Climate stress resistance in male Queensland fruit fly varies among populations of diverse geographic origins and changes during domestication

Background: The highly polyphagous Queensland fruit fly (Bactrocera tryoni Froggatt) expanded its range substantially during the twentieth century and is now the most economically important insect pest of Australian horticulture, prompting intensive efforts to develop a Sterile Insect Technique (SIT) control program. Using a “common garden” approach, we have screened for natural genetic variation in key environmental fitness traits among populations from across the geographic range of this species and monitored changes in those traits induced during domestication. Results: Significant variation was detected between the populations for heat, desiccation and starvation resistance and wing length (as a measure of body size). Desiccation resistance was correlated with both starvation resistance and wing length. Bioassay data for three resampled populations indicate that much of the variation in desiccation resistance reflects persistent, inherited differences among the populations. No latitudinal cline was detected for any of the traits and only weak correlations were found with climatic variables for heat resistance and wing length. All three stress resistance phenotypes and wing length changed significantly in certain populations with ongoing domestication but there was also a strong population by domestication interaction effect for each trait. Conclusions: Ecotypic variation in heat, starvation and desiccation resistance was detected in Australian Qfly populations, and these stress resistances diminished rapidly during domestication. Our results indicate a need to select source populations for SIT strains which have relatively high climatic stress resistance and to minimise loss of that resistance during domestication

Phenotypic and genotypic analysis for quality control of Wolbachia-infected Aedes aegypti in a dengue biocontrol program

© 2014 Dr. Heng Lin YeapThe transinfection of the primary dengue vector, Aedes aegypti mosquitoes with the maternally-inherited, endosymbiotic bacterium, Wolbachia, causes dengue transmission attenuation in the mosquito. Since Wolbachia induces cytoplasmic incompatibility (the conditional sterility which renders uninfected females sterile when mated to Wolbachia-infected males), Wolbachia-infected mosquitoes became promising candidates for population replacement of field mosquitoes with non-dengue susceptible Wolbachia-infected Ae. aegypti. Multiple Wolbachia infections have been introduced into Ae. aegypti, but only two have been trialled in the field to date, the virulent life-shortening wMelPop “popcorn” strain (year 2012) and non-virulent wMel strain (years 2011, 2013, 2014). Both strain originated from Drosophila melanogaster. Despite extensive work on laboratory fitness testing, field fitness testing has only just begun as field trials commenced. This dissertation aims to study several fitness traits such as body size and mating competition, while also develop protocols for field monitoring of released mosquitoes and Wolbachia dynamics. Ultimately, I hope to provide an estimate of fitness and also provide a different perspective into assessment methods of estimating parameters related to Wolbachia dynamics. The dissertation will begin with morphometric assessments, in particular body size and shape, which were measured via wing centroid size, wing size/thorax length ratio and wing shape. The first study which took place during the wMel-infected mosquito release in 2011 aimed to monitor released mosquitoes in comparison with field uninfected mosquitoes. I also established whether the measured morphometric traits displayed a trend with oviposition site seeking frequency. I also demonstrated the possibility of using size and shape as a proxy to assess quality of released mosquitoes. In the second study, I assessed the wMelPop-infected mosquito release in 2012 via comparing the frequency of ovipositing released infected females and field uninfected females. I also determined whether morphometric traits affected oviposition frequency among the released females. In the third study, the co-occurrence of mitochondrial variation with Wolbachia was assessed to determine whether monitoring mitochondrial variation could aid in understanding Wolbachia dynamics in the field. I also provided an extension to available models to assess specific scenarios that might be encountered during a field release. Finally, I assessed whether Wolbachia infection (wMel-infection) impacted mating competition, specifically whether uninfected females possessed the ability to evade the cost of cytoplasmic incompatibility. I discuss implications of the results and recommendations for future monitoring

Nucleotide alignment_ND4

Partial ND4 sequences. Labels match column B of "Sample_details_updated.xlsx". See comments in cell H1 for explanation of sequences labelled "...Assembly...

Boletín de Segovia: Número 148 - 1873 noviembre 3

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200

Assessing quality of life-shortening Wolbachia-infected Aedes aegypti mosquitoes in the field based on capture rates and morphometric assessments

Background: Recent releases have been carried out with Aedes aegypti mosquitoes infected with the wMelPop mosquito cell-line adapted (wMelPop-CLA) strain of Wolbachia. This infection introduced from Drosophila provides strong blockage of dengue and other arboviruses but also has large fitness costs in laboratory tests. The releases were used to evaluate the fitness of released infected mosquitoes, and (following termination of releases) to test for any effects of wMelPop-CLA on wing size and shape when mosquitoes were reared under field conditions.\ud \ud Methods: We monitored gravid females via double sticky traps to assess the reproductive success of wMelPop-CLA-infected females and also sampled the overall mosquito population post-release using Biogent Sentinel traps. Morphometric analyses were used to evaluate infection effects on wing shape as well as size.\ud \ud Results: Oviposition success as assessed through double sticky traps was unrelated to size of released mosquitoes. However, released mosquitoes with lower wing loading were more successful. Furthermore, wMelPop-CLA-infected mosquitoes had 38.3% of the oviposition success of uninfected mosquitoes based on the predicted infection frequency after release. Environmental conditions affected wing shape and particularly size across time in uninfected mosquitoes, but not in naturally-reared wMelPop-CLA-infected mosquitoes. Although the overall size and shape do not differ between naturally-reared wMelPop-CLA-infected and uninfected mosquitoes, the infected mosquitoes tended to have smaller wings than uninfected mosquitoes during the cooler November in comparison to December.\ud \ud Conclusion: These results confirm the lower fitness of wMelPop-CLA infection under field conditions, helping to explain challenges associated with a successful invasion by this strain. In the long run, invasion may depend on releasing strains carrying insecticide resistance or egg desiccation resistance, combined with an active pre-release population suppression program

Patterns of Variation in the Usage of Fatty Acid Chains among Classes of Ester and Ether Neutral Lipids and Phospholipids in the Queensland Fruit Fly

Modern lipidomics has the power and sensitivity to elucidate the role of insects’ lipidomes in their adaptations to the environment at a mechanistic molecular level. However, few lipidomic studies have yet been conducted on insects beyond model species such as Drosophila melanogaster. Here, we present the lipidome of adult males of another higher dipteran frugivore, Bactrocera tryoni. We describe 421 lipids across 15 classes of ester neutral lipids and phospholipids and ether neutral lipids and phospholipids. Most of the lipids are specified in terms of the carbon and double bond contents of each constituent hydrocarbon chain, and more ether lipids are specified to this degree than in any previous insect lipidomic analyses. Class-specific profiles of chain length and (un)saturation are broadly similar to those reported in D. melanogaster, although we found fewer medium-length chains in ether lipids. The high level of chain specification in our dataset also revealed widespread non-random combinations of different chain types in several ester lipid classes, including deficits of combinations involving chains of the same carbon and double bond contents among four phospholipid classes and excesses of combinations of dissimilar chains in several classes. Large differences were also found in the length and double bond profiles of the acyl vs. alkyl or alkenyl chains of the ether lipids. Work on other organisms suggests some of the differences observed will be functionally consequential and mediated, at least in part, by differences in substrate specificity among enzymes in lipid synthesis and remodelling pathways. Interrogation of the B. tryoni genome showed it has comparable levels of diversity overall in these enzymes but with some gene gain/loss differences and considerable sequence divergence from D. melanogaster

Sample_details

(relevant columns for ID). Column B lists all ID of samples that were considered, but not all were sequenced. Column F lists the labels in the ND5 fasta file. Column G lists the labels in the COI fasta file

Primer1

Sequence from region amplified by primer pair 1 (see Behura et al. 2011). Labels match column B of "Sample_details_updated.xlsx". See comments in cell H1 for explanation of sequences labelled "...Assembly...

Primer4

Sequence from region amplified by primer pair 4 (see Behura et al. 2011). Labels match column B of "Sample_details_updated.xlsx". See comments in cell H1 for explanation of sequences labelled "...Assembly...

Primer6

Sequence from region amplified by primer pair 6 (see Behura et al. 2011). Labels match column B of "Sample_details_updated.xlsx". See comments in cell H1 for explanation of sequences labelled "...Assembly...