Cryptic genetic diversity and associated ecological differences of Anastatus orientalis, an egg parasitoid of the spotted lanternfly

Abstract

Anastatus orientalis, native to northern China, is an egg parasitoid wasp of the spotted lanternfly (Lycorma delicatula) and is being tested as a potential biological control agent for invasive L. delicatula in the United States. As a component of these evaluations, live A. orientalis collected from Beijing and Yantai in China were reared in containment in the U.S. These specimens showed different responses in diapause behaviors to rearing conditions used previously by other researchers. To understand the primary mechanism potentially driving discrepancies in important life history traits, we used molecular tools to examine the genetic composition of A. orientalis from China and from South Korea, where the parasitoid has been introduced to aid in the population management of invasive L. delicatula. Molecular analysis of mitochondrial DNA recovered six haplotype groups, which exhibit biased frequency of abundance between collection sites. Some haplotypes are widespread, and others only occur in certain locations. No apparent pattern is observed between wasps collected from different years or emergence seasons. Uncorrected genetic distances between haplotype groups range from 0.44% to 1.44% after controlling for within-group variation. Genetic variance of A. orientalis is characterized by high levels of local diversity that contrasts with a lack of a broad-scale population structure. The introduced Korean population exhibits lower genetic diversity compared to native populations. Additionally, we created iso-female lines for major haplotype groups through laboratory rearing. Differences in diapause behavior were correlated with mitochondrial haplotype. Our results indicate that the observed life history traits in A. orientalis have a genetic base.

Effects of transgenerational photoperiod experience on the reproduction and development of Anastatus orientalis, an egg parasitoid of the spotted lanternfly

“…Wu et al. ( 43 ) used molecular tools to examine the genetic composition of A. orientalis , and the results suggest a genetic component in determining the diapause behaviors of A. orientalis . In addition, Broadley et al.…”

“…This may be due to the strain of A. orientalis used between these different studies. Wu et al (43) used molecular tools to examine the genetic composition of A. orientalis, and the results suggest a genetic component in determining the diapause behaviors of A. orientalis. In addition, Broadley et al (44) determined that the A. orientalis used previously in their study (23), which also went into diapause when exposed to long photoperiod conditions, was a homogenous colony composed of haplotype C. Because the wasps in this study responded similarly, it is highly likely that specimens from our study are composed primarily of haplotype C. However, the different results across studies also may be due to the differences in colony rearing protocol or potentially in how transgenerational effects were expressed.…”

Modelling the emergence of social-bird biological controls to mitigate invasions of the spotted lanternfly and similar invasive pests

“…Since its confirmed arrival in the USA in 2014, its growth and spread to new areas has been rapid, despite efforts to contain the spread with quarantine zones and to control the populations in infested areas [ 8 , 9 ]. In its native range, egg parasitoid Anastatus orientalis [ 10 , 11 ] and nymph parasitoid Dryinus browni [ 12 ] help control the population. It is believed that a key reason for the lanternfly’s success in the USA and elsewhere where it is invasive is a lack of natural enemies [ 13 ].…”

“…In particular, quarantines to contain the infestation, and a number of control measures to manage already-infested areas [ 8 ]. Control measures currently under consideration, or application, include a variety of insecticides [ 16 ], parasite-based biological controls [ 11 , 14 , 17 – 19 ], traps [ 20 ], egg scraping [ 21 ], bark injections and removing the preferred host [ 22 , 23 ]. However, at present, these management efforts appear to be insufficient and there are potential issues with each of them.…”