Survey of the butterflies (Lepidoptera: Rhopalocera) species of the northern coast of East Java, Indonesia

Abstract. Arof AS, Barbosa FF. 2024. Survey of the butterflies (Lepidoptera: Rhopalocera) species of the northern coast of East Java, Indonesia. Intl J Trop Drylands 8: 83-94. The cosmopolitan order Lepidoptera Linnaeus, 1758, is one of the major orders of hexapods and a megadiverse clade of holometabolous insects. Within this order is included, the mostly diurnal butterflies (Lepidoptera: Rhopalocera: Papilionoidea sensu Kawahara and Breinholt 2014). The worldwide butterfly species richness is estimated to be ~18,768 species, distributed in ~1,815 genera and seven families. This group presents well-known ecologically important species that may serve as bioindicators. They are relatively well-studied, particularly in temperate biomes, although considerable gaps in information persist in tropical areas. The study area is classified as a tropical and subtropical moist broadleaf forest biome, specifically in the Eastern Java-Bali rain forests ecoregion in the Indo-Malayan realm, and is classified as a critical or endangered biome. More specifically, this area is located on the Java island, East Java province (Oriental Java), northern coast. Also, it is part of Sundaland, which is considered one of the major biodiversity hotspots. From October 2016 to August 2024, twice at a weekly, the authors employed the exploring method along with a visual encounter survey, observing, capturing, and documenting the species encountered to access the species composition. This study covers 126 species belonging to 85 genera, 41 tribes, and 17 subfamilies of five families, and this distribution in the frequency of species among families broadly reflects the global distribution of species of butterflies. This is the first field investigation to study the butterfly richness specifically on the northern coast of East Java. The present study contributes to the knowledge of the butterfly fauna in the Indonesian archipelago. Additionally, this study contributes to future studies of the conservation of biodiversity in this key endangered region. Moreover, this study can be the first step towards future studies focusing on community ecology, population dynamics, and the use of butterflies as bioindicators in the northern coast of East Java.