虫子 is the general everyday word for any creepy-crawly. For specific insects, Chinese has: 蚊子 (wénzi, mosquito), 蜜蜂 (mìfēng, bee), 蝴蝶 (húdié, butterfly), 蚂蚁 (mǎyǐ, ant).
culture
书虫 (shūchóng, bookworm) and 网虫 (wǎngchóng, internet addict — literally 'net bug') are fun colloquial terms using 虫.
