subarctic? : a case study on the common frog, Rana temporaria
- 2005
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Ingår i: Die Naturwissenschaften. - 0028-1042 .- 1432-1904. ; 92:4, s. 188-192
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Tidskriftsartikel (refereegranskat)abstract
- Interpopulation comparisons of variation in resource availability and in allocation patterns along altitudinal and latitudinal gradients allow insights into the mechanisms shaping the life history of animals. Patterns of between-population differences in female life history traits have been studied intensively across a wide range of taxa, but similar investigations in males have remained scarce. To study if testis weight-a measure of reproductive investment-varies on a geographical scale in anurans, we focussed on the variation in relative testis weight (RelTW) and asymmetry in 22 populations of the common frog Rana temporaria along a 1,600-km latitudinal transect across the Scandinavian peninsula. We found that RelTW decreased towards the north. Body mass and body length both had independent positive effects on testes mass. We found evidence for directional asymmetry (DA) in testis weight with the right testis being larger than the left. The level of DA in testis weight was not related to latitude, but both body mass and testes mass had independent positive effects on asymmetry. We discuss the northwards decrease in RelTW in terms of a decreased reproductive investment as a possible consequence of harsher environmental conditions, and perhaps also, weaker sexual selection in the north than in the south.
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| 5. |
- Hettyey, A, et al.
(författare)
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Does testis weight decline towards the Subarctic? A case study on the common frog, Rana temporaria
- 2005
-
Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904 .- 0028-1042. ; 92:4, s. 188-192
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Tidskriftsartikel (refereegranskat)abstract
- Interpopulation comparisons of variation in resource availability and in allocation patterns along altitudinal and latitudinal gradients allow insights into the mechanisms shaping the life history of animals. Patterns of between-population differences in female life history traits have been studied intensively across a wide range of taxa, but similar investigations in males have remained scarce. To study if testis weight - ameasure of reproductive investment - varies on a geographical scale in anurans, we focussed on the variation in relative testis weight (RelTW) and asymmetry in 22 populations of the common frog Rana temporaria along a 1,600-km latitudinal transect across the Scandinavian peninsula. We found that RelTW decreased towards the north. Body mass and body length both had independent positive effects on testes mass. We found evidence for directional asymmetry (DA) in testis weight with the right testis being larger than the left. The level of DA in testis weight was not related to latitude, but both body mass and testes mass had independent positive effects on asymmetry. We discuss the northwards decrease in RelTW in terms of a decreased reproductive investment as a possible consequence of harsher environmental conditions, and perhaps also, weaker sexual selection in the north than in the south.
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| 6. |
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| 9. |
- Ryne, Camilla, et al.
(författare)
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Do anthropogenic transports facilitate stored-product pest moth dispersal? A molecular approach
- 2008
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Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904 .- 0028-1042. ; 95:2, s. 155-159
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Tidskriftsartikel (refereegranskat)abstract
- Stored-product moths cause large economic damage in food-processing industries and storage facilities. Control of indoor pests is currently dealt with locally, and control strategies seldom include different mills or cooperative industries in joint efforts to reduce infestations. In colder climates where conditions hinder flight dispersal of stored-product moths, we hypothesize that human transport between mills will facilitate dispersal. Albeit considered intuitive, this hypothesis has so far never been tested. Male moths from three mills (populations) in southern Sweden and Denmark were collected and by using AFLP pair-wise Fst values were calculated. Cluster (population) origins of the genotypes were computed by using a model-based method, STRUCTURE. The results indicate that known transportation of flour between two mills generate genetically more similar populations of the economically important stored-product moth, Ephestia kuehniella (Zell.) (Lepidoptera; Pyralidae), compared to the third mill, with another distribution area, but situated geographically in between the other mills. The STRUCTURE model placed the sampled genotypes to belong to either two or five original populations, with a higher probability of two original populations. The third mill was consistently different from the other two mills independent of the models’ calculated number of populations. Although the study was restricted to three mills and one transportation route, it highlights the possibility that transportation of food products promotes genetic mixing (i.e. dispersal) of insect pest populations. Including cooperating mills in control (or monitor) strategy schemes against stored-product pest insects would therefore be a more effective action rather than to treat each mill separately.
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| 10. |
- Tellgren-Roth, Asa, et al.
(författare)
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Keeping the blood flowing-plasminogen activator genes and feeding behavior in vampire bats
- 2009
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Ingår i: Die Naturwissenschaften. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 96:1, s. 39-47
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Tidskriftsartikel (refereegranskat)abstract
- The blood feeding vampire bats emerged from New World leaf-nosed bats that fed on fruit and insects. Plasminogen activator, a serine protease that regulates blood coagulation, is known to be expressed in the saliva of Desmodus rotundus (common vampire bat) and is thought to be a key enzyme for the emergence of blood feeding in vampire bats. To better understand the evolution of this biological function, we studied the plasminogen activator (PA) genes from all vampire bat species in light of their feeding transition to bird and subsequently mammalian blood. We include the rare species Diphylla ecaudata and Diaemus youngi, where plasminogen activator had not previously been studied and demonstrate that PA gene duplication observed in Desmodus is not essential to the vampire phenotype, but relates to the emergence of predominant mammalian blood feeding in this species. Plasminogen activator has evolved through gene duplication, domain loss, and sequence evolution leading to change in fibrin-specificity and susceptibility to plasminogen activator inhibitor-1. Before undertaking this study, only the four plasminogen activator isoforms from Desmodus were known. The evolution of vampire bat plasminogen activators can now be linked phylogenetically to the transition in feeding behavior among vampire bat species from bird to mammalian blood.
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