Across all pairs of males, Fisher's combined probability (Fisher, 1948) for equal mating success of males in a pair amounts to P = 0.0005 (χ = 27.9, df = 8).
Their reproductive system is equally simple; as in millipedes, the reproductive organs open at the bases of the second legs, males having a pair of penes.
Males have a pair of penises, which may be fused in some species.
Adult males have a pair of short, thick claspers, with the inner margins of the pelvic fins partially fused over them to form an "apron".
As a prominent sign of sexual dimorphism, only males possess a pair of short, stout horns, that extend backward from the forehead and hook slightly forward.
However, the variation in vitamin E differences within male pairs was considerable (range of differences in TIC transformed areas = 0.17 1.24), probably due to individual differences in initial proportions of vitamin E in the males of a pair.
Briefly, semen samples were collected from the two males of a pair through abdominal massage within 5 minutes of each other.
In the mating trials, a single virgin female was placed in a container with one randomly chosen male (male 1) from a pair of males, at artificial dawn (lights on).
Instead of copulating directly, the male inserts a pair of sperm-carrying organs called pedipalps into each of his mate's genital openings one at a time.
Today's fashion is geared towards the emaciated male in a pair of skinny jeans.
