Artificial selection, pre‐release diet, and gut symbiont inoculation effects on sterile male longevity for area‐wide fruit‐fly management

Abstract

Longevity is an important life-history trait for successful and cost-effective application of the sterile insect technique. Furthermore, it has been shown that females of some species -e.g., Anastrepha ludens (Loew) (Diptera: Tephritidae) -preferentially copulate with 'old', sexually experienced males, rather than younger and inexperienced males. Long-lived sterile males may therefore have greater opportunity to find and mate with wild females than short-lived males, and be more effective in inducing sterility into wild populations. We explored the feasibility of increasing sterile male lifespan through selection of long-lived strains and provision of pre-release diets with added protein, and inoculated with bacterial symbionts recovered from cultures of the gut of wild Anastrepha obliqua (Macquart). Artificial selection for long-lived A. ludens resulted in a sharp drop of fecundity levels for F1 females. Nevertheless, the cross of long-lived males with laboratory females produced a female F1 progeny with fecundity levels comparable to those of females in the established colony. However, the male progeny of long-lived males*laboratory females did not survive in higher proportions than laboratory males. Provision of sugar to A. obliqua adults resulted in increased survival in comparison to adults provided only with water, whereas the addition of protein to sugar-only diets had no additional effect on longevity. Non-irradiated males lived longer than irradiated males, and supplying a generic probiotic diet produced no noticeable effect in restoring irradiated male longevity of A. obliqua. We discuss the need to evaluate the time to reach sexual maturity and survival under stress for long-lived strains, and the inclusion of low amounts of protein and specific beneficial bacteria in prerelease diets to increase sterile male performance and longevity in the field.

Medfly Gut Microbiota and Enhancement of the Sterile Insect Technique: Similarities and Differences of Klebsiella oxytoca and Enterobacter sp. AA26 Probiotics during the Larval and Adult Stages of the VIENNA 8D53+ Genetic Sexing Strain

“…The incorporation of gut bacteria as probiotics in tephritid diets has recently received attention due to its great potential to improve the “quantitative” and “qualitative” parameters of the mass-reared strains. Most of the studies have been performed in medfly and specifically in the VIENNA 8 GSS ( Niyazi et al, 2004 ; Ben Ami et al, 2010 ; Gavriel et al, 2011 ; Hamden et al, 2013 ; Augustinos et al, 2015 ) and very few in other species, such as B. oleae ( Sacchetti et al, 2014 ), B. tryoni ( Meats et al, 2009 ), Z. tau ( Khan et al, 2014 ), and A. obliqua ( Rull et al, 2015 ).…”

“…More recently, the provision of a naturally occurring gut symbiont of B. oleae ( Pseudomonas putida ) did not confer any advantage regarding adult longevity but was beneficial for female fecundity when tested under dietary restricted conditions ( Sacchetti et al, 2014 ). Finally, in A. obliqua , adult feeding with an uncharacterized bacterial cocktail deriving from total gut extract did not have any positive effect on adult longevity ( Rull et al, 2015 ).…”

Demography of a genetic sexing strain ofAnastrepha ludens(Diptera:Tephritidae): effects of selection based on mating performance

“…For example, in C. capitata and D. melanogaster , longevity is negatively associated with reproductive traits, such as courtship (Cordts & Partridge ; Papadopoulos et al ., , ), mating (Partridge & Farquhar, ; Fowler & Partridge, ; Chapman et al ., , ; Carey et al ., ; Papanastasiou et al ., ) and fecundity (Müller et al ., ). In A. ludens , artificial selection for longevity reduced fecundity levels (Rull et al ., ). According to our findings, mating‐based selection resulted in offspring with higher fecundity rates and lower life expectancies.…”

Artificial selection on mating competitiveness ofAnastrepha ludensfor sterile insect technique application

“…Inadvertent selection on other traits, inbreeding, and genetic drift could counteract the effect of selection. Based on previous results (Harris et al, 1986;McInnis et al, 2002;Rull et al, 2015;Bosa et al, 2016;Quintero-Fong et al, 2016), the potential of selection in colony management to improve field performance of sterile males could not be discarded, but questions regarding the optimal population size and selection strength should be addressed.…”

“…Our results suggest that selection on mating competitiveness might result in a trade-off with other biological attributes, such as survival and reproduction. Perhaps these traits are polygenic and the selection could have resulted in epistatic and/or pleiotropic processes (Miyatake, 1998;Carey et al, 2005;Jalvingh et al, 2014;Rull et al, 2015). Despite the unexpected changes in survival and reproduction through rearing generations, the differences between wild and mass-reared flies were sustained.…”