Some of the biodiversity of our planet now exists only in museums, due to continuing habitat destruction and climate change. With more than 380 million entomological specimens already preserved in museums (Johnson and Owens 2023), there is much work left to document what we already have. Fortunately, new advances in DNA sequencing have given us the opportunity to get enormous amounts of information from dried specimens on pins.
 
One such advance is HyRAD-X, which uses RAD-derived probes originally developed using RNA extracted from a selection of specimens with high RNA-integrity (Schmid et al. 2017). These exome-limited probes can then be used to capture low-integrity DNA extracted from a single leg from museum specimens, followed by Illumina sequencing of the enriched libraries.
 
Ground beetles allow an excellent demonstration of this approach, as their diversity, large size, and charismatic appearance has led to them being well represented in museums. Using a HyRAD-X probe set previously developed for a higher phylogeny within the subfamily Carabinae (Toussaint et al. 2021), the authors have now applied the same probe set to produce a comprehensive phylogeny for Arcifera, a clade of four subgenera and ten species within the genus Carabus (Pauli et al. 2024).
 
Of the 96 specimens that they started out with, 90% were from natural history collections and 40% dropped out immediately due to poor DNA extraction yield. After filtering the resulting sequence reads for minimum coverage and minimum number of samples per locus, they ended up with 35 museum specimens with an average of 793 loci. Phylogenetic analysis of this data supported the current classification of these beetles.
 
Pauli et al’s. (2024) study has effectively shown the power of HyRAD-X methods for applications at the species level. In-house production of probes makes the method accessible, expanding the opportunity to use museum specimens for population genetic research.

References

Johnson KR, Owens, (IFP. 2023) A global approach for natural history museum collections. Science 379,1192-1194(2023). https://doi.org/10.1126/science.adf6434

Pauli MT, Gauthier J, Labédan M, Blanc M, Bilat J, Toussaint EFA (2024) Museomics of Carabus giant ground beetles shows an Oligocene origin and in situ alpine diversification. bioRxiv, ver. 5 peer-reviewed and recommended by Peer Community in Zoology. https://doi.org/10.1101/2024.03.21.586057

Schmid, S., Genevest, R., Gobet, E., Suchan, T., Sperisen, C., Tinner, W. and Alvarez, N. (2017), HyRAD-X, a versatile method combining exome capture and RAD sequencing to extract genomic information from ancient DNA. Methods Ecol Evol, 8: 1374-1388. https://doi.org/10.1111/2041-210X.12785

Toussaint EFA, Gauthier J, Bilat J, Gillett CPDT, Gough HM, Lundkvist H, Blanc M, Muñoz-Ramírez CP, Alvarez N (2021) HyRAD-X Exome Capture Museomics Unravels Giant Ground Beetle Evolution, Genome Biology and Evolution, Volume 13, Issue 7, evab112, https://doi.org/10.1093/gbe/evab112

Some insects are known to be phytosanitary threats on a wide diversity of plants and can have important economic and ecological impacts in their native area. This is the case of some species within the jewel beetle subfamily Agrilinae (Coleoptera: Buprestidae), which are associated with broadleaf forest declines and diebacks (Jendek & Poláková, 2014). These thermophilous borers are expected to be favoured by climate change and the global deterioration of forest health, and ultimately expand their range and damage.  

Active flight plays a crucial role in the life strategies of most insects, facilitating essential activities such as mate searching, locating trophic resources, finding favorable environmental conditions, and dispersing to or colonizing new geographic areas (Dudley, 2002). Studying flight capacities provides valuable insights into the ecology of these species and helps estimate their ability to spread within new environments. Assessing the flight capacities of pest and alien species is therefore critical for evaluating their dispersal potential and for designing effective monitoring and control strategies. 

The study by Le Souchu et al. (2024) aimed to assess intra- and interspecific variability in active flight of several Agrilinae species and to evaluate the effects of sex and mass on this variability. Using computerised flight mills, they assessed the flight performance of twelve species, most of them associated with oaks. A key feature of the study is the extensive dataset used, which reveals significant variability in flight distance and capacity among species and individuals. Body mass positively influenced flight capacity in some species, while no sexual dimorphism was observed. The findings suggest a generally low average dispersal propensity within these species and highlight the critical role of rare, exceptional individuals in driving colonization and spread patterns at both population and species levels.

Overall, the study provides a valuable comparative analysis of flight behavior and performance in several Agrilinae species associated with oak forests. Because flight behaviour and performance of these insects are poorly known despite their critical role in dispersal inside and outside native ranges and their relevance for management purposes, this study contributes to filling this gap. From a broader perspective, the findings revealed several common traits among the studied species and provide insights into the influence of different factors on flight activity.

References

Dudley, R. (2002) The biomechanics of insect flight: form, function, evolution. Princeton University Press, Princeton, N.J. https://doi.org/10.1515/9780691186344

Jendek, E., Poláková, J. (2014) Host Plants of World Agrilus (Coleoptera, Buprestidae). Springer International Publishing, Cham. https://doi.org/10.1007/978-3-319-08410-7

Le Souchu, E., Sallé, A., Bankhead-Dronnet, S., Laparie, M., Sauvard, S. (2024) Intra- and interspecific variations in flight performance of oak-associated Agrilinae (Coleoptera: Buprestidae) using computerised flight mills . bioRxiv, ver.2 peer-reviewed and recommended by PCI Zoology https://doi.org/10.1101/2024.07.01.601558