Spontaneously Aborted Embryos in the Sugarcane Aphid (Hemiptera: Aphididae)

A spontaneously abortive embryo (SAE) process in field and greenhouse populations of sugarcane aphid, Melanaphis sacchari(Zehntner)(Hemiptera: Aphididae) is described, as well as the occurrence of SAE in populations from Chiapas, Durango, Guanajuato, Nayarit, Michoacan, Queretaro, Sinaloa, and San Luis Potosi states in Mexico. This phenomenon was observed from November 2014 to December 2017 in sugarcane aphid populations grown on Sorghum bicolor (sorghum), Sorghum drummondi (Sudan grass), and Sorghum halepense (Johnson grass). No reports of this phenomenon have been recorded earlier, perhaps due to the small size of the aborted embryos (200-500 Jim), the dark color they acquire within few hours of exposure, their frequent drop from the plant, and the crowded populations of aphids.The abortion process, both simple as well as multiple and complex events, are described. Also, embryos in vivo, alcohol-fixed, and mounted individuals are described. Embryogenic stages 13 and 16-19 were identified in the aborted embryos. It is suggested that specific biotic and/or abiotic situations may intervene on the reproductive physiology of these particular populations, most probably, on the hormone balance. However, the presence of a complex symbiotic/pathogenic microbial association is not discarded, according to some observations, which are still to be studied.