Reproductive pattern in the solanum mealybug,Phenacoccus solani: A new perspective

Abstract

Background The reproductive pattern of most scale insects is ovoviviparity. The solanum mealybug, Phenacoccus solani (Hemiptera: Pseudococcidae), is known as a thelytokous parthenogenetic species, but there is still debate about the reproductive strategies of this species. Methods Here, we investigated the oviposition characteristics of P. solani and used scanning/transmission electron microscopy and RNA-seq to identify the differences between two types of eggs. Results We found that P. solani laid two types of eggs in one batch, with no significant difference in apparent size: one with eyespots that hatched and another without eyespots that failed to hatch. Furthermore, the physiological and molecular differences between the two types of eggs were highly significant. KEGG enrichment analysis revealed significant enrichment for the JAK-STAT, Notch, Hippo, and Wnt signaling pathways and dorsoventral axis formation, wax biosynthesis, cell cycle, insulin secretion, and nitrogen metabolism pathways. The results suggest that the embryo of the egg undergoes development inside the mother and only a short molting period outside the mother. Discussion Ovoviviparous species produce eggs and keep them inside the mother’s body until they are ready to hatch, and the offspring exits the egg shell during or immediately following oviposition. Therefore, we suggest that the reproductive pattern of P. solani can be described as ovoviviparity.

Construction of a Banker Plant System via the Host Switch Trait of a Natural Enemy Aenasius bambawalei

“…All experiments were conducted under controlled conditions, with a temperature range of 26-28 • C, relative humidity of 70-80%, and a photoperiod of 16 h light and 8 h dark. This environmental setup was based on the method described by Huang et al (2020) [34].…”

“…Previous studies have shown that AB can successfully switch hosts from PSS to PSI after 6 h of adaptation [34]. Thus, according to our preliminary study, two host switch patterns, the T1 host sequence (PSS-PSI-PSS) and T2 host sequence (PSI-PSS-PSI), were selected to clarify the effect of host switch pattern on the population traits of AB.…”

“…However, the host specificity of AB may vary among different populations of Phenacoccus spp. Huang et al (2020) demonstrated in laboratory trials that AB can successfully switch between PSS and another invasive species called P. solani Ferris (PSI) in China [34]. Nevertheless, the multiple host switch behavior of AB and its implications for optimizing the AB population remain poorly understood.…”

“…This includes targeting the second-and third-instar nymphs, as well as female adults of the PSS, while avoiding the first-instar nymphs [31]. Field research has demonstrated that AB can attain high parasitic rates, even reaching 95% or 100% [34]. However, the lack of suitable host stages can hinder the population development of AB and reduce its efficiency in controlling the second-instar or higher PSS, which emerge from the first instar.…”

The parasitoid Aenasius arizonensis prefers its natural host but can parasitize a nonnatural host in the laboratory: an opportunity for control of a new invasive mealybug

“…More than 200 plant species in 55 families in 24 countries around the world are attacked by PSS; it has replaced the cotton bollworm as the main pest of cotton in India and Pakistan (Fand and Suroshe 2015) and poses a great threat to cotton production in China. The solanum mealybug, Phenacoccus solani (Hemiptera: Pseudococcidae) (hereafter PSI), is native to California, North America (Chatzidimitriou et al 2016) and has been newly recorded in China, where it is considered to be a major threat to agricultural production and the ecological environment (Huang et al 2020). Both PSS and PSI belong to the same genus and are invasive in China, but they have different reproductive modes; PSI is a thelytokous parthenogenetic species, with no males in the population (Huang et al 2020), while PSS undergoes only sexual reproduction (Huang et al 2013).…”