Interesting, Bill, is your last two images suffer from exactly the opposite problems from each other, namely: 1) the fly on the pink flower is under-exposed ... while 2) the crab spider on the leaf is over-exposed.
In such cases, switching to spot metering over evaluative metering can provide a solution, or even taking and stacking two photos. In other words, for the fly photo, take a properly-exposed photo of the flower (leaving a dark fly) ... and then take a properly-exposed photo of the fly (leaving an over-exposed flower) ... and then STACK the images putting the properly-exposed fly on the properly-exposed flower. The reverse process would be done for the blown crab spider.
It is exceptionally-difficult to capture all-white spiders and such, against darker backgrounds (even yellow is darker than white) and retain the full detail of the white subject. And it is likewise difficult to capture dark subjects against lighter backgrounds, without either under-exposing the subject or over-exposing the background.
Applying graduated filters in Lightroom 3 are another way to work with this, as well as the dodge tool.
Jack
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