你可能认为寄生虫都是鬼鬼祟祟的
You might think of parasites as stealthy
想一直藏在寄主的身体里
wanting to stay hidden from their hosts
但是有些寄生虫爱求关注
But some parasites are attention seekers
更喜欢制造有意思的状况
and prefer to make a colourful statement
彩蚴吸虫就是个神奇的例子
One amazing example of this is the broodsacs.
蜗牛吃掉了含有彩蚴吸虫虫卵的鸟粪
Now the broodsacs are acquired by snails by ingesting the eggs in bird droppings.
一旦彩蚴吸虫被蜗牛吃掉
Once the parasite is consumed by the snail it transforms
它就转变成了胞蚴
into a form called the sporocyst,
能感染蜗牛的肠道
which infects the snail’s gut.
现在第二代胞蚴从中形成了
Now a second sporocyst is then formed from that,
它们使蜗牛发育出了眼柄或触角
which develops in the eye stalk or tentacleof the snail.
这些胞蚴使其具有鲜艳的颜色 有规律的搏动
This sporocyst changes colour, pulsates, flashesbright colours
使其看起来像毛虫或蛆虫
and looks quite like a caterpillar or maggot.
而且彩蚴吸虫还会使蜗牛
And the parasite also makes the snail move out
向更开阔明亮的地方移动
into more open and more well-lit areas,
那里更容易被鸟类捕食到
where it’s more likely to be hunted on by a bird.
一旦被鸟类吃掉
Once ingested by the bird the
寄生虫再次发育
parasite develops again and produces eggs
并到鸟粪中产卵
that go back out
周而复始
into the bird droppings the life cycle starts all over again.