科研之友
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摘要
Many zooplankters rely on diapausing stages to survive unsuitable conditions in time-varying habitats. In facultative sexual rotifers, reproductive effort allocated to the sexually produced diapausing eggs is at the expense of the subitaneous parthenogenetic eggs, generating a trade-off between current and future population growth. The timing and the amount of sex (the sexual pattern) affect diapausing-egg production. This switch to sex is complex because the reproductive mode is separated in distinct females: asexual (female-producing), unfertilized sexual (male-producing) and fertilized sexual (diapause-egg-producing). We studied sexual patterns and life-history variation of these females in two cryptic species (Brachionus plicatilis and Brachionus manjavacas) co-occurring in Spanish ponds. Results revealed species-specific differences in sexual pattern; B. plicatilis had an earlier and higher sex allocation. Female types allocated resources differently among life-history traits, revealing relationships between lifespan and reproductive traits that demonstrate the cost of reproduction. Sexual females reproductive traits showed between-species differences. Brachionus manjavacas unfertilized females produced more sons earlier and at a greater daily rate than B. plicatilis ones. Moreover, B. manjavacas fertilized females had higher relative allocation per diapausing egg than those of B. plicatilis. We relate these differences to the environmental uncertainty faced by each species, and discuss their implications for competitive outcome.
- 出版日期2015-4
