Back in the seventh and eighth centuries, the poets wrote fondly of 昆虫 (konchū, insects) and their association with summer.
We’re just as likely to associate 虫 (mushi, bugs) with the season these days, but I’m not sure we’ll get any 21st-century poems about the ゴキブリ (gokiburi, cockroaches) that come out with the heat anytime soon.
Summer is more likely to be associated with the sight of 蝶 (chō, butterflies) and とんぼ (tonbo, dragonflies) on a sweltering day, the buzz of a 蜂 (hachi, bee) flying from flower to flower, or a line of 蟻 (ari, ants) that has come across a Popsicle that has been dropped on the ground.