Slugs in my view are not bugs. Yet:
These slugs were found under a potted pineapple at 3:05 pm October 1. The pot was set aside and I went about my business of looking for bugs. Occasionally I checked back to see what they were up to. By 25 minutes later all the slugs but one had moved away toward shelter or the nearby soil.
On October 5, slugs were found under the same pot at 2:52 pm. Meanwhile my phone rang. I finished with that business, then realized I was thirsty, so grabbed a nice cool glass of water. Anyway, as you can see from this last shot the three slugs were dead from dehydration when I checked back at 3:34 pm. It looks like the one to the left made a run for it, but gave out not far from the point of origin.
Slugs require a cool moist environment to thrive. We typically get very little rain from May to late October in southern CA, so what slugs there are survive by hiding under things and emerging to feed only in the coolest times of the night. By the beginning of October I like to imagine the slug population is just hanging on by its radulas. Then we get the santa ana winds. These were weather conditions on the two days:
Oct 1 Max temp 83 F Min humidity 49%
Oct 5 Max temp 83 F Min humidity 9%
It appears the Oct 5 set of conditions is extreme enough to be lethal to unprotected snails in 30 minutes or less, while the Oct 1 conditions were not.
Q1. Are early October slugs slower due to reduced feeding opportunities? Q2. Do slugs move faster or slower when it is very dry out? Q3. Did the photographer feel remorse for drinking while the slugs were dehydrating? A3. Actually, yes. I'm sorry I missed the in-between photos. Q4. What is the best way to control slugs? A4. Whatever your method, make sure you can deploy it within 25 minutes.
Weather data are from CIMIS daily weather for Irvine CA which provides a decent reference point for most localities in central OC.