Incubation of turtle eggs at different temperatures: do embryos compensate for temperature during development?

Area of Science:

• Herpetology
• Developmental Biology
• Ecology

Background:

• Freshwater turtle embryos experience natural temperature fluctuations during incubation.
• Embryonic development may involve physiological adjustments to temperature changes.
• Understanding temperature effects is crucial for reptile conservation.

Purpose of the Study:

• To investigate if Brisbane river turtle (Emydura signata) embryos exhibit temperature compensation during development.
• To determine the influence of incubation temperature regimes on embryonic growth, metabolism, and development time.

Main Methods:

• Eggs of Emydura signata were incubated under four temperature regimes: constant 24°C, constant 31°C, and two swapped-temperature treatments.
• Incubation periods, hatchling mass, size, and total oxygen consumption were measured.
• Oxygen consumption patterns during late incubation were analyzed.

Main Results:

• Incubation duration varied significantly with temperature (42 days at 31°C, 78 days at 24°C).
• Hatchling mass, size, and total oxygen consumed were similar across all temperature regimes.
• Oxygen consumption patterns in late incubation were solely dependent on the temperature during that phase, not earlier temperatures.

Conclusions:

• Emydura signata embryos do not demonstrate temperature compensation in growth or development.
• Embryonic development and physiological adjustments are primarily influenced by the incubation temperature during the latter stages.
• Findings suggest limited plasticity in response to temperature fluctuations during early incubation for this species.