Food refusal
A sudden refusal of prey is common before a moult in Acanthoscurria geniculata, especially when the spider had been feeding normally beforehand.
Remove ignored live prey from the Giant White Knee enclosure instead of offering another feeder immediately.
Retreat use and webbing
Acanthoscurria geniculata may spend more time hidden, close a burrow entrance or lay heavier webbing before moulting. Leave the retreat intact.
Do not dig out a Giant White Knee simply because it has sealed itself in. Retreat closure can be normal premoult behaviour.
Abdomen changes
In species where the abdomen is visible, Acanthoscurria geniculata may show a darker exposed patch or other colour change as a new exoskeleton develops underneath.
Not every Giant White Knee shows an obvious visual change, so use abdomen appearance alongside appetite and behaviour rather than as the only sign.
What to do
When premoult looks likely in Acanthoscurria geniculata, remove live prey, keep fresh water available and keep the enclosure within its normal moisture and temperature range.
Do not increase handling, spraying or enclosure disturbance for a Giant White Knee. Stable conditions and patience are normally what the spider needs.
How long can premoult last?
Premoult in Acanthoscurria geniculata can last much longer in a large animal than in a tiny sling. The passage of time alone does not prove something is wrong.
Judge a Giant White Knee by overall condition and enclosure access to water, not by expecting every spider to moult on the same timetable.