Chung-Te Cheng

Lepidoptera are a highly diverse lineage of predominantly terrestrial insects, yet their larvae occupy diverse habitats where they may experience unexpected contact with water or accidental submersion. Such exposure may have favored adaptations that enable terrestrial lepidopteran larvae to survive underwater for short periods. Using a combination of personal and crowd-sourced observations, we document a striking diversity of behaviors displayed by Lepidoptera (32 species across 16 families) when suddenly exposed to water. This includes swimming, which we observed in 4 lepidopteran families. We developed a behavioral ontology comprising 9 distinct behaviors and 5 non-directional behaviors, each observed on the water surface. Our study highlights a largely overlooked dimension of Lepidoptera biology and establishes a framework for future research on the significance of this behavior.

A new subfamily of bagworm moths is described: Tenuipsychinae subfam. nov., to accompany the new genus Tenuipsyche gen. nov. and 2 new species, Tenuipsyche davisi sp. nov., and Tenuipsyche nishidai sp. nov., based on unique and unusual morphology, biology, and their phylogenetic position inferred via phylogenomic analysis of 13 mitochondrial protein-coding genes and 3 nuclear markers. The biology is highly distinctive in that the fungal-feeding larvae construct long, narrow bags permanently affixed to a substrate, rendering them sessile, a very unusual condition among the Psychidae. Furthermore, the genera Antillonatus, Acoremata, Guttulapsyche, and Lamyristis are transferred to Tenuipsychinae due to shared adult morphology. Species in the subfamily have winged female forms and appear to occur on most continents across the world within tropical and subtropical areas where many undescribed taxa are known. Phylogenetic analysis confirms that Tenuipsychinae is a monophyletic subfamily which forms a sister clade to the previously described female winged subfamilies Arrhenophaninae and Pseudarbelinae.

Before the present study, the family Metarbelidae in Taiwan was known for only one species, Marcopoloia discipuncta. During an investigation of the lepidopteran fauna of Kinmen island in 2022, a Stueningeria species that had never been reported by any of previous entomological studies on Kinmen was discovered. Based on the morphological characters distinct from other congeneric species, we determine the specimens from Kinmen as a species new to science. In addition, “Arbela dea" was often regarded as a timber pest in China and Taiwan. This species, however, has already been transferred to Marcopoloia and restricted to Myanmar. Another pest species, which has been misidentified as “Arbela baibarana” (a junior synonym of Marcolopoia discipuncta) in Chinese literature for long, is actually belonging to Stueningeria. We therefore consider the taxonomic identity of the Stueningeria in southern China needs to be clarified when sufficient specimens and molecular data become available.