Why the aphid Aphis spiraecola is more abundant on clementine tree than Aphis gossypii?

Abstract

Aphis spiraecola and Aphis gossypii cause harmful damages on clementine tree orchards. Weekly surveys measured the abundance of aphids (larvae, winged and wingless adults) as well as of auxiliary insects and parameters of energy metabolism. Correlatively, soluble carbohydrates, total free amino acids, free proline and condensed tannins were quantified in control and infested leaves. Both aphid species showed parallel temporal variations, but A. spiraecola was consistently more abundant regardless of the stage. Amino acids had a positive effect on both aphid species abundance, but neither condensed tannins nor auxiliary insects seemed to modulate aphid populations. Interestingly, the leaf carbohydrate content was positively correlated with the abundance of A. spiraecola, but not with that of A. gossypii. Moreover, A. gossypii's abundance was significantly down-regulated by high proline concentrations. Thus, the higher abundance of A. spiraecola could be explained by a better tolerance to high proline contents and a better conversion of foliar energy metabolites.

Population dynamics of aphids (Aphididae) on orange (Citrus sinensis ‘Thomson Navel’) and mandarin (Citrus reticulata ‘Blanco’)

“…This coincides with moderate temperature and the production of new shoots appropriate for the reproduction of aphids and consequently the occurrence of predators and parasitoids. Many researches mentioned the peak of infestation by some aphids on citrus trees in spring (Saharaoui and Hemptinne, 2009;Kamel, 2010;Yoldaş et al, 2011;Mostefaoui et al, 2014). The within-year dynamics of aphids are largely determined by seasonal changes in host quality.…”

Revalorización del Complejo de Depredadores Polífagos Asociado al Cultivo de los Cítricos, Como Agentes de Control Biológico de Plagas Claves

“…Gómez-Marco et al (2016a, b) demonstrated that a sown grass cover enriched with wild forbs improved the biological control of aphids in citrus since it promoted the early presence of predators, including Scymnus species, in citrus canopies, before aphid exponential increase. At a regional scale, either by the samplings made in this study, or by those carried out by other researchers previously in the Mediterranean region (Hermoso de Mendoza et al, 2012;Mostefaoui et al, 2014;Lebbal & Laamari, 2016), the most abundant aphid species in citrus crops has been identified to be A. spiraecola. However, although both Scymnus species are the most abundant predators registered in the region, there is some controversy about which of the two could be the most important based on their demography.…”

“…Aphis gossypii and A. spiraecola were the only two aphid species found associated with clementine citrus crops in our study; the former being the dominant one. Aphis spiraecola is the most abundant aphid species in citrus on the Mediterranean Basin (Algeria, Morocco, Tunisia, Italy, Spain) and in other countries such as the USA and Japan (Marroquín et al, 2004;Franco et al, 2006;Yahiaoui et al, 2009;Tena & García-Marí, 2011;Hermoso de Mendoza et al, 2012;Vacante & Gerson, 2012;Belati & Belabed, 2014 (Mostefaoui et al, 2014). One of the possible causes, is the deformation produced by the saliva of this species in the citrus shoot is thought to be a key factor since it confers protection against adverse environmental conditions as well as against natural enemies (Cole, 1925).…”

“…One of the possible causes, is the deformation produced by the saliva of this species in the citrus shoot is thought to be a key factor since it confers protection against adverse environmental conditions as well as against natural enemies (Cole, 1925). Aphis gossypii, unlike A. spiraecola, is known to be affected by the high concentration of some plant compounds such as proline which is produced in large quantities as a result of physiological stress (Wool & Hales, 1996;Mostefaoui et al, 2014).…”

“…Por otro lado, Mostefaoui et al (2014) demostraron que A. gossypii, a diferencia de A. spiraecola, se ve afectada por la alta concentración de algunos compuestos como la prolina, este compuesto se produce en grandes cantidades como resultado del estrés fisiológico y reduce la calidad nutricional del huésped (Wool & Hales, 1996). La relación entre estas especies de pulgones y sus depredadores mediadas por la calidad que suponen estas presas como recurso alimenticio de éstos, es probablemente otro factor determinante en la actual dominancia de las especies de pulgones en citricos.…”