Kikô Chûtai [Armored Insect Squadron] Beetras was another toyline from Takatoku. The toys from this series would later become the Deluxe Insecticons. Below is a translation of the story from the catalog that came with my Beet Gadol.

The story:

In the year 1984, mysterious tectonic upheavals occurred all over the
world.  The disruptions were caused by a war going on in the unknown
world of Komun, deep within the Earth, between the Ekim and Gyme clans.

The underground city of Komun was a parallel world with 1/10 the area
and five times the gravity of the surface world.  Its highly advanced
civilization and bountiful natural environment had been preserved by the
balance of power between those two tribes.  However, the destruction of
Nature by the surface dwellers disrupted that balance, and so the Great
Komun War began.

Thanks to that war, the surface world was in danger of being devastated,
a situation the Ekim gave top consideration.  Karim, the leader of the
Ekim, took along five insectoid mecha and their operators--Kalma, Kirlo,
Tormo and Lamil--and set forth onto the surface to do battle with the
Gyme clan as the Armored Insect Squad Beetras. Later, they were guided
by Fate into meeting the surface-dweller Mamoru, and with his help, the
battle with the Gyme to protect the Earth is about to begin once again
in the underground city of Komun...

The Armored Insect Squad Beetras is...
a group of able, chosen warriors who pilot insectoid mecha developed by
the advanced scientific powers of the Ekim clan.

These insectoid mecha are also transforming mechanisms, able to take on
any of three types of mobile form, depending on the operation:
Beet-Attacker, their battle mode; Beet-Hover, their scouting mode; and
Beet-Mobile, their burrowing mode.  Designed this way, these weapons are
able to give full play to their powers anywhere on Earth.

The characters:

BEET KARIM
(Age: 17 in surface years)
An able soldier and pilot of Gadol, this leader of the Beetras team
bears the title of "Beet", given only to a select few of the Ekim clan.

MAMORU DAICHI
(Age: 17 in surface years)
A brave young man with a strong sense of justice, Mamoru is suddenly
made the leader of the Beetras team upon Karim's death.

BEET KIRLO
(Age: 13 in surface years)
The youngest member of the group, Kirlo is a joker by nature, but with
his genius intellect, he asks all manner of difficult questions. Pilots Zeguna.

BEET KALMA
(Age: 17 in surface years)
A gallant soldier working as Karim's second-in-command, Kalma pilots
Gugal. Although cool in personality, he fights ferociously, having
sworn to avenge his father's death at the hands of the Gyme.

BEET LAMIL
(Age: 15 in surface years)
Karim's younger sister and granddaughter of the Ekim clan elder.  Though
a pretty, kind-hearted girl, this lone female of the group is also tomboyish
and loudmouthed. She pilots Papil.

BEET TORMO
(Age: 17 in surface years)
Tormo is a powerful giant of a youth, yet timid and softhearted too.
He's also an expert in mecha repair, and pilots Vadam.
 

A list of toys from the Beetras series:

Here are the names of the Beetras figures and the names of the Transformers they became:
 
Beet Gadol
Barrage
Beet Gugal
Chop Chop
Beet Zeguna
Venom
(Beet Vadam)
Ransack
(Beet Papil)
none

Beet Papil and Beet Vadam were never released. Shortly after Beetras was released, the company Takatoku Toys went bankrupt. Beet Papil never passed the prototype stage, but the design of Beet Vadam was most likely all ready for release, so it could be incorporated later in the Transformers series.. It's a pity Beet Papil never came out, as it would have made an excellent female mecha or Transformer and those are very rare!
 

Toy pictures:
 
BEET GADOL
Beet gadol the leading mech, controlled by Beet Karim. The toy has unfortunately rather loose joints and the quality relatively low compared to the other toys form Takatoku. Still it's a very cool looking and complex transforming toy.
BEET GUGAL
The plastic of this toy is of a better quality than my Beet Gadol and the joints are much more stiff. It looks a lot better than the Transformer version in my opinion. Unfortunately I don't have the sword weapon that originally came with it.
BEET ZEGUNA
Yet another cool looking mech. I do like the Transformer colors too, but this is also a neat variation. This one is also made from a better quality plastic than Gadol, though the arm attachment looks rather fragile to me, so be careful when you buy one. 
 
 
Catalogs and other pictures: