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The life cycle (LC) of cyclorrhaphans follows a well-conserved developmental program in which the different instars and stages within instars show a similar sequence of events (Denlinger & ?đárek , 1994). In spite of the evolutionary distance (around 120 MY) the duration of metamorphosis of Drosophila melanogaster and Ceratitis capitata, seems to represent a similar proportion of time of the whole life cycle, i.e. 48.1 and 50.1 %, respectively (Bainbridge and Bownes, 1981; Rabossi and Quesada-Allué,1995). The duration of stages within the puparium expressed as percent of total metamorphosis time also seems to be highly conserved between these two cyclorrhaphans, in spite of the respective slow (600 hs) C. capitata and rapid (239 hs) D.melanogaster LCs. This might also be true for certain evolutionary and ecologically distant flies, like the blood-sucking fly Haematobia irritans (Basso et al, 2011) and other muscidae (Denlinger and ?đárek, 1994). In cyclorrhaphans, when the pharate adult inside the puparium opens the puparial operculum, a stage of extrication is initiated, ending when the legs support the body and the insect is able to walk (?đárek and Denlinger,1986 & 1987). In D. melanogaster this stage has been described as Stage P15(i+ii) by Bainbridge and Bownes (1981). Then follows a phase in which the exarate imago acquires the fina size This phase have been described in D.melanogaster by Bainbridge and Bownes (1981) as Stages A1 to A3. During these first hours as ?unfinished? imago the exarate fly undergoes complex behavioral and molecular processes giving rise to final body maturation. In particular, the ptilinium cuticle region retracts and, after muscular pulsations and body expansion, the wings reach their definitive extension (Johnson and Milner,1987). Then, the final steps of cuticle sclerotization and pigmentation occur, mediated by catecholamine derivatives (Perez et al, 2002, Hopkins and Kramer, 1992), thus attaining the final external phenotype of the imago. Studies on this phase were reported in muscoids like Sarcophaga crassipalpis (?đárek and Denlinger,1986, 1987) or Glossina-Tsetse (?đárek and Denlinger, 1992). However, as far as we know, no detailed comparison between D. melanogaster and Tephritids post-ecdysis behavior has been published. We have carefully analyzed the stages after ecdysis of male exarate adults of D. melanogaster and C. capitata, to analyze and quantify the timing of events until full body maturation, when final rigidity and coloration were attained. We defined the total phase of whole body maturation phase (BMP) as starting at the moment of the operculum opening and onset of pharate adult extrication and ending when the definitive features of the body are attained. Thus, this phase of the exarate adult, BMP, represents the transition from the pharate adult to the full imago, in our experimental conditions. In Drosophila this roughly corresponds to the P15(ii) and A1-A3 stages described by Bainbridge and Bownes (1981). Extrication in males of D. melanogaster required, in average, around 21 seconds (i.e. 0.81% of the BMP), whereas in C.capitata it lasted 2.66 + 1,66 min. This difference is probably more related to the anatomy of the puparium than to differences due to insect size or life cycle length. The initial position of the exarate insect standing up on its legs for the first time (to, Fig 2, A,B) was the one after complete extrication from the puparium, that was gluedto the center of petri dishes used as arenas(see materials and methods). From the preliminary results reported in this communication, the total phase BMP including the extrication period required 42.70± 11.94min in D. melanogaster and 126.91 ± 22.60 min in C. capitata. The post-extrication behavior of both flies exarate adults was analyzed and compared. Figure 2A, B, show representative examples of the respective pathways followed in a restricted circular arena. During this post-extrication stage D. melanogaster shows a walking behavior frequently interrumped by numerous stationary periods of resting (Fig 2, A,C); whereas medflies displayed first a rapid exploratory behavior (on the average 7.86 ± 3.75min) followed by a single long period of resting (119.04 ± 25.24min) until the final phenotype of the imago is attained (Fig. 2 B,D). The diameters of the circumferences in the diagrams (Fig 2 C,D) are proportional to the duration of the resting time in that position. The length of the path for the examples in Fig. 2 was 12.65cm for D. melanogaster and 48.10cm for C. capitata. The average length of the pathways was 11.02 ± 1.91 cm for D. melanogasterand45.40 ± 13.47 cm for C. capitata. Total time for D. melanogaster periods of walking represented 6.1% of the time of the whole phase and for C. capitata the single walking period represented 11.31% of the total BMP (Fig. 1). Significantly, when the extrication times were added to the mobility times, total activity time represented 12.12% of the Drosophila BMP whereas the equivalent time for Ceratitis represented 8.15% (Fig. 1). Comparing these observations with the previously reported equivalent post-ecdysial behavior in other flies like the sarcophagids Sarcophaga crassipalpis, S. bullata and S. argirostoma (?đárek and Denlinger,1986, 1987),all seem to follow a similar pattern to that of C. capitata, very different from that of D. melanogaster and (probably) other drosophilids. The mobility parameters in our experimental conditions of reduced movement might be proportional to the remainder of the energy resources available for metamorphosis, mainly haemolymph trehalose, muscle glycogen and lipids (Bochicchio, 2012, Nestel et al, 2003) and in this case might be very different in wild conditions. Although behavior heterogeneity among individuals of each species is significant, the post-ecdysial exarate adult behavioral pattern indicates that in both flies around 90% of resting time is required during this period (Fig 1). This seems to indicate that for fully completion of exarate adult body features, a similar proportion of resting time is required in both flies. In turn, this suggeststhat in the wild, a bottleneckfor the behavior of cyclorrhaphans during the non-eating BMP might be the availability of energetic reserves to be spent duringthat phase of the life cycle. This kind of data are also important for the male-sterile programs for pest flies