How Do They Know?

Today was another one of those days where I take my bug walk during a break in the rain. I didn't find a lot of bugs, which is generally the case on days like that, which makes me wonder: Do the bugs go into shelter when it rains and they just take a long time to come back out again, or do they sense that it is going to rain some more, so they don't come out until they know the coast is clear? If they know it's going to rain some more, do they know that because they can tell from the air pressure, or is it just that they are waiting for the sun to come out, signalling that the rain is over? And in any case, why do some bugs come out during this in between period, and others don't?

I found a couple of bugs today that were more cooperative than is usual for their species, and one of them is Backyard Bug of the Day:

 Moth fly. This is a species of fly, not a species of moth, even though it does a good impersonation of one. This is a tiny insect, and usually very shy - I have been seeing them on the leaves of a particular tree for weeks, and trying to get a good picture of one, but they generally fly away before I get within a foot of one with the camera. I posted a bad picture of one a while back, so here's a better one. It gets to be Backyard Bug of the Day because it is very unlikely I will get another good shot of one this season. In all my years of doing this, I think this is maybe the third time I've been able to get one.

Random Bugs:

 Long legged fly. These will occasionally let me get a picture, but they are not usually as cooperative as this one.

 It let me get close...

 ... and then closer.

Hmmm... How would this look if I zoomed-in on this picture?

Pretty cool.

 I am pretty sure this caterpillar has grown since yesterday. I have to try to look this up, but it kind of looks like something called a false unicorn, or something like that...

 Bee! Long time no see!

Arachnid Appreciation:
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 I think this is the 21st spider species in 4 days.

 This spider was perfectly in focus for a shot and zoomed out of view just before I took the picture. This is where it went - to catch the gnat that had just landed in its web. It has quite a grip on it with its chelicerae.

 Back to the middle of the web

Another shot of fine eyes.