Cueva Del Castillo Raúl, Sanabria-Urbán Salomón, Mariño-Pérez Ricardo, Song Hojun
Universidad Nacional Autónoma de México; Facultad de Estudios Superiores Iztacala Tlalnepantla Mexico.
University of Michigan Ann Arbor Michigan USA.
Ecol Evol. 2024 Aug 21;14(8):e70188. doi: 10.1002/ece3.70188. eCollection 2024 Aug.
In many animal species, larger body size is positively correlated with male mating success and female fecundity. However, in the case of insects, in high seasonality environments, natural selection favors a faster maturation that decreases the risk of pre-reproductive death. However, this advantageous adaptation comes at a tradeoff, resulting in a reduction in body size. Maturation time is influenced by environmental factors, such as temperature, season length, and food availability during the rains. The geographic variation in these parameters provides an opportunity to study their impact on the adaptive evolution of body size in Pyrgomorphidae grasshoppers. These grasshoppers exhibit remarkable variation in body size and wing development and can be found in diverse plant communities across Africa, Asia, Australia, and tropical America. In this study, we utilized a phylogenetic approach to examine the evolution of body size, considering climatic factors, and the influence of sexual selection on size differences between males and females. We found a positive correlation between mean annual temperature and sexual size dimorphism (SSD). Remarkably, species exhibiting a strong bias toward larger females were found to be adapted to regions with higher temperatures. In the Pyrgomorphidae family, an intermediate body size was identified as the ancestral trait. Additionally, winged male and female grasshoppers were observed to be larger than their wingless counterparts. Despite the potential conflicting pressures on body size in males and females, these grasshoppers adhere to Rench's Rule, suggesting that sexual selection on males' body size may explain the evolution of SSD.
在许多动物物种中，体型较大与雄性交配成功率和雌性繁殖力呈正相关。然而，对于昆虫来说，在季节性强的环境中，自然选择倾向于更快的成熟速度，以降低繁殖前死亡的风险。然而，这种有利的适应性是有代价的，会导致体型减小。成熟时间受环境因素影响，如温度、季节长度以及雨季的食物供应情况。这些参数的地理差异为研究它们对蝗科蝗虫体型适应性进化的影响提供了机会。这些蝗虫在体型和翅发育方面表现出显著差异，在非洲、亚洲、澳大利亚和热带美洲的不同植物群落中都能找到。在本研究中，我们采用系统发育方法来研究体型的进化，考虑气候因素以及性选择对雌雄体型差异的影响。我们发现年平均温度与两性体型差异（SSD）之间存在正相关。值得注意的是，发现雌性明显偏大的物种适应于温度较高的地区。在蝗科中，中等体型被确定为祖先特征。此外，有翅的雄性和雌性蝗虫被观察到比无翅的同类体型更大。尽管雄性和雌性在体型上可能面临相互冲突的压力，但这些蝗虫遵循伦奇法则，这表明对雄性体型的性选择可能解释了两性体型差异的进化。
