Meta‐transcriptomes of the microbial communities of the different developmental life stages of <i>Anastrepha ludens</i> (Diptera: Tephritidae)

The Mexican fruit fly, Anastrepha ludens, is a polyphagous pest that is a constant threat to US agriculture because of its proximity to citrus production in border region of the United States and Mexico. Sterile Insect Technique has been used to manage and eradicate of the Mexican Fruit Fly. SIT, however, requires millions of sterile male flies to be released each week from mass-rearing facilities. The mass-reared colonies must deal with microbial infections that reduce survivorship, fecundity and male-male competition. Meta-transcriptomics joins culturing and next generation DNA sequencing techniques to understand these changing microbial communities. This study uses advances in microbial meta-transcriptome sequencing to analyze the microbial communities from the four major developmental stages of A. ludens. The composition of the microbial communities was analyzed and revealed the large transcriptional presence of the phyla Microsporidia, a known animal pathogen. Clustering and ordination analyses revealed groupings based on developmental phase for egg, larvae and pupa. Adult samples had little clustering; a not unexpected result given the known turn-over in microbial community that occurs in the first 5 d after pupation. The transcriptional activity of three known pathogens of A. ludens between developmental phases were investigated. Two of the three pathogens had significant transcriptional differences between the phases with the larvae phase having the most activity. This increase in transcriptional activity agrees with culture-based surveillance and current mitigation strategies employed in the mass-rearing facility. This result reinforces the utility of transcriptomics in combating microbial threats.