Hours after reporting his wife missing from their Annandale home, gynecologist David K. Davoudlarian had friends over for a crab dinner but made no mention of her disappearance, a former boyfriend of one of Mrs. Davoudlarian's daughters testified yesterday.

Davoudlarian, 49, "was joking around and laughing, telling gynecological jokes," said Brian Bergquist, 20, who was a frequent guest in the home at the time.

A week later, the nude and strangled body of Susan Davoudlarian, 40, was found wedged beneath the folded down back seat of her station wagon parked in the long-term lot at Dulles International Airport.

Bergquist testified in the Fairfax County Circuit Court trial of an unusual civil suit filed by Mrs. Davoudlarian's estate that seeks $10 million in damages and alleges that Dr. Davoudlarian killed his wife.

Mrs. Davoudlarian's disappearance on June 4, 1983, has never been explained, but police have said they believe she was strangled at her home and driven to the airport.

No one has been charged in her death, and Dr. Davoudlarian has denied under oath any involvement.

One of the contentions of the suit is that Dr. Davoudlarian went about his "normal routine" after his wife's disappearance, in contrast to more vigorous efforts to locate her pursued by other members of the household, Stanley Klein, one of the plaintiff's attorneys, said in an opening statement last week.

Bergquist, now a sophomore at the University of Wisconsin, was a Marine corporal at the time of Mrs. Davoudlarian's disappearance and was dating Susan Rooney, one of Mrs. Davoudlarian's two daughters from a previous marriage.

He testified that on June 5, 1983, the day of the dinner party, he and Rooney cleaned and straightened up the house at Dr. Davoudlarian's direction, but that the doctor refused to let them enter the master bedroom. "He said he would take care of it, and he was insistent," Bergquist said. He testified there was a pile of striped sheets outside the bedroom door.

Dr. Davoudlarian had reported to police he last had seen his wife in that room.

Bergquist's testimony lasted for 90 minutes, and he gave concise and exact answers under questioning. But as he left the courtroom, he collapsed in tears on a couch in a hallway that was filled with friends and relatives of the Davoudlarians.

In other testimony yesterday, the nine jurors hearing the case were told that Dr. Davoudlarian ordered $23,820 worth of stock during the week his wife was missing and paid for $31,661 worth of stock he had purchased before she disappeared.

The attorneys for Mrs. Davoudlarian's estate are expected to finish presenting evidence today or Thursday. Dr. Davoudlarian's attorneys will then give his defense.

Yesterday, the trial's sixth day, was its busiest, with the jury hearing 14 witnesses and viewing photos of Mrs. Davoudlarian's body.

For the first time, FBI agents provided details of their investigation. One agent, John L. Quill, testified that Mrs. Davoudlarian's station wagon was meticulously searched for hairs, fibers, fluids and fingerprints, but nothing of significance was found.

Agent Stanley J. Niemala testified that more than 70 cabdrivers known to be working at Dulles airport at the time were interviewed and showed Dr. Davoudlarian's photo, and that none identified him. Niemala said car rental agencies at both Dulles and National airports were checked to see if the physician had rented a car there, but no evidence was discovered that he had.