La communauté internationale prétend freiner la perte de biodiversité et maintenir les services rendus par les écosystèmes. Ces termes à la mode expriment-ils une nouvelle façon de concevoir la ...nature ? L’auteur analyse l’évolution des idées depuis le début du xxe siècle, où l’on se préoccupait de protéger la nature, jusqu’à nos jours, où il est question de gérer la biodiversité. Les bouleversements récents dans la façon dont les sciences appréhendent la nature mettent en évidence un renouvellement de paradigme. L’idée d’équilibre naturel a longtemps prévalu en écologie. Aujourd’hui, s’impose celle de changement permanent, qui appelle une réflexion éthique : comment repenser les valeurs qui fondent les relations homme-nature, sachant que la biodiversité s’inscrit dans une trajectoire ? Dans un contexte marqué par de nouveaux repères conceptuels et par l’urgence des prises de décision, les scientifiques se trouvent de plus en plus impliqués dans la mise en oeuvre de projets qui inscrivent une biodiversité « choisie » dans leurs objectifs. L’auteur ouvre la réflexion sur l’évolution qui en résulte nécessairement dans la pratique du métier de chercheur.
The spectacular invasion of the word “biodiversity” in scientific and political spheres and in the media suggested the emergence of a new scientific field. However, the diversity of the living world ...was the target of natural history since its very beginning. Ecologists did not wait for the publication of Wilson and Peter “Biodiversity” in 1988, to consider the diversity of species within ecosystems, and to address fundamental questions such as diversification processes and the functional signification of species diversity. The analysis of papers published from the 1940s to 1988 allows to understand the issues that ecologists addressed on diversity topics, and how intuitions, theoretical approaches and empirical research interacted. Did the “invention” of biodiversity enhance research? A look throughout post-1988 publications permits one to suggest an answer.
Eyespots are wing color pattern elements repeatedly observed in many butterflies,whose developmental genetics has been extensively documented. Nevertheless, theevolutionary forces shaping their ...diversification across species still remain largelyunknown. Here we investigate the evolution of eyespots in the 30 species of theneotropical genus Morpho. Morpho butterflies display a series of eyespots locatedon the ventral side of their wings, highly variable among species, ranging from large,conspicuous structures to vestigial spots. Applying geometric morphometrics to a largesample (N = 910) spanning all Morpho species and both sexes, we assess eyespotnumber, position, size, and shape. We detect a divergence in eyespot position betweenunderstory and canopy species, with an L-shaped configuration in canopy species anda line pattern in understory species, where the eyespots tend to fuse and form a stripein white and pale species. This effect is stronger than expected based on a Brownianmotion model of phylogenetic divergence, suggesting an adaptation to the microhabitatand an influence of the wing color on the evolution of pattern elements. Remarkably,this shift in color pattern is strongly correlated with a shift in wing shape. However,using a thin-plate spline interpolation, we show that the shape change is insufficientto explain the evolution of eyespot position as a developmental side effect of wingshape evolution, also pointing at an adaptive effect. Finally, we find a significant negativecorrelation between eyespot relative size and the within-species variation in eyespotnumber, position, size, and shape, suggesting a relaxed or apostatic selection on smalleyespots (rare phenotypes being favored as they are less likely to be remembered andthus detected by predators). We hypothesize that contrasted ecology may explain theobserved differences between species: large and phenotypically stable eyespots mightact as attack deflectors, small, variable faded eyespots might rather enhance crypsis,and pale species stripe pattern might disrupt the outline of the wing.
Assessing the relative importance of geographical and ecological drivers of evolution is paramount to understand the diversification of species and traits at the macroevolutionary scale. Here, we use ...an integrative approach, combining phylogenetics, biogeography, ecology and quantified phenotypes to investigate the drivers of both species and phenotypic diversification of the iconic Neotropical butterfly genus Morpho. We generated a time‐calibrated phylogeny for all known species and inferred historical biogeography. We fitted models of time‐dependent (accounting for rate heterogeneity across the phylogeny) and paleoenvironment‐dependent diversification (accounting for global effect on the phylogeny). We used geometric morphometrics to assess variation of wing size and shape across the tree and investigated their dynamics of evolution. We found that the diversification of Morpho is best explained when considering variable diversification rates across the tree, possibly associated with lineages occupying different microhabitat conditions. First, a shift from understory to canopy was characterized by an increased speciation rate partially coupled with an increasing rate of wing shape evolution. Second, the occupation of dense bamboo thickets accompanying a major host‐plant shift from dicotyledons towards monocotyledons was associated with a simultaneous diversification rate shift and an evolutionary ‘jump’ of wing size. Our study points to a diversification pattern driven by punctuational ecological changes instead of a global driver or biogeographic history.
Combining ecology, biogeography, phenotypes and phylogeny of the Neotropical Morpho butterflies, we show that microhabitat conditions explain correlated changes in host‐plants, rates of wing evolution and species diversification.
Species interactions such as mimicry can promote trait convergence but disentangling this effect from those of shared ecology, evolutionary history, and niche conservatism is often challenging. Here ...by focusing on wing colour pattern variation within and between three butterfly species living in sympatry in a large proportion of their range, we tested the effect of species interactions on trait diversification. These butterflies display a conspicuous iridescent blue coloration on the dorsal side of their wings and a cryptic brownish colour on the ventral side. Combined with an erratic and fast flight, these colour patterns increase the difficulty of capture by predators and contribute to the high escape abilities of these butterflies. We hypothesize that, beyond their direct contribution to predator escape, these wing patterns can be used as signals of escape abilities by predators, resulting in positive frequency‐dependent selection favouring convergence in wing pattern in sympatry. To test this hypothesis, we quantified dorsal wing pattern variations of 723 butterflies from the three species sampled throughout their distribution, including sympatric and allopatric situations and compared the phenotypic distances between species, sex and localities. We detected a significant effect of localities on colour pattern, and higher inter‐specific resemblance in sympatry as compared to allopatry, consistent with the hypothesis of local convergence of wing patterns. Our results provide support to the existence of escape mimicry in the wild and stress the importance of estimating trait variation within species to understand trait variation between species, and to a larger extent, trait diversification at the macro‐evolutionary scale.
From a Museum sample of 723 butterflies belonging to the closely‐related neotropical species M. achilles, M.helenor and M. deidamia, we quantified variations in dorsal wing colour patterns and show significant similarities between species within localities. This parallel variation in dorsal iridescent colour pattern across these three sympatric species could be driven by the behaviour of predators. The iridescent blue of the dorsal side of the wing combined to the brownish coloration of the ventral side produces confusing flashes during escape flight of these butterflies. The erratic flight of these butterflies associated with their peculiar coloration is assumed to enhance their escaping success. Unsuccessful predators may then give up chasing butterflies displaying similar colour patterns, resulting in increased protection for individuals sharin the same coloration. Such selection generated by the behaviour of predators could favour the local convergences of colour pattern between species.
La spettacolare invasione della parola “biodiversità” nelle sfere scientifiche e politiche così come nei media ha suggerito la possibile nascita di un nuovo campo d’indagine scientifica. Tuttavia, la ...diversità del mondo vivente è stata l’oggetto di studio della storia naturale sin dai primordi. Gli ecologi non hanno aspettato la pubblicazione di “Biodiversity” di Wilson e Peter, nel 1988, per prendere in esame la diversità delle specie all’interno degli ecosistemi e per occuparsi di questioni fondamentali come i processi di diversificazione e il significato funzionale della diversità specifica. L’analisi degli articoli pubblicati a partire dagli anni Quaranta, fino al 1988, ci permette di comprendere di quali argomenti, relativi al tema della diversità, si sono occupati gli ecologi, e come le intuizioni, gli approcci teorici e la ricerca empirica abbiano interagito. La domanda che si pone è: l’invenzione della biodiversità ha promosso la ricerca? Uno sguardo alle pubblicazioni post-1988 consente di suggerire una risposta.
Butterfly wings harbor highly diverse phenotypes and are involved in many functions. Wing size and shape result from interactions between adaptive processes, phylogenetic history, and developmental ...constraints, which are complex to disentangle. Here, we focus on the genus Morpho (Nymphalidae: Satyrinae, 30 species), which presents a high diversity of sizes, shapes, and color patterns. First, we generate a comprehensive molecular phylogeny of these 30 species. Next, using 911 collection specimens, we quantify the variation of wing size and shape across species, to assess the importance of shared ancestry, microhabitat use, and sexual selection in the evolution of the wings. While accounting for phylogenetic and allometric effects, we detect a significant difference in wing shape but not size among microhabitats. Fore and hindwings covary at the individual and species levels, and the covariation differs among microhabitats. However, the microhabitat structure in covariation disappears when phylogenetic relationships are taken into account. Our results demonstrate that microhabitat has driven wing shape evolution, although it has not strongly affected forewing and hindwing integration. We also found that sexual dimorphism of forewing shape and color pattern are coupled, suggesting a common selective force.
Eryphanis zolvizora (Hewitson, 1877) is a rare Andean endemic butterfly, described from Bolivia, which has been historically classified either as a unique species, or as part of a group of three ...allopatric species from Bolivia, Ecuador and Colombia. In this paper, the group is revised using more than 200 specimens housed in 34 European, and North and South American public and private collections. For the first time, the presence of the group in Western Ecuador and Venezuela is confirmed, and important data on Peruvian populations are provided. In some populations, individual variations of genitalia are observed. Nevertheless, male genitalia allow the distinction of four geographical groups. Considering also habitus characters, eight taxa are distinguished and considered to be subspecies, of which five are new: Eryphanis zolvizora inca ssp. nov., Eryphanis zolvizora chachapoya ssp. nov., Eryphanis zolvizora casagrande ssp. nov.., Eryphanis zolvizora reyi ssp. nov., and Eryphanis zolvizora isabelae ssp. nov. In the present state of knowledge, these taxa are allopatric, except for a possible geographic overlap in central Peru, where data are insufficient to prove sympatry. The “several subspecies vs. several species” dilemma is discussed, considering its impact for conservation action and policies.
Inventory of the caterpillars, their food plants and parasitoids began in 1978 for today's Area de Conservacion Guanacaste (ACG), in northwestern Costa Rica. This complex mosaic of 120 000 ha of ...conserved and regenerating dry, cloud and rain forest over 0-2000 m elevation contains at least 10 000 species of non-leaf-mining caterpillars used by more than 5000 species of parasitoids. Several hundred thousand specimens of ACG-reared adult Lepidoptera and parasitoids have been intensively and extensively studied morphologically by many taxonomists, including most of the co-authors. DNA barcoding -- the use of a standardized short mitochondrial DNA sequence to identify specimens and flush out undisclosed species -- was added to the taxonomic identification process in 2003. Barcoding has been found to be extremely accurate during the identification of about 100 000 specimens of about 3500 morphologically defined species of adult moths, butterflies, tachinid flies, and parasitoid wasps. Less than 1% of the species have such similar barcodes that a molecularly based taxonomic identification is impossible. No specimen with a full barcode was misidentified when its barcode was compared with the barcode library. Also as expected from early trials, barcoding a series from all morphologically defined species, and correlating the morphological, ecological and barcode traits, has revealed many hundreds of overlooked presumptive species. Many but not all of these cryptic species can now be distinguished by subtle morphological and/or ecological traits previously ascribed to 'variation' or thought to be insignificant for species-level recognition. Adding DNA barcoding to the inventory has substantially improved the quality and depth of the inventory, and greatly multiplied the number of situations requiring further taxonomic work for resolution.
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