62971. |
- Stenberg, Johan A, et al.
(författare)
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Tall herb herbivory resistance reflects historic exposure to leaf beetles in a boreal archipelago age-gradient.
- 2006
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 148:3, s. 414-425
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we introduce the coevolution-by-coexistence hypothesis which predicts that the strength of a coevolutionary adaptation will become increasingly apparent as long as the corresponding selection from an interacting counterpart continues. Hence, evolutionary interactions between plants and their herbivores can be studied by comparing discrete plant populations with known history of herbivore colonization. We studied populations of the host plant, Filipendula ulmaria (meadow sweet), on six islands, in a Bothnian archipelago subject to isostatic rebound, that represent a spatio-temporal gradient of coexistence with its two major herbivores, the specialist leaf beetles Galerucella tenella and Altica engstroemi. Regression analyses showed that a number of traits important for insect-plant interactions (leaf concentrations of individual phenolics and condensed tannins, plant height, G. tenella adult feeding and oviposition) were significantly correlated with island age. First, leaf concentrations of condensed tannins and individual phenolics were positively correlated with island age, suggesting that plant resistance increased after herbivore colonization and continued to increase in parallel to increasing time of past coexistence, while plant height showed a reverse negative correlation. Second, a multi-choice experiment with G. tenella showed that both oviposition and leaf consumption of the host plants were negatively correlated with island age. Third, larvae performed poorly on well-defended, older host populations and well on less-defended, younger populations. Thus, no parameter assessed in this study falsifies the coevolution-by-coexistence hypothesis. We conclude that spatio-temporal gradients present in rising archipelagos offer unique opportunities to address evolutionary interactions, but care has to be taken as abiotic (and other biotic) factors may interact in a complicated way.
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62972. |
- Stenberg, Johan, et al.
(författare)
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Herbivore-induced “rent-rise” in the host plant may drive a diet breadth enlargement in the tenant.
- 2008
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Ingår i: Ecology. ; 89, s. 126-133
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Tidskriftsartikel (refereegranskat)abstract
- Inter- and intra-species variations in host-plant traits are presumably involved in many host-shifts by insect herbivores, and elucidating the mechanisms involved in such shifts has been a crucial goal in insect-plant research for several decades. Here we propose that herbivore-induced evolutionary increases in host plant resistance may cause oligophagous insect herbivores to shift to other sympatric plants as currently preferred host plants become increasingly unpalatable. We tested this hypothesis in a system based on the perennial herb Filipendula ulmaria (Rosaceae), whose herbivory defense has become gradually stronger due to prolonged selection by Galerucella tenella (Coleoptera: Chrysomelidae) herbivory in a boreal archipelago. We show that Galerucella gradually increases its’ use of the alternative host plant Rubus arcticus (Rosaceae) in parallel to gradually increased resistance in Filipendula. Our results imply that by driving the evolutionary increase in Filipendula resistance, Galerucella is also gradually making the original host species more unpalatable and thereby driving its own host-breadth enlargement. We argue that such self-inflicted ‘rent rises’ may be an important mechanism behind host-plant shifts, which in turn are believed to have preceded speciation of many phytophagous insects.
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62973. |
- Stenberg, Lennart
(författare)
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Fina fynd i Norrbotten 2018
- 2018
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Ingår i: Nordrutan. ; 23:1, s. 7-10
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Tidskriftsartikel (populärvet., debatt m.m.)
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62974. |
- Stenberg, Lennart
(författare)
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Fina växtfynd under 2020
- 2021
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Ingår i: Nordrutan. ; 26:1, s. 10-13
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Tidskriftsartikel (populärvet., debatt m.m.)
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62975. |
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62976. |
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62977. |
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62978. |
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62979. |
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62980. |
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