Trapping of Air-borne Insects on Ships on the Pacific

Trapping was done during 1963 aboard military transport vessels between North America and Asia on 3 separate cruises. Several thousand specimens were collected, of which 20 were taken more than 500 km down wind from a continent or island. The majority of specimens trapped were Homoptera, Diptera, Hemiptera and Hymenoptera. This fifth report of the series of trapping articles presents preliminary data on results of three trips aboard military transport vessels. In 1963, Harrell made two round trips aboard MSTS vessels. The first trip aboard the U. S. S. Mann in April and May, was from Honolulu, to Guam, South Korea, Philippines, Guam, and return to Honolulu. The second trip, aboard the U. S. N. S. Gaffey from 23 September to 2 October, was from Honolulu to Japan, Okinawa, South Korea, Japan, Adak (Alaska), and terminated in San Francisco. In June 1963, Yoshimoto collected for one trip aboard the U. S. S. Mann between Honolulu and Japan. A more comprehensive report will be presented later, after precise identification of the specimens have been made by specialists. Methods: Nylon nets of 75 cm ring diameter were used on all three trips. As nets with detachable cones proved to be a liability in previous cruises, only nets without detachable cones were used. The rings, however, were modified with a locking hinge allowing easy replacement of damaged nets. The rings were cut in half. A 1/2 inch sleeve with an 1/8 inch hole bored and threaded in one end, was welded to one end of the ring. The other half of the ring had an 1/8 inch hole bored and threaded in it. The ring is locked by placing an 1/8 inch screw through the ends. The nets were strung in series on steel cables suspended from the mast and secured to the deck (Yoshimoto, Gressitt & Mitchell, 1962). As many nets as possible were used day and night, weather permitting. The large suction trap (Yoshimoto, Gressitt & Mitchell, 1962; Yoshimoto & Gressitt, 1963) was used by Harrell on both trips. Yoshimoto used only nylon nets on his trip aboard the U. S. S. Mann. The suction trap was modified, so that the net inside could be changed at sea if it became damaged. A small hinged door (25 X 25 cm) was cut in the aluminum cylinder so the operator could replace the nylon net which attaches on to the 1. Results of a project supported by a grant to Bishop Museum by the Biology Branch, Office of Naval Research (through Pacific Science Board, National Academy of Sciences). Previous parts of this series were by Gressitt & Nakata (1) and Yoshimoto & Gressitt (2-4). 2. Yoshimoto, Gressitt & Mitchell, 1962, Pacific Ins. 4 (4): 847-58, 1 fig.; Yoshimoto & Gressitt, 1963, op. cit. 5 (4) : 873-83. 1964 Harrell & Yoshimoto: Trapping of air-borne insects, 5 275 plastic receptacle. The door is then held shut by a wing bolt. At distances of 560 km or less from land, the equipment was checked three times a day. At greater distances the equipment was checked for specimens twice a day. Results'. Results are presented in Tables 1-7. The map indicates the various positions at which specimens were collected during the three trips. A total of 3748 specimens representing 59 different families were collected. The order Homoptera (2125 specimens representing 4 fam.) was the largest group collected. Diptera (22 fam. represented by 482 specimens) was the most diversified order collected. It must be noted that of the total number of specimens collected, 3527 were collected within a period of l l hours in the Yellow Sea area. And of a total of 2891 live specimens collected during the three trips, 2821 were collected during this ll-hour period. The 3527 specimens collected in the Yellow Sea area probably originated in China near Shantung or the Liaotung Peninsula. The wind at that time was from the direction of the Chinese coast and was blowing with considerable force. Excluding this l l hour period, a total of 221 specimens, of which 70 were alive, was collected. Twenty specimens were caught at distances over 500 km from land. A live fly collected 1800 km from the Oregon coast was the most distant specimen from land. Weather was generally favorable for collecting, and all equipment was used continually except during local storms. Yoshimoto's trip, however, was hampered because the wind constantly blew at right angles to the ship's course causing the nets to blow in and out, discharging their contents. The trip of the U.S.N.S. Gaffey to Adak, Alaska offered the Museum its first chance to do ship trapping in the North Pacific. The 19 specimens collected in this area are significant from the standpoint of the dispersal of air-borne insects in the Pacific region. Specimens collected at the port of Adak for the first time by Bishop Museum will be reported upon after further identification. Acknowledgements'. We are deeply grateful to the Biology Branch, Office of Naval Research and the Pacific Science Board (Nat'l. Acad. Sci.) and the U. S. Antarctic Research Program (Nat'l. Sci. Foundation), for their financial support. We are also grateful to Dr. S. R. Galler and Dr. H. L. Hayes (Office of Naval Research), Dr. H. J. Coolidge and Mrs. L. Smith (Pacific Science Board). We are particularly grateful to the Officers and men of the U. S. S. Mann and the U. S. N. S. Gaffey, especially Capt. C. Clark, Ltjg. D. Payne and Lt. M. Weaver of the U. S. S. Mann, and Capt. C. W. Hutcheson and Mssrs. N. Tucker and T. Ruff of the U. S. N. S. Gaffey, for their cooperation and assistance. We are also indebted to the following people who identified specimens: J. Yukawa (Diptera), D. Tsuda (Lepidoptera), M. Chujo (Coleoptera), M. Watanabe (Hemiptera), W. Voss (mites), D. Hinckley (Hymenoptera), and G. Nakahashi (Homoptera). Key to Tables 1, 2 and 5 * ship time : caught in suction trap + caught alive © caught in bridge alive (D caught in net & probable land area based on direction of prevailing wind Table 1. Trapping abc Date Wind Starting Ending 1963 Direction/Velocity Lat. Long. Lat. Long. (Degrees) (Knots) (N) (N) 30.IV *0800 30.IV 1300 30.IV 1800 l.V 0800 l.V 1200 l.V 1800 2.V 0800 6.V 1600 8.V 1200 12.V 0800 B.V 0800