Countries all over the world are making efforts to secure their biological sovereignty and preserve their biological resources in various ways, such as by joining the Convention on Biological Diversity or adhering to the Nagoya protocol. In order to preserve the variety of organisms, it is very important to identify mutual relationships between biological factors and non-biological factors (environmental factors), as these can have considerable effects on the extinction or survival of a species.

Lepidoptera, including Sphingidae, is one of the largest taxonomic groups of insects. As it has high species abundance, it shows sensitive responses to changes in environments which are a non-biological factor, while also reflecting the environmental conditions of any given region. Additionally, Lepidoptera has a relatively short life cycle. Thus, many generations appear in a short time. It produces a large issue at one time and has relatively diverse habitats. Well-known taxonomic groups of Lepidoptera have been preferred indicators of various environmental changes (Erhardt 1985, Erhardt and Thomas 1991, Daily and Ehrlich 1995, Hill et al. 1995, Hill and Hamer 1998). Butterflies and moths that are active in the daytime out of Lepidoptera have been used as biological indicators. However, butterflies are not easy to catch and often appear only rarely in forest environments. On the other hand, many taxonomic groups of moths in Lepidoptera, which are active at night, are easy to collect by using light traps. As there are numerous species, they provide strong and diverse power of discrimination for detecting a range of effects on the ecology of a region (Holloway 1977, 1985). Additionally, moths in Sphingidae are larger than other moths and are therefore easy to observe. Furthermore, they are well known taxonomically (Holloway 1977, 1985) and have been used as models of living things in various diversity studies (León-Cortés et al. 1998). Therefore, moths in Sphingidae, which are active in the daytime and at night and for which a range of species exist, are considered to be a very good taxonomical group as biological indicators responding to environmental changes.

More than 1,000 species of moths in Sphingidae have been reported around the world (Carter 1992), and it has been reported that 33 Sphinginae species and 25 Macroglossinae species (58 species in total) have inhabited or presently inhabit in Korea (Paek et al. 2010). Maintaining a database of bio-organisms over time is the only way to secure bio-diversity and to identify distributions and life patterns in the past and present related to various environmental changes, such as weather changes. Thus, in this study, fluctuations in different species according to space and time are identified by collecting information on samples of Korean Sphingid moths housed in Korea to provide basic materials with which to identify causes of species abundance and to determine the distributions of various insects, including Sphingid moths, according to environmental changes.

To secure the basic materials used in this study, we contacted 15 national institutes, universities, and laboratories that were expected to have relatively abundant samples of Sphinginae moths. These institutions were selected out of domestic organizations which were known to house Sphingid moths. To obtain more accurate and reliable data, we have included at least one institute in each region. The number of selected institutions was 7 in Seoul and Gyeonggi-do, 1 in Gangwon-do, 3 in Chungcheongdo, 1 in Jeolla-do, 1 in Gyeongsang-do and 2 on Jeju Island (Table 1). We used sample information pertaining to a total of 53 species, or 21,414 individuals excluding samples that were less reliable in some way, such as missing or faulty information on the location grid or the year of the survey (Table 2).

There were 53 Sphingidae moth species housed in Korea. As 48 species and 47 species were found in Gyeongsangnam-do and Gangwon-do, respectively, it was considered that relatively diverse species were distributed in these areas. Comparatively, in Jeollabuk-do, only 36 species were found, and 39 species were found in Chungcheongbuk-do as well as in Jeju Island (Table 3). The number of individual Sphingid moths surveyed in Korea was found to be 21,414. With regard to the number of individuals per species, Ampelophaga rubiginosa was highest, at 2,483, followed by Theretra japonica (1,716), Callambulyx tatarinovii (1,457), Acosmeryx naga (1,340), Rhagastis mongoliana (1,191), Marumba sperchius (1,083), and Dolbina tancrei (1,072). The species which showed the fewest individuals were Sphinx caliginea and Hyles gallii, with as 1 and 2, respectively. By region, where the highest number of individuals found was in Gyeongsangnam-do (4,595), followed by Gangwon-do (3,648 individuals), Gyeonggido (3,011), Jeollanam-do (2,454), and Jeju Island (2,382) (Table 4).

If we see the distribution of Sphingid moths identified up to now, the most number such as 9,498 individuals of 52 species were identified after 2000. In 1990s, 6,027 of 49 species, in 1980s 4,332 individuals of 49 species, and, in 1970s, 937 individuals of 45 species were identified. It was confirmed that more species and individuals were identified as time went by (Table 5). Species and individuals of Sphingidae identified in Korea by region and by time do not exactly mean the current distribution or biomass of Sphingidae, as they were not surveyed and identified quantitatively in survey place or time. When checking the progress of appearance by year, 17 species including Agrius convolvuli had increased in the past and then decreased as time went by (Fig. 1 and Table 6). 33 species including Meganoton scribae have continuously increased up to present (Fig. 2 and Table 6). Sphinx caliginea, H. gallii, and Hemaris fuciformis were excluded from this report, as it was difficult to judge the progress of their appearance due to their small numbers of identified samples. All southern species, including M. saishiuana, Cephonodes hylas, A. castanea, T. nessus, and T. clotho, which inhabit southern areas including Jeju Island, show a tendency to increase in terms of their numbers of individuals over time. Species inhabiting middle or northern parts of the Korean Peninsula or those spread throughout the country, including Sphingulus mus, Ambulyx schauffelbergeri, and Mimas christophi, show lower numbers over time (Appendix 1).

The appearance of Sphingid moths by month was found to be relatively diverse, as they appear from February to November. By using appearance as the starting point, species which begin to appear in May numbered 26 in total, accounting for approximately half of all species. It was also found that 15 species started to appear in April, while only 3 started to appear in June. With regard to the ending point of their appearance, the number of species lasting until August was highest, at 23, with 17 for September and 5 for October. For the peak of appearance of Sphingid moths, 21 species showed the highest frequency of appearance in July, followed by 10 species in June, 8 in August, and 6 in May. For Sphinginae, most species apart from Langia zenzeroides nawai mainly appeared from spring to summer. On the other hand, many species in Macroglossinae, including Marcroglossum stellatarum, widely appeared regardless of the season, except for mid-winter. Although there were no major differences in terms of their appearance by month between species which show an increase and those which show a decrease, species in Macroglossinae appeared earlier and disappeared later than other decreasing species in the same family (Table 7 and Appendix 2).

When analyzing major habitats and distributions by year and month using the information on Sphingidae samples housed in Korea, the southern species M. saishiuana, C. hylas, A. castanea, T. nessus, and T. clotho, which mainly inhabit Jeju Island and the southern part of Korea, have increased over time. These species are distributed throughout Southeast Asia and in the southern part of China. Both of these areas have tropical climates with high temperatures and high humidity levels which last a long time (Kim et al. 1982, Park et al. 1999, Shin 2001). These species as well have been increasing in Korea in recent years. This indicates that the habitats of these species are gradually expanding. It was reported that Jeju Island and the southern part of Korea had at this point a subtropical climate (Kwon et al 2007, Kim 2008, National Institute of Meteorological Research 2009). This climate change affects temperatures and rainfall amounts, which have major impacts on changes in bio-distributions. Species inhabiting the middle or northern parts of the Korean Peninsula or all of Korea, including S. mus, A. schauffelbergeri, and M. christophi, decreased over time. Most of them also inhabit the Russian Far East and Siberia, Northern China, and Northern Japan (Kim et al. 1982, Park et al. 1999, Shin 2001). The aforementioned species seem to prefer drier and cooler areas to the areas of Korea. In Korea, they inhabit forests and mountainous areas at high altitudes rather than the sea shores and plains at lower altitudes. Thus, it is likely that they have a topical distribution in areas which have undergone moderate climate changes. Generally, the number of individuals of Sphingidae, inhabiting southern areas, increased, while those inhabiting mainly middle or northern areas or topically in mountainous areas throughout Korea decreased in number. Additionally, it was found that species distributed widely across the nation increased, whereas species relatively few in numbers of individuals and with relatively topical distributions relative to species with wide distributions were found to be decreasing in number. It was considered that more accurate reasons for these increases and decreases should be identified through various research methods in the future.

With regard to the monthly appearance of species which mainly inhabit Jeju Island and the southern part of Korea and show recent increases in the numbers of individuals, M. saishiuana appeared from May to August, the same period reported by Shin (2001), and this is similar to that reported by Park et al. (1999) (May to July). It was considered that this species appeared once annually in spring and summer. It mainly appears in June and July, which are hotter and more humid than May, showing the highest frequency of appearance in July. Cephonodes hylas appears from June to October, which is somewhat earlier than “July to September” as reported by Park et al. (1999) and “July to November” as reported by Shin (2001). This species seems to appear twice a year from early summer to late autumn. It was considered that it made its second appearance in August, when it showed the highest frequency of appearance. Ascomeryx castanea appears from April to August, which is different from “June to August” as reported by Park et al. (1999). It appears that some individuals of this species appear in spring, and the greatest number of individuals appears in July, after which the number of individuals gradually decreases in August. Theretra nessus appears from June to September, which is slightly earlier than “July to September” as reported by Park et al. (1999) and Shin (2001). Additionally, it showed the highest frequency of appearance in the hottest month, August. Theretra clotho appears from June to August, but it was found to appear in August by Park et al. (1999). In our survey, it showed the highest frequency of appearance in June rather than in August. In fact, it showed the lowest appearance frequency in August.

With regard to monthly appearances of the species inhabiting the middle or northern parts of the Korean Peninsula or topically all areas of Korea, S. mus appears from May to August, but this is slightly earlier than “June to July” and “June to August” as reported by Park et al. (1999) and Shin (2001), respectively. Additionally, it appears to show the highest appearance frequency in June, in midsummer. Ambulyx schauffelbergeri was found to appear from April to August, but Park et al. (1999) reported that it appeared from June to August. It was noted that very few individuals appeared in spring, individuals increased in number over time, the greatest number of individuals appeared in July, and the number of individuals gradually decreased in August. Mimas christophi appears from June to August, which is slightly later than “May to August” as reported by Park et al. (1999). Although it is difficult to determine the exact time of appearance because the surveyed individuals are very few in number, it is highly probable that they appear in May. The highest appearance frequency occurs in August, the hottest month.

On the other hand, species active until relatively late in the year, such as species with very early appearance times, including L. zenzeroides nawai, or species active in the daytime, such as Macroglossinae, can be used in phenological studies by examining their starting and ending appearance times. Furthermore, more detailed research should be conducted considering changes in various environmental elements, such as climate (temperature and rainfall), vegetation (the distribution of food plants), and the destruction of wildlife habitats.