bioRxiv Science⌕ Search

Biology subjects

Lach, L.

Publications and source records attributed to Lach, L..

2 recordsLinked to original sources
bioRxiv2022

Invasive terrestrial invertebrate detection in water and soil using a targeted eDNA approach

O_LITerrestrial invasive invertebrates can rapidly colonize new areas, causing detrimental effects on biodiversity, economy, and lifestyle. Targeted environmental DNA (eDNA) methods could constitute an early detection tool given their sensitivity to small numbers of individuals. C_LIO_LIWe hypothesized that terrestrial runoff would transport eDNA from the land into adjacent water bodies and used the invasive yellow crazy ant (Anoplolepis gracilipes) as a model species to test this hypothesis. We collected water samples from four waterbodies adjacent to infestations following rainfall events for eDNA analysis. We also collected soil samples from areas of known infestations and tested five eDNA extraction methods to determine their efficiency to extract eDNA from soil. C_LIO_LIWater samples resulted in positive yellow crazy ant eDNA amplification (20-100% field replicates across all sites), even at one site located 300 m away from where ants had been detected visually. Soil samples resulted in a high percentage of false negatives when sampled from ant transit areas than from nest entrances. C_LIO_LIUnpurified DNA extracts from soil also resulted in false negative detections, and only after applying a purification step of DNA extracts, we detected yellow crazy ant eDNA in 40-100% of field replicates across all methods and sites. C_LIO_LIThis is the first study to empirically show that eDNA from a terrestrial invertebrate can be successfully isolated and amplified from adjacent or downstream waterbodies. Our results indicate that eDNA has the potential to be a useful method for detecting terrestrial invertebrates from soil and water. C_LI

genetics↗
bioRxiv2022

Genome-wide SNPs reveal the social structure and invasion pathways of the invasive tropical fire ant (Solenopsis geminata)

Elucidating invasion pathways of invasive species is often challenging because invasive populations frequently have low genetic diversity caused by genetic bottlenecks during introduction events. Genome-wide sequencing such as Restriction Site-Associated DNA Sequencing (RADseq) can overcome these challenges by generating thousands of genome-wide single nucleotide polymorphic (SNP) markers. The tropical fire ant, Solenopsis geminata, is a global invader with low genetic diversity in its introduced range, making RADseq one of the best available methods to investigate its population genetics. We used double digest RADseq to generate 3,834 SNPs to compare the genetic diversity of S. geminata in its introduced range to its most likely source of introduction, determined the invasion pathways among populations at an unprecedented level of detail for this species, and determined the social structure of S. geminata workers collected in 13 locations worldwide. We found that introduced S. geminata went through a strong genetic bottleneck. We also identified multiple secondary introduction events among S. geminata populations, indicating that the bridgehead effect is an important driver in the global spread of this species. We found that all colonies in the introduced range were polygyne (i.e., with more than one queen) which may increase their invasion success and potential to cause adverse effects.

genetics↗