Differences in food plant species of the polyphagous herbivore Mythimna separata (Lepidoptera: Noctuidae) influence host searching behavior of its larval parasitoid, Cotesia kariyai (Hymenoptera: Braconidae)

2018 ◽  
Vol 13 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Kazumu Kuramitsu ◽  
Edelyn Joy M. Vicencio ◽  
Yooichi Kainoh
2006 ◽  
Vol 41 (4) ◽  
pp. 321-328 ◽  
Author(s):  
P. Glynn Tillman

Host searching behavior of females of the endoparasitoid Toxoneuron nigriceps Vierick (Hymenoptera: Braconidae) was observed in the field for three tobacco herbivores, Heliothis virescens (F.), Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), and Manduca sexta L. (Lepidoptera: Sphingidae). The only developmentally suitable host for the parasitoid was H. virescens. Hovering, searching, and oviposition (for plants with herbivores) by T. nigriceps were observed for a combination of two plant types, plants with only herbivore-induced plant volatiles or damaged plants with herbivores, and three insect species. The six treatments were as follows: (1) plants with only H. virescens-induced plant volatiles, (2) plants with only H. zea-induced plant volatiles, (3) plants with only M. sexta-induced plant volatiles, (4) plants damaged by H. virescens, (5) plants damaged by H. zea, and (6) plants damaged by M. sexta. Parasitoid females readily hovered around and searched on plants of both types. However, females spent more time foraging for H. virescens than for the nonhosts, H. zea and M. sexta. For plants with only herbivore-induced plant volatiles, T. nigriceps females spent more time searching on H. virescens plants than on H. zea and M. sexta plants. For damaged plants, parasitoid females visited more H. virescens plants than M. sexta plants and spent more time searching for H. virescens larvae than for M. sexta and H. zea larvae. Even though T. nigriceps females laid eggs in M. sexta and H. zea larvae, oviposition was higher for H. virescens than for the nonhosts. In conclusion, T. nigriceps females utilized more of their energy searching for and parasitizing H. virescens over the nonhosts on tobacco.


Author(s):  
Peirong Li ◽  
Xinru Li ◽  
Wei Wang ◽  
Xiaoling Tan ◽  
Xiaoqi Wang ◽  
...  

Abstract The oriental armyworm, Mythimna separata (Walker) is a serious pest of agriculture that does particular damage to Gramineae crops in Asia, Europe, and Oceania. Metamorphosis is a key developmental stage in insects, although the genes underlying the metamorphic transition in M. separata remain largely unknown. Here, we sequenced the transcriptomes of five stages; mature larvae (ML), wandering (W), and pupation (1, 5, and 10 days after pupation, designated P1, P5, and P10) to identify transition-associated genes. Four libraries were generated, with 22,884, 23,534, 26,643, and 33,238 differentially expressed genes (DEGs) for the ML-vs-W, W-vs-P1, P1-vs-P5, and P5-vs-P10, respectively. Gene ontology enrichment analysis of DEGs showed that genes regulating the biosynthesis of the membrane and integral components of the membrane, which includes the cuticular protein (CP), 20-hydroxyecdysone (20E), and juvenile hormone (JH) biosynthesis, were enriched. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that DEGs were enriched in the metabolic pathways. Of these DEGs, thirty CP, seventeen 20E, and seven JH genes were differentially expressed across the developmental stages. For transcriptome validation, ten CP, 20E, and JH-related genes were selected and verified by real-time PCR quantitative. Collectively, our results provided a basis for further studies of the molecular mechanism of metamorphosis in M. separata.


1993 ◽  
Vol 83 (3) ◽  
pp. 321-328 ◽  
Author(s):  
H. van den Berg ◽  
M. J. W. Cock ◽  
G. I. Oduor ◽  
E. K. Onsongo

AbstractSmallholder crops (sunflower, maize, sorghum and cotton) were grown in experimental plots at seven sites, representing different agricultural zones of Kenya, over four seasons. Helicoverpa armigera (Hübner) (formerly Heliothis armigera) only occasionally achieved population densities sufficient to cause obvious damage to the crops, and was virtually absent from the coastal sites. At the inland sites, infestation and mortality levels varied greatly. Information is presented on the incidence of H. armigera, and the identity, distribution and frequency of its common parasitoids and (potential) predators, sampled in the experimental plots. Trichogrammatoidea spp., egg parasitoids, and Linnaemya longirostris (Macquart), a tachinid late-larval parasitoid, were the most common parasitoid species, but total percentage parasitism was rather low. Of the large complex of predators, only anthocorids and ants (predominantly Pheidole spp., Myrmicaria spp. and Camponotus spp.) were sufficiently common and widespread to be of importance in suppressing H. armigera. The abundance of predators fluctuated widely between sites, but anthocorids were most abundant at the western sites.


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