Hercules Beetle

This task is about adding words to a text so that it makes sense.
 
bug
Image source: Wikipedia (Public domain)
 
The following piece of writing has some spaces where words are missing.
 
First, read the whole piece of writing through to get an idea of what it is about. Then fill each space with ONE word so that the whole piece of writing makes sense. You are able to change answers as you go.

When you have filled in all the spaces, re-read the text to check that the whole piece of writing makes sense.

Question 1Change answer

Hercules Beetle
 
The Giant Hercules Beetle of South America can grow up to 15 centimetres in length. The ferocious looking male has two 1 toothed horns projecting from its head 2 for this reason it is sometimes  3 the Rhinoceros Beetle. Naturalists were puzzled 4 the use of these horns, but  5 has been shown that they are 6 weapons.
 
Two male beetles need little excuse to begin fighting. After staring at 7 other they make a head-on attack 8 is followed by the clashing of 9 as each beetle struggles desperately to 10 an invincible grip. Early in the 11 they may back away and then 12 in again until one succeeds in  13 a tight hold on the other's 14. The victor then begins to 15  his unfortunate foe back and forth 16 he has an unbreakable death-like grip. 17, he rears himself upright and resting 18 his hind legs holds his wildly kicking opponent high in mid-air. He then 19 his victim hard on the ground, 20 and again until he lies dead.