Superparasitism of fully-grown Ceratitis capitata (Wiedemann) larvae by naive females of Psyttalia concolor (Szepligeti) was compared for three different parasitoid/host (p/h) ratios (1/1, 1/5, and 1/10) at constant host to parasitoid exposure time (2 hours). The superparasitism effect on the amount of the emerging wasp progeny was also examined. The percentage of unparasitized hosts was significantly lower at the 1/1 p/h ratio (2.67%) compared to the 1/5 (35.5%) and 1/10 (46.7%) p/h ratios, while no significant differences were recorded between the percentage of unparasitized hosts found at the 1/5 and 1/10 p/h ratios. The percentage of single parasitized larvae found at the 1/1 p/h ratio was significantly lower (5.33%) compared to the 1/5 (28%) and 1/10 (35%) p/h ratios, whereas the values of single parasitized larvae recorded at the 1/5 and 1/10 p/h ratios were not significantly different. The amount of hosts containing 2 parasitoid eggs was 26.7%, 25.6% and 16.7% at the 1/1, 1/5 and 1/10 p/h ratios, respectively. None of these values were significantly different from one other. A significantly higher percentage (65.3%) of hosts containing >=3 parasitoid eggs was recorded at lower host availability (1/1 p/h ratio) compared to the 1/5 (10.9%) and 1/10 (1.6%) p/h ratios. Mean number of eggs laid per parasitized host was 2.86, 1.76 and 1.37 at the 1/1, 1/5 and 1/10 p/h ratios, respectively. A significantly higher number of eggs was found when comparing the 1/1 p/h ratio with all other ratios, while no significant differences were recorded between the mean number of eggs at the 1/5 and 1/10 p/h ratios. The percentage of parasitoid progeny obtained at the 1/1, 1/5 and 1/10 p/h ratios was 20%, 26.7% and 19.3%, respectively. None of these values were significantly different from one other. Moreover, host progeny showed no significant differences when comparing the different host availabilities. Overall, it was concluded that in laboratory condition the superparasitism of C. capitata fully-grown larvae by P. concolor is very frequent. A relationship between host availability and degree of superparasitism was observed, with the proportion of superparasitized host increasing at lower host availability. The finding that no significant difference in the amount of host larvae containing 2 parasitoid eggs was found among the different tested p/h ratios may be related to the amount of parasitoid emergence and suggests that for P. concolor to lay 2 eggs on fully-grown C. capitata larvae may represent the optimal condition to gain an offspring. Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts Ceratitis capitata (Tephritidae); Hymenopteran parasites; Psyttalia concolor; Superparasitism by naive females, effects on parasite progeny; Hyperparasitism; Superparasitism by naive hymenopteran females Psyttalia concolor (Braconidae); Dipteran hosts; Ceratitis capitata, effects on progeny; Hyperparasitism; Superparasitism by naive females none