Archivos de Diario para diciembre 2022

domingo, 11 de diciembre de 2022

Genus Trichromia on Rio Grande do Sul state.

Abstract: The genus Trichromia has about 116 species in the Neotropical region, but only one is known to occur in the Rio Grande do Sul state: the species Trichromia repanda. Observations of Trichromia in the Rio Grande do Sul state show two forms occurring in the state. There are several hypotheses that can explain the second form of Trichromia in the Rio Grande do Sul state: a known species of Trichromia outside of Ferro & Teston's (2009) list, a new species of Trichromia, sexual dimorphism, or population variation. The hypothesis of a new species can only be tested by examining the sexual organs, while the hypothesis of sexual dimorphism was tested by comparing descriptions and photographs of museum specimens. The hypothesis of population variation was tested by comparing images of the two forms, but none were intermediate between the two. It was concluded that both forms found in the Rio Grande do Sul state are Trichromia repanda, with one being the male form and the other being the female form.

Resumo: O gênero Trichromia tem cerca de 116 espécies na região neotropical, mas apenas uma é conhecida por ocorrer no estado do Rio Grande do Sul: a espécie Trichromia repanda. Observações de Trichromia no Rio Grande do Sul mostram duas formas ocorrendo no estado. Há algumas hipóteses que podem explicar a segunda forma de Trichromia no Rio Grande do Sul: uma espécie conhecida de Trichromia fora da lista de Ferro & Teston (2009), uma nova espécie de Trichromia, dimorfismo sexual ou variação populacional. A hipótese de nova espécie só pode ser testada verificando os órgãos sexuais, enquanto a hipótese de dimorfismo sexual foi testada através da comparação com descrições e fotografias de exemplares de museu. A hipótese de variação populacional foi testada comparando imagens das duas formas, mas nenhuma foi intermediária entre as duas. Concluiu-se que ambas as formas encontradas no Rio Grande do Sul são Trichromia repanda, sendo uma a forma masculina e a outra a forma feminina.

The genus Trichromia has about 116 species on Neotropical region (Vincent & Laguerre, 2014) but only one is known to occur on Rio Grande do Sul state, the species Trichromia repanda (Ferro & Teston, 2009). A drawing of the species can be found on the book Die Grossschmetterlinge der Erde : eine systematische Bearbeitung der bis jetzt bekannten Grossschmetterlinge, volume 6, plate 46, row d: https://www.biodiversitylibrary.org/item/250948#page/95/mode/1up . Many iNaturalist observations of Trichromia in the Rio Grande do Sul can be identified with this drawing, like this one: https://www.inaturalist.org/observations/93317890.
But others can't: https://www.inaturalist.org/observations/95476060.
Some hypothesis that can explain the second form of Trichromia on Rio Grande do Sul state:

  • A know specie of Trichromia outside of Ferro & Teston, 2009 list;
  • A new specie of Trichromia;
  • Sexual dimorphism;
  • Populacional variation.

I searched observations of the neigborhoods of Rio Grande do Sul state looking for Trichromia to test the first hypothesis. The idea was find an identification at specie level of this second Trichromia form. I could find them on Santa Catarina state and Misiones province, but none was identified at species level.
It's not possible to test new specie hypothesis unless checking sexual organs.
Vincent & Laguerre, 2017 described two new species of Trichromia that showed sexual dimorphism. To test the sexual dimorphism hypothesis I used the funet site (https://ftp.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/noctuoidea/arctiidae/arctiinae/trichromia/) looking for the descriptions of Trichromia repanda. Hampson, 1901 (https://archive.org/details/catalogueoflepid03brituoft/page/178/mode/1up?view=theater) described the female of the species: "Fore wing with the round apicalpatch conjoined by a broad band to the patch on inner area." This description matched and corroborated the sexual dimorphism hypothesis. Finally I checked BOLD Systems site looking for Trichromia repanda museum specimens and found six males and one female that also corroborated sexual dimorphism hypothesis. https://www.boldsystems.org/index.php/Taxbrowser_Taxonpage?taxid=530427.
The populational variation was tested by comparing images of the two forms. Although some variation was found, none was intermediate between the two forms.
I concluded that the two forms of Trichromia found in the Rio Grande do Sul state are both Trichromia repanda, with one being the male form and the other being the female form.

Ferro & Teston, 2009. Composição de espécies de Arctiidae (Lepidoptera) no sul do Brasil: relação entre tipos de vegetação e entre a configuração espacial do hábitat. Revista Brasileira de entomologia 53 (2): 278-286;
Vincent & Laguerre, 2014. Catalogue of the Neotropical Arctiini Leach, 1815 (Insecta, Lepidoptera, Erebidae, Arctiinae) Zoosystema 36 (2) : 137-533;
Vincent & Laguerre, 2017. Description de deux nouvelles espèces du genre Trichromia Hübner, 1815, de Guyane française (Lepidoptera, Erebidae, Arctiinae). Bulletin de la Socièté entomologique de France 122 (2) : 223-232.

Publicado el domingo, 11 de diciembre de 2022 a las 04:33 PM por regisrafael regisrafael | 0 comentarios | Deja un comentario