Highlights d Cities possess a consistent ''core'' set of non-human microbes d Urban microbiomes echo important features of cities and city-life d Antimicrobial resistance genes are widespread in cities d Cities contain many novel bacterial and viral species

BackgroundPlant chemicals can affect reproductive strategies of tephritid fruit flies by influencing sex pheromone communication and increasing male mating competitiveness.Objective and MethodologyWe explored whether exposure of Anastrepha fraterculus males to guava fruit volatiles and to a synthetic blend of volatile compounds released by this fruit affects the sexual performance of wild and laboratory flies. By means of bioassays and pheromone collection we investigated the mechanism underlying this phenomenon.ResultsGuava volatile exposure enhanced male mating success and positively affected male calling behavior and pheromone release in laboratory and wild males. Changes in male behavior appear to be particularly important during the initial phase of the sexual activity period, when most of the mating pairs are formed. Exposure of laboratory males to a subset of guava fruit volatiles enhanced mating success, showing that the response to the fruit might be mimicked artificially.ConclusionsVolatiles of guava seem to influence male mating success through an enhancement of chemical and physical signals related to the communication between sexes. This finding has important implications for the management of this pest species through the Sterile Insect Technique. We discuss the possibility of using artificial blends to improve the sexual competitiveness of sterile males.

Although exposure to plants has been shown to influence sexual behaviour in a number of phytophagous insect species, a relatively small number of fruit flies have been investigated in that respect. Here, we evaluated the effect of exposure to the pulp of guava and mango and to essential oils emanating from glands in the flavedo area of lemons on the mating success of Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) males. We also evaluated different durations of exposure and the need for physical contact with the fruit. Results showed that exposure to guava increased the mating success of both wild and laboratory males relative to non‐exposed males. In addition, exposed wild flies copulated earlier than non‐exposed males. Physical contact with the fruit or ingestion of compounds was not a prerequisite for this phenomenon to occur, since just the exposure to volatiles resulted in a significant enhancement in mating success. Exposure to mango did not affect male sexual performance. In contrast, exposure to lemon for 1 day decreased mating success of males relative to unexposed males, whereas exposure for longer periods seemed to eliminate this effect resulting in comparable mating success rates between treated and untreated males. These results provide a better understanding of the sexual behaviour of this species and may also find application for its control.

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The sterile insect technique (SIT) has been proposed as an area-wide method to control the South American fruit fly, Anastrepha fraterculus (Wiedemann). This technique requires sterilization, a procedure that affects, along with other factors, the ability of males to modulate female sexual receptivity after copulation. Numerous pre-release treatments have been proposed to counteract the detrimental effects of irradiation, rearing and handling and increase SIT effectiveness. These include treating newly emerged males with a juvenile hormone mimic (methoprene) or supplying protein to the male's diet to accelerate sexual maturation prior to release. Here, we examine how male irradiation, methoprene treatment and protein intake affect remating behavior and the amount of sperm stored in inseminated females. In field cage experiments, we found that irradiated laboratory males were equally able to modulate female remating behavior as fertile wild males. However, females mated with 6-day-old, methoprene-treated males remated more and sooner than females mated with naturally matured males, either sterile or wild. Protein intake by males was not sufficient to overcome reduced ability of methoprene-treated males to induce refractory periods in females as lengthy as those induced by wild and naturally matured males. The amount of sperm stored by females was not affected by male irradiation, methoprene treatment or protein intake. This finding revealed that factors in addition to sperm volume intervene in regulating female receptivity after copulation. Implications for SIT are discussed.

The sterile insect technique (SIT) is an environmentally friendly pest control method that relies on the introduction of sterility into the pest population by the release of sterile males. Many Tephritidae fruit fly pests are currently being controlled with SIT. Sterile insect technique efficacy can be increased if the sexual success of mass‐reared sterile males is enhanced. Phytochemicals influence the sexual behaviour of many species of phytophagous insects. Here, we evaluated the possibility of using essential oils to enhance male sexual success of the highly polyphagous fruit fly pest Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), also known as the South American fruit fly. In laboratory tests, we determined the effect of exposing males to volatiles from seven essential oils [Baccharis spartioides (Hook. & Arn) Cabrera (Asteraceae), Schinus polygama (Cav.) Cabrera, Schinus areira (L.) (Anacardiaceae), Zingiber officinale (Roscoe) (Zingiberaceae), Citrus limon (L.) Burm. F., Citrus paradisi Macfad., and Citrus sinensis (L.) Osbeck (Rutaceae)] and two monoterpenes (limonene and citral) that are present at high proportions in some of the oils we evaluated. One exposed and one non‐exposed (control) male were placed in a mating arena with one virgin female. We recorded the type of male chosen as mating partner, copula start time, and copula duration. Laboratory males exposed to the volatiles of C. limon and S. polygama essential oils achieved more matings than non‐exposed males. The rest of the oils had no effect on male mating success. In addition, limonene‐exposed males obtained significantly more matings than non‐exposed males, and citral induced a detrimental effect. Exposure to the volatiles of the various essential oils and monoterpenes did not impact on copula start time and copula duration. We discuss the role of essential‐oil volatiles on A. fraterculus males’ sexual behaviour and its implications for SIT.

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Mass-rearing protocols must be developed, in particular, a cost-effective larval diet, to implement the sterile insect technique against Anastrepha fraterculus (Wiedemann).The key elements of this diet are the optimal nutrients and their concentrations, diet supports or bulking agents, and the pH of the diet. To improve the currently used formulation and develop a more cost-effective diet, in the present study, we evaluated various supports, sugar contents, nutrient proportions and pH levels. Egg-to-pupa recovery was found to increase when agar was replaced with sponge cloth in the diet. Although low, the recovery values obtained when using the sugarcane bagasse-based diet were similar to those obtained when using the agar-based diet, but the percentage of adult emergence was lower. Larval viability was found to increase when the amount of sugar in the diet was doubled. Yet, it is still necessary to evaluate this diet on a larger scale and determine the feasibility of reusing the sponge cloth to reduce the costs of larval diets.