How can we quantitatively study insects whose larvae live beneath the forest floor? A case study at an experimental long‐term log‐removal site in Japan

This study quantified the numbers and sex ratio of adult Sericania hidana (Coleoptera: Scarabaeidae) in a subalpine forest in 2017. Data from an area littered with coarse woody debris (CWD) created by a typhoon in 1959 were compared with those from an area where CWD had been cleared by salvage logging. Three types of traps were used: flight interception traps (FITs) with a black light, pitfall traps (PITs), and soil emergence traps (SETs). Carbon and nitrogen stable isotopes were analyzed to evaluate S. hidana diets and habitats. Overall, there were more S. hidana in the unsalvaged sites than in the salvaged sites. The FITs captured only males but SETs captured both males and females. The SETs on CWD captured more S. hidana than did SETs on soil in both the salvaged and unsalvaged sites. The PITs captured only a few individuals; thus, PITs are not suitable for studying this insect, although such traps were previously reported to capture S. hidana adults. Stable isotope analyses suggested that S. hidana feeds on a variety of plant materials, including living plants and CWD. These results suggest that CWD has long‐term effects on insect populations. Soil emergence traps provide an effective method to quantitatively evaluate insect ecology, and FITs can effectively screen for the existence of insects.     

A simple microsphere-based mold to rapidly fabricate microwell arrays for multisize 3D tumor culture

Three-dimensional (3D) tumor has been considered as the best in vitro model for cancer research. In recent years, various methods have been developed to controllable prepare multisize 3D tumors. Nonetheless, reported technologies are still problematic and difficult to produce 3D tumors with highly uniform size and cell content. Here, a novel and simple microsphere-based mold approach is proposed to rapidly fabricate spherical microwell arrays for multisize 3D tumors formation, culture, and recovery. Larger amounts of HepG2 3D tumors with excellent quality and uniformity can be efficiently generated using this method. In addition, the tumor size can also be simply controlled by adjusting the diameter of the microwell arrays. All experimental results indicated that the proposed method offers a promising platform to generate and recover highly controlled multisize 3D tumors for various cell-based biomedical research.     

Identification of a large SNP dataset in Larimichthys crocea using specific‐locus amplified fragment sequencing

The large yellow croaker, Larimichthys crocea, is a commercially important drum fish (Family: Sciaenidae) native to the East and South China Sea. Habitat deterioration and overfishing have led to significant population decline and the collapse of its fishery over the past decades. Today, the market supply of L. crocea depends solely on stocks produced in hatcheries and farms. Common issues that occur in the culture of L. crocea include germplasm degradation, precocious puberty, elevated disease susceptibility and growth retardation. In this study, we employed SLAF‐seq (specific‐locus amplified fragment sequencing) technology to identify single nucleotide polymorphism (SNP) loci across the L. crocea genome. Sixty samples were selected for SLAF analysis out of 1000 progeny in the same cohort of a cultured stock. Our analysis obtained a total of 151 253 SLAFs, of which 65.88% (99 652) were identified to be polymorphic, scoring a total of 710 567 putative SNPs. Further filtration resulted in a final panel of 1782 SNP loci. The data derived from this work could be beneficial for understanding the genetics of complex phenotypic traits as well as for developing marker‐selection‐assisted breeding programs in L. crocea.     

Macroinvertebrate community response to large-woody debris additions in small warmwater streams

Half-logs are a common restoration tool used to provide cover for fish in degraded streams. These structures may also provide a stable substrate for biofilm production and aquatic macroinvertebrate colonization. Half-logs (N = 108) were installed into nine streams of the upper Wabash River basin, Indiana, in July 2003 to examine changes in aquatic macroinvertebrate community composition and functional guilds under varying land-use types. Following installation, half-logs were colonized and showed statistically significant increases in both relative abundance and taxa richness of macroinvertebrates over time. The number of Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa collected from half-logs, as a percentage of total community composition, was positively related to the percentage of canopy coverage across streams and the relative abundance of shredder taxa utilizing half-logs decreased significantly with increasing canopy coverage. Forest streams exhibited significantly lower relative abundances of individuals colonizing half-logs (mean = 14.9 taxa/0.25 m²) than fallow field and agricultural streams (mean = 29.5 and 33.1, respectively). The percentage of pollution-tolerant taxa using half-logs was highest in fallow field streams (mean = 18.4%), followed by forest and agriculture systems (mean = 15.9% and 13. 9%, respectively). These results indicate that half-logs were colonized by aquatic macroinvertebrates and exhibited changes in community composition and functional feeding guilds over time and across land-use types. The extent of colonization and use of half-logs was largely dependent upon the pre-existing in-stream habitat quality and the predominant land-use type. Handling editor: R. Bailey