INTERPATCH MOVEMENT ED THE RED MILKWEED BEETLE, TETRAOPES TETRAOPHTHALMUS - INDIVIDUAL-RESPONSES TO PATCH SIZE AND ISOLATION

Individual movement patterns and the effects of host plant patch size and isolation on patch occupancy were examined for red milkweed beetle s, Tetraopes tetraophthalmus, residing in a heterogeneous landscape. M ale beetles were found to move both more often and farther between hos t plant patches than female beetles, and this difference affected the patterns of patch occupancy observed. Overall, unoccupied milkweed pat ches were smaller and more isolated than patches occupied by beetles. Patches uninhabited by females tended to be more isolated, but not nec essarily smaller, than patches with female beetles, indicating that fe males may be affected more by patch isolation than patch size. Presenc e of male beetles on patches showed a stronger response to patch size than to patch isolation. Differences in movement between males and fem ales illustrate the need for demographically based dispersal data. Com parisons of Tetraopes interpatch movement patterns between landscapes composed of patches of different size revealed that landscapes with ov erall smaller patches may have greater rates of interpatch movement.