The genome sequence of the red-headed cardinal beetle, Pyrochroa serraticornis (Scopoli, 1763)

We present a genome assembly from an individual male Pyrochroa serraticornis (the red-headed cardinal beetle; Arthropoda; Insecta; Coleoptera; Pyrochroidae). The genome sequence is 249 megabases in span. The majority (97.92%) of the assembly is scaffolded into 10 chromosomal pseudomolecules, with the X and Y sex chromosome assembled.


Background
Pyrochroa serraticornis (Coleoptera, Pyrochroidae), the red-headed cardinal beetle, is a medium-large (10-18 mm) dorsoventrally flattened beetle with serrate (female) to pectinate (male) antennae, soft elytra and has an abdomen that widens towards its posterior end.The red head, pronotum and elytra contrast against the black underside, legs and antennae, making this a conspicuous beetle in the field.As with other Pyrochroidae this beetle has a tarsal formula of 5-5-4 with penultimate tarsomeres bilobed (Cooter, 1991;Unwin, 1984).
Pyrochroa serraticornis is widespread across Wales and most of England, with a sparser distribution in northern and southwestern English counties (Alexander et al., 2015;Brock, 2019;Buck, 1954).As a result of its general ubiquity this beetle has been illustrated in many of the popular insect guides (Brock, 2019;Burton, 1968;Chinery, 1993;Lewington, 2019;McGavin, 2005).P. serraticornis is common in woodlands, hedgerows and boundary habitats where there is a supply of decaying wood for the larvae.Adults are often found on herbaceous vegetation within these habitats.
The larvae live under the bark of various tree species where they feed on other insects, fungal hyphae and decaying cambium (Hůrka, 2005).(Buck, 1954) highlights oak and beech as host trees while Cooter (1991) adds elm (Ulmus spp.) and a rare observation of swarming males also occurred around an elm stump (Constantine, 1995).Duffy (1946) reported she often found larvae "in rotten oak logs, felled elms, willows, pear trees etc.".
Pyrochroa larvae are distinctive, dorsoventrally flattened with forward pointing jaws and two prongs (urogomphi) extending backwards from a sclerotised plate at the end of the abdomen (Cooter, 1991;Duffy, 1946).Molfini et al. (2021) report that larvae of Pyrochroa serraticornis in central Italy are morphologically different to larvae described from Britain, raising the possibility that across Europe there may be more than one species within this taxon.The genome sequence presented here can be used to investigate whether P. serraticornis, as we currently recognise it, actually contains more than one species.

Genome sequence report
The genome was sequenced from one male P. serraticornis collected from Wigmore Park, Luton, UK (latitude 51.88378, longitude -0.36861422).A total of 26-fold coverage in Pacific Biosciences single-molecule long reads and 125-fold coverage in 10X Genomics read clouds were generated.Primary assembly contigs were scaffolded with chromosome conformation Hi-C data.Manual assembly curation corrected 44 missing/misjoins and removed 2 haplotypic duplications, reducing the assembly length by 0.15% and the scaffold number by 32.76%, and increasing the scaffold N50 by 65.39%.
The final assembly has a total length of 249 Mb in 39 sequence scaffolds with a scaffold N50 of 37.2 Mb (Table 1).The majority, 97.92%, of the assembly sequence was assigned to 10 chromosomal-level scaffolds, representing 8 autosomes (numbered by sequence length), and the X and Y sex chromosome (Figure 1-Figure 4; Table 2).The assembly has a BUSCO v5.1.2 (Manni et al., 2021) completeness of 99.5% (single 98.1%, duplicated 1.4%) using the endop-terygota_odb10 reference set.While not fully phased, the assembly deposited is of one haplotype.Contigs corresponding to the second haplotype have also been deposited.

Methods
A single male P. serraticornis was collected from Wigmore Park, Luton, UK (latitude 51.88378, longitude -0.36861422) by Duncan Sivell, Natural History Museum, using a net.The sample was identified by the same individual, and stored at 4°C for 2 hours before preservation on dry ice.Unfortunately, as this specimen was collected during a COVID-19 lockdown, no image was captured prior to preservation.
DNA was extracted at the Tree of Life laboratory, Wellcome Sanger Institute.The icPyrSerr1 sample was weighed and dissected on dry ice with tissue set aside for Hi-C sequencing.Table 3 contains a list of all software tool versions used, where appropriate.

Ethics/compliance issues
The materials that have contributed to this genome note have been supplied by a Darwin Tree of Life Partner.The submission of materials by a Darwin Tree of Life Partner is subject to the Darwin Tree of Life Project Sampling Code of Practice.By agreeing with and signing up to the Sampling Code of Practice, the Darwin Tree of Life Partner agrees they will meet the legal and ethical requirements and standards set out within this document in respect of all samples acquired for, and supplied to, data were generated from thorax tissue using the Arima Hi-C+ kit and sequenced on an Illumina NovaSeq 6000 instrument.

Manee M Manee
King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia The study involves constructing a genome assembly of the red-headed cardinal beetle, Pyrochroa serraticornis.The assembled genome spans 249 megabases, with 97.92% scaffolded into 10 chromosomal pseudomolecules, including the X and Y sex chromosomes.A combination of PacBio and Illumina sequencing reads was used.This high-quality genome data is significant for understanding the genetic makeup of this species and potentially identifying more than one species within this taxon.
Is the rationale for creating the dataset(s) clearly described?

Yeon Soo Han
Chonnam National University, Cheongju-si, Chungcheongbuk-do, South Korea The manuscript on "The genome sequence of the red-headed cardinal beetle, Pyrochroa serraticornis" is well written and organized with a solid data sets, and thus valuable for the future readers in general and scientific community.It thus appears that it may worth to be acceptable.However, I recommend the authors to rewrite the biological significance of the genome data on Pyrochroa serraticornis described in this manuscript.

Is the rationale for creating the dataset(s) clearly described? Yes
Are the protocols appropriate and is the work technically sound?Yes

Are sufficient details of methods and materials provided to allow replication by others? Yes
Are the datasets clearly presented in a useable and accessible format?Yes Competing Interests: No competing interests were disclosed.
Reviewer Expertise: Insect molecular biology, Funtional genomics of the beetle insect, Tenebrio molitor, Transciptomics and Genomics I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.
commonly known as the red-headed cardinal beetle.The combined used of PacBio and Illumina sequencing on a single male yielded a high quality genome assembly for one haplotype, while contigs for the alternative haplotype have also been assembled.There is really not much more to say, except that one is impressed by the technical advances made over the last two decades that makes it possible to so readily obtain such high quality data.It would have been nice if all the Coleoptera genomes I analyzed two years ago for neuropeptide genes would have been of the same quality.
Is the rationale for creating the dataset(s) clearly described?Yes Are the protocols appropriate and is the work technically sound?Yes

Are sufficient details of methods and materials provided to allow replication by others? Yes
Are the datasets clearly presented in a useable and accessible format?Yes Competing Interests: No competing interests were disclosed.
I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.

Figure 1 .
Figure 1.Genome assembly of Pyrochroa serraticornis, icPyrSerr1.1:metrics.The BlobToolKit Snailplot shows N50 metrics and BUSCO gene completeness.The main plot is divided into 1,000 size-ordered bins around the circumference with each bin representing 0.1% of the 249,414,617 bp assembly.The distribution of scaffold lengths is shown in dark grey with the plot radius scaled to the longest scaffold present in the assembly (50,529,459 bp, shown in red).Orange and pale-orange arcs show the N50 and N90 scaffold lengths (37,181,734 and 13,582,945 bp), respectively.The pale grey spiral shows the cumulative scaffold count on a log scale with white scale lines showing successive orders of magnitude.The blue and pale-blue area around the outside of the plot shows the distribution of GC, AT and N percentages in the same bins as the inner plot.A summary of complete, fragmented, duplicated and missing BUSCO genes in the endopterygota_odb10 set is shown in the top right.An interactive version of this figure is available at https://blobtoolkit.genomehubs.org/view/icPyrSerr1.1/dataset/CAJOSL01/snail.

Yes Are the protocols appropriate and is the work technically sound? Yes Are sufficient details of methods and materials provided to allow replication by others? Yes Are the datasets clearly presented in a useable and accessible format? Yes Competing Interests:
No competing interests were disclosed.

have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.
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