The Cambrian explosion was 540 mya. Laurasia and Gondwana didnt collide until 330 mya. So for 210 million years the land was divided into two large continents. Plants and insects had already colonized the land long before Pangaea formed. It should therefore be possible to divide land plants and insects into two broad groups. One group that inhabited Laurasia and one group that inhabited Gondwana. I have googled around but I cant find any good info on this.