Afaq Uzma
Ladybird Research Laboratory, Department of Zoology, University of Lucknow, Lucknow, 226007, India.
Insect Sci. 2013 Aug;20(4):531-40. doi: 10.1111/j.1744-7917.2012.01510.x.
In the Parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), variation in body size exists between and within the sexes. The females are larger than the males. Darwin (1874) proposed the fecundity advantage hypothesis, i.e. large sized female produce more progeny, with subsequent studies supporting as well as refuting the hypothesis. Thus, in order to evaluate whether this hypothesis stands in Z. bicolorata we performed experiments to investigate the role of body size in influencing: (i) assortative mating, (ii) reproductive attributes, and (iii) growth, development and survival of offspring. It is the first attempt in this beetle. We found that size influenced assortative mating, reproductive output and offspring fitness. Larger males and females were preferred as mates over smaller ones. The pairs having larger adults as mates had higher fecundity while the egg viability was influenced by the male size only. The offspring of larger parents had fast development and higher survival indicating thereby possible better nutrient allotment by the female and supply of accessory gland proteins by the male in addition to better quality of genes.
在银胶菊叶甲虫（Zygogramma bicolorata Pallister，鞘翅目：叶甲科）中，两性之间以及性别内部均存在体型差异。雌性比雄性体型更大。达尔文（1874年）提出了繁殖力优势假说，即体型大的雌性产生更多后代，后续研究既有支持该假说的，也有反驳该假说的。因此，为了评估这一假说在银胶菊叶甲虫中是否成立，我们开展了实验，以研究体型在影响以下方面所起的作用：（i）选择性交配，（ii）生殖属性，以及（iii）后代的生长、发育和存活。这是针对这种甲虫的首次尝试。我们发现体型会影响选择性交配、繁殖产出和后代适合度。体型较大的雄性和雌性比体型较小的更受青睐成为配偶。以体型较大的成虫为配偶的配对具有更高的繁殖力，而卵的活力仅受雄性体型影响。体型较大的亲本的后代发育更快且存活率更高，这表明雌性可能进行了更好的营养分配，雄性除了提供质量更好的基因外，还供应了附属腺蛋白。
