This question is filed under: Animals, Genesis, Insects & Other Invertebrates, Simon Terry,

Question

PESTS? How did creatures like slugs get to be pests?

Answer

Simon Terry is a qualified teacher, and is an expert in snails and slugs. He is now involved full time in evangelistic work in England.  Click on name above for more details.

Personally I think slugs are an awesome part of God’s creation, so when I refer to them as pests I am using the term as it is applied to any species that has a detrimental effect on our gardens, farms, etc. Yet by this very definition we credit the creature as the cause of this conflict, which is both inaccurate and misleading. So to answer this question I will seek to trace the history of slugs from their early creation in Genesis to their current corruption and conflict with man.

God’s very good creation

Genesis 1:31 reminds us that when God made the world it was ‘very good’. Unlike gardeners today, Adam wouldn’t have thought anything God had made to be a pest, as all of creation worked with man for the glory of the Creator. This perfection of the finished creation prevents any struggle and strife over the prescribed plant groups given to man and the beasts for food because creation was very good in every sense.

Distinctive diets in the early creation.

Adam and Eve had their instructions as did the beasts as to what they were to eat. There are very clear dietary distinctions given by God. Apart from the tree of the knowledge of good and evil which man was not to eat from, two food categories were provided. Firstly for man, ‘every herb that yields seed which is on the face of all the earth,’ (Genesis 1:29 NKJV) was provided. This word ‘herb’ is similar to our word for ‘grass’ or ‘greenery’. There was also ‘every tree whose fruit yields seed; to you it shall be for food.’ (Genesis 1:29 NKJV) This clearly indicates that fruit trees were edible as well. Both these seed bearing categories were just what God intended, specifically designed for man to eat.

The beasts, birds, and everything that creeps on the earth which would have included slugs were given ‘every green herb for food,’ which is also quite specific. The beasts were given a strict colour category for their diet, which may have overlapped with man’s categories.

Genesis 1:29 also suggests a vast provision of the seed bearing herbs. The phrase ‘on the face of all the earth,’ signifies that there were no areas off limit for this group. One of the factors therefore that rules out competition for food is the immensity of the provision.

Slugs therefore in the perfect world would have been restricted to the colour category given by God and were allowed to roam free in foraging for their food.

Arrested Development

When Adam and Eve ate the fruit that they were forbidden, the world they once knew was to change. Genesis 3:17 tells us that ‘Cursed is the ground for your sake,’ (NKJV). Although man did work before the fall, now it is toilsome for him. We are given some specifics, namely thorns and thistles hindering man’s efforts in the field. Verse 18 tells us ‘In the sweat of your face you shall eat bread …’ (NKJV) illustrating the intense struggle that now exists with what has become a hostile environment. Before the ground was very good, now it is cursed. The injurious nature of species we refer to as pests (slugs included) that bring disease, suffering, and generally cause a nuisance are part of the degenerative picture we see building from chapter 3 down throughout history.

The Apostle Paul reminds us that ‘the creation eagerly waits for the revealing of the sons of God. For the creation was subjected to futility, not willingly, but because of Him who subjected it in hope; because the creation itself also will be delivered from the bondage of corruption into the glorious liberty of the children of God.’ Romans 8:19-21

Slugs like all life forms have to now live and survive in a corrupted creation. Their role is not only arrested in that they are unable to live as they once did, but that they now have to survive in a very different world, a world of struggle, disease and degeneration. As part of the degeneration of the living world it is possible that the growth and reproduction rates of slugs and other life forms have changed, bringing them into conflict with man. If the genes that control these rates are affected in any way it would create an imbalance in the field leading to a boom in the population.

Slugs at Work in the Environment

Their function, though in futility, is amazing. They play a vital role in our broken landscape which is often very much overlooked and underestimated.  Many slugs and snails are detritivores, that is to say they consume decomposing plants and animals. The ‘banana slugs’ as they are commonly known of the Genus Ariolimax contribute to the redwood forests of Western North America by clearing away all manner of living and decaying vegetation.

Banana Slug
Left: Ariolimax californicus in San Pedro County Park, Pacifica California.

Banana slugs are indigenous to these forests. There are several species in the genus. Their range extends from San Diego County of California in the south to the southern region of Alaska. They literally process the forest floor munching their way through roots, bulbs, mushrooms – some of which may compete with young redwood seedlings for light, space, water and nutrients. The slugs in turn leave nitrogen rich scats which provide fertilizer for the forest. The young trees as they mature and develop then provide the damp ecosystem which these slugs and other creatures are so dependant upon. The seeds and spores they consume work their way through the slug’s digestive system, to be later dispersed through the slugs’ droppings. The seedlings from this seed dispersal then provide future plants for the forest, in turn feeding the slugs that sowed them in the first place. It is truly amazing to consider intricacies of God’s creation and how even in futility, every organism has its place.

Yet such habitats as beautiful as they are, are not paradisiacal - it is ‘eat’ or ‘be eaten’. The banana slugs have to survive in that system. When you consider life in the wild it is a marvel that anything survives. The pressures of predation would have been entirely absent in the early creation. It is only through the sustaining power of the Lord Jesus (Colossians 1:16) that such ecosystems can survive at all.

The role of slugs in decomposition and nutrient cycles is not confined to the forest, but is active in our fields, parks and gardens. This is where their nature, arrested in futility, comes into conflict with man. Though some slug species pose no problem to our cultivation, there are some species that are notorious for decimating crops.

Grey Field SlugLeft: Deroceras reticulatum or Gray Field Slug has a wide distribution, common in gardens throughout the UK as well as in agricultural land and grassland. A medium slug with a length of 3.5-5cm. This species is considered a serious pest to crops and garden cultivations. This specimen was found crawling around at the edge of a garden in Surrey, 2012.


In 2013 UK newspapers issued warnings of a ‘Spanish slug invasion’. Arion vulgaris, better known as the ‘Spanish Slug’ is known for its particularly sticky slime, rapid growth rate and high fecundity producing twice as many eggs as other large Arionid species.

Arion vulgarisLeft: Arion vulgaris eating clover.
The Spanish Slug is considered by some to be a potentially serious threat to agriculture. These are large slugs, growing up to 15cm. Their diet is polyphagous, in that they feed on a wide range of plants, decaying organic matter and animal carcasses.
Mature animals are either brown / reddish brown or a bright orange.

Although they have an extensive omnivorous diet, they are known for their damage to commercial crops. Tristan Maclean from the John Innes Centre in Norwich said “We’re looking at a slug that can really affect food security”.

In mainland Europe these slugs can even reduce house prices. Home owners have been known to sell their property to escape them. There have also been incidents in Scandinavia where they have become a highway hazard, with entire roads being closed. Because of their cannibalistic tendency, any slug that becomes a victim of road-kill becomes a magnet for its compatriots, which through further impact create a slimy slick, causing cars to skid and crash.

Many of us fail to realise that the trouble these slugs can bring is through no fault of their own. It was our sin in Adam that has led them to cope in corruption and futility. We should be thankful for their processing of our land and soberly remorseful that the world is not the world it once was.

An Earnest Expectation

Slugs and snails and the rest of the creation, though in bondage, are waiting for an event that will change everything. Paul continues in his letter to the Romans:
‘For we know that the whole creation groans and labors with birth pangs together until now.  Not only that, but we also who have the first fruits of the Spirit, even we ourselves groan within ourselves, eagerly waiting for the adoption, the redemption of our body.  For we were saved in this hope, but hope that is seen is not hope; for why does one still hope for what he sees? But if we hope for what we do not see, we eagerly wait for it with perseverance.’  Roman 8:22-25

The whole of the creation is groaning - but is in expectation of deliverance. 2 Peter chapter 3 verses 11-12 speak of a great conflagration by fire where the elements will melt with fervent heat. After this great event the world will be rejuvenated and renewed. The struggle and degeneration will be no more. The creation will be liberated from its futility. Concord and harmony will replace conflict and corruption. What a world to look forward to!

An Earnest Question

Dear reader, will you be part of that new heavens and new earth? Do you have a part in this paradise? The only way any of us can look forward with hope is to be part of that hope. Over two thousand years ago Jesus Christ opened the way back to God by His death and resurrection. The Bible says:
‘He was wounded for our transgressions, He was bruised for our iniquities; The chastisement for our peace was upon Him, And by His stripes we are healed.’ Isaiah 53:5.

He suffered and died in our place paying the price of our rebellion. Forgiveness for our sins, everlasting life and the hope of the new world is given as a gift to those who repent (change their mind) and put their complete trust in the Lord Jesus Christ.

Peter said:
‘Blessed be the God and Father of our Lord Jesus Christ, who according to His abundant mercy has begotten us again to a living hope through the resurrection of Jesus Christ from the dead.’ 1 Peter 1:3

Without trusting the Lord Jesus Christ we pay for our sins ourselves, which is everlasting destruction. A sobering reality that God is not willing any of us face. Such is His concern for you and me in sending His Son and allowing Him to pay the terrible price for us. Thanks be to God for the certain hope, the living hope we can have in His Son!

‘Neither is there salvation in any other, for there is no other name under heaven given among men whereby we must be saved.’ Acts 4:12 (NKJV)

For more information on slugs and snails see the questions:

What is the Snail Evolution project in British Schools, and what does the evidence show? Answer here.

SNAILS: Some land snails can go underwater, so are land and sea snails the same? Answer here.

For more details on snails, creation and evolution, read Simon Terry’s articles:

The Snail evolution Project: School children across Europe are participating in a project that is claimed to show evolution in snails.  What does the study of snails really show? PDF here.

Land and Sea Snails: Separate Creations? Some land snails can go under water. Are land and sea snails the same? Is there evidence land snails evolved from sea snails? PDF here.


Images
Ariolimax californicus: Creative Commons Attribution-Share Alike 3.0 Unported license.  Photographer: Franco Folini, 2007
Deroceras reticulatum: Simon Terry
Arion vulgaris: Creative Commons Attribution-Share Alike 3.0 Unported licence. Photographer Håkan Svensson, Xauxa, 2005
Arion ater eating winter honeysuckle (below): Simon Terry