Answer: Unfortunately, based on your description I am unable to make a diagnosis long distance. I do not think however that spiders or ants would have killed it suddenly like that. Instead I suspect poor rooting or possibly a disease. I would suggest you consult with your local professional nursery staff (especially if there is a warranty) and also with your local county extension to see if they can tell you more specifically what happened and whether or not it is something that could also affect your other plants. I'm sorry you lost this one.
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