Egg hatching rate, survivorship, and sex ratio (Mean ± SE) of the <i>Ae</i>. <i>albopictus</i> HC, GUA and GT strains.

<p>^a Sex ratio was calculated as the proportion of females out of the total number of adults</p><p>Within a column, values followed by different lowercase letters were statistically different; ANOVA was performed for egg hatching rate, survivorship, and sex ratio analysis (P<0.05).</p><p>Egg hatching rate, survivorship, and sex ratio (Mean ± SE) of the <i>Ae</i>. <i>albopictus</i> HC, GUA and GT strains.</p

Developmental time (Mean ± SE) from L₁ to pupa formation and from L₁ to adult emergence of the <i>Ae</i>.<i>albopictus</i> HC, GUA and GT strains.

<p>Within a column, values followed by different lowercase letters were statistically different (P<0.05) using ANOVA and Tukey’s post hoc test analysis. Independent <i>t</i>-test was used to compare potential differences in the mean time to pupation and to emergence of males and females among the three strains studied (P<0.05).</p><p>Developmental time (Mean ± SE) from L₁ to pupa formation and from L₁ to adult emergence of the <i>Ae</i>.<i>albopictus</i> HC, GUA and GT strains.</p

Female fecundity (Mean ± SE) of the <i>Ae</i>.<i>albopictus</i> HC, GUA and GT strains.

<p>^a The number of females which laid eggs.</p><p>Within a column, values followed by different lowercase letters were statistically different (P<0.05) using ANOVA and Tukey’s post hoc test analysis.</p><p>Female fecundity (Mean ± SE) of the <i>Ae</i>.<i>albopictus</i> HC, GUA and GT strains.</p

Experimental design to test the ability of irradiated and non-irradiated HC <i>Aedes albopictus</i> females to spread <i>Wolbachia w</i>Pip into small cage GUA populations.

<p>Experimental design to test the ability of irradiated and non-irradiated HC <i>Aedes albopictus</i> females to spread <i>Wolbachia w</i>Pip into small cage GUA populations.</p

Adult survival curves for the <i>Ae</i>. <i>albopictus</i>HC, GUA and GT strains.

<p>Day number indicates time post-emergence. Kaplan-Meier curves were used to estimate the adultsurvivor function. A: Males only and fed on sugar; B: Females together with males and fed on sugar only; C: Females together with malesandfed on sugar and blood.</p

Effect of irradiation on the ovaries of <i>Aedes albopictus</i> HC strain.

<p>A: Normal egg-follicles in the non-irradiated ovary of the HC strain (30 ×). B, C and D: Gross morphological damage in ovaries of the HC strain after irradiation at 40 Gy (30 ×).</p

Residual fertility and induced sterility of HC and IHC <i>Aedes albopictus</i> males at different release ratios in the small cages.

<p>Residual fertility and induced sterility of HC and IHC <i>Aedes albopictus</i> males at different release ratios in the small cages.</p

The locations of <i>Aedes albopictus</i> larvae collected in the field of Guangzhou.

<p>The locations of <i>Aedes albopictus</i> larvae collected in the field of Guangzhou.</p

Combining the Sterile Insect Technique with <i>Wolbachia</i>-Based Approaches: II- A Safer Approach to <i>Aedes albopictus</i> Population Suppression Programmes, Designed to Minimize the Consequences of Inadvertent Female Release

<div><p>Due to the absence of a perfect method for mosquito sex separation, the combination of the sterile insect technique and the incompatible insect technique is now being considered as a potentially effective method to control <i>Aedes albopictus</i>. In this present study first we examine the minimum pupal irradiation dose required to induce complete sterility in <i>Wolbachia</i> triple-infected (HC), double-infected (GUA) and uninfected (GT) female <i>Ae. albopictus</i>. The HC line is a candidate for <i>Ae. albopictus</i> population suppression programmes, but due to the risk of population replacement which characterizes this triple infected line, the individuals to be released need to be additionally irradiated. After determining the minimum irradiation dose required for complete female sterility, we test whether sterilization is sufficient to prevent invasion of the triple infection from the HC females into double-infected (GUA) populations. Our results indicate that irradiated <i>Ae. albopictus</i> HC, GUA and GT strain females have decreased fecundity and egg hatch rate when irradiated, inversely proportional to the dose, and the complete sterilization of females can be acquired by pupal irradiation with doses above 28 Gy. PCR-based analysis of F₁ and F₂ progeny indicate that the irradiated HC females, cannot spread the new <i>Wolbachia w</i>Pip strain into a small cage GUA population, released at a 1:5 ratio. Considering the above results, we conclude that irradiation can be used to reduce the risk of population replacement caused by an unintentional release of <i>Wolbachia</i> triple-infected <i>Ae. albopictus</i> HC strain females during male release for population suppression.</p></div

Induced sterility and male mating competitiveness index of HC, IHC and IGUA <i>Aedes albopictus</i> males in the large cages at a 5:1 (sterile: fertile) ratio.

<p>Induced sterility and male mating competitiveness index of HC, IHC and IGUA <i>Aedes albopictus</i> males in the large cages at a 5:1 (sterile: fertile) ratio.</p