For the action of killing to occur full force there have to be four factors present:
a) The motivation or intention to kill a sentient being
b) A sentient being that is the object of the action
c) You have to commit the action of killing of that being
d) The being must die as a result of your action
If all four conditions are met the full karma of killing is incurred. Insects are considered sentient beings so there is the karma of killing involved in taking their life.
We have to remember SOME killing IS inevitable in the whole scheme of things. Even if we are vegetarians, the rice we eat, or the grains or veggies and fruits often have insects/worms on them. They get killed by pesticides, harvesting, etc. Furthermore, we also cannot avoid using animal products such as leather shoes, leather belts and even some furnitures like sofa also made of bull's leather etc.
In order to be innocent of ANY killing, we would indeed have to starve ourselves and getting rid of all these daily products. Even then, we would be commiting killing (of ourselves.)
In Buddha's time, many buddha's disciples attained Arhatship. They achieved highly spiritual clarivoyance who able to see microscopic organism with naked eyes within the drinking water. Many arhats realised there are millions of living organisms within so they avoid drinking water. As u know we human body cannot survive without water for a day, thus Buddha prohibited his arhat disciples from using their special ability magnifying into the water as they are drinking it.
What is the morale of the story implies? Are we going to create a paranoid in ourselves after we become a buddhist? Are we not going to capture all the pests one by one in our house or work place and bring it out to throw them away?
Indeed there are too many living creatures living around us so certain unintentional killing is unavoidable.
Talking about absolute abtrain from killing, if we skip our meals and starve ourselves for every minutes, countless living creatures such as ring worms and other biological organisms will died within our body organs.
Isn't it we commit killing acts? Buddha Himself gave several discourses about this truth in some sutras when his disciples questioned about killing karma. Whatever we can do as a living entity in this world is to protect living creatures from sufferings and minimise killing acts to our very best.
Hence, our thoughts and intention counts, as long as our conciousness is focusing in doing our daily routine activities and have mindfulness of living beings existence, this sincerity do counts.
