DOI: 10.5061/dryad.wh70rxwqc
title: Data from: How well do embryo development rate models derived from laboratory data predict embryo development in sea turtle nests?

description: Development rate of ectothermic animals varies with temperature. Here we
 use data derived from laboratory constant temperature incubation
 experiments to formulate development rate models that can be used to model
 embryonic development rate in sea turtle nests. We then use a novel method
 for detecting the time of hatching to measure the in situ incubation
 period of sea turtle clutches to test the accuracy of our models in
 predicting the incubation period from nest temperature traces. We found
 that all our models overestimated the incubation period. We hypothesize
 three possible explanations which are not mutually exclusive for the
 mismatch between our modeling and empirically measured in situ incubation
 period: (1) a difference in the way the incubation period is calculated in
 laboratory data and in our field nests, (2) inaccuracies in the
 assumptions made by our models at high incubation temperatures where there
 is no empirical laboratory data, and (3) a tendency for development rate
 in laboratory experiments to be progressively slower as temperature
 decreases compared with in situ incubation.
description: Field measurements of nest temperature, incubation period, and
 the hatch‐to‐emerge time The field procedures were similar for loggerhead
 and green turtle clutches, but the field locations and times were
 different. Experiments with loggerhead turtle clutches were conducted at
 Mon Repos Beach between December 6, 2019 and February 15, 2020, and
 experiments with green turtle clutches were conducted at Heron Island
 between December 13, 2020 and February 9, 2021. A nesting female was
 located, and immediately after oviposition had finished, her eggs were
 collected into a bucket and carried by hand to an area of the nesting
 beach which was corralled to prevent subsequent nesting turtles from
 disturbing monitored nests. An artificial nest hole was dug by hand to a
 depth of 60 cm (loggerhead turtles) or 70 cm (green turtles) and the
 collected eggs placed into this hole. When approximately 50 eggs had been
 placed in the hole, an iButton temperature data logger (iButton™ Maxim,
 Model DS1922L, resolution of 0.06°C, accuracy ± 0.2°C) programmed to log
 temperature every hour was placed in the nest and then the remainder of
 the eggs were placed on top of the logger in the nest. The hole was then
 backfilled with sand and the nest site marked with a wooden stake. The
 clutch collection and relocation procedures were completed within 1 h of
 the end of oviposition. The clutch was then left to incubate naturally on
 the beach. Two weeks before the clutch was expected to hatch, the nest was
 excavated by hand until the top layer of eggs was exposed, and a “hatching
 detector” was installed. The hatching detector consisted of a ~2‐mm‐wide
 strip of aluminum foil 15 cm long that was placed either beneath the top
 layer of eggs (loggerhead turtles) or on top of the incubating eggs (green
 turtles), and the ends of the foil were connected via alligator clips to
 wires that lead to the surface. The nest was then back‐filled with sand
 and left to continue incubation. Thereafter, between six and eight times
 per day the ends of the wires at the surface were connected to a 9‐ volt
 transistor battery in a series circuit with a 1000 ohm resistor. A
 voltmeter was then used to measure the electrical potential (emf) (V)
 across the resistor. When the aluminum foil strip was intact, the emf was
 always ~9 V, but when it was broken (by hatchlings as they emerged from
 their eggs) the emf fell dramatically to between 2 and 5 V. The emf did
 not fall to zero when the aluminum strip was broken because electricity
 continued to be conducted via ions dissolved in water within the sand in
 the nest between the broken ends of the aluminum strip. The time when the
 emf fell from 9 V was recorded as the hatch date and time.
description: See readme.txt file.