Tejeda M T, Arredondo J, Pérez-Staples D, Ramos-Morales P, Liedo P, Díaz-Fleischer F
INBIOTECA, Universidad Veracruzana, Av. Culturas Veracruzanas No. 101, Col. E. Zapata, CP 91090 Xalapa, Veracruz, Mexico.
Departamento de Biología, Ecología y Comportamiento, Desarrollo de métodos, Programa Moscafrut acuerdo SAGARPA-IICA, Camino a cacahoatales S/N, CP 30860 Metapa de Domínguez, Chiapas, Mexico.
J Insect Physiol. 2014 Nov;70:73-80. doi: 10.1016/j.jinsphys.2014.08.011. Epub 2014 Sep 18.
Water availability is recognized as one of the most important factors in the distribution and activity of terrestrial organisms. In the case of insects, hydric stress imposes a major challenge for survival because of the small surface-area-to-volume ratio they exhibit. In general, stress resistance is expected to co-vary positively with size; however, this pattern can become obscured in insects that exhibit sexual size dimorphism, as sexes differ in size and/or shape and have dissimilar resource allocations. In the present study, we use an allometric-based approach to (i) assess the desiccation and starvation stress resistance of teneral Anastrepha ludens flies, (ii) disentangle the relationships between resistance, size and sex and (iii) examine the adult fly body differences in water and lipid contents before and after exposure to stress. After controlling for sexual size dimorphism, an allometric increase of resistance with overall size was observed for all stress-based treatments. The scaling exponents that define the proportion of increase resistance varied with size traits and with type and degree of hydric stress. In this allometric relationship, and also in the relationships between mass and wing length and between size and teneral resources, the sexes maintained similar scaling exponents but differed in the intercepts. Males were more resistant to stress than females; this competitive advantage is probably linked to greater amounts of teneral lipids and more water use during stress.
水的可利用性被认为是陆地生物分布和活动的最重要因素之一。就昆虫而言，由于它们的表面积与体积之比小，水分胁迫对其生存构成了重大挑战。一般来说，抗逆性预计与体型呈正相关；然而，这种模式在表现出两性体型差异的昆虫中可能会变得模糊，因为两性在大小和/或形状上存在差异，并且资源分配也不同。在本研究中，我们采用基于异速生长的方法来：（i）评估羽化后未成熟的墨西哥按实蝇的抗干燥和抗饥饿胁迫能力；（ii）理清抗逆性、体型和性别的关系；（iii）研究成年果蝇在暴露于胁迫前后身体水分和脂质含量的差异。在控制了两性体型差异后，对于所有基于胁迫的处理，均观察到抗逆性随总体体型呈异速生长增加。定义抗逆性增加比例的标度指数随体型特征以及水分胁迫的类型和程度而变化。在这种异速生长关系中，以及在质量与翅长之间的关系和体型与羽化后资源之间的关系中，两性保持相似的标度指数，但截距不同。雄性比雌性更耐胁迫；这种竞争优势可能与羽化后更多的脂质含量以及胁迫期间更多的水分利用有关。
