ABSTRACT
The wing polyphenism of pea aphids is a compelling laboratory model with which to study the molecular mechanisms underlying phenotypic plasticity. In this polyphenism, environmental stressors such as high aphid density cause asexual, viviparous adult female aphids to alter the developmental fate of their embryos from wingless to winged morphs. This polyphenism is transgenerational, in that the pea aphid mother experiences the environmental signals, but it is her offspring that are affected. Previous research suggested that the steroid hormone ecdysone may play a role in this polyphenism. Here, we analyzed ecdysone-related gene expression patterns and found that they were consistent with a down-regulation of the ecdysone pathway being involved in the production of winged offspring. We therefore predicted that reduced ecdysone signaling would result in more winged offspring. Experimental injections of ecdysone or its analog resulted in a decreased production of winged offspring. Conversely, interfering with ecdysone signaling using an ecdysone receptor antagonist or knocking down the ecdysone receptor gene with RNAi resulted in an increased production of winged offspring. Our results are therefore consistent with the idea that ecdysone plays a causative role in the regulation of the proportion of winged offspring produced in response to crowding in this polyphenism. Our results also show that an environmentally regulated maternal hormone can mediate phenotype production in the next generation, as well as provide significant insight into the molecular mechanisms underlying the functioning of transgenerational phenotypic plasticity.
Subject(s)
Aphids/drug effects , Ecdysone/pharmacology , Morphogenesis/drug effects , Wings, Animal/drug effects , Animals , Aphids/embryology , Aphids/genetics , Crowding , Ecdysone/metabolism , Ecdysterone/pharmacology , Female , Gene Expression Regulation, Developmental/drug effects , Insect Proteins/genetics , Insect Proteins/metabolism , Morphogenesis/genetics , Pisum sativum/parasitology , Phenotype , RNA Interference , Receptors, Steroid/antagonists & inhibitors , Receptors, Steroid/genetics , Receptors, Steroid/metabolism , Signal Transduction , Triterpenes/pharmacology , Wings, Animal/embryology , Wings, Animal/metabolismABSTRACT
Esta descripción está basada en ejemplares ápteros colectados en Jamaica sobre Eupatorium sp. (Asteraceae). Se proveen fotografías e ilustraciones de la nueva especie. La nueva especie es comparada con una especie no descrita de Costa Rica. Se diferencia de Hyperomyzus (Neonasonovia) nigra (Baker) por tener siphunculi más estrechos, pocas rhinarias secundarias y el rostro más alargado.
Hyperomyzus (Neonasonovia) pullatus Hall & Garraway sp. n (Hemiptera: Aphididae) is described based on apterous specimens collected from Eupatorium sp., (Asteraceae) in Jamaica. Photos and illustrations are provided. It is compared with an undescribed species from Costa Rica. It is distinguished from Hyperomyzus (Neonasonovia) nigra (Baker) by having narrower siphunculi, less secondary rhinaria and a longer rostrum.
Subject(s)
Animals , Aphids/anatomy & histology , Aphids/classification , JamaicaABSTRACT
Hyperomyzus (Neonasonovia) pullatus Hall & Garraway sp. n (Hemiptera: Aphididae) is described based on apterous specimens collected from Eupatorium sp., (Asteraceae) in Jamaica. Photos and illustrations are provided. It is compared with an undescribed species from Costa Rica. It is distinguished from Hyperomyzus (Neonasonovia) nigra (Baker) by having narrower siphunculi, less secondary rhinaria and a longer rostrum.
