The sterile insect technique (SIT) is a pest control method that has been successful in controlling various species of fruit flies of economic importance worldwide. However, SIT procedures can affect the performance of mass‐reared sterile fruit flies, compromising the SIT effectiveness. This review aims to identify and analyze the adverse effects associated with each step of the SIT. Special emphasis is placed on identifying critical points in the SIT process that compromise the quality and highlighting the stages that require greater optimization to improve the effectiveness of the technique. We reviewed the main scientific findings that document the impact of domestication, mass‐rearing, irradiation, handling, and release on the biology, ecology, behavior, and genetic makeup of sterile males, and how they affect the performance of sterile males under natural conditions, and the effectiveness of the SIT. Although all stages of the Sterile Insect Technique (SIT) impose some degree of compromise on insect performance, domestication and mass‐rearing have the most profoundly negative impact on the field performance of sterile fruit flies. As the initial and most influential stages, they largely determine the overall quality and competitiveness of released insects, exerting a stronger impact than any subsequent SIT component.

The application of the sterile insect technique (SIT) requires the adaptation of insects to mass-rearing conditions. It is generally accepted that this adaptation may include a reduction in genetic diversity and an associated loss of desirable characteristics for the effective performance of sterile insects in the field. Here, we compare the genetic diversity of two mass-reared strains of the Mexican fruit fly, Anastrepha ludens, and a wild (WIL) population collected near Tapachula, Mexico, using seven DNA microsatellites as molecular genetic markers. The mass-reared strains were a bisexual laboratory strain (LAB) with approximately 130 generations under mass-rearing and a genetic sexing strain, Tapachula-7 (TA7), also under mass-rearing for 100 generations. Our results revealed an overall low level of genetic differentiation (approximately 15%) among the three strains, with the LAB and WIL populations being genetically most similar and TA7 most genetically differentiated. Although there were some differences in allele frequencies between strains, our results show that overall, the adaptation to mass-rearing conditions did not reduce genetic variability compared to the wild sample in terms of heterozygosity or allelic richness, nor did it appear to alter the level of inbreeding with respect to the wild populations. These results are contrary to the general idea that mass-rearing always results in a reduction in genetic diversity. Overall, our findings can contribute to a better understanding of the impact that adaptation to mass-rearing conditions may have on the genetic make-up of strains.

Male mating success depends on various traits and factors, and correctly identifying these traits can be key in the context of pest management. For tephritid pests, controlled through the sterile insect technique (SIT) traits, such as male size, can be manipulated through mass-rearing procedures. Thus, it is particularly important to understand whether male size can favor mating success. Here, we evaluated mating success of males of different sizes in Anastrepha ludens and Anastrepha obliqua, two species controlled through SIT. For both species, a morphometric analysis was performed of mated and unmated mass-reared and wild males in field cages. In both A. ludens and A. obliqua, wild females did not discriminate their mates based on male size and mated more frequently with wild males regardless of size. For mass-reared males, we found no evidence of an advantage of the large males compared to small males in mating success. However, we did find differences between the morphometric traits of mass-reared and wild males. In A. ludens, traits associated to mating success were Face Width (FW), Head Width (HW), Thorax Length (TL) and Wing Length (WL), and for A. obliqua were FW, HW, WL and WW (Wing Width). Overall, FW and TL were more consistent predictors of mating success. In conclusion, female choice seems to suggest multivariate selection, confirming that overall body size (expressed as pupal diameter, which is highly correlated with weight) is not a decisive factor in male mating success in these two species. However, morphological traits such as FW, HW, TL, WL and WW may be relevant in mating preference of wild female.

El tamaño corporal es uno de los rasgos más determinantes en la aptitud de los insectos. Para los programas de control de moscas de la fruta (Diptera: Tephritidae) que utilizan la técnica del insecto estéril, el tamaño es un indicador valioso de la calidad de los insectos de cría masiva. Sin embargo, la colonización en laboratorio y las condiciones de cría masiva pueden contribuir a la disparidad en los rasgos fenotípicos entre las poblaciones silvestres y de laboratorio, reduciendo el desempeño de los machos estériles y la efectividad de la técnica del insecto estéril. De aquí la relevancia de evaluar las posibles variaciones en el tamaño corporal (tamaño y forma) en dos especies económicamente importantes: Anastrepha ludens (Loew) y Anastrepha obliqua (Macquart). En este estudio, comparamos la distribución del tamaño de pupas de una población silvestre y de laboratorio, utilizando 3 parámetros: longitud, ancho y peso de pupas. Además, registramos el sexo de los adultos emergidos para determinar el dimorfismo sexual relacionado con el tamaño de la pupa. En A. ludens, las pupas de machos y hembras silvestres fueron más largas que las pupas de sus congéneres de laboratorio, mientras que las pupas de laboratorio fueron más anchas y pesadas que las pupas silvestres. En A. obliqua, las pupas de machos y hembras silvestres fueron significativamente más grandes que las pupas de sus congéneres de laboratorio en todos los parámetros de tamaño. Confirmamos el dimorfismo sexual en el tamaño de las pupas en ambas especies y en ambas poblaciones. Las hembras fueron más grandes que los machos en todos los parámetros de tamaño de pupa. Este estudio proporciona información útil acerca de las distribuciones del tamaño y el dimorfismo del tamaño de la pupa proporcionando datos de referencia con potenciales implicaciones y aplicaciones en la cría masiva de A. ludens y A. obliqua para la aplicación de la técnica del insecto estéril.