Dear Members of the Zoological Society of Japan

At the meeting of the Zoological Society of Japan Board of Directors held on Friday, June 5 at 2:00 PM, candidate papers for the 2020 Zoological Science Award were recommended by the Zoological Science Editorial Board. As a result of deliberation, the Board of Directors decided to confer the Zoological Science Award upon the following six papers.
The authors of the paper will be presented with a certificate and a cash prize of 50,000 yen.

Public Interest Incorporated Foundation, Zoological Society of Japan

Changing Leaf Geometry Provides a Refuge from a Parasitoid for a Leaf Miner
Haruka Aoyama, Issei Ohshima
Zoological Science 36(1): 31–37.
Field Ecology

This paper reports a previously unknown, simple, and effective defense mechanism in insects. Leaf-mining insects burrow inside leaves and feed on the interior as they grow. Apanteles watanabei, a parasitic wasp that preys on the larvae of the walnut leafminer—a leaf-mining insect—uses the host's mine trails as a clue to insert its ovipositor from the outside of the leaf and lay eggs. In response, the moth larvae fold the leaves while eating them, altering their shape and creating a three-dimensional space as they grow. As a result, the wasp's ovipositor is no longer long enough to reach the moth larvae, allowing them to escape parasitism. Based solely on behavioral observations in the field and laboratory, this is an outstanding study demonstrating that there are previously unknown battles in predator-prey relationships in the natural world.

Temperature Entrainment of Circadian Locomotor and Transcriptional Rhythms in the Cricket, Gryllus bimaculatus
Nisha N. Kannan, Yasuaki Tomiyama, Motoki Nose, Atsushi Tokuoka, Kenji Tomioka
Zoological Science 36(2): 95–104.
Behavioral Biology

The daily temperature cycle of day and night is known as a zeitgeber for the circadian clock second only to light, but many aspects of the mechanism by which temperature resets the clock remain unexplained. By designing an ingenious experimental schedule that separates temperature and light-dark cycles, this paper brilliantly demonstrated that the nocturnal cricket Gryllus bimaculatus initiates its activity one hour earlier under a temperature cycle than under a light-dark cycle, and that the expression rhythm of clock genes in the brain (optic lobes) entrains to the temperature cycle while maintaining its phase relationship with the locomotor activity rhythm. It also revealed that sensitivity to temperature changes varies depending on the type of clock gene. This is an important achievement backed by a vast amount of data toward elucidating future mechanisms.

The First Establishment of “Hand-Pairing” Cross-Breeding Method for the Most Ancestral Wing Acquired Insect Group
Masaki Takenaka, Kazuki Sekiné, Koji Tojo
Zoological Science 36(2): 136–140.
Field: Diversity and Evolution

Mayflies are an early-diverging lineage among winged insects, making them an important group for elucidating the evolution of insect flight and body plans. Using the crane-fly mayfly as a candidate model, the authors attempted a mating technique known as “hand-pairing,” which is used in Lepidoptera and other groups. Based on the evaluation of normal egg development rates, hatching success rates, and the genotypes of the offspring, they demonstrated the effectiveness of the “hand-pairing” technique in this species. This paper represents the first research achievement to establish a laboratory mating technique for a sexually reproducing mayfly species, and it is expected to greatly contribute to zoological research on mayflies and, by extension, winged insects. The selection of the crane-fly mayfly as a model candidate—which mates while resting on leaves, unlike many mayfly species that form swarms—is also highly commendable.

Life Cycle of the Japanese Green Syllid, Megasyllis nipponica (Annelida: Syllidae): Field Collection and Establishment of Rearing System
Toru Miura, Kohei Oguchi, Mayuko Nakamura, Naoto Jimi, Sakiko Miura, Yoshinobu Hayashi, Shigeyuki Koshikawa, M. Teresa Aguado
Zoological Science 36(5): 372–379.
Field: Developmental Biology

Annelids of the family Syllidae are known to exhibit a specialized mode of reproduction called fissiparity or stolonization, in which a part of the body detaches to reproduce (spawning sperm and eggs). However, the embryological mechanism by which a part of an individual becomes a complete organism remains completely unknown. Focusing on *Trypanosyllis krohnii* (green syllid), which widely inhabits Japanese coastal waters, this paper established methods for stable collection and rearing, and clarified its life history. There are still many taxa with unknown characteristics in the animal kingdom, and this paper deserves high praise for leading such a taxon into an experimental system applicable with the latest research methods, thereby broadly advancing zoology. Great developments in future evolutionary developmental biology research are highly anticipated.

Xenacoelomorph-Specific Hox Peptides: Insights into the Phylogeny of Acoels, Nemertodermatids, and Xenoturbellids
Tatsuya Ueki, Asuka Arimoto, Kuni Tagawa, Noriyuki Satoh
Zoological Science 36(5): 395–401.
Field: Diversity and Evolution

Xenacoelomorpha is a highly significant taxonomic group for considering the evolution of Bilateria, though its monophyly and phylogenetic position within the animal kingdom are still considered open to question. In this study, by comparing newly determined genomic information of the acoel *Convolutriloba longifissura* (or: a newly sequenced genome of the acoel Xenacoelomorph...) with homeobox gene sequences from public databases, the authors discovered a peptide sequence likely unique to Xenacoelomorpha in the predicted amino acid sequence of the Hox1 gene product, thus obtaining results supporting the monophyly of this taxonomic group. How the Hox gene group, which determines the anteroposterior axis of animals, evolved in bilaterians is of great interest.

Redescription of Synactinernus flavus for the First Time after a Century and Description of Synactinernus churaumi sp. nov. (Cnidaria: Anthozoa: Actiniaria)
Takato Izumi, Takuma Fujii, Kensuke Yanagi, Takuo Higashiji, Toshihiko Fujita
Zoological Science 36(6): 528–538.
Field

The genus Synactinernus of the family Sarcantheidae consists of a single species, the clover-like sea anemone, for which collection reports existed only in the original 1918 description paper. In recent years, some papers have considered it a junior synonym of the closely related genus Isactinernus and thus invalid, leaving the validity of the genus unsettled. This paper reports the discovery that sea anemone specimens collected from various locations in western Japan belong to the genus Synactinernus. Based on morphological and molecular phylogenetic analyses, the authors described a new species, Churaumi sea anemone, and established the taxonomic status of the genus. Furthermore, based on breeding records and other observations, they contributed to the understanding of ecological characteristics by confirming, for the first time in the family Sarcantheidae, transverse fission. The specimens used for the redescription of the genus Synactinernus were individuals previously kept as an unidentified species mainly at the Okinawa Churaumi Aquarium, and it is also noteworthy that the determination of this enigmatic genus, which had no collection reports for a century, was achieved through collaboration between the aquarium and researchers.