Cases of bedbugs in San Francisco rental housing are on the rise, and a recent surge may be blamed on the recent hot weather we experienced -- bedbugs thrive in temperatures of 70 and above, with the females laying more eggs and eggs hatching more quickly in the heat. As the Examiner reports, the greatest concentration of bedbugs seems to be in the Tenderloin, with its clusters of cracky SROs and such. But Uptown Almanac posted this alarming photo of a not-so-quarantined mattress lying out on the streets of the Mission last week, so other neighborhoods are clearly not immune.

Reported cases have risen 44 percent in each of the last few years, with 373 reported in 2007, 537 in 2009, and 500 already reported this year -- SFist first reported on bedbugs here in 2005. The epidemic has been on the rise in other cities like New York and Chicago, and as a bedbug expert instructed on the Rachael Ray Show last year, you ought to carefully check your luggage and clothes after traveling to make sure you aren't bringing the critters with you. Also of note, and a whole a new argument for sticking to Netflix and TiVo: Beware of bedbugs in movie theater seats! The paranoid are advised to check the crevices and seams of movie theater seats before sitting down, while the lights are still up, to see if you see anything crawling up in there.