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  • 1.
    Andersson, Jens
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Söderlund, Tony
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Interactions between predator- and diet-induced phenotypic changes in body shape of crucian carp2006In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 273, no 1585, 431-437 p.Article in journal (Refereed)
    Abstract [en]

    Predator cues and diet, when studied separately, have been shown to affect body shape of organisms. Previous studies show that the morphological responses to predator absence/presence and diet may be similar, and hence could confound the interpretation of the causes of morphological differences found between groups of individuals. In this study, we simultaneously examined the effect of these two factors on body shape and performance in crucian carp in a laboratory experiment. Crucian carp (Carassius carassius) developed a shallow body shape when feeding on zooplankton prey and a deep body shape when feeding on benthic chironomids. In addition, the presence of chemical cues from a pike predator affected body shape, where a shallow body shape was developed in the absence of pike and a deep body shape was developed in the presence of pike. Foraging activity was low in the presence of pike cues and when chironomids were given as prey. Our results thereby suggest that the change in body shape could be indirectly mediated through differences in foraging activity. Finally, the induced body shape changes affected the foraging efficiency, where crucians raised on a zooplankton diet or in the absence of pike cues had a higher foraging success on zooplankton compared to crucian raised on a chironomid diet or in the presence of pike. These results suggest that body changes in response to predators can be associated with a cost, in terms of competition for resources.

  • 2.
    Brodin, T
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Johansson, F
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Conflicting selection pressures on the growth /predation trade-off in a damselfly larvae2004In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 85, 2927-2932 p.Article in journal (Refereed)
    Abstract [en]

    Activity is an important behavioral trait that in most animals mediates a trade-off between obtaining food for growth and avoiding predation. Active individuals usually experience a higher encounter rate with food items and predators and, as a consequence, grow faster and suffer higher predation pressure than less active individuals. We investigated how predator-induced mortality and growth of the damselfly Coenagrion hastulatum depend on activity at the level of the genotype. Larvae from six different C. hastulatum families were reared in two different predator treatments: predator present or absent. Families differed in activity, and active families grew to a significantly larger size than less-active families. Within families there was a plastic response to predators. Larvae reared without predators were more active and grew larger than larvae reared with a nonlethal predator. In the presence of a lethal predator the active families experienced higher mortality than the less active families. The results illustrate that the growth/predation-risk trade-off was mediated by activity and clearly show a cost of antipredator behavior. They also suggest that variation in activity level might be genetically regulated and could explain why C. hastulatum are abundant in aquatic systems both with and without potential predators.

  • 3.
    Brodin, Tomas
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Conflicting selection pressures on the growth/predation risk trade-off in a damselfly2004In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 85, no 11, 2927-2932 p.Article in journal (Refereed)
    Abstract [en]

    Activity is an important behavioral trait that in most animals mediates a trade-off between obtaining food for growth and avoiding predation. Active individuals usually experience a higher encounter rate with food items and predators and, as a consequence, grow faster and suffer higher predation pressure than less active individuals. We investigated how predator-induced mortality and growth of the damselfly Coenagrion hastulatum depend on activity at the level of the genotype. Larvae from six different C. hastulatum families were reared in two different predator treatments: predator present or absent. Families differed in activity, and active families grew to a significantly larger size than less-active families. Within families there was a plastic response to predators. Larvae reared without predators were more active and grew larger than larvae reared with a nonlethal predator. In the presence of a lethal predator the active families experienced higher mortality than the less active families. The results illustrate that the growth/predation-risk trade-off was mediated by activity and clearly show a cost of antipredator behavior. They also suggest that variation in activity level might be genetically regulated and could explain why C. hastulatum are abundant in aquatic systems both with and without potential predators.

  • 4.
    Brodin, Tomas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bergsten, Johannes
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Predator related oviposition site selection of aquatic beetles (Hydroporus spp.) and effects on offspring life-history2006In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 51, no 7, 1277-1285 p.Article in journal (Refereed)
    Abstract [en]

    1. Theory predicts that natural selection should favour females that are able to correctly assess the risk of predation and then use that information to avoid high-risk oviposition sites to reduce the risk of offspring predation. Despite the potential significance of such behaviour on individual fitness, population dynamics and community structure, relatively few studies of oviposition behaviour connected to the risk of predation have been carried out.

    2. However, some recent studies suggest that oviposition site selection in response to risk of predation may be a common phenomenon, at least among amphibians and mosquitoes. A vast majority of previous studies have, however, neglected to investigate how the offspring are affected, in terms of fitness related parameters, by the maternal oviposition site choice.

    3. In an outdoor artificial pond experiment we tested the oviposition site selection of female aquatic beetles (Hydroporus spp.) in relation to the presence or absence of a predatory fish (Perca fluviatilis). In addition, we monitored how the oviposition site selection affected the behaviour, growth and food resource of the progeny.

    4. We show that free-flying females of the aquatic beetles Hydroporus incognitus and H. nigrita prefer to oviposit in waters without fish compared with waters with fish. Larval activity of Hydroporus spp. was unaffected by fish presence. Our results indicate that beetle larvae from females that do lay eggs in waters with fish show increased growth compared with larvae in waters without fish. We explain this difference in growth by a higher per-capita food supply in the presence of a fish predator. This finding may have important implications for our understanding of how the variance of oviposition site selection in a population is sustained.

  • 5.
    Brodin, Tomas
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Mikolajewski, D.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Behavioural and life history effects of predator diet cues during ontogeny in a damselfly larvae2006In: Oecologia, Vol. 148, 162-169 p.Article in journal (Refereed)
  • 6. De Block, M.
    et al.
    Slos, S.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Stoks, R.
    Integrating life history and physiology to understand latitudinal size variation in a damselfly2008In: Ecography, Vol. 31, 115-123 p.Article in journal (Refereed)
    Abstract [en]

    Our understanding of latitudinal life history patterns may benefit by jointly considering age and mass at maturity and growth rate. Additional insight may be gained by exploring potential constraints through pushing growth rates to their maximum and scoring physiological cost-related variables. Therefore, we reared animals of a univoltine Spanish and Belgian population and of a semivoltine Swedish population of the damselfly Enallagma cyathigerum (spanning a latitude gradient of ca 2350 km) in a common environment from the eggs until adult emergence and exposed them to a transient starvation period to induce compensatory growth. Besides age and mass at maturity and growth rate we also scored investment in energy storage (i.e. triglycerides) and immune function (i.e. total activity of phenoloxidase). At emergence, body mass was greater in Spain and Sweden and lower in Belgium, suggesting a genetic component for the U-shaped latitudinal pattern that was found also in a previous study based on field-collected adults. The mass difference between univoltine populations can be explained by the shorter development time in the Belgian population, and this despite a higher growth rate, a pattern consistent with undercompensating countergradient variation. In line with the assumed shorter growth seasons, Belgian and Swedish animals showed higher routine growth rates and compensatory growth after transient starvation. Despite a strong link with metabolic rates (as measured by oxygen consumption) populations with higher routine growth rates had no lower fat content and had higher immune function (i.e. immune function decreased from Sweden to Spain), which was unexpected. Rapid compensatory growth did, however, result in a lowered immune function. This may contribute to the absence of perfect compensating countergradient variation in the Belgian population and the lowest routine growth rates in the Spanish population. Our results underscore the importance of integrating key life historical with physiological traits for understanding latitudinal population differentiation.

  • 7.
    Englund, Göran
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Olofsson, P
    Salonsaari, J
    Öhman, Johanna
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Predation leads to assembly rules in fragmented fish communities2009In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 12, 663-671 p.Article in journal (Refereed)
    Abstract [en]

    Diamond [Assembly of species communities. In: Ecology and Evolution of Communities (eds Cody, M.L. & Diamond, J.M.). Harvard University Press, Cambridge, pp. 342–444] proposed that resource competition leads to checkerboard-like distributions of competing species. This proposal prompted research that revealed checkerboard patterns within a wide range of communities, but the mechanisms that generate such patterns are still poorly understood. Here we present whole-lake natural experiments and analyses of species–environment relationships in small coastal lake fish communities that were fragmented when land uplift isolated these lakes from the Baltic Sea, showing that a combination of predation and habitat suitability generated checkerboard distributions. Checkerboard patterns developed because two piscivores, northern pike and Eurasian perch, caused the extinction of several prey species in deep lakes. Conversely, low oxygen levels in shallow lakes caused extinction of the piscivores, and these areas served as a refuge for tolerant prey species. Based on these findings, we suggest that habitat suitability and biotic interactions should be viewed simultaneously in null models of assembly rules.

  • 8. Hovmöller, Rasmus
    et al.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    A phylogenetic perspective on larval spine morphology in Leucorrhinia (Odonata: Libellulidae) based on ITS1, 5.8S, and ITS2 rDNA sequences.2004In: Mol Phylogenet Evol, ISSN 1055-7903, Vol. 30, no 3, 653-62 p.Article in journal (Refereed)
  • 9.
    Johansson , Frank
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Söderquist , Mårten
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Bokma, Folmer
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Insect wing shape evolution: independent effects of migratory and mate guarding flight on dragonfly2009In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 97, 362-372 p.Article in journal (Refereed)
    Abstract [en]

    Although, in some insect taxa, wing shape is remarkably invariant, the wings of Anisopteran dragonflies show considerable variation among genera. Because wing shape largely determines the high energetic costs of flight, it may be expected that interspecific differences are partly due to selection. In the present study, we examined the roles of long-distance migration and high-manoeuvrability mate guarding in shaping dragonfly wings, using a phylogeny-based comparative method, and geometric morphometrics to quantify wing shape. The results obtained show that migration affects the shape of both front and hind wings, and suggest that mate guarding behaviour may also have an effect, especially on the front wing. These effects on front wing shape are at least partly independent. Our findings are interesting when compared with the geographically widespread and ecologically diverse dipterans Acalyptratae (including the genus Drosophila). The wings in that group are similar in function and structure, but show strikingly low levels of interspecific variation.

  • 10.
    Johansson, F
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Crowley, P H
    Brodin, T
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Sexual size dimorphism and sex ratios in dragonflies (Odonata)2005In: Biological Journal of the Linnean Society, Vol. 86, 507-513 p.Article in journal (Refereed)
  • 11.
    Johansson, F
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Hjelm, J
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Giles, B E
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Life history and morphology of Rana temporaria in response to pool permanence2005In: Evolutionary Ecology Research, Vol. 7, 1025-1038 p.Article in journal (Refereed)
  • 12.
    Johansson, F
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Suhling, F
    Behaviour and growth of dragonfly larvae along a permanent to temporary water habitat gradient2004In: Ecological Entomology, Vol. 29, 196-202 p.Article in journal (Refereed)
  • 13.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Body shape differentiation among mitochondrial-DNA lineages of Zacco platypus and Opsariichthys bidens (Cyprinidae). from the Chang Jiang and Xi Jiang river drainage areas in southern China2006In: Acta Zoologica Sinica, Vol. 52, 948-953 p.Article in journal (Refereed)
  • 14.
    Johansson, Frank
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Andersson, Jens
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Scared fish get lazy, and lazy fish get fat2009In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 78, no 4, 772-777 p.Article in journal (Refereed)
    Abstract [en]

    Many biological textbooks present predator-induced morphological changes in prey species as an example of an adaptive response, because the morphological change is associated with lower predation risk. Here we show that the adaptive morphological response observed in many systems may actually be an indirect effect of decreased activity which reduces the predation risk rather than a direct adaptive response. One of the classical examples comes from crucian carp, where the presence of pike leads to a deeper body. We manipulated pike cues (presence and absence) and water current (standing and running water) and found that both standing water and pike cues similarly and independently induced a deeper body. Since the presence of pike cues as well as standing water might be associated with low swimming activity, we suggest that the presence of pike causes a reduction in activity (antipredator behaviour). Reduced activity subsequently induces a deeper body, possibly because the energy saved is allocated to a higher growth rate. Our result suggests that even if morphological change is adaptive, it might be induced indirectly via activity. This important conceptual difference may be similar in many other systems.

  • 15.
    Johansson, Frank
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Englund, Göran
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Gardfjell, Hans
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Species abundance models and patterns in dragonfly communities: effects of fish predation2006In: Oikos, Vol. 114, 27-36 p.Article in journal (Refereed)
  • 16.
    Johansson, Frank
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Fang, F
    Hiagen, X
    Fish communities in small and intermediate streams in Guangxi province China2006In: Journal of Freshwater Ecology, Vol. 21, 39-45 p.Article in journal (Refereed)
  • 17.
    Johansson, Frank
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lederer, Baptiste
    Lind, Martin I
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Trait performance correlations across life stages under environmental stress conditions in the common frog, Rana temporaria2010In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, no 7, e11680- p.Article in journal (Refereed)
    Abstract [en]

    If an organism's juvenile and adult life stages inhabit different environments, certain traits may need to be independently adapted to each environment. In many organisms, a move to a different environment during ontogeny is accompanied by metamorphosis. In such organisms phenotypic induction early in ontogeny can affect later phenotypes. In laboratory experiments we first investigated correlations between body morphology and the locomotor performance traits expressed in different life stages of the common frog, Rana temporaria: swimming speed and acceleration in tadpoles; and jump-distance in froglets. We then tested for correlations between these performances across life stages. We also subjected tadpoles to unchanging or decreasing water levels to explore whether decreasing water levels might induce any carry-over effects. Body morphology and performance were correlated in tadpoles; morphology and performance were correlated in froglets: hence body shape and morphology affect performance within each life stage. However, performance was decoupled across life stages, as there was no correlation between performance in tadpoles and performance in froglets. While size did not influence tadpole performance, it was correlated with performance of the metamorphosed froglets. Experiencing decreasing water levels accelerated development time, which resulted in smaller tadpoles and froglets, i.e., a carry-over effect. Interestingly, decreasing water levels positively affected the performance of tadpoles, but negatively affected froglet performance. Our results suggest that performance does not necessarily have to be correlated between life stages. However, froglet performance is size dependent and carried over from the tadpole stage, suggesting that some important size-dependent characters cannot be decoupled via metamorphosis.

  • 18.
    Johansson, Frank
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lind, Martin I.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ingvarsson, Pär K.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Bokma, Folmer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Evolution of the G-matrix in life history traits in the common frog during a recent colonisation of an island system2012In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 26, no 4, 863-878 p.Article in journal (Refereed)
    Abstract [en]

    Studies of genetic correlations between traits that ostensibly channel the path of evolution away from the direction of natural selection require information on key aspects such as ancestral phenotypes, the duration of adaptive evolution, the direction of natural selection, and genetic covariances. In this study we provide such information in a frog population system. We studied adaptation in life history traits to pool drying in frog populations on islands of known age, which have been colonized from a mainland population. The island populations show strong local adaptation in development time and size. We found that the first eigenvector of the variance-covariance matrix (g (max)) had changed between ancestral mainland populations and newly established island populations. Interestingly, there was no divergence in g (max) among island populations that differed in their local adaptation in development time and size. Thus, a major change in the genetic covariance of life-history traits occurred in the colonization of the island system, but subsequent local adaptation in development time took place despite the constraints imposed by the genetic covariance structure.

  • 19.
    Johansson, Frank
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Rådman, Petra
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Andersson, Jens
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    The relationship between ontogeny, morphology and diet in the Chinese hook snout carp (Opsariichthys bidens)2006In: Ichthyological Research, Vol. 53, 63-69 p.Article in journal (Refereed)
  • 20.
    Johansson, Frank
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sniegula, S
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Emergence patterns and latitudinal adaptations in development time of odonata in north Sweden and Poland2010In: Odonatologica, ISSN 0375-0183, Vol. 39, no 2, 97-106 p.Article in journal (Refereed)
    Abstract [en]

    Using exuviae, data are presented on emergence dates of dragonflies from northernSweden and northwestern Poland. The 17 spp. sampled in Sweden showed considerableoverlap in emergence periods. In Sweden, Leucorrhinia rubicunda was thefirst sp. to emerge (May 31) and Sympetrum danae the last (July 19). A comparison offirst dates of emergence of spp. in Sweden and Poland showed a difference between 9and 30 days, with all Polish spp. emerging first. Compared to spring species, summerspecies and obligate univoltine summer species showed less difference in first date ofemergence between Swedish and Polish populations. In a laboratory experiment Leucorrhiniadubia was reared from both regions from the egg to final instar larva undernorthern Swedish and northwestern Polish photoperiods. Swedish larvae developedfaster under a northern Swedish photoperiod compared to a northwestern Polish photoperiod.However, no such difference in development was found for northwesternPolish larvae. This suggests that there are genetic differences between both populationsin response to photoperiod. The results are discussed in the context of compensationof larval development of northern populations in relation to photoperiod.

  • 21.
    Jonsson, Micael
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Karlsson, Cecilia
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Intermediate predator impact on consumers weakens with increasing predator diversity in the presence of a top-predator2007In: Acta Oecologica, Vol. 31, no 1, 79-85 p.Article in journal (Refereed)
    Abstract [en]

    Adding or removing a top-predator is known to affect lower trophic levels with potentially large, indirect effects on primary production. However, little is known about how predator diversity may affect lower trophic levels, or how adding or removing a top-predator influences the effects of predator diversity. Using aquatic mesocosms containing three and four trophic levels, we tested whether intermediate predator diversity affected predation on consumers and if top-predator presence influenced such effects. We found that the presence of intermediate predators suppressed the consumer population and that this suppression tended to increase with increased intermediate predator diversity when the top-predator was absent. However, with the top-predator present, increased intermediate predator diversity showed the opposite effect on the consumers compared to without a top-predator, i.e. decreased suppression of consumers with increased diversity. Hence, in our study, the loss of intermediate predator species weakened or strengthened predator–prey interactions depending on if the top-predator was present or not, while loss of the top-predator only strengthened the predator–prey interactions. Therefore, the loss of a predator species may render different, but perhaps predictable effects on the functioning of a system depending on from which trophic level it is lost and on the initial number of species in that trophic level.

  • 22.
    Lind, M I
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Testing the role of phenotypic plasticity for local adaptation: growth and development in time-constrained Rana temporaria populations2011In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 24, no 12, 2696-2704 p.Article in journal (Refereed)
    Abstract [en]

    Phenotypic plasticity can be important for local adaptation, because it enables individuals to survive in a novel environment until genetic changes have been accumulated by genetic accommodation. By analysing the relationship between development rate and growth rate, it can be determined whether plasticity in life-history traits is caused by changed physiology or behaviour. We extended this to examine whether plasticity had been aiding local adaptation, by investigating whether the plastic response had been fixed in locally adapted populations. Tadpoles from island populations of Rana temporaria, locally adapted to different pool-drying regimes, were monitored in a common garden. Individual differences in development rate were caused by different foraging efficiency. However, developmental plasticity was physiologically mediated by trading off growth against development rate. Surprisingly, plasticity has not aided local adaptation to time-stressed environments, because local adaptation was not caused by genetic assimilation but on selection on the standing genetic variation in development time.

  • 23.
    Lind, Martin I
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ingvarsson, Pär K
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Helena
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hall, David
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gene flow and selection on phenotypic plasticity in an island system of rana temporaria2011In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 65, no 3, 684-697 p.Article in journal (Refereed)
    Abstract [en]

    Gene flow is often considered to be one of the main factors that constrains local adaptation in a heterogeneous environment. However, gene flow may also lead to the evolution of phenotypic plasticity. We investigated the effect of gene flow on local adaptation and phenotypic plasticity in development time in island populations of the common frog Rana temporaria which breed in pools that differ in drying regimes. This was done by investigating associations between traits (measured in a common garden experiment) and selective factors (pool drying regimes and gene flow from other populations inhabiting different environments) by regression analyses and by comparing pairwise F(ST) values (obtained from microsatellite analyses) with pairwise Q(ST) values. We found that the degree of phenotypic plasticity was positively correlated with gene flow from other populations inhabiting different environments (among-island environmental heterogeneity), as well as with local environmental heterogeneity within each population. Furthermore, local adaptation, manifested in the correlation between development time and the degree of pool drying on the islands, appears to have been caused by divergent selection pressures. The local adaptation in development time and phenotypic plasticity is quite remarkable, because the populations are young (less than 300 generations) and substantial gene flow is present among islands.

  • 24.
    Lind, Martin
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Costs and limits of phenotypic plasticity in island populations of the common frog Rana temporaria under divergent selection pressures2009In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 63, no 6, 1508-1518 p.Article in journal (Refereed)
    Abstract [en]

    Costs and limits are assumed to be the major constraints on the evolution of phenotypic plasticity. However, despite their expected importance, they have been surprisingly hard to find in natural populations. It has therefore been argued that natural selection might have removed high-cost genotypes in all populations. However, if costs of plasticity are linked to the degree of plasticity expressed, then high costs of plasticity would only be present in populations where increased plasticity is under selection. We tested this hypothesis by investigating costs and limits of adaptive phenotypic plasticity in development time in a common garden study of island populations of the common frog Rana temporaria, which have varying levels of development time and phenotypic plasticity. Costs of plasticity were only found in populations with high-plastic genotypes, whereas the populations with the most canalized genotypes instead had a cost of canalization. Moreover, individuals displaying the most extreme phenotypes also were the most plastic ones, which mean we found no limits of plasticity. This suggests that costs of plasticity increase with increased level of plasticity in the populations, and therefore costs of plasticity might be more commonly found in high-plastic populations.

  • 25.
    Lind, Martin
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    The degree of adaptive phenotypic plasticity is correlated with the spatial environmental heterogeneity experienced by island populations of Rana temporaria.2007In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 20, no 4, 1288-1297 p.Article in journal (Refereed)
    Abstract [en]

    Although theoretical models have identified environmental heterogeneity as a prerequisite for the evolution of adaptive plasticity, this relationship has not yet been demonstrated experimentally. Because of pool desiccation risk, adaptation of development rate is important for many amphibians. In a simulated pool-drying experiment, we compared the development time and phenotypic plasticity in development time of populations of the common frog Rana temporaria, originating from 14 neighbouring islands off the coast of northern Sweden. Drying regime of pools used by frogs for breeding differed within and among the islands. We found that the degree of phenotypic plasticity in development time was positively correlated with the spatial variation in the pool-drying regimes present on each island. In addition, local adaptation in development time to the mean drying rate of the pools on each island was found. Hence, our study demonstrates the connection between environmental heterogeneity and developmental plasticity at the island population level, and also highlights the importance of the interplay between local specialization and phenotypic plasticity depending on the local selection pressures.

  • 26.
    Lind, Martin
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Persbo, Frida
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Pool desiccation and developmental thresholds in the common frog, Rana temporaria.2008In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 275, no 1638, 1073-80 p.Article in journal (Refereed)
    Abstract [en]

    The developmental threshold is the minimum size or condition that a developing organism must have reached in order for a life-history transition to occur. Although developmental thresholds have been observed for many organisms, inter-population variation among natural populations has not been examined. Since isolated populations can be subjected to strong divergent selection, population divergence in developmental thresholds can be predicted if environmental conditions favour fast or slow developmental time in different populations. Amphibian metamorphosis is a well-studied life-history transition, and using a common garden approach we compared the development time and the developmental threshold of metamorphosis in four island populations of the common frog Rana temporaria: two populations originating from islands with only temporary breeding pools and two from islands with permanent pools. As predicted, tadpoles from time-constrained temporary pools had a genetically shorter development time than those from permanent pools. Furthermore, the variation in development time among females from temporary pools was low, consistent with the action of selection on rapid development in this environment. However, there were no clear differences in the developmental thresholds between the populations, indicating that the main response to life in a temporary pool is to shorten the development time.

  • 27. Mikolajewski, D J
    et al.
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Joop, G
    Phenotypic plasticity in gender specific life-history: effects of food availability and predation2005In: Oikos, Vol. 110, 91-100 p.Article in journal (Refereed)
    Abstract [en]

    If environmental conditions vary, plasticity in life-history traits is predicted. A recent model indicates that males and females should differ in life-history traits, because sexes differ in optimal attributes depending on species ecology. In this study we test the impact of two biotic factors in combination (presence/absence of predators and low/high food level) on gender specific life-history traits in the damselfly Coenagrion puella (Odonata). Results show that predator presence and low food density decreased activity in both sexes. Additionally, individuals with less food grew more slowly, emerged later, remained smaller and had a higher mortality. At low food densities, however, and in contrast to former investigations, individuals from treatments with predator presence were the same size or larger than individuals without predators. Gender had a strong impact on larval activity and life-history traits and sexes differed in development. Females were less active and took longer to complete development, but emerged at a larger size, weight and fat content. This study highlights the importance of gender specific approaches in life-history research.

  • 28. Mikolajewski, D J
    et al.
    Johansson, F
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Morphological and behavioral defenses in dragonfly larvae: trait compensation and co-specialization2004In: Behavioral Ecology, Vol. 15, 614-620 p.Article in journal (Refereed)
  • 29. Mikolajewski, D J
    et al.
    Johansson, F
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Brodin, T
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Condition dependent behaviour amongst damselfly populations2004In: Canadian Journal of Zoology, Vol. 82, 653-659 p.Article in journal (Refereed)
  • 30. Mikolajewski, Dirk J
    et al.
    De Block, Marjan
    Rolff, Jens
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Beckerman, Andrew P
    Stoks, Robby
    Predator-driven trait diversification in a dragonfly genus: covariation in behavioral and morphological antipredator defense2010In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 64, no 11, 3327-3335 p.Article in journal (Refereed)
    Abstract [en]

    Proof for predation as an agent shaping evolutionary trait diversification is accumulating, however, our understanding how multiple antipredator traits covary due to phenotypic differentiation is still scarce. Species of the dragonfly genus Leucorrhinia underwent shifts from lakes with fish as top predators to fishless lakes with large dragonfly predators. This move to fishless lakes was accompanied by a partial loss and reduction of larval spines. Here, we show that Leucorrhinia also reduced burst swimming speed and its associated energy fuelling machinery, arginine kinase activity, when invading fishless lakes. This results in patterns of positive phylogenetic trait covariation between behavioral and morphological antipredator defense (trait cospecialization) and between behavioral antipredator defense and physiological machinery (trait codependence). Across species patterns of trait covariation between spine status, burst swimming speed and arginine kinase activity also matched findings within the phenotypically plastic L. dubia. Our results highlight the importance of predation as a factor affecting patterns of multiple trait covariation during phenotypic diversification.

  • 31. Mikolajewski, Dirk Johannes
    et al.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Wohlfahrt, Bianca
    Stoks, Robby
    Invertebrate predation selects for the loss of a morphological antipredator trait.2006In: Evolution Int J Org Evolution, ISSN 0014-3820, Vol. 60, no 6, 1306-10 p.Article in journal (Refereed)
  • 32.
    Mobley, Kenyon B.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lussetti, Daniel
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Englund, Göran
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bokma, Folmer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Morphological and genetic divergence in Swedish postglacial stickleback (Pungitius pungitius) populations2011In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 11, 287- p.Article in journal (Refereed)
    Abstract [en]

    Background: An important objective of evolutionary biology is to understand the processes that govern phenotypic variation in natural populations. We assessed patterns of morphological and genetic divergence among coastal and inland lake populations of nine-spined stickleback in northern Sweden. Coastal populations are either from the Baltic coast (n = 5) or from nearby coastal lakes (n = 3) that became isolated from the Baltic Sea (< 100 years before present, ybp). Inland populations are from freshwater lakes that became isolated from the Baltic approximately 10,000 ybp; either single species lakes without predators (n = 5), or lakes with a recent history of predation (n = 5) from stocking of salmonid predators (~50 ybp).

    Results: Coastal populations showed little variation in 11 morphological traits and had longer spines per unit of body length than inland populations. Inland populations were larger, on average, and showed greater morphological variation than coastal populations. A principal component analysis (PCA) across all populations revealed two major morphological axes related to spine length (PC1, 47.7% variation) and body size (PC2, 32.9% variation). Analysis of PCA scores showed marked similarity in coastal (Baltic coast and coastal lake) populations. PCA scores indicate that inland populations with predators have higher within-group variance in spine length and lower within-group variance in body size than inland populations without predators. Estimates of within-group PST (a proxy for QST) from PCA scores are similar to estimates of FST for coastal lake populations but PST > FST for Baltic coast populations. PST > FST for PC1 and PC2 for inland predator and inland no predator populations, with the exception that PST < FST for body size in inland populations lacking predators.

    Conclusions: Baltic coast and coastal lake populations show little morphological and genetic variation within and between groups suggesting that these populations experience similar ecological conditions and that time since isolation of coastal lakes has been insufficient to demonstrate divergent morphology in coastal lake populations. Inland populations, on the other hand, showed much greater morphological and genetic variation characteristic of long periods of isolation. Inland populations from lakes without predators generally have larger body size, and smaller spine length relative to body size, suggesting systematic reduction in spine length. In contrast, inland populations with predators exhibit a wider range of spine lengths relative to body size suggesting that this trait is responding to local predation pressure differently among these populations. Taken together the results suggest that predation plays a role in shaping morphological variation among isolated inland populations. However, we cannot rule out that a causal relationship between predation versus other genetic and environmental influences on phenotypic variation not measured in this study exists, and this warrants further investigation.

  • 33.
    Nilsson-Örtman, Viktor
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Stoks, Robby
    De Block, Marjan
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Generalists and specialists along a latitudinal transect: patterns of thermal adaptation in six species of damselflies2012In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 93, no 6, 1340-1352 p.Article in journal (Refereed)
    Abstract [en]

    Tropical organisms colonizing temperate environments face reduced average temperatures and dramatic thermal fluctuations. Theoretical models postulate that thermal specialization should be favored either when little environmental variation is experienced within generations or when among-generation variation is small relative to within-generation variation. To test these predictions, we studied six temperate species of damselflies differing in latitudinal distribution. We developed a computer model simulating how organisms experience environmental variation (accounting for diapause and voltinism) and performed a laboratory experiment assaying thermal sensitivities of growth rates. The computer model showed opposing latitudinal trends in among-and within-generation thermal variability: within-generation thermal variability decreased toward higher latitudes, whereas relative levels of among-generation thermal variability peaked at midlatitudes (where a shift in voltinism occurred). The growth experiment showed that low-latitude species were more thermally generalized than mid- and high-latitude species, supporting the prediction that generalists are favored under high levels of within-generation variation. Northern species had steeper, near-exponential reaction norms suggestive of thermal specialization. However, they had strikingly high thermal optima and grew very slowly over most of the thermal range they are expected to experience in the field. This observation is at present difficult to explain. These results highlight the importance of considering interactions between life history and environmental variation when deriving expectations of thermal adaptation.

  • 34.
    Nilsson-Örtman, Viktor
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Stoks, Robby
    University of Leuven.
    De Block, Marjan
    University of Leuven.
    Johansson, Helena
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Latitudinally structured variation in the temperature dependence of damselfly growth rates2013In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 16, no 1, 64-71 p.Article in journal (Refereed)
    Abstract [en]

    The Metabolic Theory of Ecology predicts that the slope of the rate–temperature relationship, E, remains consistent across traits and organisms, acting as a major determinant of large-scale ecological patterns. Although E has recently been shown to vary systematically, we have a poor understanding of its ecological significance. To address this question, we conducted a common-garden experiment involving six damselfly species differing in distribution, estimating E at the level of full-sib families. Each species was sampled throughout its latitudinal range, allowing us to characterise variation in E along a latitudinal gradient spanning 3600 km. We show that E differs among populations and increases with latitude. E was right-skewness across species, but this was largely an artefact of the latitudinal trend. Increased seasonality towards higher latitude may contribute to the latitudinal trend in E. We conclude that E should be seen as a trait involved in local adaptation.

  • 35.
    Nilsson-Örtman, Viktor
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Stoks, Robby
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Competitive interactions modify the temperature dependence of damselfly growth rates2014In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 95, no 5, 1394-1406 p.Article in journal (Refereed)
    Abstract [en]

    Individual growth rates and survival are major determinants of individual fitness, population size structure, and community dynamics. The relationships between growth rate, survival, and temperature may thus be important for predicting biological responses to climate change. Although it is well known that growth rates and survival are affected by competition and predation in addition to temperature, the combined effect of these factors on growth rates, survival, and size structure has rarely been investigated simultaneously in the same ecological system. To address this question, we conducted experiments on the larvae of two species of damselflies and determined the temperature dependence of growth rate, survival, and cohort size structure under three scenarios of increasing ecological complexity: no competition, intraspecific competition, and interspecific competition. In one species, the relationship between growth rate and temperature became steeper in the presence of competitors, whereas that of survival remained unchanged. In the other species, the relationship between growth rate and temperature was unaffected by competitive interactions, but survival was greatly reduced at high temperatures in the presence of interspecific competitors. The combined effect of competitive interactions and temperature on cohort size structure differed from the effects of these factors in isolation. Together, these findings suggest that it will be challenging to scale up information from single-species laboratory studies to the population and community level.

  • 36. Outomuro, David
    et al.
    Bokma, Folmer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hind Wing Shape Evolves Faster than Front Wing Shape in Calopteryx Damselflies2012In: Evolutionary biology, ISSN 0071-3260, E-ISSN 1934-2845, Vol. 39, no 1, 116-125 p.Article in journal (Refereed)
    Abstract [en]

    Wing shape has been shown in a variety of species to be influenced by natural and sexual selection. In damselflies, front- and hind wings can beat independently, and functional differentiation may occur. Males of Calopteryx damselflies show species-specific nuptial flights that differ in colour signalling with the hind wings. Therefore, hind wing shape and colour may evolve in concert to improve colour display, independent of the front wings. We predicted that male hind wing shape evolves faster than front wing shape, due to sexual selection. Females do not engage in sexual displays, so we predicted that females do not show differences in divergence between front- and hind wing shape. We analysed the non-allometric component of wing shape of five European Calopteryx taxa using geometric morphometrics. We found a higher evolutionary divergence of hind wing shape in both sexes. Indeed, we found no significant differences in rate of evolution between the sexes, despite clear sex-specific differences in wing shape. We suggest that evolution of hind wing shape in males is accelerated by sexual selection on pre-copulatory displays and that this acceleration is reflected in females due to genetic correlations that somehow link the rates of wing shape evolution in the two sexes, but not the wing shapes themselves.

  • 37. Outomuro, David
    et al.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    The effects of latitude, body size, and sexual selection on wing shape in a damselfly2011In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 102, no 2, 263-274 p.Article in journal (Refereed)
    Abstract [en]

    Under natural selection, wing shape is expected to evolve to optimize flight performance. However, other selective factors besides flight performance may influence wing shape. One such factor could be sexual selection in wing sexual ornaments, which may lead to alternative variations in wing shape that are not necessarily related to flight performance. In the present study, we investigated wing shape variations in a calopterygid damselfly along a latitudinal gradient using geometric morphometrics. Both sexes show wing pigmentation, which is a known signal trait at intra- and interspecific levels. Wing shape differed between sexes and, within the same sex, the shape of the hind wing differed from the front wing. Latitude and body size explained a high percentage of the variation in wing shape for female front and hind wings, and male front wings. In male hind wings, wing pigmentation explained a high amount of the variation in wing shape. On the other hand, the variation in shape explained by pigmentation was very low in females. We suggest that the conservative morphology of front wings is maintained by natural selection operating on flight performance, whereas the sex-specific differences in hind wings most likely could be explained by sexual selection. The observed sexual dimorphism in wing shape is likely a result of different sex-specific behaviours. (C) 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102, 263-274.

  • 38.
    Petrin, Zlatko
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Schilling, Emily G
    Loftin, Cynthia S
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Predators shape distribution and promote diversification of morphological defenses in Leucorrhinia, Odonat2010In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 24, no 5, 1003-1016 p.Article in journal (Refereed)
    Abstract [en]

    Predators strongly influence species assemblages and shape morphological defenses of prey. Interestingly, adaptations that constitute effective defenses against one type of predator may render the prey susceptible to other types of predators. Hence, prey may evolve different strategies to escape predation, which may facilitate adaptive radiation of prey organisms. Larvae of different species in the dragonfly genus Leucorrhinia have various morphological defenses. We studied the distribution of these larvae in relation to the presence of predatory fish. In addition, we examined the variation in morphological defenses within species with respect to the occurrence of fish. We found that well-defended species, those with more and longer spines, were more closely associated with habitats inhabited by predatory fish and that species with weakly developed morphological defenses were more abundant in habitats without fish. The species predominantly connected to lakes with or without fish, respectively, were not restricted to a single clade in the phylogeny of the genus. Our data is suggestive of phenotypic plasticity in morphological defense in three of the studied species since these species showed longer spines in lakes with fish. We suggest that adaptive phenotypic plasticity may have broadened the range of habitats accessible to Leucorrhinia. It may have facilitated colonization of new habitats with different types of predators, and ultimately, speciation through adaptive radiation.

  • 39. Sniegula, Szymon
    et al.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Photoperiod affects compensating developmental rate across latitudes in the damselfly Lestes sponsa2010In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 35, no 2, 149-157 p.Article in journal (Refereed)
    Abstract [en]

    1. Although there is a great deal of theoretical and empirical data about the life history responses of time constraints in organisms, little is known about the latitude-compensating mechanism that enables northern populations' developmental rates to compensate for latitude. To investigate the importance of photoperiod on development, offspring of the obligatory univoltine damselfly Lestes sponsa from two populations at different latitudes (53°N and 63°N) were raised in a common laboratory environment at both northern and southern photoperiods that corresponded to the sites of collection.

    2. Egg development time was shorter under northern photoperiod regimes for both populations. However, the northern latitude population showed a higher phenotypic plasticity response to photoperiod compared with the southern latitude population, suggesting a genetic difference in egg development time in response to photoperiod.

    3. Larvae from both latitudes expressed shorter larval development time and faster growth rates under northern photoperiod regimes. There was no difference in phenotypic plastic response between northern and southern latitude populations with regard to development time.

    4. Data on field collected adults showed that adult sizes decreased with an increase in latitude. This adult size difference was a genetically fixed trait, as the same size difference between populations was also found when larvae were reared in the laboratory.

    5. The results suggest phenotypic plasticity responses in life history traits to photoperiod, but also genetic differences between north and south latitude populations in response to photoperiod, which indicates the presence of a latitudinal compensating mechanism that is triggered by a photoperiod.

  • 40. Sniegula, Szymon
    et al.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Nilsson-Örtman, Viktor
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Differentiation in developmental rate across geographic regions: a photoperiod driven latitude compensating mechanism?2012In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 121, no 7, 1073-1082 p.Article in journal (Refereed)
    Abstract [en]

    Genetic differentiation and phenotypic plasticity in growth rates along latitudinal gradients may benefit our understanding of latitudinal compensating mechanisms in life history patterns. Here we explore latitudinal compensatory growth mechanisms with respect to photoperiod in northern and southern populations of two damselfly species, Coenagrion puella and C. pulchellum. In addition we compared size of field-collected adults from southern and northern populations. Eggs from females in copulating tandems were collected at two or three localities for each species in each geographic region. Eggs were transported to the laboratory and the experiment started when the eggs hatched. The role of photoperiod on the expression of larval growth rate was evaluated under controlled laboratory conditions. Both species had lower growth rate when reared in the northern photoperiod, which is counter to expectations if species use photoperiodic cues to trigger compensatory growth. Instead, both species displayed countergradient variation in growth rates, which probably enable northern populations to compensate for the shorter growth season in the north. The smaller size of field-collected adults from northern populations also supports the view that these species compensate for the shorter growth season by investing in growth and development but accomplish this at the expense of decreased final size.

  • 41. Sniegula, Szymon
    et al.
    Nilsson-Örtman, Viktor
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Growth Pattern Responses to Photoperiod across Latitudes in a Northern Damselfly2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 9, e46024- p.Article in journal (Refereed)
    Abstract [en]

    Background: Latitudinal clines in temperature and seasonality impose strong seasonal constraints on ectotherms. Studies of population differentiation in phenotypic plasticity of life history traits along latitudinal gradients are important for understanding how organisms have adapted to seasonal environments and predict how they respond to climate changes. Such studies have been scarce for species with a northern distribution. Methodology/Principle Finding: Larvae of the northern damselfly Coenagrion johanssoni originating from semivoltine central, partivoltine northern, and partivoltine northernmost Swedish populations were reared in the laboratory. To investigate whether larvae use photoperiodic cues to induce compensatory growth along this latitudinal gradient, larvae were reared under two different photoperiods corresponding to a northern and southern latitude. In addition, field adult size was assessed to test the strength of possible compensatory growth mechanisms under natural conditions and hatchling size was measured to test for maternal effects. We hypothesized that populations originating from lower latitudes would be more time constrained than high-latitude populations because they have a shorter life cycle. The results showed that low-latitude populations had higher growth rates in summer/fall. In general northern photoperiods induced higher growth rates, but this plastic response to photoperiod was strongest in the southernmost populations and negligible in the northernmost population. During spring, central populations grew faster under the southern rather than the northern photoperiod. On the other hand, northern and northernmost populations did not differ between each other and grew faster in the northern rather than in the southern photoperiod. Field sampled adults did not differ in size across the studied regions. Conclusion/Significance: We found a significant differentiation in growth rate across latitudes and latitudinal difference in growth rate response to photoperiod. Importantly, growth responses measured at a single larval developmental stage in one season may not always generalize to other developmental stages or seasons.

  • 42. Stoks, R
    et al.
    De Block, M
    Van de Meutter, F
    Johansson, F
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Predation cost of rapid growth: behavioural coupling and physiological decoupling2005In: Journal of Animal Ecology, Vol. 74, 708-715 p.Article in journal (Refereed)
1 - 42 of 42
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