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Evolutionary pathways driven by female mate choice : the curious case of the squalius alburnoides allopolyploid fish complex
Publication . Morgado-Santos, Miguel; Vicente, Luís A., 1955-; Magalhães, Maria Filomena, 1964-; Pereira, Maria João Collares, 1952-
Many asexual animals are sexual parasites that reproduce with sympatric species, leading to genetic, ecological and behavioural challenges. Several mechanisms allow the coexistence of sexuals and asexuals, and, over time, the latter may regain sexual reproduction and develop an independent reproductive dynamics, paving the way to the arising of new species through hybrid speciation. Mate choice may play a relevant role in all evolutionary stages of asexual organisms, either contributing to their persistence in hybrid state or routing them towards hybrid speciation. Here, we studied mate choice in the allopolyploid cyprinid Squalius alburnoides, namely its role in driving the evolutionary pathways of this hybrid complex. Bridging together genetic, theoretical and experimental approaches, we aimed at assessing: a) the role of mate choice in driving population stability or routing populations towards hybrid speciation; b) the influence of egg allocation, fertilization rate and offspring survival in shaping the reproductive dynamics and genomotype composition of populations; and c) the gameplay between mate choice by hybrid females and genetic introgression and variability. In the one hand, mate choice by hybrid females seems able to uphold the persistence of populations in their hybrid state by maintaining the reproductive dynamics between the interdependent genomotypes and sympatric congeneric species, and also by guaranteeing the maintenance of high genetic variability. On the other hand, when particular conditions are met, mate choice by hybrid females may also route populations towards hybrid speciation, namely via tetraploidization. The findings reported herein also include the first ever described case of naturally occurring androgenesis in vertebrates. In a general perspective, Squalius alburnoides’ hard-to-combine features challenge even the most conservative views about the role of hybridization in species’ diversification. Studying this allopolyploid complex is like looking at a snapshot of evolution and, undoubtedly, a privilege to every passionate evolutionary biologist.
Questioning the proverb ‘more haste, less speed’: classic versus metabarcoding approaches for the diet study of a remote island endemic gecko
Publication . Gil, Vanessa; Pinho, Catarina J.; Aguiar, Carlos A.S.; Jardim, Carolina; Sampaio e rebelo, Rui; Vasconcelos, Raquel
Dietary studies can reveal valuable information on how species exploit their habitats and
are of particular importance for insular endemics conservation as these species present
higher risk of extinction. Reptiles are often neglected in island systems, principally the
ones inhabiting remote areas, therefore little is known on their ecological networks.
The Selvagens gecko Tarentola (boettgeri) bischoffi, endemic to the remote and integral
reserve of Selvagens Archipelago, is classified as Vulnerable by the Portuguese Red
Data Book. Little is known about this gecko’s ecology and dietary habits, but it is
assumed to be exclusively insectivorous. The diet of the continental Tarentola species
was already studied using classical methods. Only two studies have used next-generation
sequencing (NGS) techniques for this genus thus far, and very few NGS studies have
been employed for reptiles in general. Considering the lack of information on its diet
and the conservation interest of the Selvagens gecko, we used morphological and
DNA metabarcoding approaches to characterize its diet. The traditional method of
morphological identification of prey remains in faecal pellets collected over a longer
period was compared with metabarcoding of samples collected during rapid surveys.
Molecular results revealed that this species is a generalist, feeding on invertebrate, plant
and vertebrate items, whereas the morphological approaches were unable to detect the
latter two. These results opened up new questions on the ecological role of the Selvagens
gecko that deserves to be further explored, such as the possible predation on seabirds,
plant services or trophic competition with the sympatric Madeira lizard Teira dugesii.
Metabarcoding identified a greater diversity of dietary items at higher taxonomic
resolution, but morphological identification enabled calculation of relative abundances
and biomasses of ingested arthropods, and detected a dietary shift on invertebrate
preys between seasons. Results of this study highlight the global applicability of rapid
metabarcoding surveys for understudied taxa on remote islands that are difficult to
access. We recommend using the metabarcoding approach, even if ‘speedy’ sampling
only is possible, but we must highlight that disregarding long-term ecological data may
lead to ‘hasty’ conclusion.
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Fundação para a Ciência e a Tecnologia
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5876
Número da atribuição
PEst-OE/BIA/UI0329/2014