SURVEYING MITES (ACARINA) PHORETIC ON THE SOUTHERN PINE BEETLE (COLEOPTERA: SCOLYTIDAE) WITH STICKY TRAPS

Can. ~ n t . 108: 809-8 13 i 1976) Sticky traps caught large numbers of mites that adhere tightly or ride in protected places on attacking southern pine beetles and retr~eved some of the mites that are loosely attached. Of the 2539 beetles surveyed, only 39.6% carried mites. Seven species of phoretic mites were found; the two most common, Tursorrernus krur~rzi and Trichouropc>dcz uusrrulis. showed no preference for either beetle sex but preferred to ride on specific parts of the body. Phoretic mites of the southern pine beetle, Dendroctonus frontalis Zimmerman 1868, can be collected in two basic ways: from beetles emerging from infested wood or from those attacking trap trees. The former rnethod is easier and yields a greater variety and number of mites, but the latter may provide a more realistic sample of which mites actually reach the tree. Although 18 species of mites have been recorded as phoretic on the southern pine beetle (Hurlbutt 1967; Lindquist 197 1 ; Lindquist and Hunter 1965; McGraw and Farrier 1969; Moser and Roton 197 1; Moser, unpub. data; Smiley and Moser 1970; Woodring 1966; Woodring and Moser 1970), there have been few, if any, mites recorded from flying beetles. The easiest way to trap large numbers of attacking southern pine beetles is with sticky traps. Although many mites will be lost when the sticky material is harvested, some mites attach more firmly than others to the beetle or are in more protected Locations, and the method might give reliable estimates for the more tenacious species. The purpose of this study was to determine if the method has any survey potential for phoretic mites. Methods and Materials Traps devised by T. L. Payne and J. E. Coster (personal communication) (Fig. 1) were made from 0.3-m square pieces of hardware cloth coated with Stickern Special@.' They were placed on eight loblolly pines (Pinus taeda L. 1753) at heights of 0.6, 2.4, 4.3, and 6.1 m on one side of the tree and at 1.5, 3.3, and 5.2 m on the opposite side. Traps were lowered for examination with pulleys. Beetles were induced to attack by the hanging of female-infested bolts at 4.8 m for 2 to 3 days until a mass attack began. Bolts were then removed. Collections were made weekly from 3 June through 28 August 1973. Beetles were manually removed from the traps and placed in vials of kerosene, which dissolved the Stickem adhering to the specimens. A total of 56 vials representing the eight trees and seven heights comprised each weekly sample. For each beetle found in the study, the following data were recorded: date, height of trap, sex, species, and number and body location of the mites. The data were then summarized for each mite. Results and Discussion Only 39.6% of the 2539 beetles surveyed possessed mites. Tarsonemus krarztzi Smiley and Moser 1974. and Tricho~lropoda australis Hirschmann 1972, the most common species, each rode on more than 23% of the beetles. Neither showed a phoretic preference for either beetle sex. Five other species occurred infrequently to rarely, but they may be found to be more common once a more efficient trap system is developed. 'Ment~on of trade name 1s solely to identify materlal used and does not imply endortement by the U S Department of