Introductory Chapter: Lepidoptera Biodiversity and Conservation in the Twenty-First Century

1. Introduction

1.1 Biodiversity

Lepidoptera is one of the most widespread and extensively recognizable insect orders in the world. It is the second-largest and the most diverse order within the class Insecta. It is characterized into four distinct groups: butterflies, skippers, micromoths, and macromoths. It includes 126 families, 46 super-families, and 174,250 species. Of these, butterflies alone contribute 70,820 species. They are scattered worldwide excluding Antarctica. It signifies 10% of the total defined species of living organisms. They are a symbol of beauty and grace (Figure 1) [1, 2, 3].

Figure 1.

General criteria of the pyramid for taxonomic rank of Lepidoptera with examples [4, 5, 6].

2. Conservation

Lepidoptera species globally are confronted with a multitude of challenges, ranging from habitat loss, degradation to climate change, invasive species, intensified agriculture, afforestation, fragmentation, limited host plant availability, inadequate nectar sources, disruption of ecological interactions, unsustainable resource use, pollution, the expanding human population, overconsumption of resources, and various other anthropogenic factors. These challenges have contributed to the deterioration of ecosystems and pose a significant threat to the survival of these species. In the twenty-first century, one of the most pressing challenges they face is the reversal of biodiversity decline and the restoration of ecosystems. Recognizing the urgency, the European Agenda 2030 emphasizes the priority of biodiversity conservation. Consequently, it is essential to develop specific conversation tools, including action plans for threatened species, assessment protocols for sustainable agriculture, and models for prioritization of species and areas. In conclusion, effectively addressing the numerous challenges faced by Lepidoptera species and implementing comprehensive conservation measures are imperative to reverse the decline in biodiversity and restore ecosystems. Current policies exhibit significant gaps in protecting Lepidoptera biodiversity, emphasizing the need for urgent action and holistic approaches.

3. Variability

Lepidoptera have great variability in size depending on generation, latitude, altitude, or climate. There are also variations in the wing ornamentation due to seasonal and geographical variations. They show sexual dimorphism, many species have differences between male and female, often minimal differences, but which can go in some species to a totally different coloring or ornamentation, such as in the common Azure, Polyommatus icarus (Rottemburg, 1775) [7, 8]. The black grass-dart butterfly, Ocybadistes knightorum Lambkin and Donaldson, 1994, is a species of butterfly belonging to the Hesperiidae family. This species exists only in New South Wales. Throughout the power source Boambee region, its availability is extremely constrained (Figure 2) [11, 12, 13].

Figure 2.

(i) Sexual dimorphism in the common Azure, Polyommatus icarus (Rottemburg, 1775); a: male; b: female; c: mating view from below, male on the left; (ii): limited distribution: d: black grass-dart butterfly, Ocybadistes knightorum Lambkin and Donaldson, 1994; (iii) geographic variability in the white admiral, Limenitis arthemis (Drury, 1773), e: subspecies, white admiral butterfly, L. a. arthemis (Drury, 1773); f: subspecies, the red-spotted purple, L. a. astyanax Butler, 1869; (iv) seasonal variability in map butterfly, Araschnia levana Linnaeus, 1758, g: spring form of A. levana; h: Prorsa summer form of A. levana; (v) the two forms of Apatura: i: the lesser purple emperor, A. Ilia Rhône 1969 form; j: purple emperor, A. clyta Rhône 1969 form; (vi) regardless of all these factors, there is always some individual variability, no two butterflies are ever the same; k: peacock butterfly, Aglais io (Linnaeus, 1758), classic specimen; l: A. io, an aberrant specimen [9, 10].

4. International Union for Conservation of Nature (IUCN)

Lepidoptera numbers are, universally, continuing to decrease [14]. The components that cause losses have been numerous although interdependent, but a lot of them remain to be entirely known [15, 16]. The Red List was created by the International Union for Conservation of Nature (IUCN) in 1964. After that, it has been utilized as a vital sign of the state of the global Lepidoptera biodiversity. The Red List can be employed as a tool to educate and inspire initiatives that might contribute toward the conservation of butterfly biodiversity, which is essential when you would like all of the species to live. They can serve as more than simply a list of Lepidoptera species and their state as a barometer of life. Governments use the Red List Index (RLI) to monitor how they are progressing toward goals all minimizing Lepidoptera biodiversity loss. The RLI displays variations in the cumulative mortality risk for Lepidoptera species. The mission and objectives of IUCN serve to promote and support communities across every continent in protecting the authenticity and variety of nature, as well as in ensuring that all uses that involve natural assets are fair and environmentally responsible. Extinct, extinct in the wild, critically endangered, endangered, vulnerable, on risk, data deficient, and not evaluated are some of the categories that consist of species on the Red List (Table 1). To keep track of all threatened species, the IUCN created the Red Data Book of Lepidoptera species. Through this book, the IUCN is trying to create awareness about the endangered Lepidoptera species [17, 18, 19].

Table 1.

The International Union for Conservation of Nature’s (IUCN) red list categories for species [17, 18, 19].

5. Red List 2022

The IUCN Red List, which is annually produced, is largely acknowledged as the most complete collection of data on the threat to extinction facing Lepidoptera species around the world. According to the IUCN Red List and the World Wildlife Fund (WWF) of the UK, the fact has been included that Lepidoptera species are declining (Tables 2 and 3) [17, 18, 19].

Table 2.

The world declining butterfly and skipper species according to the IUCN Red List [17, 18, 19].

Table 3.

The world declining moths species according to the IUCN Red List [17, 18, 19].

6. Conservation under climate change

Lepidoptera provides a vast range of ecosystem services, including pollination of flowers, which are also outstanding indicators of environmental quality, have a significant esthetic value, and provide enjoyment to public around the biosphere. Lepidoptera can be affected in many ways. Utmost frequently, species can be changed in their range, in distribution, and in population size. Additionally, Lepidoptera may alter their phenology in response to climate change, for example, as a consequence of changes in the climate, some species have already changed the entire geographic distance, typically relocating to higher latitudes or elevations. Butterflies and moths emerge earlier in spring due to high temperature. There are many examples of disturbance of vital interactions with prey and food plants. Though, additional implications from the changing climate are not yet fully understood. At present, there are many species in danger and are going to become extinct than ever before, placing biodiversity at a crossroads. Because connectivity and terrain availability are frequently scarce, if they have been even noticed, it is exceedingly difficult to establish conservation measures as a result of the extent to which anthropogenic activity has been ruined, degraded, and separated the landscape. Because many species and their ecosystems are less able to respond due in large part to anthropogenic terrorizations. It is particularly challenging to build successful preservation plans according to the problem of changing the climate. Preservation schemes must contain an environmentally climatic friendly adaptability element, either right from the beginning as well as a final optional subsequent addition [20, 21, 22, 23].

7. Conservation initiatives

Lepidoptera, predominantly butterflies and large moths, are prevalent goals for conservation efforts and serve as flagship species. They can offer assistance to expose the requirement for habitat and resource protection and the ecological value of invertebrates [24]. An alliance of participant aquariums, botanical gardens, museums, zoos, partner organizations, projects, and center was established in 2001 with the collaboration of local, federal, and state organizations to aid in the conservation of endangered, threatened, and vulnerable Lepidoptera species of North America. Habitats were also created to sustain them. Many of the partnerships formed through the initiative results of projects provide a chance to increase their conservation efforts. The conservation program has been developed for the benefit of Lepidoptera. Laboratories such as Special Projects Labs have been established in the McGuire Center for Lepidoptera and Biodiversity, which are the home to several butterflies’ conservation projects, of which one such popular project is the Mimi blue. For the conservation projects for butterflies and moths, no more space is required and it is easy for organizations of all sizes to participate [25, 26, 27].

8. Reintroduction, translocation, and captive breeding

The terms reintroduction, translocation, and captive breeding are sometimes used interchangeably, but in fact, they have distinct meanings. Reintroduction refers to the deliberate movement and release of a species within its native range after it has vanished. Translocation refers to the relocation of living things from one location to another through human intervention. As a result, it may be a method to introduce creatures back into the wild while also encouraging them to move outside of their natural area. The production of new individuals from animals kept in captivity is known as captive breeding. As a result, it may be a method of obtaining the source of the creatures for rebirth or relocation [28, 29, 30, 31].

9. Biodiversity heritage relicts

Numerous landscapes constitute the outcome of interactions between biological mechanisms, the economy, as well as a community’s social and administrative structures. Consequently, certain landscapes could include lingeringly degraded habitats hosting evidence of former biodiversity as a result of human-induced alterations throughout history, which are known as biodiversity patrimony relicts [32].

10. Habitat restoration

The habitat restoration of Lepidoptera is a recent concept in human history. In order to ensure that native Lepidoptera and humans may continue to use the land, disturbed habitats must be identified and their native Lepidoptera must be restored. It works to restore regions where the habitat has been destroyed. It is a major contributing component in the global extinction crisis facing Lepidoptera species. The typical abundance and distribution of Lepidoptera species in the habitats are altered by its destruction. If the land is to remain productive in the future, repair of all these forms of disruptions is necessary. It is significant for a variety of reasons, including pragmatism, economics, and esthetics. Restoring habitats can facilitate the return of Lepidoptera to disturbed areas for the sake of recreational activities or for its own sake. By restoring biotic (e.g., species composition, interspecies interactions) and abiotic (e.g., disturbance, soil chemistry, and water content) elements to historical levels, it is possible to protect, manage, and restore plants, which are important elements for the restoration of butterflies and moths species. Restoration of ecosystems in the right way shows that there were once many species in the region instead of only one in monoculture. For reestablishment of flora, soil conditions are crucial, because they will decide what will grow and where. Aeration, mineral content, soil moisture, and the presence of microbes are all significant aspects to take into account for habitat restoration [33, 34, 35].

11. Citizen Science

For changing our environment, over large geographic areas, Citizen Science is proving to be an operative tool in tracking the rapid pace. It is widespread progressively attractive in regions like North America as well as in a few European nations. Public and school age participants have been engaged in gathering scientific data to promote long-term environmental monitoring. The Citizen Scientists are generally those volunteers who participate in such schemes. More recently, volunteers are used by the Irish butterfly and the bumblebee monitoring programs to collect information regarding detections involving these species. Most of the aforementioned networks as well as projects have as their major objective the gathering of information necessary for monitoring shifts within the variety and growth of Lepidoptera. In Green wave, youngsters engage in investigation-based learning scientific endeavors that are both simple and practical. Altogether, several diverse networks aid toward spreading an understanding about serious ecological problems including the decline in biodiversity as well as the impact of climate change. Whereas concurrently, the children, school pupils, and general population promote the development of scientific skills. Furthermore, they provide scientific data which have great value, by which we can track the environmental changes for improvements toward preserving the biodiversity of Lepidoptera [36, 37, 38].

12. Genetic diversity: a case study of the threatened large blue butterfly, Maculinea arion

In reintroductions, an imperative factor is the amount of genetic diversity captured, when introducing the individuals of Lepidoptera in the environment. When populations of Lepidoptera are introduced, at first they are very small, and thus are susceptible to stochastic events and genetic drift. The degree of genetic diversity that has been retained is important for populations’ long-term survival and their ability to adapt to climate change through evolution. Many European nations have observed the loss of numerous butterfly species on a national level. The great blue butterfly, Maculinea arion (Linnaeus, 1758), which was once extinct in the UK in 1979, was later brought back from Sweden due to its global vulnerability. On five sites in the UK and seven sites on Oland, including the source population, the genetic diversity of the reintroduced M. arion over 19 generations after translocation was examined. The reintroduced and source populations showed comparable levels of genetic diversity, however, the UK and Swedish groups showed genetic differentiation. Significant genetic heterogeneity between recently arrived UK groups that were only a few kilometers apart was also discovered. Several private alleles that were not present in the source population in 2011 were present in the reintroduced groups. As a result, they already comprise a distinct subset of M. arion’s northwestern populations’ genetic diversity. The findings demonstrated that for this species, the IUCN and other guidelines used in the 1990s for relocation and maintaining the greatest amount of genetic variety during reintroductions were essentially acceptable. It will, therefore, be helpful for guiding the expanding use of reintroductions as a tactic for the conservation of endangered Lepidoptera species (Figure 3) [39].

Figure 3.

Studying the genetic diversity of reintroduced and source populations to evaluate reintroduction plans: A case study of the threatened large blue butterfly, Maculinea arion (Linnaeus, 1758) [39].

13. Conclusion

In reality, Lepidoptera species are declining worldwide. The IUCN, WWF, and other associations are trying to combat diminishing of Lepidoptera species. The intimidations and challenges to Lepidoptera conservation and recovery continue to grow. As the number of targeted species-specific recovery programs has been initiated with involving the integration of ex-situ and in-situ components. For the conservation of Lepidoptera species, great efforts have been mandated with significant commitments of funds, labor, and time. Nevertheless, it is also needed to involve the government to achieve identified recovery targets. Conservation techniques must improve the use of evaluations supported by evidence and utilize them more effectively for systematic preparation in order to accomplish the best restoration achievements. Lepidoptera species preservation remains a young as well as an underdeveloped discipline in numerous aspects. The abundance of vertebrate-based examples, successes, and—possibly most importantly—lessons experienced must be used to its advantage.