Voight J R
Biol Bull. 1995 Oct;189(2):113-119. doi: 10.2307/1542461.
In the translucent mid-water octopod Eledonella pygmaea, the posterior salivary glands that release proteolytic enzymes into the esophageal crop grow five times faster in males than in females. I suggest that the sexes vertically partition the water column and that large glands have evolved in males as a result of their deepwater habitat. Members of the species undergo ontogenetic vertical descent and are suggested to mate at the lower end of the adult depth range where receptive females signal males with light organs. Selection for increased fitness is inferred to result in females increasing their fecundity by feeding at the upper limit of the adult range and in mature males increasing their encounters with mates by living at depths where mating occurs. To further increase their fitness, mature males--despite occurring in a prey-limited habitat--must expend energy to visually detect potential mates, to travel over wide areas, and to attempt to copulate. To increase the energy available to them, males at depth may exploit bioluminescent prey. The large glands protect the translucent males from increased predation by physically blocking light emitted by bioluminescent prey in their crops, and by speeding digestion.
在半透明的中水层章鱼矮艾氏章鱼（Eledonella pygmaea）中，向食管嗉囊释放蛋白水解酶的后唾液腺在雄性中的生长速度比雌性快五倍。我认为，两性在水柱中呈垂直分布，并且由于雄性的深水栖息地，大型腺体在雄性中进化而来。该物种的成员经历个体发育过程中的垂直下降，并且被认为在成年深度范围的下限处交配，在那里，处于接受状态的雌体用发光器官向雄体发出信号。据推测，对适应性增强的选择导致雌性通过在成年范围的上限处觅食来提高其繁殖力，而成熟雄性则通过生活在交配发生的深度来增加与配偶相遇的机会。为了进一步提高其适应性，成熟雄性——尽管处于猎物有限的栖息地——必须消耗能量来视觉探测潜在配偶、在广阔区域游动并试图交配。为了增加它们可利用的能量，处于较深水域的雄性可能会捕食发光猎物。大型腺体通过物理阻挡其嗉囊中发光猎物发出的光以及加快消化，保护半透明的雄性免受更高的捕食风险。
