In reply to snoop6060: I've only noticed mosquitoes on Kalymnos at night or late evenings in the restaurants, etc. I would definitely cover up with trousers & socks if you are eating out in the evenings, and you can buy an effective plug-in repellent from the local shops, to keep your apartment free during the night.
You should be fine during the day, while climbing or on the beach, etc.
Have a good trip!