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- Abrun, Pouria, et al.
(författare)
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Wolbachia impairs post-eclosion host preference in a parasitoid wasp
- 2021
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Ingår i: Science of Nature. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 108:2
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Tidskriftsartikel (refereegranskat)abstract
- Host preference behavior can result in adaptive advantages with important consequences for the fitness of individuals. Hopkin’s host-selection principle (HHSP) suggests that organisms at higher trophic levels demonstrate a preference for the host species on which they developed during their own larval stage. Although investigated in many herbivorous and predatory insects, the HHSP has, to our knowledge, never been tested in the context of insects hosting selfish endosymbiotic passengers. Here, we investigated the effect of infection with the facultative bacterial symbiont Wolbachia on post-eclosion host preference in the parasitoid wasp Trichogramma brassicae (Hymenoptera: Trichogrammatidae). We compared host preference in Wolbachia-infected individuals and uninfected adult female parasitoids after rearing them on two different Lepidopteran hosts, namely the flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) or the grain moth Sitotroga cerealella (Lepidoptera: Gelechiidae) in choice and no choice experimental design (n = 120 wasps per each choice/no choice experiments). We showed that in T. brassicae, Wolbachia affects the post-eclosion host preference of female wasps. Wolbachia-infected wasps did not show any host preference and more frequently switched hosts in the laboratory, while uninfected wasps significantly preferred to lay eggs on the host species they developed on. Additionally, Wolbachia significantly improved the emergence rate of infected wasps when reared on new hosts. Altogether, our results revealed that the wasp’s infection with Wolbachia may lead to impairment of post-eclosion host preference and facilitates growing up on different host species. The impairment of host preference by Wolbachia may allow T. brassicae to shift between hosts, a behavior that might have important evolutionary consequences for the wasp and its symbiont.
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| 2. |
- Arnemo, Jon
(författare)
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Seasonal changes in eicosanoid metabolism in the brown bear
- 2018
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Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 105
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Tidskriftsartikel (refereegranskat)abstract
- Polyunsaturated fatty acids (PUFAs) exert several important functions across organ systems. During winter, hibernators divert PUFAs from oxidation, retaining them in their tissues and membranes, to ensure proper body functions at low body temperature. PUFAs are also precursors of eicosanoids with pro- and anti-inflammatory properties. This study investigated seasonal changes in eicosanoid metabolism of free-ranging brown bears (Ursus arctos). By using a lipidomic approach, we assessed (1) levels of specific omega-3 and omega-6 fatty acids involved in the eicosanoid cascade and (2) concentrations of eicosanoids in skeletal muscle and blood plasma of winter hibernating and summer active bears. We observed significant seasonal changes in the specific omega-3 and omega-6 precursors. We also found significant seasonal alterations of eicosanoid levels in both tissues. Concentrations of pro-inflammatory eicosanoids, such as thromboxane B2, 5-hydroxyeicosatetraenoic acid (HETE), and 15-HETE and 18-HETE, were significantly lower in muscle and/or plasma of hibernating bears compared to summer-active animals. Further, plasma and muscle levels of 5,6-epoxyeicosatrienoic acid (EET), as well as muscle concentration of 8,9-EET, tended to be lower in bears during winter hibernation vs. summer. We also found lower plasma levels of anti-inflammatory eicosanoids, such as 15dPGJ(2) and PGE(3), in bears during winter hibernation. Despite of the limited changes in omega-3 and omega-6 precursors, plasma and muscle concentrations of the products of all pathways decreased significantly, or remained unchanged, independent of their pro- or anti-inflammatory properties. These findings suggest that hibernation in bears is associated with a depressed state of the eicosanoid cascade.
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| 3. |
- 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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| 4. |
- Ballen, Cissy, et al.
(författare)
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Predictors of telomere content in dragon lizards
- 2012
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Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904 .- 0028-1042. ; 99:8, s. 661-664
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Tidskriftsartikel (refereegranskat)abstract
- Telomeres shorten as a consequence of DNA replication, in particular in cells with low production of telomerase and perhaps in response to physiological stress from exposure to reactive oxygen species, such as superoxide. This process of telomere attrition is countered by innate antioxidation, such as via the production of superoxide dismutase. We studied the inheritance of telomere length in the Australian painted dragon lizard (Ctenophorus pictus) and the extent to which telomere length covaries with masscorrected maternal reproductive investment, which reflects the level of circulating yolk precursor and antioxidant, vitellogenin. Our predictors of offspring telomere length explained 72 % of telomere variation (including interstitial telomeres if such are present). Maternal telomere length and reproductive investment were positively influencing offspring telomere length in our analyses, whereas flow cytometry-estimated superoxide level was negatively impacting offspring telomere length. We suggest that the effects of superoxide on hatchling telomere shortening may be partly balanced by transgenerational effects of vitellogenin antioxidation.
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| 8. |
- Bywater, Robert P., et al.
(författare)
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The preferred conformation of dipeptides in the context of biosynthesis
- 2013
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Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 1432-1904 .- 0028-1042. ; 100:9, s. 853-859
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Tidskriftsartikel (refereegranskat)abstract
- Globular proteins are folded polypeptide structures comprising stretches of secondary structures (helical (alpha- or 3(10) helix type), polyproline helix or beta-strands) interspersed by regions of less well-ordered structure ("random coil"). Protein fold prediction is a very active field impacting inte alia on protein engineering and misfolding studies. Apart from the many studies of protein refolding from the denatured state, there has been considerable interest in studying the initial formation of peptides during biosynthesis, when there are at the outset only a few residues in the emerging polypeptide. Although there have been many studies employing quantum chemical methods of the conformation of dipeptides, these have mostly been carried out in the gas phase or simulated water. None of these conditions really apply in the interior confines of the ribosome. In the present work, we are concerned with the conformation of dipeptides in this low dielectric environment. Furthermore, only the residue types glycine and alanine have been studied by previous authors, but we extend this repertoire to include leucine and isoleucine, position isomers which have very different structural propensities.
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| 9. |
- 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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| 10. |
- Dekker, Teun
(författare)
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Olfaction in the female sheep botfly
- 2010
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Ingår i: Naturwissenschaften. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 97, s. 827-835
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Tidskriftsartikel (refereegranskat)abstract
- The nasal botfly Oestrus ovis (Diptera, Cyclorrhapha: Oestridae) is a myiasis-causing insect species, which affects the health of sheep, goats and humans. Gravid females are viviparous and larviposit into the animal's nostrils. Host-searching and larvipositing flies are visually guided and influenced by climatic conditions, whereas olfaction seemed to play no role in this process. However, here, we show that the antennae of adult O. ovis female flies are relatively small but well developed and inhabited by several types of olfactory sensilla. Further, we show that the antennal lobes of this species receive input from antennal afferents and consist of a clearly defined glomerular organisation. We also give the first evidence of the fly's ability to detect several synthetic odour compounds. Our findings provide a morpho-functional basis for future investigations on olfactory-mediated behaviour of this insect pest.
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