Butterflies & Moths: Why are they important?

Introduction

“Lepidoptera” is an order of insects that includes butterflies and moths. There are about 250,000 species of the Lepidoptera. This group makes up nearly a quarter of the total number of described species of living organisms. In other words, Lepidoptera is one of the most widespread and widely recognizable insect orders in the world. 

These insects live and breed in widely differing habitats from mangrove swamps and salt marshes, wetlands and grasslands to lowland and highland forested areas and mountain zones.  In fact, they live everywhere except the Antarctic.

Differences between butterflies and moths

There are many differences between butterflies and moths in physical appearance, structure and habits. The diagram below touches on some of the differences (though even these have exceptions).

From now on I will refer only to butterflies (to avoid saying butterflies and moths every time)

Butterflies perform extremely important functions in maintaining the health of our planet and are an important component of its rich biodiversity.  (And apart from their intrinsic value they contribute to the well-being of humans in quite specific ways.) These delicate, short-lived organisms are a vital element of conservation in general and in particular of conservation for invertebrates.

1. Butterflies (like bees) pollinate plant

About one third of the food people eat depends on the work of pollinators such as butterflies. Pollinators help to move pollen from one plant to another and therefore help flowering plants to reproduce. This pollinating service depends on the fact that many butterflies feed on the sugar-rich nectar produced by flowers. (Others feed on succulent interior parts of ripe fruits and on tree sap.) Butterflies

are particularly attracted to big, colourful (especially red, scented flowers that produce a lot of nectar and provide a landing platform. The butterfly lands on a chosen flower and uncurls a long tube-like tongue (called a proboscis) to suck up nectar from deep inside the flower.

Meanwhile they accidentally gather pollen grains on their bodies and long, thin, legs. Then as they fly from one flower to another, they often deposit the pollen on the female element (anther) of the other flower, allowing fertilization to occur.

Butterflies favour red/pink flowers and some yellow flowers. (Moths, on the other hand, are attracted by white (which is easy to see in the dark), bees are especially attracted by blue flowers, flies like white and yellow, and wasps brown and yellow, beetles white and cream.)

photo by Richard Wakefield, for Shades of Zimbabwe calendar

Butterflies are important pollinators as they travel longer distances than honey bees which stay close to the hive. This is beneficial to plants and the planet as it promotes more widespread genetic variation and resistance to diseases.

2. Butterflies are an important part of the food chain or cycle

The food chain is an intertwined system of food sources such as vegetation, herbivores, omnivores, and microorganisms and results in necessary nutrient transfer within the ecosystem. Everything needs to eat, and for many creatures that feed on insects, butterflies act as a food source. Butterflies in all stages of their life cycle provide food to other animals in the ecosystem including birds, bats, mice, scorpions and various reptiles and amphibians and other insects such as ants. Birds are fond of butterfly caterpillars because they move slowly and are easy to catch.

A butterfly chrysalis – the final larval stage before the adult butterfly emerges – is vulnerable because it is anchored to rocks, plants or other structures and provides food for many other forms of life. The population of butterflies in an ecosystem has a ripple effect on the population of other organisms in the environment. Consequently, a decline in the butterfly population in the ecosystem also results in a decrease in the population of birds, mice, and other animals that rely on them as primary sources of food.

3. Butterflies can act as natural pest control

Related to the above point, although adult butterflies typically do not prey on animals some butterflies are in fact also predators   The larvae (or caterpillars) of various species of butterfly, e.g. the hoverfly and harvester butterfly feed on aphids which attack plants.

Butterflies in the larval stage consume the leaves of host plants and some caterpillars eat flowers or seed pods as well. Because they are typically very specific about the type of plant on which they feed they may help plants lose leaves prior to autumn or help to keep certain undesirable plant species from propagating out of control. For example, during its caterpillar stage, the monarch butterfly only eats milkweed plants, which are considered a weed by horticulturalists and farmers. Other adult butterfly species eat rotting fruit, carrion or animal excrement, thus controlling waste materials.

4. Butterflies are important indicators of a healthy environment

Ecosystems rely on every animal, insect, and plant to maintain balance and thrive. There are certain types of organisms that are referred to as “environmental indicators”. If these species are present, then it is a sign of a healthy environment. Insects like fleas, flies and cockroaches are highly adaptable and cannot be reliably used as indicators. Butterflies on the other hand are environmental indicators because they require resources that are only found in a functioning and often somewhat pristine habitat.

Scientists use the presence or absence of butterflies as a predictor of whether an ecosystem is healthy and research into the size of butterfly populations is a particularly accurate way of measuring how stable an ecosystem is. An environment that attracts butterflies would also be fertile for the growth of plants and serve as a suitable habitat for other lifeforms, including a wide range of other invertebrates, which comprise over two-thirds of all species. An area that attracts butterflies, for example, will also bring native bees. And bees will be followed by birds.

In Zimbabwe, butterfly observations were used in this way for a project to re-vegetate the mine dumps at Hwange Colliery. A baseline population was studied in nearby Hwange National Park and then the success of the re-vegetation programme was measured in terms of how closely the butterfly population on the former dumps came to resemble the population in the National Park.

And to make the same point from the other end, butterflies rely on specific conditions and environmental cues to complete their delicate life cycle and are particularly sensitive to environmental threats such as habitat destruction and climate change. Adult and larval forms are sensitive to pesticides. Changes in climate will impact butterflies because temperature changes and rainfall amounts may alter breeding and migration patterns and timing. Loss or fragmentation of habitat – for example, losing chunks of cover as a result of construction or defoliation – increases predation and also affects migration. Behavioral changes of a butterfly population in an ecosystem or the sudden decline in the population of butterflies in a certain area can be a warning of an impending environmental calamity or possible habitat loss for other animals.

5. Butterflies are important in various sorts of scientific research

Following on from the above point, scientists have been studying butterflies for about 300 years. This long history of butterfly study has provided a unique data resource on an insect group which is unmatched in geographical scale and timescale with any other species group.

This has proved extremely important for scientific research on climate change. For example, scientists focusing on one species in North America (Edith’s checkerspot butterflies) can demonstrate clearly that the distribution of these butterflies has shifted further north and to higher elevations as the result of an increase in temperature.

It is also relatively easy to study butterflies because they are small and their life cycle is relatively short. If you studied population changes in elephants the work would have to be carried out by generations of scientists. Butterflies (and moths to a lesser extent) are an extremely important group of ‘model’ organisms used to investigate many areas of biological research, including such diverse fields as navigation, pest control, embryology, mimicry, evolution, genetics, population dynamics and biodiversity conservation.

As many species of butterflies are highly specialized, individual species can be of particular benefit to science. For example, Europe’s meadow brown butterfly produces a natural antibiotic that may be useful for humans.

Monarch butterflies choose specific plants, like milkweed, as food for their larvae. They lay eggs on toxic leaves ready for the caterpillars to emerge and eat. This reduces parasites in larvae and caterpillars and stops predators from eating them. This results in more caterpillars surviving and becoming butterflies, increasing the monarch population. Scientists are investigating how plants with anti-parasitic properties like milkweed could benefit people. Every butterfly and moth has developed its own suite of chemicals to deter predators and parasites, find a mate, and overcome the chemical defences of its host plant. Each of these chemicals has a potential value that science could reveal.

6. Butterflies are beautiful and fascinate people

A species or type of wildlife does not have to justify its existence by being attractive to humans! Slugs, antlion larvae and Marabou storks are vital parts of biodiversity no matter what humans feel about them, their habits or their physical appearance.

But that being said, butterflies have fascinated humans since time immemorial. There are many references to butterflies and moths in literature, from the Bible through Shakespeare to the present day, and from poetry to musical lyrics. Butterflies are often portrayed as the essence of nature or as representing freedom, beauty or peace. Butterflies are used by advertisers and illustrators the world over as way of indicating that something is environmentally friendly. Naturalist and veteran broadcaster Sir David Attenborough maintains that time spent in nature, including just watching butterflies in a home garden, is good for our mental health. He is quoted as saying, ‘A few precious moments spent watching a stunning red admiral or peacock butterfly feeding amongst the flowers in my garden never fails to bring me great pleasure.’

People enjoy seeing butterflies both around their homes and in the countryside. The study of butterflies has been a common hobby, particularly in Victorian times. Butterflies provide enthusiasts with a great deal of pleasure. Like bird watchers, butterfly spotters are always on the lookout for a  rare species.

Over 10,000 people record butterflies and moths in the UK alone. Over 850 butterfly sites are monitored each week in the UK and collectively volunteers have walked the equivalent of the distance to the moon counting butterflies. Several hundreds of thousands of people garden for wildlife in the UK, many of them specifically for the protection and encouragement of butterflies and moths.

Butterflies can promote tourism. In recent years, butterfly tourism has increased in popularity as thousands of people travel abroad each year looking for butterflies and moths, seeking to enjoy the beauty of these insects in their natural habitat. 

In Texas, USA, there is an annual butterfly festival where you can see over 400 species of butterfly. This contributes to the local economy, with tickets costing hundreds of dollars. Eco-tours bring valuable income to many European countries and developing countries around the world (e.g. the valley of the butterflies in Rhodes and the Monarch butterfly roost in Mexico).

Videos about Zimbabwean Butterflies

Zimbabwean butterfly enthusiast James Wakefield has provided us with a wealth of information on butterflies in the following video.

SOURCES

“Five Reasons Why Butterflies Are Important & How to Help”, Wildlife Informer, https://wildlifeinformer.com/why-butterflies-are-important/

“How you can tell the difference between a butterfly and a moth”, Everyday Mysteries, https://www.loc.gov/everyday-mysteries/zoology/item/how-can-you-tell-the-difference-between-a-butterfly-and-a-moth/

“Why butterflies matter”, Butterfly Conservation,  https://butterfly-conservation.org/butterflies/why-butterflies-matter

“Six Reasons Why Butterflies are Important” by Keira Gaynor, Wildlife & Animals, https://www.ecoredux.com/butterflies-are-important

“Why Are Butterflies Important?” By Hayley Ames, Sciencing, https://sciencing.com/birds-drink-hummingbird-water-8164922.html

“What do Butterflies do for the Environment?” By Robert Korpella,   Sciencing, https://sciencing.com/butterflies-important-8749269.html

“Why butterflies are beneficial to the environment”,
https://www.environment.sa.gov.au › benefits-of-butterflies “Why Are Butterflies Important To The Ecosystem?, World Atlas, https://www.worldatlas.com/articles/why-are-butterflies-important-to-the-ecosystem.html