When I attempt to load the map I was playing yesterday with either v1.6 or 1.7 everything was fine. This morning I updated mods as usual and when I tried to load my map from yesterday the game crashes with the usual note to look in the current_log file. The log documents the crash but does not appear to identify any specific mod. Then, to identify what version of which mod was the issue I started backing off versions. I isolated it conclusively to being between your 1.7 (which works) and 1.8 (game crashes). All other mods at most recent version.

Logs and crash data here http://bitviper.org/factorio/crash-data.zip

Thank you for the detailed report.
0.1.8 introduced 10 legged mk3 spidertrons; the crash was likely caused by the game not knowing how to migrate existing mk3 spidertrons from havong 8 legs to having 10 legs.
I shall try to replicare and look at what I can do to stop the crash, but as of now I am kinda clueless.

Managed to reproduce the crash and can verify; the crash is caused by the Mk3 having to change from 8 to 10 legs, and existing Mk3 Spidertron entities with 8 legs in 0.1.8 causing the crash. I will see what I can do to fix this issue. However, if you are desperate to try versions 0.1.8 and above, you can remove any Mk3 spidertrons in the world running on 0.1.7, update to 0.1.8 and spawn them back in. As I said, not the optimal solution, but I just tested it and it works. Will however still try to professionally patch this.

Apparently this can't be fixed until the next release; https://forums.factorio.com/viewtopic.php?f=30&t=88035&p=506964&hilit=spidertron+leg#p506964
Sorry, but other than the solution given above I can't really help.