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| African Swallowtail Butterfly - Papilio dardanus | |
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| Tweet Topic Started: Jun 12 2014, 03:50 PM (1,604 Views) | |
| Taipan | Jun 12 2014, 03:50 PM Post #1 |
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African Swallowtail Butterfly - Papilio dardanus![]() Scientific classification Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Papilionidae Genus: Papilio Species: Papilio dardanus Papilio dardanus (the African Swallowtail, Mocker Swallowtail or Flying Handkerchief), is a species of butterfly in the family Papilionidae (the Swallowtails). The species is broadly distributed throughout sub-Saharan Africa. The British entomologist E. B. Poulton described it as "the most interesting butterfly in the world". Classification Molecular studies have provided evidence that this species' closest relative is Papilio phorcas, with Papilio constantinus being the next closest. It is a member of the Papilio genus of which Papilio appalachiensis and Papilio xuthus are also members. Papilio dardanus is the nominal member of the dardanus species-group. The members of the clade are:
Subspecies Listed alphabetically.
![]() Ecozone Afrotropic ecozone Mimicry The species shows polymorphism in wing appearance, though this is limited to females, which are often given as an example of Batesian mimicry in insects. This female-limited mimicry was first described in 1869 by Roland Trimen. Males have a more or less uniform appearance throughout the species' range, but females come in at least 14 varieties or morphs. Some female morphs share a very similar pattern of colouration with various species of distasteful butterfly (e.g. from the Danainae, a subfamily of nymphalids), while others have been found that mimic male appearance (andromorphs). The persistence of these various morphs or different types of females may be explained by frequency dependent selection. Cook et al. suggest that Batesian mimics gain a fitness advantage by avoiding predators, but suffer harassment from males (see sexual conflict), whereas andromorphs (male mimics) are vulnerable to predation but are not harassed by male mating attempts. Such female-limited Batesian mimicry is not unique to this species, even in the genus Papilio. For instance Papilio memnon shows a similar case of polymorphism in females. Similarly, male mimicry has been observed in another insect, a damselfly (Ischnura ramburii) which also appears to have evolved camouflage to avoid sexual coercion by males. |
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| Taipan | Jun 12 2014, 03:57 PM Post #2 |
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African Swallowtail butterfly: Genetic secrets of nature's master of mimicry unraveled Date: June 11, 2014 Source: University of Exeter Summary: Scientists investigating how one of the greatest shape shifters in the natural world is able to trick predators to avoid being eaten have identified the gene behind the fascinating feat. The African Swallowtail butterfly, also known as the 'Mocker Swallowtail' or the 'Flying Handkerchief,' can appear to change both color and shape. ![]() Scientists have discovered the genetic switch that allows female swallowtails to look like different Monarch butterflies and thus avoid being eaten. Scientists investigating how one of the greatest shape shifters in the natural world is able to trick predators to avoid being eaten have identified the gene behind the fascinating feat. The African Swallowtail butterfly, also known as the 'Mocker Swallowtail' or the 'Flying Handkerchief,' can appear to change both colour and shape. Males of the species fly boldly around the tree tops, their rapid flight making them look like shaking handkerchiefs, however females lurk in the bushes and pretend to be examples of Monarch butterflies that are nasty to eat. The females mimic different Monarchs in different parts of Africa and how they do this has long been a mystery. In an international collaboration involving scientists from the Natural History Museum, Imperial College London, the University of Cambridge and researchers in Nairobi, Paris and Jena in Germany, The University of Exeter's Professor Richard ffrench-Constant (correct spelling) has helped solve the genetic switch that allows female swallowtails to look like different Monarch butterflies and thus avoid being eaten. "This mimicry is not just a simple change of colour and pattern," says Prof ffrench-Constant, "but the females also lose their characteristic swallow tails and even fly slowly like Monarch butterflies." This unique combination of shape-shifting makes the mimicry more convincing for predatory birds and once they learn to avoid one warning pattern, they will then avoid similar looking butterflies. Dr Martijn Timmermans of Imperial College London, who led the study, said: "The wings of the Mocker Swallowtails have bewildered biologists for almost a century. By pinpointing the switch, we have revealed a unique mechanism. It is really exciting to show that all this diversity is determined by variation in just a single gene." The genetic switch appears to be the gene called 'engrailed', a gene previously shown to be important in patterning the early embryo of fruit flies. The engrailed gene belongs to a family of genes called transcription factors that switch on networks of genes responsible for all aspects of development. Previously the engrailed gene has been shown to be important in setting up patterning in developing fruit fly embryos, however, nature seems to have redeployed this gene into much later patterning -- the patterning of a butterfly wing. This allows the engrailed gene to function both early in embryo development and then later as a master mimicry switch gene by changing the colour and shape of the butterflies wing. "We still have a lot to learn" adds ffrench-Constant, "we don't really understand how this gene can control such a wide range of characteristics and how this mimicry is limited only to the female of the species. However, such questions are bound to provide significant challenges for the team in the future." http://www.sciencedaily.com/releases/2014/06/140611093805.htm Journal Reference: M. J. T. N. Timmermans, S. W. Baxter, R. Clark, D. G. Heckel, H. Vogel, S. Collins, A. Papanicolaou, I. Fukova, M. Joron, M. J. Thompson, C. D. Jiggins, R. H. ffrench-Constant, A. P. Vogler. Comparative genomics of the mimicry switch in Papilio dardanus. Proceedings of the Royal Society B: Biological Sciences, 2014; 281 (1787): 20140465 DOI: 10.1098/rspb.2014.0465 Abstract The African Mocker Swallowtail, Papilio dardanus, is a textbook example in evolutionary genetics. Classical breeding experiments have shown that wing pattern variation in this polymorphic Batesian mimic is determined by the polyallelic H locus that controls a set of distinct mimetic phenotypes. Using bacterial artificial chromosome (BAC) sequencing, recombination analyses and comparative genomics, we show that H co-segregates with an interval of less than 500 kb that is collinear with two other Lepidoptera genomes and contains 24 genes, including the transcription factor genes engrailed (en) and invected (inv). H is located in a region of conserved gene order, which argues against any role for genomic translocations in the evolution of a hypothesized multi-gene mimicry locus. Natural populations of P. dardanus show significant associations of specific morphs with single nucleotide polymorphisms (SNPs), centred on en. In addition, SNP variation in the H region reveals evidence of non-neutral molecular evolution in the en gene alone. We find evidence for a duplication potentially driving physical constraints on recombination in the lamborni morph. Absence of perfect linkage disequilibrium between different genes in the other morphs suggests that H is limited to nucleotide positions in the regulatory and coding regions of en. Our results therefore support the hypothesis that a single gene underlies wing pattern variation in P. dardanus. http://rspb.royalsocietypublishing.org/content/281/1787/20140465 |
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6:22 PM Jul 11