DOI: 10.5061/dryad.0cfxpnwch
title: Soybean HPR virulence and parasitism by Aphelinus

description: Invasions by insect species that become pests are an increasing problem
 for agriculture. Introductions of parasitoids from the regions of pest
 origin and breeding plants resistant to invasive pests can reduce invasive
 pest abundance and impact. Whether interactions between parasitoids and
 plant resistance are positive or negative depends on the detailed
 mechanisms. We studied the effects of susceptible versus
 resistant soybean and avirulent versus virulent soybean aphid on the
 parasitoids Aphelinus certus and Aphelinus glycinis, the first
 with a broad host range and the second with a narrow host
 range. Both parasitoid species parasitized virulent aphids at
 least as much as avirulent aphids on susceptible and resistant soybeans.
 Aphelinus certus parasitized fewer avirulent aphids than virulent aphids
 on resistant soybean and fewer avirulent aphids on resistant versus
 susceptible soybean. The number of aphids parasitized by A. glycinis did
 not vary with the treatments. Emergence rates of parasitoid
 progeny were high for both parasitoids and did not vary with the
 treatments. Progeny sex ratios of the parasitoids did not vary with plant
 resistance or aphid virulence. However, for A. certus, there was
 a small effect of the interaction between plant resistance and aphid
 virulence. Body masses of female and male progeny of A.
 certus did not vary with the treatments. However, body masses of female
 progeny of A. glycinis were larger on susceptible versus resistant
 soybeans and on virulent versus avirulent aphids. Body masses of male
 progeny of A. glycinis were larger on susceptible versus resistant
 plants. Parasitism by A. certus is known to be
 density-dependent, and given that density-dependent parasitism has been
 found in several other species of Aphelinus, parasitism by A. glycines is
 very likely also to be density-dependent. Given the higher densities of
 virulent versus avirulent aphids on resistant soybean reported in the
 literature, these parasitoids should parasitize more virulent than
 avirulent aphids on resistant soybean and would limit the abundance of
 virulent soybean aphid if much of the soybean acreage had resistant
 plants. Little research has been published previously on the
 combined impacts of plant resistance and herbivore virulence on
 parasitoids. If our results hold true in other systems, plant resistance
 and biological control may be more compatible in suppressing herbivore
 virulence than has sometimes been proposed.
description: # Soybean HPR virulence and parasitism by *Aphelinus* Dataset DOI:
 [10.5061/dryad.0cfxpnwch](10.5061/dryad.0cfxpnwch) ## Description of the
 data and file structure DATA DESCRIPTION We tested the effects of plant
 resistance and aphid virulence on the numbers of aphids parasitized, as
 well as parasitoid emergence, sex ratio, and body mass of females and
 males in randomized complete-block experiments separately for the two
 species of parasitoids. The experimental unit was a potted plant covered
 with a cage (10x22cm) and infested with 100 mixed-instar aphids. There
 were 48 units planted with susceptible soybeans and 48 planted with
 resistant soybeans. For each level of resistance, 24 units were infested
 with avirulent aphids and 24 were infested with virulent aphids, for a
 total of 96 experimental units. Among the experimental units, 40 were
 exposed to one parasitoid species, and 40 to the other parasitoid species.
 We added a single, female parasitoid, previously exposed to males, a day
 after aphid infestation, and we removed the female a day later. After two
 weeks, we harvested the plants and later counted the number of mummified
 aphids and the numbers and genders of adult parasitoid progeny. We weighed
 the parasitoid progeny to get mean body masses for each experimental unit
 with parasitoids. Because females of many parasitoid species are larger
 than males, we weighed females and males separately and analyzed the
 effects of the treatments on the masses of females and males separately.
 We calculated progeny emergence rates for experimental units with at least
 four mummified aphids, which reduced replication from 40 experimental
 units for each parasitoid species to 20 for *A. certus* and 21 for *A.
 glycinis*.  | variable | definition | | :------------------ |
 :-------------------------------------------------------------------------
 | | wasp\_species | species of parasitoid | | country | collection country
 | | city | collection city | | site | collection site | | year |
 collection year | | biotype | Aphis glycines virulence biotype (1 =
 avirulent; 4 = virulent) | | wasp\_id | parasitoid indicator | | wasp\_pop
 | parasitoid subpopulation | | soybean\_accession | soybean accession
 indicator | | alleles | resistance alleles | | block | randomization block
 | | location | location within randomization block | | date\_in | date
 parasitoids added aphid cage | | time\_in | date parasitoids added aphid
 cage | | date\_out | date parasitoids added aphid cage | | time\_out |
 date parasitoids added aphid cage | | wasp\_fate | whether the parasitoid
 was live, dead, or missing when removed from the aphid cage | |
 plant\_fate | whether the plant was live or dead when the mummies were
 harvested | | n\_mum | number of mummified aphids | | n\_emer | number of
 mummified aphids from which parasitoids emergec | | n\_adult | number of
 adult parasitoid progeny | | n\_males | number of adult male parasitoid
 progeny | | n\_males\_weighed | number of males weighed | | weight\_males
 | weight of males (micrograms of dry mass) | | n\_females | number of
 adult female parasitoid progeny | | n\_females\_weighed | number of
 females weighed | | weight\_females | weight of females (micrograms of dry
 mass) | ## Access information NA