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News Article | May 23, 2017
Site: www.eurekalert.org

The spectacular variety of colours and patterns that butterflies use to ward off potential predators may result from highly localised environmental conditions known as "microhabitats", researchers have found. The study, by an international team of researchers, attempts to explain why, even though butterfly species have evolved to mimic one another's wing patterns to more efficiently signal their toxicity, they nevertheless maintain a kaleidoscopic array of patterns overall. This paradox applies not just to butterflies, but to a wide range of species, and addresses broader questions about how many different defensive strategies can be optimal in one place. Although many species have evolved warning colour patterns that signal to predators that they are bad to eat, there is still a remarkable diversity of these patterns. Scientists predict that all species should converge on the same pattern, but this has clearly not happened. In the new study, the researchers focused on an area of Ecuadorian rainforest where butterfly species copy each other's markings to deter insect-eating birds. The birds have learned that butterflies which exhibit certain patterns are toxic. There are, however, numerous different examples of these so-called "mimicry rings", with the butterflies using a wide range of different colours and patterns to achieve the same result. The researchers found that small and highly localised differences between parts of the forest, which are often only a few hundred metres apart, could explain why this happens. Although they do not seem dramatically dissimilar from one another, these microhabitats expose the butterflies to different predators. As a result, the pattern that is the most effective signal to predators may differ from one part of the forest to another. The study was carried out by academics from the University of Cambridge, UK; the University of Florida, US; and the National Museum of Natural History/National Centre for Scientific Research in France. Chris Jiggins, Professor of Evolutionary Biology at St John's College, University of Cambridge, and a co-author, said: "This is a really big question in science - why are there so many species, particularly in the tropical rainforests? Mimicry in these butterflies offers one opportunity to understand why the tropics are so incredibly diverse." "What we found is that different insect-eating birds encounter different butterflies in these distinctive parts of the forest. This explains why, despite the effects of mimicry, the butterflies have maintained different patterns. Even though they are not living very far apart, they are signalling to different predators." The study is unusual in that the scientists examined this question by looking at predator species and their prey together - something which is often difficult to achieve. "This helped us to find evidence that supports earlier, theoretical predictions that microhabitat preferences in predators and prey could enhance mimicry diversity," co-author Marianne Elias, from MNHN/CNRS, said. They studied an area of rainforest close to the Napo River, a tributary of the Amazon. A range of low hills there contains two distinctive microhabitats: small valleys with streams, and low ridges. These have slightly different natural features, such as subtle changes in light and temperature, and variations in plant life. The team marked out four pairs of 30 metre-diameter plots, each consisting of either an area of valley or a section of ridge. They then documented the relationship between 64 species of butterflies (including 58 species of ithomiines, commonly known as clearwing butterflies), and 127 species of local insectivorous birds, including tyrant flycatchers, jacamars and antbirds. Ithomiine butterflies have evolved a number of contrasting mimicry rings, often using bright colours such as orange and yellow to warn the birds about their toxicity. The researchers also studied the abundance of butterflies and their interactions with predators at different heights. "We threw ropes over the trees, climbed up and hung there in a harness to record how high the butterflies were flying," Jiggins said. They found that different butterfly mimicry rings gravitate towards topographically distinctive areas and fly at different heights. Similarly, different bird species tend to occur in different microhabitats. These behavioural tendencies influence predation rates. At ridge sites, for example, birds targeted butterflies from the mimicry ring known as 'eurimedia' (which are yellow and black), more than a mimicry ring called 'hermias' (which have a tiger-like pattern, with intermingled orange, yellow and black). In valley sites, the situation was the reverse. The researchers showed this by putting dead butterfly specimens in the "wrong" areas, where the birds - clearly unfamiliar with their markings - attacked these specimens more than those displaying the locally abundant pattern. Microhabitats are, however, probably only one of several causes of diversity in the butterflies' mimicry rings. Other factors, such as seasonal variations in predators, or the fact that different species are active at different times of day, may also be significant. The study adds to a developing picture of the very complex interrelationships between plants, herbivores and predators in which even small ecological changes can have a knock-on effect for multiple species and, it would seem, their diversity. "Mimicry is a form of mutualism in which species are connected by each other's presence," Jiggins added. "In these amazingly diverse Amazonian rainforests there are lots of opportunities for such mutualistic interactions, which help to generate and stabilise diversity." The study, Maintaining mimicry diversity, is published in Proceedings of the Royal Society B.


News Article | May 23, 2017
Site: phys.org

The study, by an international team of researchers, attempts to explain why, even though butterfly species have evolved to mimic one another's wing patterns to more efficiently signal their toxicity, they nevertheless maintain a kaleidoscopic array of patterns overall. This paradox applies not just to butterflies, but to a wide range of species, and addresses broader questions about how many different defensive strategies can be optimal in one place. Although many species have evolved warning colour patterns that signal to predators that they are bad to eat, there is still a remarkable diversity of these patterns. Scientists predict that all species should converge on the same pattern, but this has clearly not happened. In the new study, the researchers focused on an area of Ecuadorian rainforest where butterfly species copy each other's markings to deter insect-eating birds. The birds have learned that butterflies which exhibit certain patterns are toxic. There are, however, numerous different examples of these so-called "mimicry rings", with the butterflies using a wide range of different colours and patterns to achieve the same result. The researchers found that small and highly localised differences between parts of the forest, which are often only a few hundred metres apart, could explain why this happens. Although they do not seem dramatically dissimilar from one another, these microhabitats expose the butterflies to different predators. As a result, the pattern that is the most effective signal to predators may differ from one part of the forest to another. The study was carried out by academics from the University of Cambridge, UK; the University of Florida, US; and the National Museum of Natural History/National Centre for Scientific Research in France. Chris Jiggins, Professor of Evolutionary Biology at St John's College, University of Cambridge, and a co-author, said: "This is a really big question in science - why are there so many species, particularly in the tropical rainforests? Mimicry in these butterflies offers one opportunity to understand why the tropics are so incredibly diverse." "What we found is that different insect-eating birds encounter different butterflies in these distinctive parts of the forest. This explains why, despite the effects of mimicry, the butterflies have maintained different patterns. Even though they are not living very far apart, they are signalling to different predators." The study is unusual in that the scientists examined this question by looking at predator species and their prey together - something which is often difficult to achieve. "This helped us to find evidence that supports earlier, theoretical predictions that microhabitat preferences in predators and prey could enhance mimicry diversity," co-author Marianne Elias, from MNHN/CNRS, said. They studied an area of rainforest close to the Napo River, a tributary of the Amazon. A range of low hills there contains two distinctive microhabitats: small valleys with streams, and low ridges. These have slightly different natural features, such as subtle changes in light and temperature, and variations in plant life. The team marked out four pairs of 30 metre-diameter plots, each consisting of either an area of valley or a section of ridge. They then documented the relationship between 64 species of butterflies (including 58 species of ithomiines, commonly known as clearwing butterflies), and 127 species of local insectivorous birds, including tyrant flycatchers, jacamars and antbirds. Ithomiine butterflies have evolved a number of contrasting mimicry rings, often using bright colours such as orange and yellow to warn the birds about their toxicity. The researchers also studied the abundance of butterflies and their interactions with predators at different heights. "We threw ropes over the trees, climbed up and hung there in a harness to record how high the butterflies were flying," Jiggins said. They found that different butterfly mimicry rings gravitate towards topographically distinctive areas and fly at different heights. Similarly, different bird species tend to occur in different microhabitats. These behavioural tendencies influence predation rates. At ridge sites, for example, birds targeted butterflies from the mimicry ring known as 'eurimedia' (which are yellow and black), more than a mimicry ring called 'hermias' (which have a tiger-like pattern, with intermingled orange, yellow and black). In valley sites, the situation was the reverse. The researchers showed this by putting dead butterfly specimens in the "wrong" areas, where the birds - clearly unfamiliar with their markings - attacked these specimens more than those displaying the locally abundant pattern. Microhabitats are, however, probably only one of several causes of diversity in the butterflies' mimicry rings. Other factors, such as seasonal variations in predators, or the fact that different species are active at different times of day, may also be significant. The study adds to a developing picture of the very complex interrelationships between plants, herbivores and predators in which even small ecological changes can have a knock-on effect for multiple species and, it would seem, their diversity. "Mimicry is a form of mutualism in which species are connected by each other's presence," Jiggins added. "In these amazingly diverse Amazonian rainforests there are lots of opportunities for such mutualistic interactions, which help to generate and stabilise diversity." More information: Maintaining mimicry diversity: optimal warning colour patterns differ among microhabitats in Amazonian clearwing butterflies, Proceedings of the Royal Society B, rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2017.0744


Humbert J.F.,French National Institute for Agricultural Research | Quiblier C.,MNHN | Quiblier C.,University Paris Diderot | Gugger M.,Institute Pasteur Paris | Gugger M.,French National Center for Scientific Research
Analytical and Bioanalytical Chemistry | Year: 2010

Harmful phytoplankton species are a growing problem in freshwater and marine ecosystems, because of their ability to synthesize toxins that threaten both animal and human health. The monitoring of these microorganisms has so far been based on conventional methods, mainly involving the microscopic counting and identification of cells, and using analytical and bioanalytical methods to identify and quantify the toxins. However, the increasing number of microbial sequences in the GeneBank database and the development of new tools in the last 15 years nowadays enables the use of molecular methods for detection and quantification of harmful phytoplankton species and their toxins. These methods provide species-level identification of the microorganisms of interest, and their early detection in the environment by PCR techniques. Moreover, real time PCR can be used to quantify the cells of interest, and in some cases to evaluate the proportion of toxin-producing and non-toxin-producing genotypes in a population. Recently, microarray technologies have also been used to achieve simultaneous detection and semi-quantification of harmful species in environmental samples. These methods look very promising, but so far their use remains limited to research. The need for validation for routine use and the cost of these methods still hamper their use in monitoring programs. © 2010 Springer-Verlag.


News Article | October 28, 2015
Site: www.nature.com

In 1942, French photographer Robert Doisneau (perhaps best known for his image of a couple kissing outside the Hotel de Ville) was commissioned to record life behind the scenes at the various arms of the National Museum of Natural History (MNHN) in Paris. Most of the images have never been published. They are a unique document of the work of a research institute in occupied France during the Second World War. Now, a small jewel of an exhibition brings them out of the stores where they were taken, and places them in the limelight where they belong. Doisneau was a member of the French Resistance; he produced fake identity papers for his comrades-in-arms. The commission to photograph two Paris museums, the botanical gardens and a zoo that are part of the MNHN, was offered to him by the influential publisher Maximilien Vox (real name, Samuel Monod), acting on behalf of the Vichy government. Sympathetic to the Germans, this puppet regime wanted to vaunt the vitality of French intellectual life under its beneficent new rulers. Why did Doisneau agree to such a dubious assignment? Recently returned from the army, he probably just needed the cash. His first baby had only recently been born, and a commission from Vox was not something that a young photographer turned down. Furthermore, lauding France's academic excellence need not have struck him as a betrayal. What Doisneau found as he toured the museums and gardens was a vibrant research institute — despite, rather than because of, the intrusion of world events. Paul Rivet, director of the MNHN's Museum of Man, was in exile in Colombia. Others had just returned from military service or prisoner-of-war camps — including the palaeontologist Camille Arambourg, now remembered for defending Neanderthals against accusations of simian brutishness. A demobilized botanist, André Guillaumin, was searching for coal to heat the vast greenhouses. A major effort was under way to reorganize the collections, which were just starting to return, having been evacuated in 1939. Publication had been slowed but not stopped by the censors. At the Museum of Man, a resistance cell had been dismantled and its members executed or deported. Emerging from such tensions, the images take on extra significance. Doisneau wrote later that he was struck by the contrast between the moment of history he inhabited — of which his growling stomach served as a constant reminder — and the geological epochs spanned by the collections. He used that contrast to powerful effect. Some of the images seem downright insolent, such as that of Paul Budker of the Laboratory of Fish and Colonial Animals gazing into a jar of baby sharks — a Frenchman inspecting imprisoned predators. Others find a wistful wisdom in scenes from the museum's daily life. One such is The Funeral Procession of the Jaguar: the beast is pushed in a wheelbarrow over cobbles to the taxidermy department. Another, showing a white-coated woman with a wizened corpse on her hip and a faraway look in her eyes, Doisneau entitled The Surprising Lightness of a Peruvian Mummy. Vox had envisaged a collection called The Face of Science. Overtaken by events, it never saw the light of day. In November 1942, Allied forces landed in North Africa, prompting the Germans to invade previously unoccupied southern France, rendering the Vichy government impotent. The photos were consigned to the museum library. In 1990, the museum invited Doisneau back to complete his project. This postscript was a good idea: the contrast between the two sets of photos speaks volumes. Doisneau was in his late seventies and famous. The museum, too, had changed, and Doisneau delighted in discovering its three new subterranean floors of storage. The later images are as closely observed as the earlier ones. But now — as in a picture of a stuffed gorilla in a lift, emerging from or descending into the museum's bowels — the irony is less loaded, and the delight floats free.


Geerinckx T.,Ghent University | Herrel A.,M.N.H.N. | Adriaens D.,Ghent University
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology | Year: 2011

Suckermouth armored catfishes (Loricariidae) use their suckermouth for inspiration, feeding, and attachment to substrates. The sucker consists of a pre-valvular cavity, formed by a modified lip disc, and is separated from the larger post-valvular buccal cavity by a muscular oral valve. The combination of respiration and suction attachment seems paradoxal, as a properly functioning suction device would need a sucker without leakage (yet inspiration must occur via the sucker), and continuous subambient pressure in the sucker cavity (even during expiratory mouth floor elevation). In the loricariid Pterygoplichthys disjunctivus, the anatomy of the suckermouth structures was examined, and a kinematic analysis was performed to acquire insights into how respiration and attachment are combined. High-speed external and X-ray recordings show that suckermouth attachment influences respiratory parameters such as decreasing excursion amplitudes of mouth floor elements, and the way water enters the mouth via furrows in the lip disc. Respiration, however, continues during attachment and is not blocked. Our data show that the muscular oral valve actively separates the post-valvular buccal cavity from the pre-valvular sucker cavity. Volume changes of this pre-valvular cavity are opposite to those of the post-valvular cavity and assure sucker function even during expiration. These volume changes are caused by movements of the lower lip, the lower jaws, and the oral valve. The lateral inflow furrow openings, controlled by the maxillary barbels, can occur unilaterally. Morphological and kinematic data also show that the opercle is anatomically and functionally decoupled from the gill opening. © 2010 Wiley-Liss, Inc., A Wiley Company.


Ruff C.B.,Johns Hopkins University | Puymerail L.,French National Center for Scientific Research | Macchiarelli R.,MNHN | Macchiarelli R.,University of Poitiers | And 2 more authors.
Journal of Human Evolution | Year: 2015

The original hominin femur (Femur I) and calotte discovered at Trinil, Java by Eugene Dubois in 1891/1892 played a key role in the early history of human paleontology by purportedly demonstrating the contemporaneity of archaic cranial form with modern human erect (bipedal) posture. On this basis, both specimens were subsequently assigned to Pithecanthropus erectus, later transferred to Homo erectus. However, chronological and phylogenetic links between the two have been questioned from the beginning. Four additional hominin partial femora (Femora II-V) from Trinil were subsequently described but have played a relatively minor part in evolutionary scenarios. Here we present the results of a new analysis of structural and density characteristics of the Trinil femora obtained using computed tomography. Trinil Femur I shows none of the characteristics typical of early Homo femora from elsewhere in Asia or Africa, including a relatively long neck, increased mediolateral bending rigidity of themid-proximal shaft, or a low position of minimum mediolateral breath on the shaft. In contrast, Femora II-V all demonstrate features that are more consistent with this pattern. In addition, material density distributions within the specimens imply more recent and less complete fossilization of Femur I than Femora II-V. Thus, it is very likely that Trinil Femur I derives from a much more recent time period than the calotte, while the less famous and less complete Femora II-V may represent H.erectus at Trinil. The morphological variation within the Trinil femora can be attributed to broader changes in pelvic morphology occurring within the Homo lineage between the Early and late Middle Pleistocene. © 2015 Published by Elsevier Ltd.


Massoni J.,University Pierre and Marie Curie | Cassone J.,MNHN | Durette-Desset M.-C.,French Natural History Museum | Audebert F.,University Pierre and Marie Curie
Parasitology Research | Year: 2011

The morphogenesis (studied for the first time) and the chronology of the life cycle of Graphidium strigosum (Dujardin, 1845) were studied in detail in its natural host, Oryctolagus cuniculus. Naive rabbits were each infected per os with G. strigosum infective larvae (L3). Animals were euthanized each day for the first 10 days after infection (DAI), then every 2 days from 12 to 40 DAI. The free living period lasted 5-8 days at 24°C. By 1 DAI, all the larvae were exsheathed in the stomach. The third molt occurred between 9 and 17 DAI. The last molt occurred between 24 and 32 DAI. The prepatent period lasted 42-44 DAI, while the patent period lasted at least 13 months. For each experiment, the morphology of the different stages of the life cycle was described. The chronology of the G. strigosum life cycle and its morphogenesis were compared to those of different Haemonchidae parasites of ruminants (Ostertagia ostertagi, Teladorsagia circumcincta, Haemonchus contortus, and Haemonchus placei) in their natural hosts. © 2011 Springer-Verlag.


In the past 50 years, the turbot is referred to either as Scophthalmus maximus (Linnaeus, 1758) or Psetta maxima (Linnaeus, 1758) in the literature. Norman (1931) had argued that the valid name for the turbot was Scophthalmus maximus. However, his recommendation was never universally accepted, and today the confusing situation exists where two generic names are still being used for this species. We address this issue by analysing findings from recently published works on the anatomy, molecular and morphological phylogenetic systematics, and ecology of scophthalmid fishes. The preponderance of evidence supports the strong recommendation to use Scophthalmus as the valid generic name for the turbot. Acceptance of this generic name conveys the best information available concerning the systematic relationships of this species, and also serves to simplify the nomenclature of scophthalmid flatfishes in publications on systematics, fisheries and aquaculture, fishery statistics, ichthyofaunal and field guides for the general public, and in various legal and conservation-related documents. This paper reinforces the conclusions of Chanet (2003) with more arguments.


Reeb C.,MNHN | Bardat J.,MNHN
Cryptogamie, Bryologie | Year: 2014

The genus Riccardia, Aneuraceae is often considered as puzzling by bryologists, because of its great polymorphism, and African species have not been studied as a whole for several years. A type revision of the African species assigned to Riccardia is presented in order to get a clear view of the historical background before examination of recent material. Among the type material, two new citations are reported for Africa: Riccardia inconspicua (Steph.) Reeb et Bardat belonging to the subgenus Thornoneura and Lobatiriccardia cf. coronopus (De Not.) Furuki belonging to the closed genus Lobatiriccardia, not known before for Africa. Some synonyms have been corrected. The major taxonomical decisions will only be presented with the future revision of the African genus, after complete examination of variations based on recent collections or herbaria specimen, and on the results given by complementary tools, such as molecular and architectural analysis. © 2014 Adac. Tous droits réservés.


Goutte S.,MNHN | Dubois A.,MNHN | Legendre F.,MNHN
PLoS ONE | Year: 2013

Habitat characterisation is a pivotal step of any animal ecology study. The choice of variables used to describe habitats is crucial and need to be relevant to the ecology and behaviour of the species, in order to reflect biologically meaningful distribution patterns. In many species, acoustic communication is critical to individuals' interactions, and it is expected that ambient acoustic conditions impact their local distribution. Yet, classic animal ecology rarely integrates an acoustic dimension in habitat descriptions. Here we show that ambient sound pressure level (SPL) is a strong predictor of calling site selection in acoustically active frog species. In comparison to six other habitat-related variables (i.e. air and water temperature, depth, width and slope of the stream, substrate), SPL had the most important explanatory power in microhabitat selection for the 34 sampled species. Ambient noise was particularly useful in differentiating two stream-associated guilds: torrents and calmer streams dwelling species. Guild definitions were strongly supported by SPL, whereas slope, which is commonly used in stream-associated habitat, had a weak explanatory power. Moreover, slope measures are non-standardized across studies and are difficult to assess at small scale. We argue that including an acoustic descriptor will improve habitat-species analyses for many acoustically active taxa. SPL integrates habitat topology and temporal information (such as weather and hour of the day, for example) and is a simple and precise measure. We suggest that habitat description in animal ecology should include an acoustic measure such as noise level because it may explain previously misunderstood distribution patterns. © 2013 Goutte et al.

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