Effect of <i>Providencia rettgeri</i> (suspension at 1 and 2%) on egg to pupae recovery.

<p>Control corresponds to non infected eggs. Male represent brown pupae and Female represent white pupae. Each bar shows mean percentage ± SE.</p

The relative density of cDNA amplicons of <i>Cecropin</i> gene expression (Log₂ transformed fold) in infected post-mating <i>Ceratitis capitata</i> males and females compared to virgin ones.

<p>Each bar shows mean ± SE. Different symbols correspond to a significant difference, (*) for the females (F) and (#) for the males (M), (Multivariate analysis, MANOVA).</p

Effect of mating status and infection by injection with <i>Providencia rettgeri</i> on male and female <i>Ceratitis capitata</i> mortality.

<p>Virgin infected flies are flies from experiment “Infection by injection”. Each bar shows mean percentage± SE. Different symbols correspond to a significant difference (LSD test) for the males (*) and (#) for females.</p

Evaluation of <i>Providencia rettgeri</i> pathogenicity against laboratory Mediterranean fruit fly strain (<i>Ceratitis capitata</i>)

<div><p>The Mediterranean fruit fly (medfly) <i>Ceratitis capitata</i> (Wiedemann) (Diptera: Tephritidae), is often referred to as the most severe agricultural pest. Its biological control is mainly through the Sterile Insect Technique (SIT). Colonization, mass-rearing conditions and the irradiation process impact the competitiveness of sterile males and disrupt symbiotic associations by favoring some bacterial species and suppressing others. Levels of <i>Providencia</i> species have been shown to fluctuate considerably in the gut of the medfly laboratory strain Vienna 8 under irradiation, increasing by up to 22%. This study aimed to determine the pathogenicity of <i>Providencia rettgeri</i> isolated from the gut of laboratory Vienna 8 medfly strains by examining the effects of 1) two different treatment doses on egg-hatching and development and 2) two infection methodologies (ingestion and injection) of male and female adults according to their mating status. Treatment of eggs with <i>P</i>. <i>rettgeri</i> (2%) significantly decreased the mean egg to pupae recovery rate. Our data showed significant high mortality in flies with both injection and ingestion after 24 hours without any effect of sex. Microbial counts demonstrated that the bacteria could proliferate and replicate in adult flies. There was a significant sex-dependent effect after infection, with mortality decreasing significantly for males more than females. <i>Providencia rettgeri</i> can be considered as a potential pathogen of <i>C</i>. <i>capitata</i>. Mating protected males and females against infection by <i>P</i>. <i>rettgeri</i> by triggering an immune response leading to double the levels of <i>Cecropin</i> being secreted compared to infected virgin adults, thus reducing the virulence of the bacteria.</p></div

Expression of 7 immune genes in <i>Ceratitis capitata</i> inoculated with <i>P</i>. <i>lilacinum</i> for the times analyzed (0h, 24h, 72h, and 144h).

The bottom and top “whiskers” represent minimum and maximum values, respectively. The thick line bisecting the box represents the median. The bottom and top of the box represent the 25th and 75th percentiles, respectively. Asterisks indicate a significant difference (* pS1 Data.</p

Average amounts of lipid, glycogen, and sugar in infected larvae (red) and non-infected larvae (blue) of <i>Ceratitis capitata</i>.

Error bars indicate the standard error. (*) indicates a significant difference between columns (P<0.05).</p

Variance Analysis tables of the complete linear models for the 7 genes of the study.

Variance Analysis tables of the complete linear models for the 7 genes of the study.</p

Digestive glycosyl hydrolase activities after fungal inoculation to <i>Ceratitis capitata</i> (24 to 144 hours post-inoculation).

Blue and red bars chart represent glycosyl hydrolase activities mg protein for non-infected and infected flies respectively. (A) β –galactosidase activities; (B) α-glucosidase activities; (C) α-galactosidase activities and (D) β–glucosidase activities. Substrates used: PNPaglu, PNPbglu, PNPagal, PNPbgal. Error bars indicate the standard error. (* p<0.05, ** p<0.01, *** p<0.001).</p

Effect of <i>P</i>. <i>lilacinum</i> on fecundity and fertility of <i>Ceratits capitata</i>.

(A) Bar chart illustrating the mean number of eggs laid by non-infected and infected females of C. capitata; (B) Bar chart showing the mean proportion of eggs that hatched from eggs laid by non-infected and infected females of C. capitata. Error bars indicate the standard error. (*) indicates a significant difference between infected adults and non-infected (p<0.05).</p

Digestive proteinase activities after fungal inoculation to <i>Ceratitis capitata</i> (24 to 144 hours post-inoculation).

(A) Blue bar charts represent azocaseinolytic activities per mg of protein for non-infected flies; red bar charts represent azocaseinolytic activities per mg of protein for infected flies. (B) Blue bar charts represent hemoglobinasic activities per mg of protein for non-infected flies; red bar charts represent hemoglobinasic activities per mg of protein for infected flies. Error bars indicate the standard error. (* p<0.05, ** p<0.01, *** p<0.001).</p