Thus, because of the takeover or disruption of efficient sperm transfer, males in male-biased sex ratio may decrease the amount of sperm transfer and finish the copulation in a shorter duration.
The pre-mating visit was initiated by the male 3 4 d before the copulation, in which mutual signaling between sexes with movement of antennules, maxillipeds, chelipeds, and pleopods occurred.
This strategy represents an effective way to restore contact with the decamping female and hence to enhance the courtship vigor and thus the copulation efficiency in the dark (ninaB360d in Figure 2B; p = 0.03; for definition of copulation efficiency, see Materials and Methods).
For female copulants, fecundity reduction correlated with transferred sperm numbers in the first copulation, while differences in transferred quantities of seminal fluid were not detected.
Winged and wingless males neither differed in behaviour during precopulatory courtship nor in behaviour and duration of the copulation itself [10].
Greater investments in the first copulations with reduced future copulation investments has been reported for other Orthoptera, such as Requena verticalis or Ephippiger ephippiger (Orthoptera: Tettigoniidae) in which males donate a nutrient rich spermatophylax (Gwynne et al., 1984).
Alternatively, masturbation could be adaptive and function to remove old sperm from the reproductive tract to increase the proportion of competitive or fertile sperm in the next copulation [20], [21].
In the successful copulation, after male and female gametes were mixed together, they immediately adhered to one another, the result being the formation of numerous clumps and zygotes by fusion of male and female gametes.
Interestingly, the fecundity reduction correlated with sperm numbers in the first copulation, while differences in seminal fluid quantities were not found.
In fact, we found that sperm donation in the first copulation after an isolation period was twice as high towards imposed females compared to hermaphrodites.
