Taxonomic Status and Population Oscillations of Aphidius colemani Species Group (Hymenoptera: Braconidae) in Southern Brazil

Abstract

Aphidius colemani (Viereck) was reported in Brazil before the Biological Control Program of Wheat Aphids (BCPWA) when Mediterranean genotypes were introduced from France and Israel. This species was re-described as a complex called A. colemani group composed of three species. Consequently, uncertainty remains about which parasitoid of the group is occurring in southern Brazil. This study has two main objectives: (i) re-examine the species status of A. colemani group collected during the introduction of parasitoids and from a 10-year (2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018) monitoring program in wheat fields in northern Rio Grande do Sul (RS), Brazil; (ii) describe the variation in the population density of parasitoids and its association with meteorological factors during this period. We examined 116 specimens from the Embrapa Wheat entomological collection, and those collected in Moericke traps in Coxilha, RS. All the parasitoids of the A. colemani group from the BCPWA period were identified as Aphidius platensis (Brèthes). In traps, 6541 cereal aphid parasitoids were collected, of which 61.9% (n = 4047) were from A. colemani group and all those were identified as A. platensis. Temperature was the factor that effected population density with the highest number of parasitoids recorded in the winter months. Sex ratio changed between years varying from 0.50 to 0.97. The parasitoid A. platensis was the only species in the A. colemani group sampled during 10 years of monitoring.

Oscillation, synchrony, and multi-factor patterns between cereal aphids and parasitoid populations in southern Brazil

“…The response of parasitoids to air temperature was first observed by Santos et al . (2019). Parasitoids of the Aphidius genus (the dominant genus in this study) have faster development in temperatures between 15 and 25°C, and temperatures closer to 20°C are optimum for population growth.…”

“…Among the existing insect-pest species, aphids are among the most widespread worldwide, damaging wheat crops throughout their entire cycle (Dedryver et al ., 2010; Parizoto et al ., 2013; Rebonatto et al ., 2015; Brewer et al ., 2019). Biological control has been applied through parasitoids to reduce both direct and indirect damages caused by aphids in cereal crops (Andrade et al ., 2016; Yang et al ., 2017; Santos et al ., 2019). However, studies to detect the meteorological variables that influence population dynamics in aphid–parasitoid systems under field conditions are still scarce (Harrington et al ., 2007; Bell et al ., 2015; Honek et al ., 2018).…”

Suitability and Profitability of a Cereal Aphid for the Parasitoid Aphidius platensis in the Context of Conservation Biological Control of Myzus persicae in Orchards

“…Though it is currently unclear whether they studied A. colemani per se, as the identity of this species is not clear yet, it is possible that they have also studied A. platensis, as A. colemani is now a complex of cryptic, sibling species [ 49 , 75 , 76 ]. It was considered as a group, together with two other close species: A. transcaspicus and A. platensis , probably used as synonyms in several taxonomic descriptions [ 52 , 55 , 77 ]. Host fidelity is maximized in constant environments, where a continuous supply of aphid hosts is found [ 37 ]; e.g., parasitoids from the aphid hosts S. avenae, Acyrthosiphon pisum Harris (Hemiptera: Aphididae) alfalfa race and A. pisum pea race showed a preference for their natal host [ 51 ].…”

Viroses em trigo no brasil: uma visão histórica

“…Essas práticas irão minimizar os reservatórios de vírus e vetores nas áreas de cultivo de trigo. O controle biológico utilizando espécies de microhimenópteros teve grande êxito no Brasil, reduzindo significativamente a população de afídeos (SALVADORI & TONET 2001;SALVADORI & SALLES 2002;SANTOS et al 2019).…”