Unless I’m misinformed, the bugs in broccoli melt under high heat.
Could you find a source for that? The following link from OU’s website, confirming my previous post, seems to indicate otherwise:
http://www.oukosher.org/index.php/consumer/recipes/chinese_chicken_pasta_salad_pareve/
It is virtually impossible to perform a comprehensive inspection on raw broccoli. Parboil the broccoli for ten seconds to soften the florets and stems. An additional benefit of parboiling is that aphids often turn from green to brown and the florets from light to dark lush green. The contrast of colors makes the insects more easily detectable after this process. Submerge in cold water immediately after parboiling to preserve the flavor and firmness of the vegetable.
The parboiling could be the reason why frum brands of broccoli are offered frozen rather than fresh.