duplicate packets from virtual machine

I have a windows 7 virtual machine running on a windows 8.1 host. The virtual network adapter in the virtual machine is bridged to the ethernet adapter on the host. I am using wireshark to monitor the ethernet adapter on the host. It seems that any packets originating from the virtual machine are captured in wireshark twice. What is the reason for this? Can I fix this somehow so that duplicate frames aren't captured?