Wifi101 ad-hoc network
Apparently you can have an ad-hoc network, you can see the example on the github here: 
https://github.com/arduino-libraries/WiFi101/blob/master/examples/AP_SimpleWebServer/AP_SimpleWebServer.ino

It shows how to create an open ad-hoc network, for a secured one, you might need to check the datasheet + the method implement "beginAP".