| 1. |
- Celorio-Mancera, Maria de la Paz, et al.
(författare)
-
Mechanisms of macroevolution : polyphagous plasticity in butterfly larvae revealed by RNA-Seq
- 2013
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 22:19, s. 4884-4895
-
Tidskriftsartikel (refereegranskat)abstract
- Transcriptome studies of insect herbivory are still rare, yet studies in model systems have uncovered patterns of transcript regulation that appear to provide insights into how insect herbivores attain polyphagy, such as a general increase in expression breadth and regulation of ribosomal, digestion- and detoxification-related genes. We investigated the potential generality of these emerging patterns, in the Swedish comma, Polygonia c-album, which is a polyphagous, widely-distributed butterfly. Urtica dioica and Ribes uva-crispa are hosts of P. c-album, but Ribes represents a recent evolutionary shift onto a very divergent host. Utilizing the assembled transcriptome for read mapping, we assessed gene expression finding that caterpillar life-history (i.e. 2nd vs. 4th-instar regulation) had a limited influence on gene expression plasticity. In contrast, differential expression in response to host-plant identified genes encoding serine-type endopeptidases, membrane-associated proteins and transporters. Differential regulation of genes involved in nucleic acid binding was also observed suggesting that polyphagy involves large scale transcriptional changes. Additionally, transcripts coding for structural constituents of the cuticle were differentially expressed in caterpillars in response to their diet indicating that the insect cuticle may be a target for plant defence. Our results state that emerging patterns of transcript regulation from model species appear relevant in species when placed in an evolutionary context.
|
|
| 2. |
- Gamberale-Stille, Gabriella, et al.
(författare)
-
Host plant choice in the comma butterfly-larval choosiness may ameliorate effects of indiscriminate oviposition
- 2014
-
Ingår i: Insect Science. - : Wiley. - 1672-9609 .- 1744-7917. ; 21:4, s. 499-506
-
Tidskriftsartikel (refereegranskat)abstract
- In most phytophagous insects, the larval diet strongly affects future fitness and in species that do not feed on plant parts as adults, larval diet is the main source of nitrogen. In many of these insect host plant systems, the immature larvae are considered to be fully dependent on the choice of the mothers, who, in turn, possess a highly developed host recognition system. This circumstance allows for a potential mother-offspring conflict, resulting in the female maximizing her fecundity at the expense of larval performance on suboptimal hosts. In two experiments, we aimed to investigate this relationship in the polyphagous comma butterfly, Polygonia c-album, by comparing the relative acceptance of low- and medium-ranked hosts between females and neonate larvae both within individuals between life stages, and between mothers and their offspring. The study shows a variation between females in oviposition acceptance of low-ranked hosts, and that the degree of acceptance in the mothers correlates with the probability of acceptance of the same host in the larvae. We also found a negative relationship between stages within individuals as there was a higher acceptance of lower ranked hosts in females who had abandoned said host as a larva. Notably, however, neonate larvae of the comma butterfly did not unconditionally accept to feed from the least favorable host species even when it was the only food source. Our results suggest the possibility that the disadvantages associated with a generalist oviposition strategy can be decreased by larval participation in host plant choice.
|
|
| 3. |
- Janz, Niklas, et al.
(författare)
-
No effect of larval experience on adult host preferences in Polygonia c-album (Lepidoptera: Nymphalidae): on the persistence of Hopkins' host selection principle
- 2009
-
Ingår i: Ecological Entomology. - Oxford : Blackwell. - 0307-6946 .- 1365-2311. ; 34:1, s. 50-57
-
Tidskriftsartikel (refereegranskat)abstract
- 1. The possible effect of juvenile imprinting or 'chemical legacy' on the subsequent oviposition - often called the 'Hopkins' host selection principle' - has been a controversial but recurrent theme in the literature on host-plant preference. While it appears possible in principle, experimental support for the hypothesis is equivocal. The present study points out that it is also important to consider its theoretical implications, and asks under what circumstances, if any, it should be favoured by natural selection. 2. Following this reasoning, it is predicted that host preference in the polyphagous butterfly Polygonia c-album L. (Lepidoptera, Nymphalidae) should not be influenced by larval environment. This was tested by rearing larvae on three natural host plants: the high-ranked Urtica dioica and the medium-ranked Salix cinerea and Ribes uva-crispa, and exposing the naive females to oviposition choices involving the same set of plants. 3. It was found that larval host plant had no effect on oviposition decisions of the adult female. Hence, the Hopkins' host selection principle does not seem to be applicable in this species. 4. Based on recent insights on how accuracy of environmental versus genetic information should affect the control of developmental switches, the conditions that could favour the use of juvenile cues in oviposition decisions are discussed. Although the Hopkins' host selection hypothesis cannot be completely ruled out, we argue that the circumstances required for it to be adaptive are so specific that it should not be invoked as a general hypothesis for host selection in plant-feeding insects.
|
|
| 4. |
- Moberg, Christina, et al.
(författare)
-
De unga gör helt rätt när de stämmer staten
- 2022
-
Ingår i: Aftonbladet. - 1103-9000.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
|
|
| 5. |
- Nylin, Sören, 1959-, et al.
(författare)
-
Geographical variation in host plant utilization in the comma butterfly: the roles of time constraints and plant phenology
- 2009
-
Ingår i: Evolutionary Ecology. - Dordrecht : Springer. - 0269-7653 .- 1573-8477. ; 23, s. 807-825
-
Tidskriftsartikel (refereegranskat)abstract
- What is the role of time-constraints in determining geographical variation in the resource use of organisms? One hypothesis concerning phytophagous insects predicts a local narrowing of host plant range at localities where a short development time is important (because an additional generation per season is only just possible), with increased specialization on host plants permitting fast development. To test this hypothesis, populations of the polyphagous comma butterfly (Nymphalidae: Polygonia c-album) from five European areas (localities in Norway, Sweden, England, Belgium and Spain) were sampled and the preferences of laboratory-reared female butterflies were investigated, by a choice test between Salix caprea and the fastest host Urtica dioica. The results suggest that females of both of two northern univoltine populations (time-stressed from Norway and time-relaxed from Sweden) accept the slow host S. caprea to a higher degree than females of more southern populations with partial additional generations (time-stressed). We thus found partial support for the tested hypothesis, but also conflicting results that cast doubt on its broad generality. Moreover, a split-brood investigation on Swedish stock demonstrated that larval performance is similar on S. caprea and U. dioica early in the summer, but that later in the season S. caprea is a much inferior host. This is reflected by a seasonal trend towards specialization on U. dioica and also provides a simpler explanation than the time-constraints theory for avoidance of S. caprea (and other woody hosts) in areas with two or more generations of insects per year, illustrating the importance of plant phenology as a constraint on resource use in phytophagous insects. Absolute and relative larval performance on the two hosts varied little among populations across Europe, but lower survival on S. caprea in the populations most specialized on U. dioica and related plants may be indicative of performance trade-offs.
|
|
| 6. |
- Nylin, Sören, et al.
(författare)
-
Vestiges of an ancestral host plant: preference and performance in the butterfly Polygonia faunus and its sister species P. c-album
- 2015
-
Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 40:3, s. 307-315
-
Tidskriftsartikel (refereegranskat)abstract
- 1. In the study of the evolution of insect-host plant interactions, important information is provided by host ranking correspondences among female preference, offspring preference, and offspring performance. Here, we contrast such patterns in two polyphagous sister species in the butterfly family Nymphalidae, the Nearctic Polygonia faunus, and the Palearctic P. c-album. 2. These two species have similar host ranges, but according to the literature P. faunus does not use the ancestral host plant clade-the urticalean rosids'. Comparisons of the species can thus test the effects of a change in insect-plant associations over a long time scale. Cage experiments confirmed that P. faunus females avoid laying eggs on Urtica dioica (the preferred host of P. c-album), instead preferring Salix, Betula, and Ribes.3. However, newly hatched larvae of both species readily accept and grow well on U. dioica, supporting the general theory that evolutionary changes in host range are initiated through shifts in female host preferences, whereas larvae are more conservative and also can retain the capacity to perform well on ancestral hosts over long time spans.4. Similar rankings of host plants among female preference, offspring preference, and offspring performance were observed in P. c-album but not in P. faunus. This is probably a result of vestiges of larval adaptations to the lost ancestral host taxon in the latter species. 5. Female and larval preferences seem to be largely free to evolve independently, and consequently larval preferences warrant more attention.
|
|
| 7. |
- Söderlind, Gustaf, et al.
(författare)
-
Adaptive Time-Stepping and Computational Stability
- 2006
-
Ingår i: Journal of Computational and Applied Mathematics. - : Elsevier BV. - 0377-0427. ; 185, s. 225-243
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the effects of adaptive time-stepping and other algorithmic strategies on the computational stability of ODE codes. We show that carefully designed adaptive algorithms have a most significant impact on computational stability and reliability. A series of computational experiments with the standard implementation of Dassl and a modified version, including stepsize control based on digital filters, is used to demonstrate that relatively small algorithmic changes are able to extract a vastly better computational stability at no extra expense. The inherent performance and stability of Dassl are therefore much greater than the standard implementation seems to suggest.
|
|
| 8. |
- Söderlind, Gustaf, et al.
(författare)
-
Evaluating Numerical ODE/DAE Methods, Algorithms and Software
- 2006
-
Ingår i: Journal of Computational and Applied Mathematics. - : Elsevier BV. - 0377-0427. ; 185:2, s. 244-260
-
Tidskriftsartikel (refereegranskat)abstract
- Until recently, the testing of ODE/DAE software has been limited to simple comparisons and benchmarking. The process of developing software from a mathematically specified method is complex: it entails constructing control structures and objectives, selecting iterative methods and termination criteria, choosing norms and many more decisions. Most software constructors have taken a heuristic approach to these design choices, and as a consequence two different implementations of the same method may show significant differences in performance. Yet it is common to try to deduce from software comparisons that one method is better than another. Such conclusions are not warranted, however, unless the testing is carried out under true ceteris paribus conditions. Moreover, testing is an empirical science and as such requires a formal test protocol; without it conclusions are questionable, invalid or even false. We argue that ODE/DAE software can be constructed and analyzed by proven, ''standard'' scientific techniques instead of heuristics. The goals are computational stability, reproducibility, and improved software quality. We also focus on different error criteria and norms, and discuss modifications to Daspk and Radau5. Finally, some basic principles of a test protocol are outlined and applied to testing these codes on a variety of problems.
|
|
| 9. |
- Söderlind, Lina, 1982-, et al.
(författare)
-
Effects of sequential diets in the comma butterfly, Polygonia c-album: testing predictions from gene expression
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Differential gene expression, depending on host plant diet, has been found in the larval mid-gut of the polyphagous butterfly Polygonia c-album. Expression similarities between the hosts elm/sallow and between elm/stinging nettle suggest that there are special patterns of genes for utilizing trees and others for urticalean rosids. In order to assess the importance of different genes tailored to host use, we investigated the costs of switching larval diet. Negative effects were expected to be more pronounced when switching between nettle/sallow than between elm/nettle (urticalean rosids) or elm/sallow (trees) since similarities in mid-gut gene expression are fewer. However, larvae seemed surprisingly good at adjusting to new environments. Although costs were found after a single switch from sallow to nettle in the 3rd instar as well as on a daily basis the results were not consistent. More surprisingly, we found evidence that costs are involved with a single diet switch to elm. Results suggest rapid physiological adjustment to the new environment, signifying that the induced gene expression is reversible or at least does not seem to inhibit the induction of another gene complex.
|
|
| 10. |
- Söderlind, Lina, et al.
(författare)
-
Genetics of diapause in the comma butterfly Polygonia c-album
- 2011
-
Ingår i: Physiological entomology (Print). - : Wiley. - 0307-6962 .- 1365-3032. ; 36:1, s. 8-13
-
Tidskriftsartikel (refereegranskat)abstract
- The processes of local adaptation and ecological speciation can be better understood by studying the genetic background of life-history decisions. The sex chromosomes host genes for many population differences in the Lepidoptera and therefore the inheritance of diapause determination in the butterfly Polygonia c-album may be hypothesized to be sex-linked. In the present study, Polygonia c-album (L.) from Spain and Sweden and hybrid offspring are raised under an LD 17 : 7 h photocycle that induces most pure Swedish individuals to develop into the diapausing dark morph and most pure Spanish individuals into the light and directly-developing morph. If inheritance of the daylength threshold for diapause is X-linked, as is known to be the case for host-plant preferences, females should follow the developmental path of their male parents' populations. However, female hybrids instead have a diapause propensity intermediate to that of their parental stocks and, consequentially, diapause determination is not X-linked. However, male hybrids eclose as the diapausing morph to a higher extent than females and, moreover, this pattern is more pronounced in the Spanish female x Swedish male cross than in the reciprocal cross. Hence, it is concluded that the genetic determination of the critical daylength for diapause is mainly autosomal but with some influence of sex-linked genes and/or parental effects, possibly as an effect of the importance of protandry for males. Such sex effects could provide a starting point for the evolution of population differences inherited on the sex chromosomes.
|
|
| 11. |
|
|
| 12. |
- Söderlind, Lina, 1982-
(författare)
-
Life-history consequenses of host plant choice in the comma butterfly
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is much evidence that herbivory is a key innovation for the tremendous success of insect. In this thesis I have investigated different aspects of host plant utilization and phenotypic plasticity using the polyphagous comma butterfly, Polygonia c-album. Even though external conditions affect a phenotypic plastic response, the outcome is often influenced by a genetic background which may differ among populations. In Paper I we suspected the genetic background to seasonal polymorphism to be X-linked. However, results from interspecific hybridization between two populations suggested that diapause response is instead inherited in a mainly autosomally additive fashion, with a possible influence of sexual antagonism on males. In Paper II we showed that female oviposition preference is not a plastic response influenced by larval experience, but has a genetic background coupled to host plant suitability. Further, there is a strong individual correlation between larval host plant acceptance and female host plant specificity (Paper III). We believe this to be a larval feed-back genetically linked to female host specificity: offspring to ‘choosy’ specialist mothers benefit by remaining on the original host while offspring to less discriminating generalist mothers should risk inspecting the surroundings, thus compensating for potential poor female choice. In the larval mid-gut, genes are differentially expressed depending on host plant diet (Paper IV). Therefore, we expected to find fitness consequences of host plant switch. However, although growth rate was affected in a few treatments, larvae were generally surprisingly good at adjusting to new diets (Paper V). To conclude, host plant choice in both female and larval life stage is connected to performance. Combined with increased understanding about the plastic response to diet intake and seasonal polymorphism we have gained further insights into the processes of local adaptations and speciation in the Lepidoptera.
|
|
| 13. |
- Söderlind, Lina, 1982-, et al.
(författare)
-
When mother does not know best : Contrasting host plant choice across life stages in individuals of the comma butterfly
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Since host plant choice is often crucial for the fitness of herbivorous insects we investigated if individual variation in such decisions is consistent throughout life. In the comma butterfly, Polygonia c-album, (Nymphalidae, Nymphalini) newly hatched larvae and adult females have been found to rank hosts plants similarly, suggesting that the host plant recognition mechanisms could be preserved through metamorphosis. We measured preference for Urtica dioica relative to Salix cinerea when the plants were encountered by the same individuals in the two different life stages, finding no relationship between the two measurements. This was however found when we instead measured acceptance of a suboptimal host: First instar larvae were placed on the suboptimal S. cinerea, and were scored as to whether they accepted this host or if they instead moved to feed on the generally more preferred host U. dioica. The same individuals were then tested once more as ovipositing females, in a cage setup arranged so that females would encounter the low-ranked hosts S. cinerea and Betula pubescens more often than the high-ranked host U. dioica.Individuals that chose to abandon S. cinerea as larvae differed in oviposition behaviour later in life from those that accepted this low-ranked host, but did so by laying a higher proportion eggs on the low-ranked hosts as adults. We interpret this initially unexpected result as a result of possible genetic correlation between female host-plant specificity and larval acceptance for the plant chosen by their mother: Offspring of ‘choosy’ specialist mothers have a strong tendency to remain on their original host, whereas less discriminating generalist mothers beget larvae with lower acceptance for their original plant when it is suboptimal. Ecologically, this presents a further explanation for how a generalist oviposition strategy can be sustained since larval mobility to some extent compensates for poor female choice.
|
|
