屎殼郎因推糞球而聞名,，但直至最近，科學家才以數(shù)據(jù)證明它們是地球上已知的最強壯昆蟲：一種名為食糞金龜?shù)氖簹だ煽梢酝苿酉喈斢谧陨眢w重1000多倍的糞球,。
英國《皇家學會生物學分會學報》24日刊登倫敦大學和西澳大利亞大學研究者聯(lián)合發(fā)表的一項研究報告,。報告說，可監(jiān)測到的數(shù)據(jù)顯示,，蜣螂目中的雄性食糞金龜最多可推動相當于自身體重1141倍的糞球,。
報告形象地比喻，雄性食糞金龜之強壯好比一名體重70千克的人推動80噸重物,。目前,，世界上已知相對力氣最大的動物是一種螨，這種螨的力氣比雄性食糞金龜略大,。但在昆蟲界,，沒有任何昆蟲可與食糞金龜比強壯。
科學家在研究雄性食糞金龜?shù)纳盍曅院蟀l(fā)現(xiàn)，爭奪交配權(quán)是這一物種在進化過程中氣力不斷增加的主要動因,。在交配時,，雌性食糞金龜一般藏在隧道內(nèi)，爭奪雌性配偶的雄性食糞金龜須在隧道內(nèi)兩兩對決,，以各自的角頂牛,，被推出隧道者出局。
正是在長期爭奪“女友”過程中,，食糞金龜?shù)靡赃M化體格,，成為昆蟲界的大力士。（生物谷Bioon.com）
屎殼郎立新功
生物谷推薦原文出處：
the journal Proceedings of the Royal Society B doi: 10.1098/rspb.2010.0257 ,、
Mating tactics determine patterns of condition dependence in a dimorphic horned beetle
Robert J. Knell1,* and Leigh W. Simmons2
The persistence of genetic variability in performance traits such as strength is surprising given the directional selection that such traits experience, which should cause the fixation of the best genetic variants. One possible explanation is ‘genic capture’ which is usually considered as a candidate mechanism for the maintenance of high genetic variability in sexual signalling traits. This states that if a trait is ‘condition dependent’, with expression being strongly influenced by the bearer's overall viability, then genetic variability can be maintained via mutation-selection balance. Using a species of dimorphic beetle with males that gain matings either by fighting or by ‘sneaking’, we tested the prediction of strong condition dependence for strength, walking speed and testes mass. Strength was strongly condition dependent only in those beetles that fight for access to females. Walking speed, with less of an obvious selective advantage, showed no condition dependence, and testes mass was more condition dependent in sneaks, which engage in higher levels of sperm competition. Within a species, therefore, condition dependent expression varies between morphs, and corresponds to the specific selection pressures experienced by that morph. These results support genic capture as a general explanation for the maintenance of genetic variability in traits under directional selection.
