Spatial dynamics of nesting behavior: Lizards shift microhabitats to construct nests with beneficial thermal properties

Abstract

Because temperature affects the growth, development, and survival of embryos, oviparous mothers should discriminate carefully among available nesting sites. We combined a radiotelemetric study of animal movements with a spatial mapping of environmental temperatures to test predictions about the nesting behavior of the eastern fence lizard (Sceloporus undulatus). Females made large excursions from their typical home ranges to construct nests in exposed substrates. These excursions appeared to be related solely to nesting because all females returned to forested habitat immediately afterward. On average, <1% (range = 0-8%, n = 19) of the area used by a female during nesting was contained within the area used before and after nesting. The selection of nesting sites matched predictions based on laboratory studies of embryonic performance; specifically, females nested in extremely open habitat at a mean of 6 cm depth. Spatial mapping of soil temperatures revealed that temperatures of nesting areas exceeded those of areas typically used by females, indicating that females preferred to construct warm nests that speed embryonic growth and development. However, this behavior could reduce the survivorship of females because of the need to rapidly navigate unfamiliar and exposed terrain.

Adaptive accuracy of temperature oviposition preferences in newts

“…Although several studies demonstrated the availability of environmental temperatures for T p,o in terrestrial habitats (Kingsolver 1979;Shine and Harlow 1996;Warner and Shine 2008;Angilletta et al 2009), our results show that even in aquatic, i.e. more thermally harsher, environments vertical thermal stratification enables females to chose between thermally more or less suitable sites for oviposition.…”

“…This suggests the anticipatory maternal effect of oviposition temperature preferences, referred to as the maternal manipulation hypothesis (Webb et al 2006). However, the evidence for the maternal preference-offspring performance matching, mostly stems from laboratory experiments with no or limited information about thermal conditions in natural populations (but see Angilletta et al 2009). The adaptive significance of this transgenerational coadaptation depends, among others, on how closely preferred oviposition temperatures approach local phenotypic optimum (i.e.…”

Resolving the life cycle alters expected impacts of climate change

“…On each day of the year, we allocated a nest to microhabitats with each combination of shade (0, 25, 50, 75 or 100%) and depth (3, 6, 9 or 12 cm). These combinations captured the range of microhabitats for natural nests [24]. For each nest, we calculated: (i) minimal and maximal temperatures, (ii) the mean survival rate of embryos, (iii) the mean incubation period, and (iv) the number of days between hatching and winter dormancy (i.e.…”

“…Thermal stress can occur daily during a brief period in the afternoon when soil temperatures peak. Although embryos cannot survive prolonged exposure to such extremes [25,26], they grow and develop rapidly during brief daily exposures [14,24]. Still, even a brief exposure to a temperature of sufficient magnitude causes death by cardiac arrest [27].…”

High-resolution niche models via a correlative approach: Comparing and combining correlative and process-based information

“…For example, Kearney and Porter (2004) expressed thermal GIS layers as the minimum number of degree-days required by a clutch of Heteronotia binoei eggs to hatch, and Lovvorn et al (2009) expressed viable habitat as pixels where energy intake was greater than energy cost. Angilletta et al (2009) compared predicted and measured temperatures at nest sites via a spatially-explicit model of soil temperatures. Application of prey and predator spatial distribution is not as easily achieved, but future research may benefit from comparing suitability models for those taxa as input features for a study species' own ecological niche model …”