Snails, Slugs And Eco-Friendly Shade Coffee

Coffee Forests in India are unique not just because they are positioned in one of the 10 hot spots in the Western Ghats, but earn a place of ecological significance for the incredible wealth of biodiversity they possess in terms of flora and fauna. The Coffee forests teem with both macro and micro wildlife, microorganisms, herbs, shrubs and tree diversity, with a high degree of endemism some species, which are not present in any part of the Planet. The multi layered tree canopy provides the ambient temperature, shade and energy balance in terms of symbiosis and other mutually beneficial interactions.

The Western Ghats also recognized as a mega biodiversity hot spot is has recorded 269 species of snails, 75 % of which are endemic to the region.

Species diversity and endemism of land snails of the Western Ghats.

To date, 1,488 species belonging to 26 families and 140 genera have been recorded from India. Of these, 270 species of land snails have been recorded from the Western Ghats area and constitute about 18 per cent of the country’s total land snail fauna. The land snail fauna of the Western Ghats includes members of 24 families and 57 genera. Land snails constitute about six per cent of the total species on Earth.

Al these years we were busy mapping the biodiversity of coffee forests in terms of Mammals & bird life. It is a fact that smaller and lesser known species, especially the invertebrate species have not got their due, even though they exist in far greater numbers. We got interested in snails & slugs because scientific literature points out that they are potential and reliable indicators of the health of the ecosystem they inhabit. Another interesting observation we found was that some of the snails which are endemic to the Coffee Forests are found nowhere else on the Planet. Depending on the topography of the Coffee forest, many species have very restricted ranges within the region. There is a decline in diversity and local endemism during the summer months. Understanding the diversity, endemism and distribution of land snails inside Coffee Forests will be an ideal way to develop bio indicator tools to monitor the health of the Coffee ecosystem.

An interesting fact

The last registry on land snails was done a century ago by the British. It was called “Fauna of British India”. The Fauna of British India had recorded 240 species and few of them are extinct in the present day. This may be due to the fact that the   Western Ghats has undergone significant man made transformations due to various factors like timber logging, sand and ore mining, building of dams, rail roads and interlinking of water ways. Habitat destruction and fragmentation may be the single most important factor for loss of species and extinction of a few others.


Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusk. The word slug is also often used as part of the common name of any gastropod mollusk that has no shell, a very reduced shell, or only a small internal shell, particularly sea slugs and semi slugs (this is in contrast to the common name snail, which applies to gastropods that have a coiled shell large enough that the animal can fully retract its soft parts into the shell).


Snails and slugs can be found in a very wide range of environments, including wetlands, aquatic habitats, streams, ponds, rivers, coffee shrubs, and the tree canopy. Although land snails may be more familiar to laymen, marine snails constitute the majority of snail species, and have much greater diversity and a greater biomass. Numerous kinds of snail can also be found in fresh water.

Ecological Significance of Land snails

Land snails and slugs form an important component in the coffee forest ecosystem because they provide a number of ecosystem services that are beneficial to the coffee ecology. They are important in the food chain and are vital agents in recycling of nutrients. Many snails are herbivorous, eating plants or algae from surfaces, though a few land species and many marine species are omnivores or predatory carnivores. Inside the coffee ecosystem they are also preyed upon by birds and reptiles. Snails also act as important bio monitoring agents.

Another important aspect about snails or slugs is that, these small animals require calcium and other nutrients for growth and reproduction. These snails are in turn consumed by a wide variety of predators that also rely on snails for their calcium and other nutrients.

Coffee, Snails and Slugs

Because some species of slugs are considered agricultural pests, we need to understand their feeding behavior. A small number of species are serious pests of agriculture and horticulture crops. They are capable of destroying foliage faster than plants can grow causing serious economic damage. A few years back (2015, 2016) many Coffee Planters were alarmed when a particular snail species started eating the Arabica Coffee Leaves during the monsoon season. In fact there was a population explosion of snails restricted to a small agro climatic region and the damage to Coffee plants was restricted.

Significant damage was observed in Arabica and to a lesser extent in Robusta.

We also need to understand the behavior of snails and slugs. In certain cases introduced snails from abroad are causing havoc in terms of rapid multiplication. We are not certain, regarding the number of species of indigenous snails that act as pests of coffee and other multiple crops grown along with Coffee. Scientific reports indicate that some snails are pests in many horticultural crops causing widespread economic damage. Understanding their behaviour will enable timely remedial action.

Feeding Habits

Snails and slugs feed on a wide variety of organic materials. Inside shade coffee, it is pretty common to observe the abundance of slugs, especially during the monsoon period in compost pits or areas where mushrooms emerge. Scientific reports indicate that they also feed on lichens, mushrooms, and even carrion. Some slugs are predators and eat other slugs and snails, or earthworms.

Factors affecting Species

We have noticed that the distribution and abundance of terrestrial molluscs are affected by environmental factors. We have observed a surge in population of a certain species of snails during the early monsoon period and a resurgence of some other species during the early onset of monsoon.

The distribution and habitat is significantly affected not only by global warming but also due to habitat destruction in terms of timber logging and converting certain landscapes to sun loving cash crops like ginger, oil palm and other crops. The Coffee forests are undergoing rapid transformation and this may lead to the disappearance of many species because of their high sensitivity to changes to impact of climate change.

Decline in population

There may be many diverse reasons for the erratic distribution of various species of snails and slugs. We assume that a combination of biotic (Photosynthetic Organisms (i.e. Primary producers), Herbivores, Carnivores, Omnivores) and abiotic factors (Abiotic factors are the non-living components of a habitat. The abiotic factors in an ecosystem are grouped into soil (edaphic), air, topography, meteorology, availability of water and quality of water. The meteorological factors are temperature, wind, sun, humidity and precipitation.) may influence the occurrence, distribution and population trends of snails. However, in our opinion the single most defining factor is due to the fact that the Coffee forests with their varied topography and wide diversity of habitats along with wet and dry conditions, greatly influence the snail diversity. Soil profile and nutrient status, especially calcium content plays an important role in snail population. Calcium is a prerequisite because it is a major factor for their survival as it is required for their shell formation. Several studies have shown that Calcium is positively correlated with species richness and density.

In recent times, due to shortage of manpower, it is common practice among the coffee community to use high powered sprayers to control weeds, pests and diseases using herbicides, weedicides and pesticides. The impact of these chemicals on the local flora and fauna including endemic land snails as well as other invertebrates is unknown. It is important to understand the impact of various package of practices of coffee on land snails and slugs because snails are sensitive to every single minute changes in the coffee ecosystem.


We noticed some species easily adapt to high temperature stress and prolonged drought like conditions, where as other species can easily adapt to very heavy rainfall conditions.

Dr.Madhyastha,a leading expert in this field is of the opinion that these small animals need to be brought under a regular biodiversity protection programme. “The largest number of extinction has been in mollusks and slugs as they were slow moving which made their habitat smaller and any sudden imbalance or alteration in the habitat will destroy their existence,”.


To date very little information is available on the distribution status and threats of land snails and slugs in India. Ecologists are yet to understand the ecological significance of Snails inside Coffee Forests. An in-depth study in terms of species distribution, population and other aspects will throw light on the exact symbiotic or antagonistic role they play in the coffee ecosystem. We also need to prepare a blue print in terms of biological control instead of chemical control so as to target species specific target organisms, there by safeguarding the fauna of the entire ecosystem.


Anand T Pereira and Geeta N Pereira. 2009. Shade Grown Ecofriendly Indian Coffee. Volume-1.

Bopanna, P.T. 2011.The Romance of Indian Coffee. Prism Books ltd.



Species diversity

Land snails

Rare land snails

Terrestrial Snails

Pilbara snail

Why Land Snails?






Ecofriendly Coffee Pollinators Other than Bees & Butterflies

Almost all Coffee Planters, worldwide are of the opinion that Bees and butterflies are the only agents of pollination of coffee and other mixed crops associated with coffee. This is not true. There are many other agents of pollination closely associated with coffee forests.

Pollinators come in all shapes and sizes and includes birds, insects and mammals. Research data indicates that more than 100,000 different kinds of animals, pollinate over 250,000 different kinds of plants. It is interesting to note that pollinators, irrespective of the group they belong to are often adapted to pollinate specific plants. It is for this very reason, it is very important to protect all kinds of biodiversity within the Coffee Ecosystem.


It is a fact that three fourths of the world’s flowering plants and almost all food crops depend on animal pollinators to reproduce.  Bees and butterflies constitute a major part of pollination. Apart from Honeybees and butterflies, there are many other species of insects like ants, wasps, moths, flies, dragonflies, damselflies, grasshoppers, Beetles, bats, humming birds and other animals that play an important role in pollination and fruit set in coffee. Pollinators are economically, socially and culturally important.

Readers, worldwide need to understand that India’s shade grown eco-friendly coffee forests are unique when compared with other coffee producing Nations, because they are grown under the canopy of a three tiered shade system which includes a heterogeneous tree population comprising of native and introduced trees, herbs, shrubs, flowering plants, fruits, spices and other mixed crops. In short the coffee ecosystem provides an ideal environment for all pollinators because of the accessibility to flowers all year round. Flowering can be observed either from trees, herbs, shrubs, weeds, or fruit plants or spices. In some varieties, flowering is staggered there by providing a continuous source of pollen and nectar. The diverse coffee ecosystem has many symbiotic roles to play with the surrounding biotic community. Especially, when it comes to the flowering morphology of various trees, fruit crops, herbs, spices and other plants, we notice an interdependency of certain species of native insect pollinators with their corresponding host plants. Most plants have a definite flower morphology, colour, blooming sequence, characteristic scent pattern that will attract a particular type of pollinator to meet its protein requirement. In some species this symbiotic relationship between plant and pollinator has evolved over thousands of years and is so interconnected that the absence of one can signal the extinction of the other. Hence, it is important to understand that all flora and fauna inside coffee forests have a role to play in the productivity of the ecosystem. Maintaining a healthy population of pollinators is a pre requisite for reproduction and maintenance of genetic diversity inside coffee forests.

The Coffee Community in India has always been proactive in terms of conservation of biodiversity. In recent years, due to price drop in coffee and allied crops and also due to global warming, biodiversity loss has alarmingly increased. This impact has significantly impacted many species of beneficial insects, especially the pollinators.


We have not come across any scientific study on the agents involved in the pollination of coffee and other mixed crops apart from honey bees and butterflies. We record a few observations of pollination by insects and are of the view that due to a significant reduction in population of honey bees and butterflies, Planters should take note of other agents which are also equally important in facilitating pollination inside coffee forests.

All kinds of pollinating agents have very high-energy needs that must be met for their survival. Key resources such as pollen and nectar are met from a variety of flowers that bloom throughout the season.

Understanding Pollinator Habitats

Each type of pollinator requires a specific habitat.

Bees and wasps require nest sites, Beetles, butterflies, moths, flies and some wasps require larval feeding sites, others require hunting sites and over wintering sites. The selection of sites is based on areas where the natural enemies or predator population is low. Coffee farmers need to protect these sites to support the pollinator populations.

Entomophily – pollination by insect.

Damselflies and Dragonflies


Scientific evidence points out to the fact that dragonflies and damselflies may rest on flowers, but don’t carry enough pollen from flower to flower to be considered pollinators. We are of a different opinion because our observations point out that damselflies repeatedly fly from one coffee flower to the other and may play an important role in pollination. However with respect to dragonflies, we have not observed such frequent activity.

Myrmecophily – pollination by Ants

We have observed different species of ants, Black and red in colour visiting coffee flowers during blossom to collect energy rich nectar. However, we are not sure as to how effective the various species of ants are in helping with pollination.

Chiroperophily or Bat Pollination


The coffee forests are gifted with many bat species. Some are tiny in size and the others huge with a long wing span. They are often referred to as the night shift pollinators. Research data clearly shows that over 300 species of fruit depend on bats for pollination which also includes mangoes, guvas, sapotas, bananas, and figs.

Cantharophily – pollination by beetle.


We have observed many beetle species involved in coffee and mixed crop pollination. Beetles comprise the largest set of pollinating animals, due to sheer numbers. They are responsible for pollinating 88% of the 240,000 flowering plants globally.

Scents associated with beetle pollination are often spicy (Crab apples), sweet (Chimonananthus), or fermented (Calycanthus).

Ornithophily or Bird Pollination

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Our scientific study on coffee forests has shown that over 100 species of birds habit the coffee ecosystem. Some are resident and others migratory in nature. However, during the coffee blossom, we have noticed only a handful of species directly involved in coffee pollination. A majority of them are the humming birds. We are still studying and documenting the birds involved in pollination of coffee and allied crops like areca and oil palm.

Sapromyiophily – pollination by Flies

We have observed a few types of flies during coffee flowering but have yet to ascertain their role in pollination. However, scientific evidence points out that flies even though are not as hairy as bees and as efficient in carrying pollen, but some are good pollinators.




The Coffee ecosystem is gifted with many different species of wasps and all the species are excellent pollinators.

Melittophily or hymenopterophily – pollination by bumblebee.

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The population of bumble bees, especially during coffee flowering is significantly higher when compared to other seasons. This may throw light on the important role they play in pollination of coffee.

Pollination by spiders


We have noticed a high level of activity of different species of spiders during blossom and are not sure if they are directly involved in pollination.

Why are pollinators at risk?

Air and water pollution due to indiscriminate use of fertilizers and pesticides.

Habitat loss and fragmentation of forests.

Widespread disease and pest incidence due to the impact of global warming.

How to safe guard pollinators

First and foremost use Integrated Pest management practices that reduce the dependency on chemical control of pests.

Allow a part of the Farm to remain wild (No commercial cultivation of any crop)

Habitat restoration and Habitat enhancement will provide multiple benefits (Supporting pollinators, Attraction of beneficial insects, Predators, Less use of chemicals on farm)

Add to the diversity of the farm. In a way provide for multiple crops (farm site).

Provide flowering plants (garden) where flowers should be available throughout the entire growing season. These plants should provide overlapping blooming times so that flowers are available to provide pollen and nectar throughout the season.

It is desirable to include a variety of plants with different flower colours, sizes and shapes as well as varying plant heights and growth habits to encourage the maximum numbers and diversity of pollinators.



Next to oil, coffee is the largest traded commodity and employs 25 million unskilled workers in almost 80 coffee producing Countries. Coffee represents an important source of income for marginal farmers in most developing Countries.

However, a recent report brought out by the Food and Agriculture Organization of the United Nations clearly states that Pollinators vital to our food supply are under threat, threatening millions of livelihoods and hundreds of billions of dollars’ worth of food supplies. The Millennium Ecosystem Assessment concluded that with the global decline in the amount of pollinators, there is not a complete loss of fruit or seeds, but a significant decrease in quantity and viability in fruits, and a lower number of seeds.


Anand T Pereira and Geeta N Pereira. 2009. Shade Grown Ecofriendly Indian Coffee. Volume-1.

Bopanna, P.T. 2011.The Romance of Indian Coffee. Prism Books ltd.

Janet Marinelli, Editor in Chief, 2005. Flowering Plants, Pollinators, and the Health of the Planet.  First American Edition. Dorling Kindersley Limited (DK Publishing, Inc.). New York. 512 Pages.

Animal Pollination

Pollinators vital to our food supply

Economic value of tropical forest

Insects & Pollinators

Other Pollinators

Pollinator Biology and Habitat

The Hidden Beauty of Pollination

What Are Pollinators? Types, Importance

pollinating insect species