Reproductive life history of snakes in temperate regions: what are the differences between oviparous and viviparous species?

Abstract

Studying life history (LH) allows a broader understanding of organisms and populations’ responses to their environments. Snakes display an immense diversity in terms of reproductive traits, which is reflected in LH traits. The aim of this study is to compare reproductive biology and morphological variables in viviparous and oviparous snakes of a temperate South American community. We studied nearly 1000 specimens of eight oviparous and seven viviparous species pertaining to the four taxonomic families that inhabit the Paraná basin floodplain. Dimorphic variables did not show a different tendency between oviparous and viviparous species. Our results showed that the reproductive mode determined some reproductive traits of a snake’s LH, such as reproductive frequency and reproductive potential. Oviparous snakes reproduce annually, while viviparous snakes reproduce biannually or multi-annually. All species showed seasonal reproductive cycles and no correlation between clutch size (fecundity) and maternal body size. The reproductive strategy of both oviparous and viviparous species of the Paraná River floodplain was to adjust their reproductive cycles to both hydrological cycle of the river and temperature regime. The reproductive traits under study are suggested to have been influenced by environmental factors as well as by genetic characteristics. The studied assemblage is the result of an admixture of evolutionarily distinct clades, each contributing a set of species with different reproductive traits. Although we do not ignore this fact, we emphasize the importance of studying reproductive LH as raw material for an integrative analysis.

Different solutions lead to similar life history traits across the great divides of the amniote tree of life

“…Viviparity, however, evolved many times in squamate reptiles [22], and furthermore manifests great variability in the degree of fetal provisioning and placentationfrom ovoviviparity to placental mammal-like nutrient exchange [124]. This allows meaningful testing of the effects of viviparity in a phylogenetic context [45,57,97,118,[125][126][127][128][129] which makes the Squamata a fantastic model in which to directly test for the evolutionary implications the evolution of viviparity may have had for life history evolution.…”

Lista comentada de las serpientes de la Argentina, con referencias a su sistemática, distribución geográfica, dieta, reproducción, potencial peligrosidad y etimologías

“…Paren entre 1 y 30 crías (Orrego Aravena, 1971;Miranda et al, 1982;Cardinale & Ávila, 1997;Sawaya et al, 2008). Bellini et al (2019) realizaron un estudio muy interesante de los rasgos reproductivos de esta y otras especies de serpientes del noreste de la Argentina (Bothrops diporus, Helicops infrataeniatus, H. leopardinus, Thamnodynastes chaquensis, T. hypoconia, T. strigatus, Hydrodynastes gigas, Erythrolamphrus semiaureus, Leptophis ahaetulla, Micrurus altirostris, Paraphimophis rusticus, Philodryas patagoniensis, Xenodon dorbignyi y Xenodon merremii) y la influencia de factores ambientales como el ciclo hidrológico del río Paraná y el régimen de temperatura, en relación con la historia filogenética de cada una de las especies.…”

“…Los rasgos reproductivos dependen en gran medida de la historia filogenética de cada especie, reflejando el clado al que pertenecen (Bellini et al, 2019). Los mismos autores resaltan que la plasticidad en los rasgos reproductivos del grupo de serpientes neotropicales que estudiaron fue influenciada por factores ambientales, como el ciclo hidrológico del río Paraná y el régimen de temperatura, como así también por su propia historia evolutiva.…”

“…Localidad tipo: Surinam. Tipo de reproducción: Vivípara Bellini et al, 2019) paren de 1 a 29 crías (Carreira et al, 2005;Carreira & Maneyro, 2013).…”

“…Probablemente de la desembocadura del rio Paraguay de acuerdo con Gans (1964) (Nogueira et al, 2019). Tipo de reproducción: Ovípara (López et al, 2009;Bellini et al, 2019;Eisfeld at al., 2019). Alimentación: Anfibios anuros, renacuajos y peces (Bellini et al, 2015;Alcalde et al, 2019).…”