Hokkaido Museum

Abstract We found a presumably new species that is closely related to Lordiphosa collinella but different from it in the range of host plants. Lordiphosa collinella is a generalist breeding on a wide variety of decayed herbaceous plants. In contrast, the new form almost specializes in breeding on Pachysandra terminalis . First, we delineate the latter specialist as a new species, Lordiphosa yuktopakina sp. nov. The hypothesis that they are sibling but distinct species is highly supported by studies of breeding ecology, morphology, genetic differentiation and reproductive isolation. Lordiphosa yuktopakina is estimated to have differentiated from L . collinella approximately 0.121 million years ago. For the ancestor of L . yuktopakina to use P. terminalis as an alternative host plant, the fly should have surmounted the hard texture of the host plant tissue. Lordiphosa yuktopakina has achieved this by making the ovipositor more robust and increasing the size of the cephalopharyngeal skeleton and the allometry of the mouth hook with larger teeth especially in the 1st instar larva. These adaptations to the newly acquired host plant should be reflected in the female reproductive traits. Thus, the two Lordiphosa species studied here provide a new instance of recent speciation with change and specialization to a particular host plant.

The Uchinami pluton, which is distributed upstream of the Uchinami-gawa River in Ono City, Fukui Prefecture, consists mainly of altered quartz diorite, granodiorite, and quartz monzodiorite. A previous study reported a Cretaceous K–Ar whole-rock date (106.5 Ma) of the pluton and interpreted it as one of the Cretaceous (post-Tetori–Pre-Nohi) plutonic rocks in the northern part of central Japan. We performed U–Pb dating of zircons from two rock samples of the Uchinami pluton and obtained weighted average 206Pb/238U dates of 189.3 ± 1.8 Ma and 189.7 ± 1.6 Ma (2σ). The difference between the U–Pb zircon dates and the K–Ar whole-rock date is ca. 80 million years, which is too long for the duration of cooling of the pluton from the crystallization of the zircons. Instead, the K–Ar whole-rock date presumably indicates the rejuvenation by the Miocene intrusive rocks (e.g. Arashimadake Cauldron). Thus, the Uchinami pluton is reasonably a member of the Jurassic Hida Younger Granite but not a Cretaceous pluton.

A super-rich and extremely diverse assemblage of insect fossils has been well-documented from mid-Cretaceous Kachin amber (ca. 99 Ma) in the Kachin State of northern Myanmar. In contrast, only four beetle (Coleoptera) species have formally been described from the slightly older Lower Cretaceous Hkamti (Khamti) amber (ca. 110 Ma), also originating from northern Myanmar’s Sagaing Region. The polyphagan beetle superfamily Staphylinoidea, encompassing approximately 75,000 species, is among the largest superfamilies in the animal kingdom. This study records 11 staphylinoid fossils, providing a comprehensive overview of the Hkamti amber biota. These fossils were classified into three families (Hydraenidae, Colonidae, and Staphylinidae). The highest paleodiversity was observed in the rove beetle family Staphylinidae; nine specimens from six staphylinid subfamilies (Osoriinae, Tachyporinae, Aleocharinae, Steninae, Solieriinae, and Scydmaeninae) were identified. With the exception of Steninae, all are reported for the first time from Hkamti amber. Notably, the discoveries of colonid, osoriine, aleocharine, and stenine (previously recorded) beetles represent the oldest known fossils for these groups. Additionally, the hydraenid and tachyporine fossils are the earliest biological amber inclusions reported for their respective familiy or subfamiliy. Three new species are herein described: Colonellus (Colonellus) hkamtiensis sp. nov. (Colonidae), Cretochirus elongatus sp. nov. (Staphylinidae: Osoriinae: Leptochirini), and Prosolierius antennatus sp. nov. (Staphylinidae: Solieriinae). These findings underscore the presence of a potentially diverse Staphylinoidea paleofauna in Hkamti amber, although it remains likely underestimated, warranting further investigation. This study highlights a striking similarity in entomofaunal composition between the Hkamti and Kachin amber deposits, supporting a previously suggested close affinity between the two. Additionally, the fossils described here provide valuable calibration points for future molecular dating analyses.

Phytodietus (Weisia) clavotibialis Shimizu & Konishi, 2018 (Hymenoptera: Ichneumonidae: Tryphoninae: Phytodietini) is a rare and poorly known Darwin wasp, previously known only from the female holotype collected in Japan. In this study, the male is described for the first time based on two specimens. One of these was reared from a tortricid leaf-roller moth feeding on Rhododendron reticulatum D. Don ex G. Don, marking the first host record for both the species and the subgenus Weisia Schmiedeknecht from Tortricidae. New distribution records from India and Taiwan extend the known range of P. (W.) clavotibialis and reveal a biogeographic pattern resembling that of its closest relative, P. (W.) pitambari Kaur & Jonathan, 1979. Partial sequences of mitochondrial CO1 and nuclear 28S rDNA genes were newly obtained, representing the first molecular data for Weisia, and were used in a preliminary phylogenetic analysis. Although the subgenus Euctenopus Ashmead was not included in our analysis, the molecular phylogeny recovered Weisia as the most basal lineage within the genus Phytodietus Gravenhorst, supporting its recognition as a distinct subgenus, while the monophyly of the subgenera Phytodietus and Neuchorus Uchida was not supported. Given the longstanding confusion and our results, it is concluded that these subgenera are best treated as a single subgenus; thus, Neuchorus syn. nov., together with its previously recognized synonym Doratistes Seyrig, is synonymized under Phytodietus. Additionally, P. (W.) clavotibialis appears to be associated with secondary natural environments characteristic of Satoyama landscapes, raising conservation concerns due to ongoing habitat degradation.

Ectoparasitic copepods in the genus Salmincola Wilson, 1915 are considered harmful to host salmonids, yet experimental studies on the mechanism by which these copepods affect hosts are critically limited. We evaluated the effects of the mouth-attaching Salmincola markewitschi Shedko & Shedko, 2002 on juvenile white-spotted charr Salvelinus leucomaenis (Pallas, 1814). We used a parasite removal experiment where all individuals were artificially infected, and then parasites were removed in one group (i.e., treatment), while the copepods were left in another group (i.e., control). We hypothesized that the copepods reduce host feeding, thereby reducing host body condition and growth. The alternative hypothesis is that parasites do not change host feeding, or even increase because of the compensation for the negative effect. In this case, host condition and growth would not be reduced. The control group had lower food consumption, body condition, and growth compared to the treatment. Thus, S. markewitschi negatively affected hosts by reducing host feeding, and no behavioral compensation was observed. It remains unknown, however, whether reduced feeding was due to impaired swallowing or physiological stresses caused by infections. Further experiments on gill- and body surface-attaching Salmincola species could provide deeper insights into how these parasites influence host health.

Evolutionary novelties are commonly identified as drivers of lineage diversification, with key innovations potentially triggering adaptive radiation. Nevertheless, testing hypotheses on the role of evolutionary novelties in promoting diversification through deep time has proven challenging. Here we unravel the role of the raptorial appendages, with evolutionary novelties for predation, in the macroevolution of a predatory insect lineage, the Superfamily Mantispoidea (mantidflies, beaded lacewings, thorny lacewings, and dipteromantispids), based on a new dated phylogeny and quantitative evolutionary analyses on modern and fossil species. We demonstrate a single origin of the raptorial foreleg and its associated novelties as key innovations triggering an early radiation of raptorial mantispoids from the Late Triassic to the Early Jurassic. Subsequently, the evolution of the raptorial foreleg influenced the diversification in different modes among lineages. At times, it might have limited the morphological diversity of other body parts and led to lineage constraint by intensifying competition and lowering environmental resilience, for example, in thorny lacewings, whose extant diversity is meager. Conversely, in mantidflies, reduced emphasis on foreleg novelties and increased plasticity in other body parts may lead to better adaptation to predator-prey interactions and environmental shifts, thus maintaining a stable or accelerated level of diversification. We also reveal how major environmental change and lineage interactions interplayed with raptorial novelties in shaping the significant oscillations of mantispoid diversification over deep time, especially the abrupt shift near the mid-Cretaceous. However, by excluding a substantial portion of samples from the mid-Cretaceous of Myanmar, these shifts of some evolutionary parameters, such as morphological disparity, body size, and diversification rates, became inconspicuous and might be overestimated due to sampling bias. Our results uncover the intricate evolutionary patterns and profound significance of raptorial specializations, providing new insights into the role of novelties in forming evolutionary trajectories, both for the better and worse.

The authors declare no competing interests.

Abstract Ectoparasitic copepods in the genusSalmincolaWilson, 1915 are considered harmful to host salmonids, yet experimental studies on whether and how these copepods affect hosts are critically limited. We evaluated the effects of the mouth-attachingSalmincola markewitschiShedko and Shedko, 2002 on juvenile white-spotted charrSalvelinus leucomaenis(Pallas, 1814) using a parasite removal experiment where all individuals were artificially infected, and then parasites were removed in one group (i.e., treatment), while the copepods were left in another group (i.e., control). We hypothesized that the copepods reduce host feeding, thereby reducing host body condition and growth. The alternative hypothesis is that parasites do not change host feeding, or even increase because of the compensation for the negative effect. In this case, host condition and growth would not be reduced. The control group (parasite remained) had lower food consumption, body condition, and growth compared to the treatment (parasite removed). Thus,S. markewitschinegatively affected hosts by reducing host feeding, and no behavioral compensation was observed. It remains unknown, however, whether reduced feeding was due to impaired swallowing or physiological stresses caused by infections. Further experiments on gill- and body-surface-attachingSalmincolaspecies could provide deeper insights into how these parasites influence host health.