Life cycle of Poratia salvator (Diplopoda: Polydesmida: Pyrgodesmidae)

摘要

Even though millipedes display high plasticity in their reproductive strategies, they are poorly studied in the tropical region. The present study describes the biological cycle and reports the parthenogenetic reproduction of Poratia salvator Golovatch & Sierwald, 2000 under environmental conditions. Collections were carried out in Pantanal of Mato Grosso and in Várzea Grande, state of Mato Grosso, Brazil. The individuals were kept at room temperature in individual plastic pots. All 18 females used in the experiment reproduced parthenogenetically, resulting in a total of 699 young individuals. Of these, 18% survived until the adult phase. The lowest survival rate of P. salvator was recorded for the first developmental stage (46%). The mean duration of each developmental stage ranged between 6.8 ± 0.8 days for stage I and 14.9 ± 10.4 days for stage VI. The reproductive adult phase of females was the longest phase in the development, followed by the juvenile and pre-reproductive adult phases. The mean time of maturity was 75.1 ± 23.6 days. The mean duration of the total development was 66.1 ± 16.7 days. The number of eggs per nest varied between seven and ten, and the emergence of young individuals occurred after an average of 9.9 ± 1.4 days. Sexual proportion was 1 male:139.8 females, which indicates a tendency towards a parthenogenetic reproduction in this species.