Conference Agenda

Rhipicephalus australis (Australian cattle tick) was introduced to Australia with Brahman cattle and belongs to a cryptic species group with R. annulatus and R. microplus. The tick microbiome is a target for control strategies, but few studies have investigated discrete tissues of R. microplus and no studies have utilised an un-biased metagenome approach.

Gut and salivary gland (SG) tissues were dissected from 60 semi-engorged adult female ticks, 3 replicates for each tissue. DNA was sequenced using the PromethION 24 (ONT) long read sequencer with adaptive sampling to deplete the tick genome. Tick and bovine reads were removed by mapping against relevant genomes (Minimap2). Assembled reads were classified using Kraken2 and species abundance was determined with Bracken2.9.

There was no statistical difference in alpha diversity between gut and SG tissues (p = 0.4), but ordination analysis revealed differences in species composition between the tissues. While all samples were dominated by Escherichia coli, Clostridium botulinum and Babesia bigemina were confined to the gut and Coxiella-like endosymbiont (CLEAA) sequences were identified only in SG. Species of the genus Borrelia were also identified, warranting further investigation. The identification of endosymbiotic species provides a potential new target for cattle tick control.

Ticks and tick-borne diseases (TTBDs) pose a global challenge with (re)emerging diseases affecting humans and animals. To promote animal welfare and advance future research on TTBDs, artificial tick feeding system (ATFS) is becoming an important tool. Herein, we have systematically reviewed the current knowledge on ATFS used for soft and hard ticks. A critical appraisal of 196 articles published between 1912 and 2024 revealed that capillary feeding, membrane feeding systems and semi-automated membrane feeding systems have been used to study tick biology, complete life cycle of several tick species, tick-pathogen interactions, and discover drugs and anti-tick vaccine targets under controlled environment. The majority of studies (n = 123) have used a membrane feeding system as it resembles the tick feeding on animals. It appears that there is a need for (i) finding improved attachment stimuli to enhance the success rate of tick feeding, (ii) optimising conditions for different ticks and their life stages, and (iii) developing effective ways to control entomopathogenic fungal growth during prolonged blood feeding periods. Therefore, international collaborative efforts could be made to improve the utility of ATFS in studying TTBDs and promoting animal welfare.

Microinjecting double stranded RNA (RNAi) into insect embryos can target and degrade specific messenger RNA transcripts and therefore restrict protein production. Here, we use RNAi on a sheep blowfly ectoparasite, Lucilia cuprina, to identify novel targets for pest control applications. Candidate genes were identified using transcriptomic and proteomic analysis, generated from comparisons between larvae feeding directly on sheep with larvae feeding on control agar-based media. Eighty highly expressed genes on sheep-fed groups were identified, and these genes were further filtered using lethality and phenotypic data inferred from the model organism Drosophila melanogaster. RNA injection and silencing of two of these selected genes caused high embryo lethality or developmental arrest and death at the first instar larval stage (mortality rate >90%). Quantitative PCR confirmed RNAi lowered the expression of the targeted messenger RNA levels. Gene silencing was further confirmed using three independent double stranded RNA constructs targeting the same gene. These essential, insect-specific proteins could be used for developing new insecticides and /or provide the foundation for developing environmental-friendly RNAi biopesticides against this agricultural pest.

The Australian sheep blowfly, Lucilia cuprina dorsalis, is a major sheep ectoparasite causing subcutaneous myiasis (flystrike) which can lead to reduced livestock productivity and in severe instances, death of the affected animals. Additionally, this species serves as a primary coloniser of carrion, an efficient pollinator, and is used in maggot debridement therapy and forensic investigations. The identification of closely related species within the genus Lucilia is challenging using classical morphological methods, complicating the resolution of their population structure. In this study, we report the complete mitochondrial (mt) genome of L. c. dorsalis from the Northern Territory (NT), Australia, where sheep are prohibited animals unlike the rest of Australia. The mt genome is 15,943 bp in length, comprising 13 protein-coding genes (PCGs), two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and a non-coding control region. Phylogenetic analyses of 56 species/taxa of dipterans indicated that L. c. dorsalis and L. sericata are the closest among all sibling species of the genus Lucilia, which helps to explain species evolution within the family Luciliinae. This study provides the first complete mt genome sequence for L. c. dorsalis derived from the NT, Australia to facilitate species identification and examination of the evolutionary history of these blowflies.

The Australian sheep blowfly, Lucilia cuprina dorsalis, is a facultative ectoparasite whose larvae feed on the living tissues of domestic sheep in agricultural regions. In contrast, the closely related subspecies, Lucilia cuprina cuprina, is primarily found in urban areas and exhibits limited parasitic behavior. This study investigates the genetic and behavioral factors underlying the trophic adaptations of these two subspecies, aiming to identify genes and genomic regions associated with their physiological diversification and feeding habits. Behavioral assays were conducted to assess larval feeding preferences by measuring responses to different diets (rotten and fresh meat) at two temperatures (33ºC and 25ºC). These behavioral experiments, combined with comparative genomic analyses, aim to reveal potential differences in feeding behaviors between the subspecies. Our findings will enhance the understanding of the genetic mechanisms driving trophic specialization and the evolutionary processes contributing to the speciation of Lucilia cuprina.

The Australian sheep blowfly, Lucilia cuprina dorsalis, is a serious sheep parasite causing subcutaneous myiasis (flystrike) resulting in production losses, injury or mortality. Flystrike control relies heavily on breech modification surgery (mulesing) and insecticide treatments; however, widespread and accelerating resistance to existing insecticides is occurring with a limited understanding of the emergence of resistance alleles in Australian blowfly populations. An integrated genomics methodology, combining Oxford Nanopore Technologies (ONT) and Illumina sequencing with high-throughput chromosomal conformation capture sequencing (Hi-C), was used to achieve a chromosomal-level assembly of this important pest. The comprehensive assembly will provide valuable insights into the genetic makeup, evolutionary history, and potential mechanisms underlying key biological processes in L. c. dorsalis. Furthermore, the chromosomal-level genome facilitates the study of genetic variation within blowfly populations across the country, which is crucial for monitoring the emergence and spread of resistance alleles against control measures like insecticides.