雌性昆蟲在繁殖結(jié)束后通常會死去，而日本研究人員日前卻發(fā)現(xiàn)了繁殖結(jié)束后依然生存的雌性蚜蟲,。這種長壽蚜蟲分泌黏液擊退天敵，幫助子孫生存下去。
東京大學(xué)教授島田正和與研究生植松圭吾發(fā)現(xiàn)的這種長壽蚜蟲是一種日本特有的蚜蟲品種中的雌性,，它們生活在常綠的蟻母樹上,。這種蚜蟲出生半年后就開始不斷繁殖，在喪失繁殖能力以后,，它們?nèi)岳^續(xù)分泌黏液，攻擊瓢蟲等天敵,，幫助子孫實現(xiàn)自立,。
大部分靈長類到了不能妊娠、生育的年齡就要準(zhǔn)備迎接死亡,，而人類的女性卻能夠活到當(dāng)奶奶的歲數(shù),。有一種“老奶奶假說”認(rèn)為，女性長壽是為了更好地照顧子孫,，幫助他們繁殖,。
這是人們首次在昆蟲世界里發(fā)現(xiàn)這一現(xiàn)象。研究人員認(rèn)為,，這有可能是這種蚜蟲為了切實留下后代的一種進(jìn)化策略,。
這一成果已刊登在最新一期美國科學(xué)雜志《當(dāng)代生物學(xué)》上。(生物谷Bioon.net)
生物谷推薦原文出處：
Current Biology doi:10.1016/j.cub.2010.04.057
Altruistic Colony Defense by Menopausal Female Insects
Keigo Uematsu, Mayako Kutsukake, Takema Fukatsu, Masakazu Shimada, Harunobu Shibao
Recent studies have suggested that an extended postreproductive life span, such as life after menopause in human females, will evolve when the indirect (kin-selected) fitness benefits from altruistic behavior are greater than the direct fitness benefits from continuing reproduction [1,2,3,4]. Under some conditions in which postreproductive altruism is more beneficial and/or continuing reproduction is more costly, the postreproductive life span can be shaped by natural selection [5, 6,5, 6]. However, indirect fitness benefits during postreproductive survival have been documented mainly in intelligent mammals such as humans and cetaceans, in which elder females possess enhanced social knowledge through learning [7,8,9,10]. Here we show that postreproductive females of the gall-forming aphid Quadrartus yoshinomiyai (Nipponaphidini) can gain indirect fitness benefits through their altruistic colony defense. These females cease reproduction around the time of gall opening and defend the colony by sticking themselves to intruding predators with a waxy secretion that is accumulated in their body with aging. Our results suggest that the presence of an age-related trait for altruistic behavior promotes the evolution of postreproductive altruism in this social insect via kin selection under natural selection imposed by predators.
