| 1. |
- Johansson, Frank, et al.
(författare)
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Mixed support for an alignment between phenotypic plasticity and genetic differentiation in damselfly wing shape
- 2023
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Ingår i: Journal of Evolutionary Biology. - : John Wiley & Sons. - 1010-061X .- 1420-9101. ; 36:2, s. 368-380
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Tidskriftsartikel (refereegranskat)abstract
- The relationship between genetic differentiation and phenotypic plasticity can provide information on whether plasticity generally facilitates or hinders adaptation to environmental change. Here, we studied wing shape variation in a damselfly (Lestes sponsa) across a latitudinal gradient in Europe that differed in time constraints mediated by photoperiod and temperature. We reared damselflies from northern and southern populations in the laboratory using a reciprocal transplant experiment that simulated time-constrained (i.e. northern) and unconstrained (southern) photoperiods and temperatures. After emergence, adult wing shape was analysed using geometric morphometrics. Wings from individuals in the northern and southern populations differed significantly in shape when animals were reared in their respective native environment. Comparing wing shape across environments, we found evidence for phenotypic plasticity in wing shape, and this response differed across populations (i.e. G x E interactions). This interaction was driven by a stronger plastic response by individuals from the northern population and differences in the direction of plastic wing shape changes among populations. The alignment between genetic and plastic responses depended on the specific combination of population and rearing environment. For example, there was an alignment between plasticity and genetic differentiation under time-constrained, but not under non-time-constrained conditions for forewings. We thus find mixed support for the hypothesis that environmental plasticity and genetic population differentiation are aligned. Furthermore, although our laboratory treatments mimicked the natural climatic conditions at northern and southern latitudes, the effects of population differences on wing shape were two to four times stronger than plastic effects. We discuss our results in terms of time constraints and the possibility that natural and sexual selection is acting differently on fore- and hindwings.
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| 2. |
- Corral-Lopez, Alberto, et al.
(författare)
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Field evidence for colour mimicry overshadowing morphological mimicry
- 2021
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Ingår i: Journal of Animal Ecology. - : John Wiley & Sons. - 0021-8790 .- 1365-2656. ; 90:3, s. 698-709
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Tidskriftsartikel (refereegranskat)abstract
- Imperfect mimicry may be maintained when the various components of an aposematic signal have different salience for predators. Experimental laboratory studies provide robust evidence for this phenomenon. Yet, evidence from natural settings remains scarce.We studied how natural bird predators assess multiple features in a multicomponent aposematic signal in the Neotropical ‘clear wing complex’ mimicry ring, dominated by glasswing butterflies.We evaluated two components of the aposematic signal, wing colouration and wing morphology, in a predation experiment based on artificial replicas of glasswing butterflies (model) and Polythoridae damselflies (mimics) in their natural habitat. We also studied the extent of the colour aposematic signal in the local insect community. Finally, we inspected the nanostructures responsible for this convergent colour signal, expected to highly differ between these phylogenetically distinct species.Our results provide direct evidence for a stronger salience of wing colouration than wing morphology, as well as stronger selection on imperfect than in perfect colour mimics. Additionally, investigations of how birds perceive wing colouration of the local insect community provides further evidence that a UV‐reflective white colouration is being selected as the colour aposematic signal of the mimicry ring. Using electron microscopy, we also suggest that damselflies have convergently evolved the warning colouration through a pre‐adaptation.These findings provide a solid complement to previous experimental evidence suggesting a key influence of the cognitive assessment of predators driving the evolution of aposematic signals and mimicry rings.
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| 3. |
- Eroukhmanoff, Fabrice, et al.
(författare)
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Patterns of Phenotypic Divergence in Wing Covariance Structure of Calopterygid Damselflies
- 2009
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Ingår i: Evolutionary Biology. - : Springer Science and Business Media LLC. - 0071-3260 .- 1934-2845. ; 36:2, s. 214-224
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Forskningsöversikt (refereegranskat)abstract
- Comparing species differences in covariance patterns of traits subject to divergent selection pressures can increase our understanding to the mechanisms of phenotypic divergence. Different species of calopterygid damselflies have diverged in the melanized wing patch of males. This trait serves multiple ecological functions and has behavioral consequences in terms of sexual selection, interspecific interactions, reproductive isolation. We compared the phenotypic variance-covariance matrices (P) of wing traits among nine populations of four European species of calopterygid damselflies. We found modest divergence in covariance structure among populations of the same species, but strong divergence between species. Interestingly, the orientation of the first eigenvector of P (P (max) ) differed more between closely related species than between distantly related species, although this pattern was absent when overall covariance structures were compared. We also found that distantly related species but geographically closer had converged towards a similar covariance structure. Finally, divergence in covariance structure was correlated with divergence in wing patch length, but not with other wing traits. This last finding suggests that divergent selection on wing patch length might have affected the stability of P. These results indicate that P might not only reflect ancestral developmental pathways but might also be influenced by current ecology.
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| 4. |
- Glenszczyk, Mateusz, et al.
(författare)
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The jumping spider Saitis barbipes lacks a red photoreceptor to see its own sexually dimorphic red coloration
- 2022
-
Ingår i: Science of Nature. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 109:1
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Tidskriftsartikel (refereegranskat)abstract
- Examining the role of color in mate choice without testing what colors the study animal is capable of seeing can lead to ill-posed hypotheses and erroneous conclusions. Here, we test the seemingly reasonable assumption that the sexually dimorphic red coloration of the male jumping spider Saitis barbipes is distinguishable, by females, from adjacent black color patches. Using microspectrophotometry, we find clear evidence for photoreceptor classes with maximal sensitivity in the UV (359 nm) and green (526 nm), inconclusive evidence for a photoreceptor maximally sensitive in the blue (451 nm), and no evidence for a red photoreceptor. No colored filters within the lens or retina could be found to shift green sensitivity to red. To quantify and visualize whether females may nevertheless be capable of discriminating red from black color patches, we take multispectral images of males and calculate photoreceptor excitations and color contrasts between color patches. Red patches would be, at best, barely discriminable from black, and not discriminable from a low-luminance green. Some color patches that appear achromatic to human eyes, such as beige and white, strongly absorb UV wavelengths and would appear as brighter “spider-greens” to S. barbipes than the red color patches. Unexpectedly, we discover an iridescent UV patch that contrasts strongly with the UV-absorbing surfaces dominating the rest of the spider. We propose that red and black coloration may serve identical purposes in sexual signaling, functioning to generate strong achromatic contrast with the visual background. The potential functional significance of red coloration outside of sexual signaling is discussed.
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| 5. |
- Kunce, Warren, et al.
(författare)
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Combined effects of microplastics and a pyrethroid on the benthic invertebrate, Chironomus Riparius
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- There is growing evidence of widespread contamination of freshwater ecoystems with microplastics, plastic polymers that are < 5 mm. While a wide variety of organisms have been reported to ingest microplastics, the biological effects of chronic microplastic ingestion are not well understood. Microplastics can adsorb organic pollutants in aqueous environments which made lead to increased exposure to these chemicals if desorption occurs after ingestion. Alternatively, relatively clean microplastics may adsorb chemicals in the gut decreasing their bioavailability. This study investigates the effects of chronic sediment exposure to latex-based polystyrene microspheres alone and in combination with the pyrethroid pesticide, esfenvalerate, on the life-history traits of the benthic invertebrate, Chironomus riparius, under two scenarios: abundant food and limited food. We found that chronic sediment exposure to 1.0 and 10.0 µm latex-based polystyrene latex microspheres, a low concentration of esfenvalerate and a combination of the 1.0 µm microspheres and esfenvalerate led to no significant effects on survival, development time, emergence, or sex of C. riparius when food was abundant. However, effects of exposure did become apparent when food was insufficient indicating that these contaminants may be stressors with an energy cost to the organism.
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| 6. |
- Outomuro, David, et al.
(författare)
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A potential pitfall in studies of biological shape : Does size matter?
- 2017
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 86:6, s. 1447-1457
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Forskningsöversikt (refereegranskat)abstract
- 1. The number of published studies using geometric morphometrics (GM) for analysing biological shape has increased steadily since the beginning of the 1990s, covering multiple research areas such as ecology, evolution, development, taxonomy and palaeontology. Unfortunately, we have observed that many published studies using GM do not evaluate the potential allometric effects of size on shape, which normally require consideration or assessment. This might lead to misinterpretations and flawed conclusions in certain cases, especially when size effects explain a large part of the shape variation. 2. We assessed, for the first time and in a systematic manner, how often published studies that have applied GM consider the potential effects of allometry on shape. 3. We reviewed the 300 most recent published papers that used GM for studying biological shape. We also estimated how much of the shape variation was explained by allometric effects in the reviewed papers. 4. More than one-third (38%) of the reviewed studies did not consider the allometric component of shape variation. In studies where the allometric component was taken into account, it was significant in 88% of the cases, explaining up to 87.3% of total shape variation. We believe that one reason that may cause the observed results is a misunderstanding of the process that superimposes landmark configurations, i.e. the Generalized Procrustes Analysis, which removes isometric effects of size on shape, but not allometric effects. 5. Allometry can be a crucial component of shape variation. We urge authors to address, and report, size effects in studies of biological shape. However, we do not propose to always remove size effects, but rather to evaluate the research question with and without the allometric component of shape variation. This approach can certainly provide a thorough understanding of how much size contributes to the observed shaped variation.
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| 7. |
- Outomuro, David, et al.
(författare)
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A preliminary study on female-limited colour polymorphism in Lestes sponsa
- 2014
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Ingår i: INT J ODONATOL. - : Worldwide Dragonfly Association. - 1388-7890. ; 17:2-3, s. 89-93
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Tidskriftsartikel (refereegranskat)abstract
- Female-limited colour polymorphisms are widespread in Odonata, usually showing an androchrome and one or more gynochromes. Androchromes have been hypothesized to function as male mimics with a consequent decrease of male harassment, although males may also learn to recognize the different female colour morphs. In the Eurasian damselfly Lestes sponsa, the occurrence of two female colour morphs (androchrome and gynochrome) has been known since the beginning of the twentieth century, although this has been generally overlooked. In this work, we studied a Swedish population of L. sponsa by counting the number of females of each morph during nine consecutive days, as well as the number of tandems. Androchromes showed blue pruinescence at similar body parts as males, although more limited at the tip of the abdomen. Moreover, androchromes also showed bright blue coloured eyes as males. We found no indication that androchromes might be a result of age changes in female coloration. The androchrome morph accounted for 19% of the female population. Androchromes did not form tandems at a lower frequency than expected in the population, given the frequency of presence of each morph. Therefore our results suggest that either androchromes in this species do not function as male mimics, or that the population has reached equilibrium with equal fitness for each morph. Other aspects of male harassment and learned mate-recognition, as well as female morph behaviour, would shed light on the evolutionary and ecological significance of female morphs in this species.
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| 8. |
- Outomuro, David, et al.
(författare)
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Allometry of secondary, primary and non-sexual traits in the beautiful demoiselle (Calopteryx virgo)
- 2012
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Ingår i: Canadian Journal of Zoology. - 0008-4301 .- 1480-3283. ; 90, s. 1094-1101
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Tidskriftsartikel (refereegranskat)abstract
- The static allometry between the size of a trait and the body size results from the net selection forces acting on the evolution of both the trait and the body size. An increased knowledge of the functional significance of traits is necessary to understand observed allometric patterns. We studied several traits of males of the beautiful demoiselle (Calopteryx virgo meridionalis Selys, 1873), for which there is a good functional knowledge of the genitalic traits and ornaments. We found positive allometry for the wing spot size (considered a secondary sexual trait) and for the distal width (but not length) of the anal appendages, which are used for grasping the female prior to copulation. Regarding the male secondary genitalia, the length but not the width of the big horns of the aedeagus showed an isometric pattern. The aedeagus shaft length showed a negative allometric pattern, while its distal width did not show a significant regression. The slopes of the regressions were higher when using wing length than when using body length as estimators of body size, with the exception of wing spot length. Results are discussed based on the functional significance of the study traits, as well as the pre- and post-copulatory selective pressures acting on them.
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| 9. |
- Outomuro, David, et al.
(författare)
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Antagonistic natural and sexual selection on wing shape in a scrambling damselfly
- 2016
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 70:7, s. 1582-1595
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Tidskriftsartikel (refereegranskat)abstract
- Wings are a key trait underlying the evolutionary success of birds, bats, and insects. For over a century, researchers have studiedthe form and function of wings to understand the determinants of flight performance. However, to understand the evolutionof flight, we must comprehend not only how morphology affects performance, but also how morphology and performanceaffect fitness. Natural and sexual selection can either reinforce or oppose each other, but their role in flight evolution remainspoorly understood. Here, we show that wing shape is under antagonistic selection with regard to sexual and natural selectionin a scrambling damselfly. In a field setting, natural selection (survival) favored individuals with long and slender forewings andshort and broad hindwings. In contrast, sexual selection (mating success) favored individuals with short and broad forewings andnarrow-based hindwings. Both types of selection favored individuals of intermediate size. These results suggest that individualsface a trade-off between flight energetics and maneuverability and demonstrate how natural and sexual selection can operate insimilar directions for some wing traits, that is, wing size, but antagonistically for others, that is, wing shape. Furthermore, theyhighlight the need to study flight evolution within the context of species’ mating systems and mating behaviors.
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| 10. |
- Outomuro, David, et al.
(författare)
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Bird predation selects for wing shape and coloration in a damselfly
- 2015
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 28:4, s. 791-799
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Tidskriftsartikel (refereegranskat)abstract
- Wing shape is related to flight performance, which is expected to be under selection for improving flight behaviours such as predator avoidance. Moreover, wing conspicuousness, usually involved in sexual selection processes, is also relevant in terms of predation risk. In this study, we examined how predation by a passerine bird, the white wagtail Motacilla alba, selects wing shape and wing colour patch size in males of the banded demoiselle Calopteryx splendens. The wing colour patch is intra- and intersexually selected in the study species. In a field study, we compared wings of live damselflies to wings of predated damselflies which are always discarded after predation. Based on aerodynamic theory and a previous study on wing shape of territorial tactics in damselflies, we predicted an overall short and broad wing, with a concave front margin shape to be selected by predation. This shape would be expected to improve escaping ability. Moreover, we predicted that wing patch size should be negatively selected by predation. We found that selection operated differently on fore- and hindwings. In contrast to our predictions, predation favoured a slender general forewing shape. However, the predicted wing shape was favoured in hindwings. We also found selection favouring a narrower wing colour patch. Our results suggest different roles of fore- and hindwings in flight, as previously suggested for Calopteryx damselflies and shown for butterflies and moths. Forewings would be more involved in sustained flight and hindwings in flight manoeuvrability. Our results differ somehow from a recently published work in the same study system, but using another population, suggesting that selection can fluctuate across space, despite the simplicity of this predator-prey system.
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| 11. |
- Outomuro, David, et al.
(författare)
-
Body and wing size, but not wing shape, vary along a large-scale latitudinal gradient in a damselfly
- 2021
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- Large-scale latitudinal studies that include both north and south edge populations and address sex differences are needed to understand how selection has shaped trait variation. We quantified the variation of flight-related morphological traits (body size, wing size, ratio between wing size and body size, and wing shape) along the whole latitudinal distribution of the damselfly Lestes sponsa, spanning over 2700 km. We tested predictions of geographic variation in the flight-related traits as a signature of: (1) stronger natural selection to improve dispersal in males and females at edge populations; (2) stronger sexual selection to improve reproduction (fecundity in females and sexual behaviors in males) at edge populations. We found that body size and wing size showed a U-shaped latitudinal pattern, while wing ratio showed the inverse shape. However, wing shape varied very little along the latitudinal gradient. We also detected sex-differences in the latitudinal patterns of variation. We discuss how latitudinal differences in natural and sexual selection regimes can lead to the observed quadratic patterns of variation in body and wing morphology via direct or indirect selection. We also discuss the lack of latitudinal variation in wing shape, possibly due to aerodynamic constraints.
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| 12. |
- Outomuro, David, et al.
(författare)
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Distribution of the Iberian Calopteryx damselflies and its relation with bioclimatic belts : Evolutionary and biogeographic implications
- 2010
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Ingår i: Journal of Insect Science. - 1536-2442. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Using bioclimatic belts as habitat and distribution predictors, the present study examines the implications of the potential distributions of the three Iberian damselflies, Calopteryx Leach (Odonata: Calopterygidae), with the aim of investigating the possible consequences in specific interactions among the species from a sexual selection perspective and of discussing biogeographical patterns. To obtain the known distributions, the literature on this genus was reviewed, relating the resulting distributions to bioclimatic belts. Specific patterns related to bioclimatic belts were clearly observed in the Mediterranean region. The potential distribution maps and relative frequencies might involve latitudinal differences in relative abundances, C. virgo meridionalis Selys being the most abundant species in the Eurosiberian region, C. xanthostoma (Charpentier) in the northern half of the Mediterranean region and C. haemorrhoidalis (Vander Linden) in the rest of this region. These differences might explain some previously described latitudinal differences in secondary sexual traits in the three species. Changes in relative abundances may modulate interactions among these species in terms of sexual selection and may produce sexual character displacement in this genus. C. virgo meridionalis distribution and ecological requirements explain its paleobiogeography as a species which took refuge in Iberia during the Wurm glaciation. Finally, possible consequences in species distributions and interactions are discussed within a global climate change context.
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| 13. |
- Outomuro, David, et al.
(författare)
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Does allometry of a sexually selected ornamental trait vary with sexual selection intensity? : A multi-species test in damselflies
- 2014
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 39:3, s. 399-403
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Tidskriftsartikel (refereegranskat)abstract
- Ornaments may show hyperallometry in certain taxa, i.e. large individuals have proportionally larger ornaments than small ones. One hypothesis suggests that higher sexual selection intensity leads to steeper hyperallometric patterns. This study tested whether an ornamental trait subject to both intra- and intersexual selection showed steeper allometric slopes than when subject solely to intrasexual selection. The study employed the sexually selected male wing pigmentation of 14 calopterygid species (damselflies) that differ in sexual selection intensity (intrasexual selection versus intra- and intersexual selection). Hyperallometry was not a uniform pattern in the study species. Furthermore, the allometric slopes did not differ between sexual selection intensities. The allometry of ornamental traits is therefore highly variable even among related species. Other selection pressures-probably species-specific and at a local scale-acting on wing pigmentation might explain the diversity of allometric patterns.
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| 14. |
- Outomuro, David, et al.
(författare)
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Habitat variation and wing coloration affect wing shape evolution in dragonflies
- 2013
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 26:9, s. 1866-1874
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Tidskriftsartikel (refereegranskat)abstract
- Habitats are spatially and temporally variable, and organisms must be able to track these changes. One potential mechanism for this is dispersal by flight. Therefore, we would expect flying animals to show adaptations in wing shape related to habitat variation. In this work, we explored variation in wing shape in relation to preferred water body (flowing water or standing water with tolerance for temporary conditions) and landscape (forested to open) using 32 species of dragonflies of the genus Trithemis (80% of the known species). We included a potential source of variation linked to sexual selection: the extent of wing coloration on hindwings. We used geometric morphometric methods for studying wing shape. We also explored the phenotypic correlation of wing shape between the sexes. We found that wing shape showed a phylogenetic structure and therefore also ran phylogenetic independent contrasts. After correcting for the phylogenetic effects, we found (i) no significant effect of water body on wing shape; (ii) male forewings and female hindwings differed with regard to landscape, being progressively broader from forested to open habitats; (iii) hindwings showed a wider base in wings with more coloration, especially in males; and (iv) evidence for phenotypic correlation of wing shape between the sexes across species. Hence, our results suggest that natural and sexual selection are acting partially independently on fore- and hindwings and with differences between the sexes, despite evidence for phenotypic correlation of wing shape between males and females.
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| 15. |
- Outomuro, David, et al.
(författare)
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Hind wing shape evolves faster than front wing shape in Calopteryx damselflies
- 2012
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Ingår i: Evolutionary biology. - : Springer Science and Business Media LLC. - 0071-3260 .- 1934-2845. ; 39:1, s. 116-125
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Tidskriftsartikel (refereegranskat)abstract
- 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 nonallometric 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 sexspecific 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.
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| 16. |
- Outomuro, David, et al.
(författare)
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Male wing shape differs between condition-dependent alternative reproductive tactics in territorial damselflies
- 2014
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 91, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Territorial contests between males without weaponry are based on costly displays and can result in condition-dependent alternative reproductive tactics that maximize male fitness. Physiological and morphological traits such as fat content, body size or the expression of secondary sexual traits have been shown to contribute to male territory-holding potential. When territorial contests are based on flight displays, wing morphology is expected to contribute to the territory-holding potential of a male through its effects on flight performance. We explored whether wing shape contributed to the territory-holding potential of males of three species of Calopteryx damselflies. Males of these species show two distinct, condition-dependent behavioural tactics: territorial and nonterritorial. Previous studies have shown that territorial males have higher fitness than nonterritorial males. We used mark-recapture to determine male tactics within the populations and compared wing shape, size and wing coloured spot size (a secondary sexual trait) between tactics. Territorial males of all three species had shorter and slightly broader hindwings than nonterritorial males. In two species, forewings of territorial males were longer and broader than forewings of nonterritorial males. Wing size and wing spot size did not differ between tactics. We suggest that the wing shape of territorial males might confer better flight manoeuvrability, which would be advantageous for territorial contests. Therefore, wing shape is likely to be an important trait contributing to territory-holding potential in condition-dependent alternative reproductive tactics based on flight displays. (C) 2014 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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| 17. |
- Outomuro, David, et al.
(författare)
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Multitrait aposematic signal in Batesian mimicry
- 2016
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 70:7, s. 1596-1608
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Tidskriftsartikel (refereegranskat)abstract
- Batesian mimics can parasitize Müllerian mimicry rings mimicking the warning color signal. The evolutionary success of Batesian mimics can increase adding complexity to the signal by behavioral and locomotor mimicry. We investigated three fundamental morphological and locomotor traits in a Neotropical mimicry ring based on Ithomiini butterflies and parasitized by Polythoridae damselflies: wing color, wing shape, and flight style. The study species have wings with a subapical white patch, considered the aposematic signal, and a more apical black patch. The main predators are VS-birds, visually more sensitive to violet than to ultraviolet wavelengths (UVS-birds). The white patches, compared to the black patches, were closer in the bird color space, with higher overlap for VS-birds than for UVS-birds. Using a discriminability index for bird vision, the white patches were more similar between the mimics and the model than the black patches. The wing shape of the mimics was closer to the model in the morphospace, compared to other outgroup damselflies. The wing-beat frequency was similar among mimics and the model, and different from another outgroup damselfly. Multitrait aposematic signals involving morphology and locomotion may favor the evolution of mimicry rings and the success of Batesian mimics by improving signal effectiveness toward predators.
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| 18. |
- Outomuro, David, et al.
(författare)
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Preference for supernormal stimuli tends to override initially learned associations for conspicuous prey traits : implications from a laboratory study
- 2020
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Ingår i: Journal of ethology. - : SPRINGER JAPAN KK. - 0289-0771 .- 1439-5444. ; 38:3, s. 365-371
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Tidskriftsartikel (refereegranskat)abstract
- How predators select on conspicuous prey traits is not well understood. We used a laboratory setup to investigate the role of learning in predator choice of conspicuous visual traits. We used a generalist predator, the great tit, and coloured wings of males of two species of damselflies as prey. Wing pigmentation differs between the species in colour (green vs. blue) and size (large vs. small). Wing pigmentation is a sexually selected trait that experiences negative selection by avian predators. Inexperienced great tits showed no preference for the colour or the size of wing pigmentation. Great tits were then repeatedly exposed to rewarded wings with either large or small wing patch size. When these experienced birds were exposed to both wing patch sizes for the first time, they tended to prefer the wings with the large patch, irrespective of their previous experience. Our results suggest that the choice of the predator was based on an initial association of the trait to a reward followed by a preference for a supernormal stimulus, probably due to a larger sensory stimulation. We discuss the implications of our laboratory results in the light of previous estimates of damselfly predation risk under field conditions.
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| 19. |
- Outomuro, David, et al.
(författare)
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The effects of latitude, body size, and sexual selection on wing shape in a damselfly
- 2011
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 102:2, s. 263-274
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 20. |
- Outomuro, David, et al.
(författare)
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The Evolution of Wing Shape in Ornamented-Winged Damselflies (Calopterygidae, Odonata)
- 2013
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Ingår i: Evolutionary biology. - : Springer Science and Business Media LLC. - 0071-3260 .- 1934-2845. ; 40:2, s. 300-309
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Forskningsöversikt (refereegranskat)abstract
- Flight has conferred an extraordinary advantage to some groups of animals. Wing shape is directly related to flight performance and evolves in response to multiple selective pressures. In some species, wings have ornaments such as pigmented patches that are sexually selected. Since organisms with pigmented wings need to display the ornament while flying in an optimal way, we might expect a correlative evolution between the wing ornament and wing shape. We examined males from 36 taxa of calopterygid damselflies that differ in wing pigmentation, which is used in sexual displays. We used geometric morphometrics and phylogenetic comparative approaches to analyse whether wing shape and wing pigmentation show correlated evolution. We found that wing pigmentation is associated with certain wing shapes that probably increase the quality of the signal: wings being broader where the pigmentation is located. Our results also showed correlated evolution between wing pigmentation and wing shape in hind wings, but not in front wings, probably because hind wings are more involved in signalling than front wings. The results imply that the evolution of diversity in wing pigmentations and behavioural sexual displays might be an important driver of speciation due to important pre-copulatory selective pressures.
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| 21. |
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| 22. |
- Outomuro, David, et al.
(författare)
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The price of looking sexy : visual ecology of a three-level predator–prey system
- 2017
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 31:3, s. 707-718
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Tidskriftsartikel (refereegranskat)abstract
- Colour signals and colour vision play a pivotal role in intraspecific communication and predator-prey interactions. However, the costs of expressing conspicuous sexual signals at multiple trophic levels have been largely overlooked. Sexual signals can also experience character displacement in sympatric populations of closely related species, leading to potential changes in conspicuousness. We here investigate a bird-damselfly-fruit fly predator-prey system, where two closely related damselfly species have conspicuous, sexually selected wing coloration. The damselflies can occur in sympatry and allopatry, and reproductive character displacement in the coloration size has been previously reported. We quantify the damselfly wing reflectance from replicated sympatric and allopatric populations, and use receptor noise models to investigate the visual discriminability of the wing coloration for the bird, damselfly and fly vision systems, against natural backgrounds. We perform electroretinograms to study damselfly eye sensitivity. We also estimate damselfly predation risk in natural populations. We find that the chromatic component of wing coloration makes males highly discriminable to the predator, but not to the prey. However, female wing coloration is predominantly cryptic for the predator and prey, and interestingly, also for male damselflies. A female being cryptic to conspecifics likely reduces male harassment. The estimates of predation risk partially support the discriminability results. We also show that there is no difference in colour vision sensitivity between the two damselfly species and sexes, and no difference in wing coloration or its discriminability between sympatric and allopatric populations. Our results suggest that sexually selected traits can be antagonistically selected by predators and prey and that this antagonistic selection can be sex-dependent: males are paying a large cost in terms of conspicuousness, while females remain mostly cryptic. Our study thus emphasizes the need for investigating visual communication at multitrophic levels since the degree of colour discriminability can differ between predators, prey and the focal species.
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| 23. |
- Outomuro, David, et al.
(författare)
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Wing morphology and migration status, but not body size, habitat or Rapoport's rule predict range size in North-American dragonflies (Odonata: Libellulidae)
- 2019
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Ingår i: Ecography. - : WILEY. - 0906-7590 .- 1600-0587. ; 42:2, s. 309-320
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Tidskriftsartikel (refereegranskat)abstract
- Understanding why species range sizes vary is important for predicting the impact of environmental change on biodiversity. Here we use a multi-variable approach in a phylogenetic comparative context to understand how four morphological, two ecological, and two eco-geographical variables are associated with range size, latitudinal range and longitudinal range in 81 species of North-American libellulid dragonflies. Our results show that: 1) migratory species and species with a more expanded basal hindwing lobe have a larger range size; 2) opposite to Rapoport's rule, latitudinal range is negatively correlated with mid-range latitude; 3) longitudinal range is predicted by wing morphology and migration; 4) body size and larval habitat are not correlated with range size, latitudinal range or longitudinal range. These results suggest that dispersal-related traits, such as wing shape and migratory status, are important factors in predicting the range size of libellulid dragonflies. In addition, the reverse Rapoport's rule suggests that more northern-centred species might be more specialized than more southern-centred species. We suggest that the variables predicting range size are likely imposed by taxon-specific morphological, ecological, physiological and behavioural traits. Taxon-specific knowledge is thus necessary to understand the dynamics of range sizes and is important to implement successful restoration and conservation plans of threatened species.
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| 24. |
- Outomuro, David, et al.
(författare)
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Wing pigmentation in Calopteryx damselflies : a role in thermoregulation?
- 2011
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Ingår i: Biological Journal of the Linnean Society. - 0024-4066 .- 1095-8312. ; 103:1, s. 36-44
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Tidskriftsartikel (refereegranskat)abstract
- Body melanization may show adaptive variation related to thermoregulation ability, and it is to be expected that the degree of melanization will change among populations or closely related species across environmental gradients of solar radiation and/or environmental temperature. Some melanized secondary sexual traits may also play a role in sexual selection, leading to interpopulation variation, which would not be predicted by thermoregulation pressures alone. We studied the relationships between the interpopulation variation in wing pigmentation level (i.e. melanized secondary sexual trait) of two closely related species of Calopteryx damselfly, and both solar radiation and maximum environmental temperature estimates. Wing pigmentation differs between these species, is gender specific and is used in species' discrimination. Only Calopteryx virgo meridionalis males showed a significant negative partial correlation between wing pigmentation degree and temperature. However, C. virgo meridionalis females showed a positive significant partial correlation between wing pigmentation degree and solar radiation. Wing pigmentation in Calopteryx xanthostoma males was not related to solar radiation or temperature. Thus, thermoregulation pressures poorly explained the observed variations in wing pigmentation between populations, although they might have an adaptive significance at the species' level. As wing pigmentation showed important latitudinal variation, several other selection pressures which might act on melanized traits are briefly discussed. (C) 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103, 36-44.
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| 25. |
- Outomuro, David, et al.
(författare)
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Wing shape allometry and aerodynamics in calopterygid damselflies : a comparative approach
- 2013
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 13, s. 118-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Wing size and shape have important aerodynamic implications on flight performance. We explored how wing size was related to wing shape in territorial males of 37 taxa of the damselfly family Calopterygidae. Wing coloration was also included in the analyses because it is sexually and naturally selected and has been shown to be related to wing shape. We studied wing shape using both the non-dimensional radius of the second moment of wing area (RSM) and geometric morphometrics. Lower values of the RSM result in less energetically demanding flight and wider ranges of flight speed. We also re-analyzed previously published data on other damselflies and dragonflies. Results: The RSM showed a hump-shaped relationship with wing size. However, after correcting for phylogeny using independent contrast, this pattern changed to a negative linear relationship. The basal genus of the study family, Hetaerina, was mainly driving that change. The obtained patterns were specific for the study family and differed from other damselflies and dragonflies. The relationship between the RSM and wing shape measured by geometric morphometrics was linear, but relatively small changes along the RSM axis can result in large changes in wing shape. Our results also showed that wing coloration may have some effect on RSM. Conclusions: We found that RSM showed a complex relationship with size in calopterygid damselflies, probably as a result of other selection pressures besides wing size per se. Wing coloration and specific behavior (e.g. courtship) are potential candidates for explaining the complexity. Univariate measures of wing shape such as RSM are more intuitive but lack the high resolution of other multivariate techniques such as geometric morphometrics. We suggest that the relationship between wing shape and size are taxa-specific and differ among closely-related insect groups.
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| 26. |
- Sniegula, Szymon, et al.
(författare)
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Do males with higher mating success invest more in armaments? : An across-populations study in damselflies
- 2017
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 42:4, s. 526-530
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Tidskriftsartikel (refereegranskat)abstract
- 1. Males with higher mating success would be expected to invest more in traits that facilitate mating, leading to steeper allometry of those traits with respect to body size. Across-population studies following latitudinal variation in male mating success are an excellent study system to address this question.2. Males of the damselfly Lestes sponsa were used to investigate whether the allometric patterns of the length and width of the anal appendages, used for grasping the female prior tomating, corresponded to male mating success. Across a large latitudinal gradient, it was hypothesised that there is a larger investment in the grasping apparatus, i.e. a steeper allometric slope, following higher mating success.3. Behavioural observations in field enclosures showed the highest mating success at high latitude, while there were no significant differences in mating success between the central and low latitudes. Positive allometry was found for the length of the anal appendages in high-latitude males, while central-and low-latitude males showed no significant regressions of the traits on body size.4. These results partially support the hypothesis, as high-latitude, more successful males invested more in the length ( but not the width) of the grasping apparatus than did central-and low-latitude males. Therefore, higher mating success might be facilitated by larger investment in armaments. Intraspecific studies on allometric patterns of traits that participate in mating success might offer new insights into the role of those traits in the reproductive behaviour of a species.
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| 27. |
- Varg, Javier Edo, 1988-, et al.
(författare)
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Microplastic exposure across trophic levels : effects on the host microbiota of freshwater organisms
- 2022
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Ingår i: Environmental Microbiome. - : Springer Nature. - 2524-6372. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundMicroplastics are a pervasive pollutant widespread in the sea and freshwater from anthropogenic sources, and together with the presence of pesticides, they can have physical and chemical effects on aquatic organisms and on their microbiota. Few studies have explored the combined effects of microplastics and pesticides on the host–microbiome, and more importantly, the effects across multiple trophic levels. In this work, we studied the effects of exposure to microplastics and the pesticide deltamethrin on the diversity and abundance of the host–microbiome across a three-level food chain: daphnids–damselfly–dragonflies. Daphnids were the only organism exposed to 1 µm microplastic beads, and they were fed to damselfly larvae. Those damselfly larvae were exposed to deltamethrin and then fed to the dragonfly larvae. The microbiotas of the daphnids, damselflies, and dragonflies were analyzed.ResultsExposure to microplastics and deltamethrin had a direct effect on the microbiome of the species exposed to these pollutants. An indirect effect was also found since exposure to the pollutants at lower trophic levels showed carry over effects on the diversity and abundance of the microbiome on higher trophic levels, even though the organisms at these levels where not directly exposed to the pollutants. Moreover, the exposure to deltamethrin on the damselflies negatively affected their survival rate in the presence of the dragonfly predator, but no such effects were found on damselflies fed with daphnids that had been exposed to microplastics.ConclusionsOur study highlights the importance of evaluating ecotoxicological effects at the community level. Importantly, the indirect exposure to microplastics and pesticides through diet can potentially have bottom-up effects on the trophic webs.
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| 28. |
- Varg, Javier Edo, 1988-, et al.
(författare)
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Single and combined effects of microplastics, pyrethroid and food resources on the life-history traits and microbiome of Chironomus riparius
- 2021
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 289
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Tidskriftsartikel (refereegranskat)abstract
- There is growing evidence of widespread contamination of freshwater ecosystems with microplastics. However, the effects of chronic microplastic ingestion and its interaction with other pollutants and stress factors on the life history traits and the host-microbiome of aquatic invertebrates are not well understood. This study investigates the effects of exposure to sediment spiked with 1 mu m polystyrene-based latex microplastic spheres, an environmentally realistic concentration of a pyrethroid pesticide (esfenvalerate), and a combination of both treatments on the life-history traits of the benthic-dwelling invertebrate, Chironomus riparius and its microbial community. The chironomid larvae were also exposed to two food conditions: abundant or limited food in the sediment, monitored for 28 and 34 days respectively. The microplastics and esfenvalerate had negative effects on adult emergence and survival, and these effects differed between the food level treatments. The microbiome diversity was negatively affected by the exposure to microplastics, while the relative abundances of the four top phyla were significantly affected only in the high food level treatment. Although the combined exposure to microplastics and esfenvalerate showed some negative effects on survival and emergence, there was little evidence for synergistic effects when compared to the single exposure. The food level affected all life-history traits and the microbiota, and lower food levels intensified the negative effects of the exposure to microplastics, esfenvalerate and their combination. We argue that these pollutants can affect crucial life-history traits such as successful metamorphosis and the host-microbiome. Therefore, it should be taken into consideration for toxicological assessment of pollutant acceptability. Our study highlights the importance of investigating possible additive and synergic activities between stressors to understand the effects of pollutants in the life story traits and host-microbiome.
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