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When octopuses mate, the male keeps the female quite literally at arm\u2019s length. <\/p>\n
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For the act, the male has a special arm called a hectocotylus, which it uses to deposit a sack of sperm inside the female\u2019s reproductive system.<\/p>\n
However, scientists have not been clear about how exactly this arm locates the right place when the male cannot see what he is doing. Now, a new study has discovered how hectocotylus is guided. <\/p>\n
Male octopuses \u2018taste\u2019 female hormones<\/p>\n
During sex, the male octopus<\/a> inserts the hectocotylus inside the female\u2019s mantle – a bag-like structure behind the eyes that holds all of her major organs, including reproductive ones – and feels around until he finds her oviduct.<\/p>\n How he does this has been revealed in a paper<\/a> published in the journal Science this week.<\/p>\n Researchers found that the mating arm is a sensory organ which, like octopuses\u2019 other arms, is loaded with suckers that contain chemotactile receptors. <\/p>\n In the other seven arms, the receptors help the creatures to \u2018taste\u2019 their surroundings, functioning like a tongue to locate food or identify harmful microbes. <\/p>\n But in the hectocotylus, which is normally held close to the body when not mating<\/a>, their function hasn\u2019t been clear. <\/p>\n During their research, scientists found that the female octopus\u2019s oviduct produces enzymes that generate the sex hormone progesterone. <\/p>\n They discovered that the receptors allow the males\u2019 mating arm to detect the progesterone, meaning they can fertilise a mate, even if they cannot see their sexual partner.<\/p>\n The researchers also found that amputated specialist arms of male octopuses<\/a> moved in response to progesterone \u2013 but not when in contact with other, similar hormones.<\/p>\n After examining hectocotylus cells from three individuals, the team detected up to three times more chemotactile receptors and three times more neurons in the mating arm than in a normal arm. <\/p>\n Octopuses can mate without seeing<\/p>\n