對于盜蛛而言,，沒有什么比送出咀嚼過的食物更能表達愛意了,。在這種歐洲蛛形綱動物的某些種群里，雄性蜘蛛必須把捕獲的昆蟲用蛛絲纏繞起來,，作為禮物送給雌性蜘蛛,，否則雌性蜘蛛不會同意做它的伴侶。
雄性蜘蛛在求愛期間隨身攜帶數(shù)個小小的昆蟲包,，但目前科學家們尚不清楚這些多余的“行李”在多大程度上影響雄性蜘蛛的奔跑和戰(zhàn)斗能力,。待解的問題還有，這些八條腿的動物是否也會欺騙：把一些不能吃的東西或者是已經(jīng)干透的昆蟲尸體一起放進它們的禮物包中,，使禮物看起來更大,。
研究者們在野外觀察了58只雄性盜蛛之后，把相關(guān)研究結(jié)果刊發(fā)在這個月的《動物行為》（Animal Behaviour）雜志網(wǎng)絡(luò)版上,，其中涉及了上述兩個問題,。
在這58只雄性蜘蛛里，23只攜帶了禮物包,，所有的禮物包中都有新捕獲的昆蟲的肢體,。在另外一些實驗室觀察中，科學家們發(fā)現(xiàn),，當雄性蜘蛛互相打斗時,，帶禮物者顯然并沒有因為禮物的妨礙而輸給不帶禮物者，盡管有一些更強壯的,、攜帶或不攜帶禮物的雄性蜘蛛會從弱一些的同類那里偷走禮物包,。實驗室觀察還發(fā)現(xiàn)，禮物包的確會影響雄性蜘蛛的奔跑能力,。計時測驗結(jié)果顯示,，攜帶禮物的蜘蛛奔跑速度比同樣大小的、不攜帶禮物的雄性蜘蛛慢了42%,。這一數(shù)據(jù)首次顯示了對于昆蟲和蜘蛛來說,，攜帶禮物的代價是什么。
研究人員還推測,，這種為愛甘當苦力的行為能夠顯示雄性蜘蛛獲得并保有食物的能力,。（生物谷Bioon.com）
doi:10.1016/j.anbehav.2012.03.007
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Gift carrying in the spider Pisaura mirabilis: nuptial gift contents in nature and effects on male running speed and fighting success
Pavol Prokop, Michael R. Maxwel
Males of the spider Pisaura mirabilis offer prey items as nuptial gifts to females. While gift giving in this species has received attention in captivity, the ecological context of these gifts remains largely unknown. First, we examine the occurrence of gift carrying by males in nature. Field data reveal that gift-carrying males are frequent in nature (40% of captured males), and that all gifts contain fresh arthropod prey. Gift mass was positively correlated with the longest diameter of the gift. Thus, males do not appear to ‘cheat’ by inflating their gifts with inedible items, air or loosely wrapped silk. Second, we examine two ecological costs to gift-carrying males: the effects of gifts on male running speed and male fighting success. Gift carrying reduced male running speed, but did not affect male fighting success in male–male contests. The former result is the first demonstration of a transportation cost associated with gift carrying in an arthropod.
