The golden lanceheadBothrops insularis(Serpentes: Viperidae) relies on two seasonally plentiful bird species visiting its island habitat

Abstract

Adult individuals of the island pitviper Bothrops insularis have a diet based on birds. We analysed bird species recorded in the gut of this snake and found that it relies on two out of 41 bird species recorded on the island. When present, these two prey species were among the most abundant passerine birds on the island. A few other migrant birds were very occasionally recorded as prey. A resident bird species (Troglodytes musculus) is the most abundant passerine on the island, but seems able to avoid predation by the viper. Bothrops insularis is most commonly found on the ground. However, during the abundance peak of the tyrannid passerine Elaenia chilensis on the island, more snakes were found on vegetation than on the ground. We suggest that one cause may be that these birds forage mostly on vegetation, and thus cause the snakes to search for prey on this arboreal substratum.

The vascular flora and vegetation of Queimada Grande Island, São Paulo State, southeastern Brazil

“…Due to the absence of frugivorous mammals on QGI (Marques et al 2002), birds are apparently the main local dispersers of those diaspores, and several species are known to feed on the fruits of Guapira opposita, Myrsine guianensis, and Syagrus romanzoffiana, which fructify during long periods of time and represent an important food resource for the local avifauna (Montanhini 2010). Two omnivorous passerines that visit the island at different times of the year are the main dietary items of the endemic and critically endangered pit viper Bothrops insularis (Marques et al 2012). The historical use of the island, especially during the period when the lighthouse was manually operated (1909)(1910)(1911)(1912)(1913)(1914)(1915)(1916)(1917)(1918)(1919)(1920)(1921)(1922)(1923)(1924)(1925), strongly influenced the current vegetation cover of QGI and its flora.…”

“…According to Guimarães et al (2014), the local climate is subtropical with two distinct seasons: rainy and warm (October-March) and dry and cold (AprilSeptember). Average monthly temperatures ranged from 18.3°C (August) to 27.2°C (March) in [2007][2008], and rainfall from 0.2 mm (July) to 135.2 mm (December) (Marques et al 2012). The general climate for the coast where QGI is located is classified as Af (Tropical, rainforest), following the Köppen's system (Rolim et al 2007).…”

“…The golden lancehead pit viper, Bothrops insularis (Amaral, 1921), is endemic to the island and is critically endangered both nationally (Brasil 2014) and globally (Marques et al 2004). Although several studies have been carried out on QGI focusing on the biology of this snake (e.g., Wüster et al 2005, Martins et al 2008, Marques et al 2012, Guimarães et al 2014), information about the island's vegetation cover is still extremely incipient (Martins et al 2008, Bataus & Reis 2011. Data on its flora are quite rare in the literature, except for Campos & Mello-Filho (1966), who presented a study of the flora that referred to approximately twenty (mostly ruderal) species.…”

<b>Monitoramento das oscilações anuais nos níveis de testosterona plasmática e andrógenos fecais de machos de jararaca-ilhoa (<i>Bothrops insularis</i>) mantidos em cativeiro</b>

“…This study contributes to the validation of a new longitudinal evaluation method of sex steroids in B. insularis, with the knowledge of the reproductive biology of tropical snakes and the conservation of endangered animals. ANDRADE, 2010;MARQUES et al, 2012;GUIMARÃES et al, 2014), o conhecimento sobre a biologia reprodutiva de Bothrops insularis ainda é principiante e as informações a respeito da sazonalidade são conflitantes. Enquanto alguns trabalhos realizados in situ e a partir de espécimes depositados em coleção científica (KASPEROVICZUS, 2009;ALMEIDA-SANTOS, 2013) afirmam haver sazonalidade reprodutiva de fêmeas e machos, inclusive com um período de quiescência testicular, outro trabalho realizado pelo mesmo grupo mostra não haver diferença expressiva na qualidade seminal de animais mantidos em cativeiro (SILVA et al, 2015).…”

Evolução das estratégias reprodutivas de Bothrops jararaca (Serpentes: Viperidae)

“…B. insularis da ilha da Queimada Grande, se alimenta de aves migratórias (MARQUES et al, 2002b;MARQUES et al, 2012), alimento altamente estocástico e menos calórico se comparado a um roedor. Bothrops alcatraz se alimenta de lacraias e pequenos lagartos, alimentos com baixo teor calórico Estudos futuros são necessários para uma melhor compreensão do ciclo das populações insulares.…”