Bakonyi Gábor, Seres Anikó
Department of Zoology and Ecology Institute for Wildlife Management and Nature Conservation, Hungarian University of Agriculture and Lif Sex on the Beach: Sexual Size Dimorphism Among Aquatic Bugs (Nepomorpha) Inhabiting Different Habitats e Sciences Gödöllő Hungary.
Ecol Evol. 2025 Jun 5;15(6):e71501. doi: 10.1002/ece3.71501. eCollection 2025 Jun.
Aquatic bugs (Nepomorpha) are a species-rich taxon of insects inhabiting all types of freshwaters, often at high densities, and some are among the dominant predators in aquatic food webs. In contrast to the vertebrates and some other arthropod taxa, sexual dimorphism in aquatic bugs is a poorly investigated issue; the present work is the first comprehensive analysis in this field. Morphological differences between the sexes are generally minor, except that female body size is usually longer than that of males. There is no information on the extent of sexual dimorphism in Nepomorpha, except in Belostomatidae and Corixidae. We examined the patterns of sexual size dimorphism (SSD) of 1195 species and subspecific taxa (about 45% of the known species) and whether they conform to Rensch's rule (RR) at the infraorder, superfamily, family and genus levels. We attempted to identify the potential causes of the observed patterns. Our assumption that females are longer-bodied in most aquatic bug species is falsified. Species living in habitats near the edges of water bodies had higher SSD than in all other habitats. The most likely reason for the large intersexual size difference here is that, unlike the species living in other habitats, the species here are sit-and-wait predators. Our results indicate that sexual selection (including fertility selection) plays an important role in the development of SSD. Moreover, it is probable that water-edge habitats and the associated sit-and-wait lifestyle increase sexual selection pressure and the degree of SSD in Nepomorpha. Converse RR, typical for many insects, characterises Nepomorpha as a whole, and two of its superfamilies. At the family and genus levels, however, roughly half of the taxa obey RR and half of them obey converse RR.
水生蝽（负子蝽科）是一类物种丰富的昆虫分类群，栖息于各种类型的淡水环境中，通常密度很高，并且有些是水生食物网中的主要捕食者。与脊椎动物和其他一些节肢动物分类群不同，水生蝽的两性异形是一个研究较少的问题；目前的工作是该领域的首次全面分析。除了雌性体型通常比雄性长之外，两性之间的形态差异一般较小。关于负子蝽科的两性异形程度，除了在田鳖科和划蝽科之外，没有相关信息。我们研究了1195个物种和亚种分类单元（约占已知物种的45%）的性大小二态性（SSD）模式，以及它们在亚目、总科、科和属水平上是否符合伦施法则（RR）。我们试图确定观察到的模式的潜在原因。我们关于大多数水生蝽物种中雌性身体更长的假设被证伪。生活在水体边缘附近栖息地的物种比其他所有栖息地的物种具有更高的SSD。这里两性之间体型差异大的最可能原因是，与生活在其他栖息地的物种不同，这里的物种是坐等型捕食者。我们的结果表明，性选择（包括生育力选择）在SSD的发展中起重要作用。此外，很可能水体边缘栖息地以及相关的坐等型生活方式增加了负子蝽科的性选择压力和SSD程度。许多昆虫典型的反向RR表征了整个负子蝽科及其两个总科。然而，在科和属水平上，大约一半的分类单元遵循RR，另一半遵循反向RR。
