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Male nursery web spiders often woo potential lady-friends with gifts wrapped in silk. Mating may ensue, during which a female unspools the present, expecting to find a tasty treat. But the males can be unscrupulous. Some offerings contain inedible¹ plant seeds or empty insect exoskeletons.

How do males get away with such egregious³ behavior?

Researchers provided males with potential gifts—either a fly or an inedible item, such as a bit of cotton. Other males had to give it a shot with no gift at all.

The empty-handed males were mostly unsuccessful at mating. Whereas those with a gift could get the girl. But if the gift was worthless, the females quickly realized the deceit and pushed the copulating males off. Which gave the males less time to transfer sperm⁴.

The study is in the journal BMC Evolutionary⁵ Biology.

Females clearly prefer males bearing edible² presents. But some males know they can get limited action without expending⁶ the energy on a real gift. And the females laid almost the same amount of eggs fertilized⁷ by males bearing real or phony gifts. With both strategies successful, the behavior gets maintained. And the species stays stocked with deadbeat dads.

Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.

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收听单词发音

1 inedible
adj.不能吃的，不宜食用的
参考例句：
The food was totally inedible.食物完全无法下咽。 These chemicals make the fruit inedible.这些化学品使这种水果不宜食用。

2 edible
n.食品，食物；adj.可食用的
参考例句：
Edible wild herbs kept us from dying of starvation.我们靠着野菜才没被饿死。 This kind of mushroom is edible,but that kind is not.这种蘑菇吃得，那种吃不得。

3 egregious
adj.非常的，过分的
参考例句：
When it comes to blatant lies,there are none more egregious than budget figures.谈到公众谎言，没有比预算数字更令人震惊的。 What an egregious example was here!现摆着一个多么触目惊心的例子啊。

4 sperm
n.精子，精液
参考例句：
Only one sperm fertilises an egg.只有一个精子使卵子受精。 In human reproduction,one female egg is usually fertilized by one sperm.在人体生殖过程中，一个精子使一个卵子受精。

5 evolutionary
adj.进化的；演化的，演变的；[生]进化论的
参考例句：
Life has its own evolutionary process.生命有其自身的进化过程。 These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

6 expending
v.花费( expend的现在分词 )；使用（钱等）做某事；用光；耗尽
参考例句：
The heart pumps by expending and contracting of muscle. 心脏通过收缩肌肉抽取和放出（血液）。来自互联网 Criminal action is an action of expending cost and then producing profit. 刑事诉讼是一种需要支付成本、能够产生收益的活动。来自互联网

7 Fertilized
v.施肥( fertilize的过去式和过去分词 )
参考例句：
The study of psychology has recently been widely cross-fertilized by new discoveries in genetics. 心理学研究最近从遗传学的新发现中受益匪浅。 Flowers are often fertilized by bees as they gather nectar. 花常在蜜蜂采蜜时受粉。