The metabolic cost of nesting: body condition and blood parameters of Caiman crocodilus and Melanosuchus niger in Central Amazonia

José António Lemos Barão-Nóbrega,Jaydione Luiz Marcon,Robinson Botero-Arias,António José Arsénia Nogueira,Boris Marioni,William Ernest Magnusson,Ronis Da Silveira,Emerson Silva Lima

doi:10.1007/s00360-017-1103-8

Abstract

Although nesting ecology is well studied in several crocodilian species, it is not known how nest attendance influences physiology and body condition of nesting females. In this study, we describe body condition and serum biochemical values of nesting female, non-nesting female and male spectacled caiman (Caiman crocodilus) and black caiman (Melanosuchus niger) in two areas of Central Amazonia. We also evaluated the effect of nest age and nest distance to water on body condition and blood parameters of nesting females. Body condition and plasmatic concentrations of glucose, triglycerides, lactate and uric acid of nesting females were significantly different from those of non-nesting females and males in C. crocodilus, but not in M. niger. Our study also demonstrated that nest age and distance to water had a negative effect on female body condition in C. crocodilus, but not in M. niger. Female C. crocodilus attending older nests or nests built further away from permanent water bodies tended to have lower body condition. Our results demonstrate that the nesting strategy of C. crocodilus has a metabolic cost associated with nest attendance for nesting females, which appear to depend on accumulated energetic reserves during nest attendance. In contrast, nest attendance had little effect on the physiology of female M. niger.

Highlights

Body condition analysis is a non-destructive and non-invasive method that has proven valuable in ecological fields of many invertebrate (Moya-Laraño et al 2008) and vertebrate species (Kitaysky et al 1999; Stevenson and Woods 2006; Mazzotti et al 2009)
This study reports on the influence of nest attendance on body condition and physiological state of female caimans, and how these are affected by nesting strategy, by comparing two species (C. crocodilus and M. niger) in Central Amazonia
This study provides evidence that nest attendance has a metabolic cost for nesting females in Caiman crocodilus, but not in Melanosuchus niger

Summary

Introduction

Body condition analysis is a non-destructive and non-invasive method that has proven valuable in ecological fields of many invertebrate (Moya-Laraño et al 2008) and vertebrate species (Kitaysky et al 1999; Stevenson and Woods 2006; Mazzotti et al 2009). At least three of the four crocodilian species that occur in the Amazon basin construct their mound nests in várzea (seasonal flooded forest) habitats during the annual dry season, when the water levels are at their lowest values (Thorbjarnarson et al 2000; Villamarín et al 2011). Nesting females of the sympatric black caiman (Melanosuchus niger) construct their nests close to the water, usually near lakes isolated from the main water canal during the dry season (Da Silveira et al 1997; Villamarín et al 2011). Female M. niger remain near their nests during the egg incubation period, usually in the water (where they have access to food resources), and often defend them aggressively (more energy demanding than just attending) against potential predators (Thorbjarnarson et al 2000)

Methods

Results

Conclusion