Feeding and Reproductive Behavior of Ips Avulsus

Abstract

Ips avulsus (Eichhoff) parent adults were introduced into pine inner bark-glass plate observation units where they periodically fed as follows: chips of excised inner bark were taken into the buccal cavity, compressed, and the resulting pellet of exhausted tissue was expelled from the mouth. Microscopic examination of sectioned and whole guts showed contents consisting principally of symbionts, starch grains, and small amounts of very fine material. Ventral dilator muscles of the pharynx were well-developed and the alimentary tract was of the elongate type reported in liquid-feeding insects. Gelatinous feces were produced and deposited on the roof of the male's nuptial chamber, where they were consumed by consorting beetles or adhered to their bodies. Adult reproductive behavior was similar to that reported for Ips pini (Say) and Ips paraconfusus Lanier. I. avulsus copulation lasted an average of 35 sec (range, 22-45 sec) at 30@*C. Pairs mated 3 times at about 10-min intervals, after which each female isolated herself from the associated male in his nuptial chamber by packing the egg gallery behind her with boring material.