Learn about butterflies day: how the evolution of Lepidoptera contributed to a world full of colors

Today is the Learn about butterflies day! Let us dive a little bit into the evolutionary history of butterflies, and we can readily establish that indeed these insects should be celebrated! One of many reasons why, is the fact that without them, the world would not have been as brightly colored as it is now.

The order Lepidoptera

Lepidoptera, the order of insects which includes butterflies and moths, is one of the largest and most widespread insect orders in the world, with about 160,000 described species. In the last decades, research to Lepidoptera evolution has become more and more advanced (https://www.annualreviews.org/doi/pdf/10.1146/annurev-ento-031616-035125). The first research started in the 1970s with morphological studies, i.e., research into the shape and form of Lepidoptera species to classify them in different classes. Later, research advanced to the use of molecular techniques to acquire elaborate data on DNA sequences. This enabled researchers to classify about 46 superfamilies within the Lepidoptera group.

The oldest Lepidopteran fossil is from an organism living in the early Jurassic (193 million years ago). Unfortunately, the Lepidopteran fossil record is limited due to the high fragility of the scale-covered wings and bodies. Still, data suggests that the Lepidoptera order played a huge role in the large-scale radiation and diversification of angiosperms (flowering plants). Angiosperms are now the most diverse and largest group within the plant kingdom, with about 300.000 species, representing 80% of all known green plants. They are the plants that produce flowers and seeds.


But how can butterflies influence the formation of so many different species of flowering plants? This happened because of the process of coevolution. Coevolution is the evolutionary change of multiple populations or species as a result of the interactions between those populations or species. Butterflies feed on nectar, which could be produced by the angiosperms. Angiosperms are insect-pollinated plants, meaning that the transport of reproductive material relies on insect traffic going from one plant to another. So, both species groups depend on each other to survive and reproduce. This led to the opportunity for even more specific plant-pollinator  interactions. 

A pollinator can be generalized, i.e., it can feed on multiple species of nectariferous plants, or it can be specialized, i.e., it has specific features that are compatible with only one nectariferous species. The same applies for the plants, they can be pollinated by several species or they can be specialized and adapt in such a way that only one pollinator species can pollinate. Being a specializer, both as a pollinator and as a plant, comes with certain advantages. For the plant, pollination can become more efficient and less pollen is wasted. For the pollinator, a ‘private’ food source means less competition with other species. This ‘selective advantage’ to become specializers led to the great diversification of Lepidoptera (butterflies and moths) and angiosperms (flowering plants). 

Coevolution: P. apollo and its host plants

What does this mean for the Apollo butterfly and its host plants? The Apollo butterfly lives on open, rocky slopes and alpine meadows in the mountains. It is specialized to feed on the plants that occur in these habitats and the plants depend on the Apollo for pollination and thereby their reproduction. This shows the delicate interactive balance between flora and fauna in these ecosystems, and the necessity to preserve all the important actors.

So let’s celebrate today as The learn about butterflies day and take some time to appreciate their role in the evolution of flowers!

To extra celebrate the Apollo butterfly, you can now test your knowledge in a quiz! Browse our website for information if you do not know the answer and try to get as many points as possible. 

Who do you think came first, the butterfly or the flowering plant?

Öbb goes glyphosate-free: a win for Apollo!

What is glyphosate?

Glyphosate is the active ingredient used in herbicides. It is used for example in Roundup, from which you may have heard because it is a globally used and discussed herbicide. Glyphosate is a chemical compound that inhibits a certain enzyme in plants and is used to kill plants that are seen as weeds, especially in agriculture. Agricultural crops can be genetically engineered to be glyphosate-resistant, enabling farmers to use it without damaging their own crops.  But it is also used in, for example, home gardening and weed control by local governments in cities and villages. 

Glyphosate was first brought to the market to be used as herbicide in 1974 as Roundup by Monsanto in the United States. Now, glyphosate is one of the most widely used herbicides in the world. 

Glyphosate, trains, and half-time

The Austrian railway company, Öbb, used glyphosate to keep the train tracks free from plants. From 2022 onwards, they adapted an environment-friendly strategy of using glyphosate-free products. Where in 2021 Öbb used 5.3 tons of glyphosate on the train tracks, in 2022 this was zero. 

An interesting fact about glyphosate is that its ‘half-life’ (the time needed to reduce the initial amount by half) is typically about 47 days in the field (although this varies dependent on the type of soil). But if we take into account the 47 days, this would mean that now in the beginning 2024, two years later, there is only little glyphosate from the 5.3 tons of glyphosate sprayed in 2021 left, because the initial amount has halved about 17 times!  

Good news for P. Apollo and other insects

The decision to go glyphosate-free by the Öbb is good news for insects in Austria. Glyphosate not only destructs suitable habitats for butterflies and insects by killing the plants they feed and lay eggs on, it also impacts the fauna on a more chemical level. 

Glyphosate inhibits the production of Melanin, which is a pigment found in all life kingdoms. Melanin plays an important role in a diverse range of biological functions. For example, we produce melanin in our skin to for UV protection. In insects, melanin plays a crucial role in the immune system. During melanization (the process of making of melanin), several chemical components resulting from this process are used to defend the organism from harmful bacteria, fungi, and other pathogens. The inhibition of melanization leads to a higher susceptibility to pathogens in insects and thereby increasing mortality and decreasing population sizes.

The inhibition of melanin is only one reason why glyphosate is harmful for insects. Studies suggest that there are even more pathways of how glyphosate use leads to increased insect mortality. This highlights why it is such good news for PApollo and other insects that Öbb stopped using glyphosate.

Rest of Europe?

The debate in Europe about the use of glyphosate is still ongoing. Unfortunately, the European Commission has reauthorized the herbicide for another 10 years. There are several initiatives going on to legally challenge this decision, such as this one by the Pesticide Action Network Europe.

In Austria, the government voted for a partial ban on glyphosate in 2021, meaning that there is a usage ban in ‘sensitive’ areas and for private use. However, the professional use of glyphosate, including agriculture, remains allowed. 

Hopefully, more companies will independently decide to stop using glyphosate, just as Öbb did!

Do you want to know more about the effect of glyphosate on insects? Leave a comment!