Phylogeography of two neotropical species of the genus Araneus (Araneidae)

Author(s)

Elen Arroyo Peres

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2015-02-27

Examining board members

Vera Nisaka Solferini; Cristina Yumi Miyaki; Gustavo Quevedo Romero; Marcos Roberto Dias Batista; Maria Tereza Chiarioni Thomé

• Advisor: Vera Nisaka Solferini

Abstract

In this work, we have studied the phylogeographic patterns of two spiders of the genus Araneus (Araneidae) to contribute to the knowledge about the biogeography of the Neotropical region. For both species, we estimated the genetic diversity, the population structure, haplotype networks, phylogenetic inferences and the demographic history using one mitochondrial (Cytochrome Oxidase I, COI) and one nuclear (Internal Transcribed Subunit II, ITS2) marker; and presented the results in two separate manuscripts. In the first, "Pleistocene niche stability and lineage diversification in the subtropical spider Araneus omnicolor", we have tested the influence of the Quaternary climatic oscillations on the demography of A. omnicolor, a species restricted to South American subtropical region. The paleoclimatic modeling indicated that A. omnicolor¿s distribution remained stable during the Late Pleistocene. Besides, the comparison among 14 demographic models through an Approximate Bayesian Computation (ABC) approach pointed to panmixia with stability as the most probable model, although the other demographic analyses had indicated recent expansion, suggesting a complex scenario for this species. In the second manuscript, "Conexões entre Amazônia e Mata Atlântica reveladas por Araneus venatrix", we have analyzed the patterns of A. venatrix, a species that occurs in humid Neotropical environments (Amazonia, Atlantic Forest and gallery forests located in the dry diagonal between these biomes). We have detected a deep divergence between a clade restricted to Southern Atlantic Forest and the other, distributed in all other Brazilian regions, on Late Miocene. These results suggest that the expansion of Cerrado biome and the consequent split of rainforests are coincident with a progressive cooling and dryness that occurred during the Tertiary, although some degree of connectivity between these biomes had remained until today. The analyses showed that the northern Atlantic Forest populations are genetically more similar to Amazonian populations than to the ones from southern Atlantic Forest, indicating that the processes related to the lineages diversification in these biomes are not completely independent. This work has showed that studies focused on widely distributed taxa contribute with important information regarding the history of Neotropical Rainforests. Both manuscripts suggest intriguing scenarios for South America and reveal the importance of more research with organisms as spiders, which are abundant but scarcely explored in Neotropics. Our results contribute to the general knowledge of the group and also to a better comprehension of the biogeographic history of Neotropical region (AU)

• FAPESP's process: 10/50624-2 - Phylogeography of Araneus guttatus (Arachnida: Araneae)
• Grantee: Elen Arroyo Peres
• Support Opportunities: Scholarships in Brazil - Doctorate