scholarly journals Chemical signals act as the main reproductive barrier between sister and mimetic Heliconius butterflies

2020 ◽  
Vol 287 (1926) ◽  
pp. 20200587 ◽  
Author(s):  
M. F. González-Rojas ◽  
K. Darragh ◽  
J. Robles ◽  
M. Linares ◽  
S. Schulz ◽  
...  

Colour pattern is the main trait that drives mate recognition between Heliconius species that are phylogenetically close. However, when this cue is compromised such as in cases of mimetic, sympatric and closely related species, alternative mating signals must evolve to ensure reproductive isolation and species integrity. The closely related species Heliconius melpomene malleti and H. timareta florencia occur in the same geographical region, and despite being co-mimics, they display strong reproductive isolation. In order to test which cues differ between species, and potentially contribute to reproductive isolation, we quantified differences in the wing phenotype and the male chemical profile. As expected, the wing colour pattern was indistinguishable between the two species, while the chemical profile of the androconial and genital males' extracts showed marked differences. We then conducted behavioural experiments to study the importance of these signals in mate recognition by females. In agreement with our previous results, we found that chemical blends and not wing colour pattern drive the preference of females for conspecific males . Also, experiments with hybrid males and females suggested an important genetic component for both chemical production and preference. Altogether, these results suggest that chemicals are the major reproductive barrier opposing gene flow between these two sister and co-mimic species.

2019 ◽  
Author(s):  
M.F. González-Rojas ◽  
K. Darragh ◽  
J Robles ◽  
M. Linares ◽  
S Schulz ◽  
...  

ABSTRACTColour pattern has been long recognised as the trait that drives mate recognition betweenHeliconiusspecies that are phylogenetically close. However, when this cue is compromised such as in cases of mimetic, sympatric and closely related species, alternative mating signals must evolve to ensure reproductive isolation and species integrity. The closely related speciesHeliconius melpomene malletiandH. timareta florencia, occur in the same geographic region and despite being co-mimics they display strong reproductive isolation. In order to test which cues differ between species, and therefore potentially contribute to reproductive isolation, we quantified differences in wing phenotype and male chemical profile. As expected, wing colour pattern was indistinguishable between the two species while the chemical profile of their male sex pheromones showed marked differences. We then conducted behavioural experiments to study the importance of these signals in mate recognition by females. In agreement with our previous results, we found that pheromones and not wing colour pattern drive the preference of females by conspecific males. In addition, experiments with hybrid males and females suggested an important genetic component for both pheromone production and preference. Altogether, these results suggest that pheromones are the major reproductive barrier opposing gene flow between these two sister and co-mimic species.


1967 ◽  
Vol 15 (3) ◽  
pp. 501 ◽  
Author(s):  
H Wolda

A number of samples from wild populations of the Queensland fruit fly, Dacus tryoni and D. neohumeralis, were studied. There is a considerable variation in the colour pattern on the humeral callus. This variation is continuous so that any criterion for distinguishing between "intermediates" and "good species" is purely arbitrary. It was found in areas where D. neohumeralis does not occur as well as in localities where it is very abundant. By whatever criterion one defines intermediates, there appears to be no relation between the frequency of such forms and the presence or absence of D. neohumeralis or with the relative proportions of the two species in the population. However, flies with only a very small yellow area on an otherwise brown humeral callus were found only in Cairns where D. neohumeralis is usually the most abundant species. A similar variation in humeral callus pattern was found in other related species, such as D. kraussi and D. halfordiae. It is concluded that the intermediate colour forms may not be hybrids between D. tryoni and D. neohumeralis but variants of D. tryoni and, possibly the darker forms from Cairns, of D. neohumeralis.


2020 ◽  
Author(s):  
Camille Le Roy ◽  
Camille Roux ◽  
Elisabeth Authier ◽  
Héloïse Bastide ◽  
Vincent Debat ◽  
...  

AbstractThe emergence and persistence of closely-related species in sympatry is puzzling because the potential gene flow and the common local selective pressures may lead to either merging or competitive exclusion. Some species of Morpho butterflies occurring in sympatry display highly similar wing colour patterns. Associated with erratic flight abilities, their bright colouration may limit predator success and discourage future attacks. The evolution of similar colouration in sympatric species is thus likely under local selection by predators (i.e. escape mimicry). Such phenotypic similarity may promote interspecific territoriality and/or reproductive interference, questioning how closely-related co-mimetic species become sexually isolated and coexist in sympatry. We performed a series of field experiments using flying Morpho dummies placed in a natural habitat where wild males commonly patrol. Analysing the interactions of wild Morpho with different dummies, we show that similarity in wing colour pattern leads to interspecific territoriality and courtship among sympatric species. Using genomic data, we then showed that sympatric Morpho species are surprisingly strictly isolated despite their close relatedness and the observed heterospecific interactions. Finally, using a mark-recapture experiment, we discovered a strong temporal segregation in patrolling activity of males from two co-mimetic sister species. Such divergence in phenology may favour sympatry between closely-related species, despite behavioural interferences induced by the local convergence in colour pattern. Altogether, our findings show that temporal segregation may facilitate the co-existence of closely-related species sharing the same ecological niche, suggesting that phenological shifts may represent an overlooked factor of sympatric speciation. Our study therefore highlights how the evolution of multiple traits may favour species diversification in sympatry by partitioning niche in different dimensions.


Author(s):  
Kosei Sato ◽  
Daisuke Yamamoto

The main theme of the review is how changes in pheromone biochemistry and the sensory circuits underlying pheromone detection contribute to mate choice and reproductive isolation. The review focuses primarily on gustatory and non-volatile signals in Drosophila. Premating isolation is prevalent among closely related species. In Drosophila, preference for conspecifics against other species in mate choice underlies premating isolation, and such preference relies on contact chemosensory communications between a female and male along with other biological factors. For example, although D. simulans and D. melanogaster are sibling species that yield hybrids, their premating isolation is maintained primarily by the contrasting effects of 7,11-heptacosadiene (7,11-HD), a predominant female pheromone in D. melanogaster, on males of the two species: it attracts D. melanogaster males and repels D. simulans males. The contrasting preference for 7,11-HD in males of these two species is mainly ascribed to opposite effects of 7,11-HD on neural activities in the courtship decision-making neurons in the male brain: 7,11-HD provokes both excitatory and inhibitory inputs in these neurons and differences in the balance between the two counteracting inputs result in the contrasting preference for 7,11-HD, i.e., attraction in D. melanogaster and repulsion in D. simulans. Introduction of two double bonds is a key step in 7,11-HD biosynthesis and is mediated by the desaturase desatF, which is active in D. melanogaster females but transcriptionally inactivated in D. simulans females. Thus, 7,11-HD biosynthesis diversified in females and 7,11-HD perception diversified in males, yet it remains elusive how concordance of the changes in the two sexes was attained in evolution.


2010 ◽  
Vol 42 (2) ◽  
pp. 499
Author(s):  
Pietro Lo Cascio ◽  
Ignazio Sparacio

<em>Anthaxia</em> (<em>Haplanthaxia</em>) <em>flaviae</em> n. sp. from the Aeolian Islands (Italy, Sicily) belonging to the <em>A</em>. (<em>H</em>.) <em>olympica</em> Kiesenwetter, 1880 species-group is described, illustrated and compared with <em>A</em>. (<em>H</em>.) <em>scutellaris</em> (Gené, 1839), the most closely related species. From this latter, the new species differs mainly for size and body shape, colour pattern of elytrae, shape of antennomera, margin of anterior tibiae and shape of aedeagus. Some zoogeographical considerations concerning the insular distribution of this endemic taxon are briefly discussed.


2020 ◽  
Vol 287 (1931) ◽  
pp. 20201267
Author(s):  
Steven M. Van Belleghem ◽  
Paola A. Alicea Roman ◽  
Heriberto Carbia Gutierrez ◽  
Brian A. Counterman ◽  
Riccardo Papa

Müllerian mimicry strongly exemplifies the power of natural selection. However, the exact measure of such adaptive phenotypic convergence and the possible causes of its imperfection often remain unidentified. Here, we first quantify wing colour pattern differences in the forewing region of 14 co-mimetic colour pattern morphs of the butterfly species Heliconius erato and Heliconius melpomene and measure the extent to which mimicking colour pattern morphs are not perfectly identical. Next, using gene-editing CRISPR/Cas9 KO experiments of the gene WntA , which has been mapped to colour pattern diversity in these butterflies, we explore the exact areas of the wings in which WntA affects colour pattern formation differently in H. erato and H. melpomene. We find that, while the relative size of the forewing pattern is generally nearly identical between co-mimics, the CRISPR/Cas9 KO results highlight divergent boundaries in the wing that prevent the co-mimics from achieving perfect mimicry. We suggest that this mismatch may be explained by divergence in the gene regulatory network that defines wing colour patterning in both species, thus constraining morphological evolution even between closely related species.


1997 ◽  
Vol 20 (4) ◽  
pp. 583-585 ◽  
Author(s):  
Denise Selivon ◽  
João S. Morgante

The reproductive isolation between two closely related species, Anastrepha bistrigata and A. striata, was studied in the laboratory. Interespecific copulation attempts were observed, but examination of the spermathecae showed that sperm transference did not occur, even after a prolonged period of contact between the mating pairs. These results indicate prezygotic isolation. The analysis of the hourly distribution of mating activities under laboratory conditions, here described for the first time for A. bistrigata, clearly showed differences for the two species, the activities being concentrated in the afternoon period for A. striata and in the morning for A. bistrigata


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