Blooper

As Hopper is flying away carrying Flik, Tuck & Roll pull off his right antenna. Just as Hopper ditches Tuck & Roll, you see him flying away with both antennae still intact. Then there is a cut to Tuck & Roll holding the removed antenna.

When the fly paper lands on P.T. Flea and catches fire, he is standing near the top of the fly paper. After it burns, he is standing in the middle of the burn patch.

About 20 minutes into the movie, in Rosie and Dim's "lion tamer" scene, we clearly see that Rosie accidentally whips Dim's left foot. A few minutes later, as she's getting a bandage for him, he's whimpering and holding up his right foot for her.

When Dot flies after the circus caravan, and gets Flik to return, Flik is sitting off the back of the cart, so he can catch Dot. As soon as Flik turns down Dot's request for help, he's sitting in the front of the wagon.

Rosie disappears briefly from Dim's back as they fly to Ant Island.

When Flik goes to the bar to try to hire some warrior bugs, he watches a mosquito order a "Bloody Mary - O+". The mosquito clearly is a male, while in reality only female mosquitoes drink blood.

Many of the characters have fewer legs than their real counterparts. Francis, Gypsy Moth, Manny, PT Flea, the mosquitoes, fireflies, and all the ants have four legs instead of six. Tuck and Roll have eight legs instead of fourteen. Heimlich has four thoracic legs instead of six. (The number of caterpillar prolegs can vary by species.)

In reality ants and termites are natural enemies more than any other insect as grasshoppers are only vegetarians rather than omnivores like ants and termites.

The sun is sufficiently far away that moving the outline of the bird a few feet higher in the air wouldn't appreciably alter the size of the shadow it casts.

Despite the title, none of the characters are bugs, scientifically speaking. True bugs are only found in the Orders Hemiptera and Homoptera, and none of the characters are members of either order.

Flik couldn't reach the back of his invention when he tried to get a seed for Dot. Later, as the grasshoppers arrive and he runs toward the offering stone, he is caught by a blade of grass and is flung backwards, and all the seeds fall out of his invention. And later, when all the other ants have gathered inside the anthill, he is seen running toward the offering stone with his invention full of seeds. He couldn't have put them back in, because he can't reach his invention when it is on. A few shots before, he is seen running out of the grain stalk forest with his invention on, so it could very well be because he's cut down a new stalk.

When Flik is trying to put his load on the food pad, he knocks over the grain/seeds and berries down in to the water. None of the grain/seeds or berries float.

When the leaf template of the bird is placed in the sun's path to make a shadow on the ground, the direction of the bird is placed in the sky, different to the way the shadow is on the ground.

In the first shot of the film, the sun is glinting off the water to the left of center, but when the view pulls back to show the island the shadows are all falling to the left, as if the sun is to the right of center.

When the angry grasshopper Thumper is first seen, he is being controlled and restrained by two other grasshoppers. In all other scenes, he is neither being controlled nor restrained.

Before the "royal huddle" decides to send Flik away, if Princess Atta's mouth is watched when she says "He can't mess anything up", the word "screw" is what was animated as opposed to the word "mess".

The film is strongly implied to take place around the equator or the tropics, as both Hopper and the Queen mention it will soon be the raining season. However, Hopper sarcastically wishes the ants to have a nice summer and that him and his thugs will return when the last leaf falls which is autumn/fall. The countryside has fresh green meadows and normal trees. However, countries around the equator or tropics only have two seasons: dry and wet. Only countries in the northern and southern hemispheres except the poles have the four temperate seasons.

The film never explains why the ants must serve and do whatever the grasshoppers want with no mention of them making a deal, or an ant causing a major offense, or anything that is the cause for their devoted and manifest servitude.

During the bird attack, Heimlich and Slim distract the bird and then hide in a crevasse. In the following scene, they are seen visiting Francis in the medical room with no evidence as to how they escaped the crevasse.

The usages of deus ex machina for the way the ants supposedly built the altar above a body of water so they could offer the initial pile of food to the grasshoppers, which would eventually fall in the water and then cause the adventure to begin.

When Flik is leaving Ant Island, the two boys who follow him are making fun of him. One boy says, "My dad says he is going to die." When Flik left the island, the same boy says, "Your dad is right. He's gonna die."

When Flik, Dot, and her friends use the fake bird to attack the grasshoppers, all the bugs use berry juice to fool the grasshoppers into thinking that they're bleeding. Insect blood isn't red like human blood. Instead, it's almost colorless like water.

When PT arrives at the ant hill he doesn't have the ability to fly across the old river bed, but he still is able to reach the ant hill quickly, with his circus wagon after being sighted by the look-out ants.

When the circus bugs are getting ready to leave Ant Island at the end of the film Heimlich's voice can be heard saying Thank you! Although he is still inside his cocoon transforming into a butterfly and doesn't come out of his cocoon until the circus bugs leave and Manny and Francis have to come back to carry him away.

After the Queen addresses Mr. Soil, he responds "Yes, Your Highness?". The title "Your Highness" is reserved for princesses. Queens are called "Your Majesty".