Stomach flushing affects survival/emigration in wild lizards: a study case with rainbow lizards (Agama agama) in Nigeria

Abstract

Stomach flushing is one of the proposed techniques to study lizard diets. Apparently, it is ranged, together with direct observation and faecal analysis, as a non-harmful method for dietary studies. Some works explored the usefullness of stomach flushing, but we lack information about its effect on lizard's survival probabilities. In this paper we studied the effect of stomach flushing in an urban population of the rainbow lizard (Agama agama) from Calabar (Nigeria). During a period of five months of 2010, 147 lizards were noosed, sexed and individually marked. One group of lizards was stomach flushed only once, whereas the rest of lizards were not flushed. The flushed sample of lizards showed a lower survival than non-flushed lizards of all sex and age classes. In this study, the pictured diet from stomach flushing was very similar to results obtained with a faecal analysis of the same lizard population. Thus, both methods seem to be reliable to study the diet of the rainbow lizard. However, our results indicate that stomach flushing increases the probability of mortality (or at least emigration rates) in all age and sex classes, precluding its extensive use as a method to study lizard's diets.

Life in the suburbs: artificial heat source selection for nocturnal thermoregulation in a diurnally active tropical lizard

“…This latter hypothesis is unlikely, given that around 65 % of the electric panels were not used by A. agama but were used by geckos (Hemidactylus angulatus), which may possibly be a nocturnal competitor with A. agama. Snakes of the genus Lamprophis and cats are mainly nocturnal foraging predators (for snakes see Akani et al, 2008;Chippaux and Jackson, 2019; for cats see Ogan and Jurek, 1997;Hall et al, 2000). Our observations of predation events support the notion of (i) A. agama constituting an important food source for the mesopredator communi-ties inhabiting suburban Afrotropical areas (Luiselli et al, 2002;Akani et al, 2008;Rodewald and Gehrt, 2014) and that (ii) there should be high risks for diurnal terrestrial activity, especially movement between diurnal home territories and retreats sites.…”

“…Harris, 1964;Cloudsley-Thompson, 1981) that has enabled some species to survive even in areas outside their native African range (Enge et al, 2004;Leache et al, 2009;Wagner et al, 2009). An example of this ecological plasticity is the rainbow lizard (Agama agama), an agamid that has adapted to life in suburban habitats throughout West Africa (Chapman and Chapman, 1964;Akani et al, 1999Akani et al, , 2011Leaché et al, 2017) and has been the focus of numerous studies across African regions (e.g. Yeboah, 1982;Anibaldi et al, 1998;Adeoye and Ogunbanwo, 2007) including the Niger Delta of Nigeria (e.g.…”

“…Yeboah, 1982;Anibaldi et al, 1998;Adeoye and Ogunbanwo, 2007) including the Niger Delta of Nigeria (e.g. Akani et al, 2011Akani et al, , 2013. A diurnal species (Cloudsley-Thompson, 1981;Yeboah, 1982;Anibaldi et al, 1998), A. agama on occasion may also be active nocturnally (Pauwels et al, 2004).…”

Exotic Hobos: Release, escape, and potential secondary dispersal of African red-headed agamas (Agama picticaudaPETERS, 1877) through the Florida railway systems

“…African red-headed agamas are semi-arboreal, and thrive in urban environments within both their native and introduced ranges (Akani et al 2013;Enge et al 2004;Luiselli et al 2011;Yeboah, 1982). Although their diet is primarily insectivorous, they are opportunistic omnivores that have been documented eating fruit and discarded anthropogenic food items (Akani et al 2013;Anibaldi et al 1998;Chapman and Chapman, 1964;Harris, 1964;Ofori et al 2018;Yeboah, 1982).…”

Natural Diet of European Green Lizards, Lacerta viridis (Squamata: Lacertidae): A Comparison of Macroscopic and Molecular Identification Methods

“…For this purpose, a stomach flushing method can be used (Legler and Sullivan 1979; Herrel et al 2006). Yet, even if all safety precautions are taken, it is possible to harm or even kill investigated individuals (Pietruszka 1981; Barreto-Lima 2009; Akani et al 2011). Other methods include the investigation of stomach contents by means of the doubly labelled water technique (Peterson et al 1998) and by means of stable isotopes (Seminoff et al 2006).…”