The director was Irwin Allen, and the cast included Michael Caine, Katharine Ross, Richard Widmark, Richard Chamberlain, Olivia de Havilland, Ben Johnson, Lee Grant, Jose Ferrer, Patty Duke, Slim Pickens, Bradford Dillman, Fred MacMurray (in his final film appearance), and Henry Fonda. It received negative reviews and was a box-office failure, and many consider it to be one of the worst films ever made. It did receive a nomination for the Academy Award for Best Costume Design (Paul Zastupnevich). This is the last film to be edited by Harold F. Kress.
A group of soldiers led by Maj. Baker (Bradford Dillman) is ordered to investigate the basement level of a missile base which appears to have been attacked and the garrison all but wiped out. After Baker contacts his commander, Gen. Slater (Richard Widmark), they begin to investigate a civilian van found parked at the base. It is revealed to be owned by a scientist named Dr. Bradford Crane (Michael Caine), one of the few survivors of the attack, but not someone stationed at the base. Slater orders two helicopters to track a large airborne mass moving slowly away from the base. The mass is revealed to be a swarm of bees, which engulfs the two helicopters, killing their crews. Crane insists to Slater that the base was attacked by this swarm, composed of deadly African killer bees. Slater doesn't trust Crane, but Helena Anderson (Katharine Ross), one of the base's doctors, supports Crane's story.
Meanwhile, in the countryside, a family is attacked by a swarm of the bees. Paul (Christian Juttner), their teenage son, manages to escape in a Mustang, although he is also stung, and crashes into the Marysville town square, where the citizens are preparing for the annual flower festival. The boy is brought into the hands of military personnel, where he hallucinates a vision of giant bees attacking him, due to the aftereffects of the bee stings.
Crane is put in charge by the President, much to Slater's annoyance, and calls in many experts to help. Wheelchair-bound Dr. Walter Krim (Henry Fonda) arrives at the base and confirms to Crane that the very war they have feared for a long time has started with the bees. At the gates of the base, Slater must confront angry country bumpkin Jed Hawkins (Slim Pickens), who demands to see the dead body of his son, who was killed by the bees. Hawkins takes the body bag and departs, leaving the entire watching crowd silent over the loss. Slater suggests airdropping poison on the swarm, but Crane considers the ecological possibilities of the situation and overrules him, instead focusing on a solution that will kill the bees without harming people and the environment.
Recovering from his earlier bee attack, Paul and two of his friends go in search of the hive to firebomb it, which results only in angering the bees, which make their way to Marysville and kill hundreds, including some children at the local school. Crane and Helena take shelter at the local diner, with pregnant café waitress Rita (Patty Duke Astin). Reporter Anne McGregor (Lee Grant) watches from the safety of her news van, hoping to get some exciting footage about the siege. After this most recent attack, Slater suggests evacuating many of the townsfolk in a train. However, the bees engulf the train as well, causing it to derail and crash, killing most of the occupants including a love triangle made up of school superintendent Maureen Scheuster (Olivia de Havilland), retiree Felix Austin (Ben Johnson), and town Mayor and drug-store owner Clarence Tuttle (Fred MacMurray).
Rita, confined to a hospital bed, gives birth to her child, falling in love with the doctor in the process, but Paul, who has fallen ill again, succumbs to the after-effects of the stings and dies, devastating Helena. The savage swarm heads for Houston, so Crane drops eco-friendly poison pellets designed by Dr. Hubbard (Richard Chamberlain) on them, but the bees ignore the pellets, evidently intelligent enough to sense danger. Working on an antidote to the bees' venom, Dr. Krim self-injects to keep track of the results, although the trial proves fatal, and Krim dies from the effects of the venom. Meanwhile, nuclear power plant manager Dr. Andrews (Jose Ferrer) is convinced that his plant can withstand the attacks of the bees, ignoring the warnings of Dr. Hubbard. However, at that moment, the alarm sounds and the bees invade the plant, killing both Andrews and Hubbard, as well as completely destroying the plant and wiping out an entire town.
Washington orders that operations to stop the bees be placed under military control and Slater takes charge. He orders the evacuated city of Houston to be deliberately torched by soldiers with flame-throwers, hoping the conflagration will destroy the swarm. Helena, who was stung during the attack on Marysville, falls seriously ill again. Crane analyzes tapes from the original bee attack of the base and comes to the conclusion that their alarm system attracted the swarm into the base as the sound resembled a signal from the swarm's queen. The bees break into the headquarters building so Slater and Baker use a flame thrower to allow Crane and Helena to escape, but at the cost of their own lives. Helicopters successfully manage to lure the bees out to sea, placing floating buoys, with speakers emitting the sound Crane discovered, into an area of water doused with oil. When the swarm arrives, the oil is set ablaze by missiles fired from the nearby coast, destroying all of the bees.
The film was announced in 1974 at the height of the disaster movie craze. It was part of $38 million worth of projects Irwin Allen had lined up, others including The Day the World Ended. The script was written by Stirling Sillipant, who had written The Towering Inferno for Allen. He said in December 1974 that Allen hoped to start filming in April 1975. Production was delayed in part because Allen decided to leave Fox for Warner Bros.
Estimates of the numbers of bees used in the production ranged between 15 million and 22 million, including 800,000 bees with their stingers removed to enable the cast to work safely with them. A total of 100 people were employed in the production to care for and transport the bees during the film shoot. Only one cast member, Olivia de Havilland, was stung during the production.
It was one of two disaster films (the other being 1979's Beyond the Poseidon Adventure) directed solely by the "master of disaster" Allen, who had experience directing several films and many episodes of his TV shows. The film is listed in Golden Raspberry Award founder John J.B. Wilson's book The Official Razzie Movie Guide as one of the 100 Most Enjoyably Bad Movies Ever Made, where Wilson states that under Allen's unsubtle direction, "despite the enormous production budget, The Swarm turned the tale of an invasion of killer bees into the ultimate B movie." On its release, The Sunday Times described The Swarm as "simply the worst film ever made". Time Out magazine called The Swarm a "risibly inadequate disaster movie". Leslie Halliwell called The Swarm a "very obvious disaster movie with risible dialogue", and suggested its commercial failure was partly due to the fact that prior to its release, several American television movies with similar plots had been broadcast. Richard Velt in the Wilmington Morning Star stated "The Swarm may not be the worst movie ever made. I'd have to see them all to be sure. It's certainly as bad as any I've seen." Velt also stated "All the actors involved in this fiasco should be ashamed".
The film was a notorious box-office bomb upon its release in 1978, barely making it two weeks in theaters. Michael Caine, despite his other film failures, claims it is the worst film he ever made (along with his decade-earlier film The Magus and his later film Ashanti): "It wasn't just me, Hank Fonda was in it too, but I got the blame for it", he claimed in an interview with Michael Parkinson.
The musical score was composed by Academy Award winner Jerry Goldsmith and used French horns and such to sound like the humming of bees.
The score was originally released on LP on Warner Bros. Records in 1978 at the same time of the film's release, but has long since gone out of print. An expanded, remastered score was released in 2002 in a limited edition by Prometheus Records and contained over 40 minutes of previously unreleased material. It has also gone out of print.Track listing
All compositions by Jerry Goldsmith
Side 1:"Main Title" (3:39)
"A Gift of Flowers" (1:57)
"The Bees' Picnic" (2:16)
"Tommy's Death" (4:16)
"The Bees Arrive" (5:45)
Side 2:"Bees Inside" (6:04)
"Don't Take Him" (2:32)
"Exact Instructions" (4:36)
"A Boy's Story" (1:47)
"End Title" (3:05)
The film was released initially at 116 minutes but when released on laserdisc in 1992, it was expanded to 156 minutes with additional scenes. This version is also included on all DVD releases worldwide, alongside a 22-minute featurette, "Inside the Swarm", and the original theatrical trailer.
The end credits to the film included a disclaimer which read: 'The African killer bee portrayed in this film bears absolutely no relationship to the industrious, hardworking American honey bee [sic] to which we are indebted for pollinating vital crops that feed our nation.'
According to an article in HR published on 24 Feb 1978, the American Bee Association considered taking legal action against the film's producers for defaming the American Honey-Bee but it is unknown if the lawsuit was ever filed.
In 2010, the film was said to be in negotiations for a remake, with Roy Lee of Vertigo Entertainment producing.