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Does Triatoma brasiliensis occupy the same environmental niche space as Triatoma melanica?

de Souza Rde C, Campolina-Silva GH, Bezerra CM, Diotaiuti L, Gorla DE - Parasit Vectors (2015)

Bottom Line: The ecological niche models show that the environmental spaces currently occupied by T. brasiliensis and T. melanica are similar although not equivalent, and associated with the caatinga ecosystem.Wing size and shape analyses based on seven landmarks of 72 field specimens confirmed consistent differences between T. brasiliensis and T. melanica.Our results suggest that the separation of the two species should be attributed to a factor that does not include the current environmental conditions.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, CEP 30.190-002, Belo Horizonte, Minas Gerais, Brazil. rita@cpqrr.fiocruz.br.

ABSTRACT

Background: Triatomines (Hemiptera, Reduviidae) are vectors of Trypanosoma cruzi, the causative agent of Chagas disease, one of the most important vector-borne diseases in Latin America. This study compares the environmental niche spaces of Triatoma brasiliensis and Triatoma melanica using ecological niche modelling and reports findings on DNA barcoding and wing geometric morphometrics as tools for the identification of these species.

Methods: We compared the geographic distribution of the species using generalized linear models fitted to elevation and current data on land surface temperature, vegetation cover and rainfall recorded by earth observation satellites for northeastern Brazil. Additionally, we evaluated nucleotide sequence data from the barcode region of the mitochondrial cytochrome c oxidase subunit I (CO1) and wing geometric morphometrics as taxonomic identification tools for T. brasiliensis and T. melanica.

Results: The ecological niche models show that the environmental spaces currently occupied by T. brasiliensis and T. melanica are similar although not equivalent, and associated with the caatinga ecosystem. The CO1 sequence analyses based on pair wise genetic distance matrix calculated using Kimura 2-Parameter (K2P) evolutionary model, clearly separate the two species, supporting the barcoding gap. Wing size and shape analyses based on seven landmarks of 72 field specimens confirmed consistent differences between T. brasiliensis and T. melanica.

Conclusion: Our results suggest that the separation of the two species should be attributed to a factor that does not include the current environmental conditions. However, as the caatinga is a biome that has existed in the area for at least the last 18,000 years, past conditions might have had an influence in the speciation process. The DNA Barcoding approach may be extended to these members of the subfamily Triatominae.

No MeSH data available.


Related in: MedlinePlus

Wing centroid size variation among males and females of T. brasiliensis and T. melanica. This shows the sexual size dimorphism. The group mean is shown as a box between the quartiles (25th and 75th percentiles) and the standard deviations are shown as lines. Units are pixels
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Fig2: Wing centroid size variation among males and females of T. brasiliensis and T. melanica. This shows the sexual size dimorphism. The group mean is shown as a box between the quartiles (25th and 75th percentiles) and the standard deviations are shown as lines. Units are pixels

Mentions: As expected, there was a significant difference in centroid size values in both sexes and species (P < 0.001) (Fig. 2). A consistent sexual size dimorphism was observed, where the female wings were larger than the males. Wing size was largest in T. brasiliensis, as observed by Costa and colleagues [42].Fig. 2


Does Triatoma brasiliensis occupy the same environmental niche space as Triatoma melanica?

de Souza Rde C, Campolina-Silva GH, Bezerra CM, Diotaiuti L, Gorla DE - Parasit Vectors (2015)

Wing centroid size variation among males and females of T. brasiliensis and T. melanica. This shows the sexual size dimorphism. The group mean is shown as a box between the quartiles (25th and 75th percentiles) and the standard deviations are shown as lines. Units are pixels
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4496957&req=5

Fig2: Wing centroid size variation among males and females of T. brasiliensis and T. melanica. This shows the sexual size dimorphism. The group mean is shown as a box between the quartiles (25th and 75th percentiles) and the standard deviations are shown as lines. Units are pixels
Mentions: As expected, there was a significant difference in centroid size values in both sexes and species (P < 0.001) (Fig. 2). A consistent sexual size dimorphism was observed, where the female wings were larger than the males. Wing size was largest in T. brasiliensis, as observed by Costa and colleagues [42].Fig. 2

Bottom Line: The ecological niche models show that the environmental spaces currently occupied by T. brasiliensis and T. melanica are similar although not equivalent, and associated with the caatinga ecosystem.Wing size and shape analyses based on seven landmarks of 72 field specimens confirmed consistent differences between T. brasiliensis and T. melanica.Our results suggest that the separation of the two species should be attributed to a factor that does not include the current environmental conditions.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, CEP 30.190-002, Belo Horizonte, Minas Gerais, Brazil. rita@cpqrr.fiocruz.br.

ABSTRACT

Background: Triatomines (Hemiptera, Reduviidae) are vectors of Trypanosoma cruzi, the causative agent of Chagas disease, one of the most important vector-borne diseases in Latin America. This study compares the environmental niche spaces of Triatoma brasiliensis and Triatoma melanica using ecological niche modelling and reports findings on DNA barcoding and wing geometric morphometrics as tools for the identification of these species.

Methods: We compared the geographic distribution of the species using generalized linear models fitted to elevation and current data on land surface temperature, vegetation cover and rainfall recorded by earth observation satellites for northeastern Brazil. Additionally, we evaluated nucleotide sequence data from the barcode region of the mitochondrial cytochrome c oxidase subunit I (CO1) and wing geometric morphometrics as taxonomic identification tools for T. brasiliensis and T. melanica.

Results: The ecological niche models show that the environmental spaces currently occupied by T. brasiliensis and T. melanica are similar although not equivalent, and associated with the caatinga ecosystem. The CO1 sequence analyses based on pair wise genetic distance matrix calculated using Kimura 2-Parameter (K2P) evolutionary model, clearly separate the two species, supporting the barcoding gap. Wing size and shape analyses based on seven landmarks of 72 field specimens confirmed consistent differences between T. brasiliensis and T. melanica.

Conclusion: Our results suggest that the separation of the two species should be attributed to a factor that does not include the current environmental conditions. However, as the caatinga is a biome that has existed in the area for at least the last 18,000 years, past conditions might have had an influence in the speciation process. The DNA Barcoding approach may be extended to these members of the subfamily Triatominae.

No MeSH data available.


Related in: MedlinePlus