Partial refuges from biological control due to intraspecific variation in protective host traits

Abstract

Predicting how much of a host or prey population may be attacked by their natural enemies is fundamental to several subfields of applied ecology, particularly biological control of pest organisms. Hosts or prey can occupy refuges that prevent them from being killed by natural enemies, but habitat or ecological refuges are challenging or impossible to predict in a laboratory setting-which is often where efficacy and specificity testing of candidate biological control agents is done. Here we explore how intraspecific variation in continuous traits of individuals or groups that confer some protection from natural enemy attack-even after the natural enemy has encountered the prey-could provide partial refuges.The size of these trait-based refuges (i.e., the proportion of prey that survive natural enemy encounters due to protective traits) should depend on the relationship between trait values and host/prey susceptibility to natural enemy attack and on how common different trait values are within a

Genetic relationships among laboratory lines of the egg parasitoid Trissolcus japonicus from native and adventive populations

“…These findings were followed by detections in the western USA in 2015 (Milnes et al 2016), Switzerland and eastern Canada in 2017 (Gariepy and Talamas 2019;Stahl et al 2019), western Canada and Italy in 2018 (Peverieri et al 2018;Abram et al 2019), and several other locations throughout Europe and North America thereafter (e.g., Dieckhoff et al 2021;reviewed in Conti et al 2021). In the meantime, extensive research has been done on the parasitoid's host range and basic biology (reviewed in Conti et al 2021;Abram et al 2022), and intentional introductions of laboratory lines and redistributions of adventive lines are ongoing in Italy and the United States, respectively (Lowenstein et al 2019;Conti et al 2021). Stahl et al (2019) did a preliminary haplotype analysis of the DNA barcode region of the mitochondrial cytochrome c oxidase I (COI) gene among populations of T. japonicus from Switzerland, Japan, and China, finding five haplotypes among Japanese specimens (one of which was the same as the single haplotype found in Switzerland) and a single base-pair difference between Swiss and Chinese specimens.…”

A checklist of Platygastridae and Scelionidae (Hymenoptera, Platygastroidea) of Iran

“…Several attempts have been made for biological control of insect pests through introduction (Waterhouse, 1998;Ehler, 2002;Abram et al, 2020;Conti et al, 2021) and augmentation (Sharififar, 2000;Askarianzadeh et al, 2008;Khan et al, 2014;Abdi et al, 2015;Forouzan et al, 2018Forouzan et al, , 2020 of scelionids, as well as the surveys to find methods for their conservation (Safavi, 1960(Safavi, , 1973Radjabi, 2000;Amir-Maafi et al, 2002;Jamshidnia et al, 2010;Sayadmansour et al, 2009). To a lesser extent, species of Platygastridae have also been candidates for conservation biological control programs (Chavalle et al, 2015(Chavalle et al, , 2018McLennan, 2021;Abram et al, 2022). Some scelionids are known to attack the eggs of predatory insects, e.g., Chrysoperla carnea (Stephens, 1836) (Neuroptera, Chrysopidae) (Shahpouri Arani et al, 2005) and Podisus maculiventris (Say, 1832) (Hemiptera, Pentatomidae) (Allahyari et al, 2004) and have thus been considered hampering agents that may disrupt the effectiveness of a biological control program.…”