How many times must this be repeated?
The plant pest law—which is cited as the reason why ants cannot be transported across state lines—defines a plant pest as any non-human organism which causes or can potentially cause direct or indirect damage or disease to any plant or plant product.
But just because the USDA does not actively enforce the law to the letter (how could they?) does not make the spread of organisms to which the law would apply any more legal, from a purely technical standpoint.
Many of, if not all, the organisms you mentioned have complex relationships with plants. As an extreme, but nevertheless completely possible hypothetical, even an alien spider could displace native spiders, while also preferentially targeting certain bees and other pollinators, thereby having an indirect but damaging effect on one or more plants. The fact that, due to our incomplete scientific understanding of the universe and all its infinite possibilities, this outcome cannot be ruled out completely, and yet the law is worded in such a way as to make an astronomically improbable chance occurrence have the equal weight as a scenario in which the probability is significantly likely, just goes to show how badly the law was written, and that only scientists—not government bureaucrats—can be tasked with properly enforcing it.
With regards to sterile ant workers, even Pogonomyrmex workers sold in ant farms required a waiver by the USDA at one point. If one were advertising and shipping worker ants to customers all over the US, one would likely pop up on the USDA radar and be asked to apply for an exemption, as well. The law does not differentiate between organisms that can reproduce and ones that can't.
Edited by drtrmiller, December 14 2017 - 8:06 AM.