Thing is, it actually makes sense from a flavor perspective for Sticky Web not to be available to all spider Pokemon. While all spiders do produce silk, a lot of them don't spin webs. Diving bell spiders do create webs underwater, though (albeit just as a home and to provide structure to their diving bell, not for prey capture), so it oughta be able to learn it. Galvantula actually shouldn't, though, since based on its morphology it seems to be a hybrid of a tarantula and a jumping spider and neither of those families are web-builders. Ariados is kinda debatable, since Spinarak is based on Theridion grallator (a web-builder) and that would make me think it should keep that, but Ariados' morphology is partway between that of web-building spiders and certain ant-mimic and wasp-mimic jumping spiders (including the delightfully strange Orsima ichneumon).
Anyway, to make sure this post isn't totally off-topic, what are your thoughts on the possible utility of Lunge over Leech Life as the Bug STAB of choice? Because you're not doing all that much damage with Leech Life, the recovery will be pretty limited, but the Attack drop could potentially be pretty useful for Araquanid's longevity (and that of of its partner in doubles).
