Variation in Oviposition Preference of Heliothis virescens in Relation to Macroevolutionary Patterns of Heliothine Host Range

Evolution ◽  
1990 ◽  
Vol 44 (5) ◽  
pp. 1326 ◽  
Author(s):  
Michael Waldvogel ◽  
Fred Gould
2019 ◽  
Author(s):  
Peng Zhang ◽  
Matthew W Turnbull

1.AbstractPolydnaviruses are dsDNA viruses associated with endoparasitoid wasps. Delivery of the virus during parasitization of a caterpillar and subsequent virus gene expression is required for production of an amenable environment for parasitoid offspring development. Consequently, understanding of Polydnavirus gene function provides insight into mechanisms of host susceptibility and parasitoid wasp host range. Polydnavirus genes predominantly are arranged in multimember gene families, one of which is the vinnexins, which are virus homologues of insect gap junction genes, the innexins. Previous studies of Campoletis sonorensis Ichnovirus Vinnexins using various heterologous systems have suggested the four encoded members may provide different functionality in the infected caterpillar host. Here, we expressed two of the members, vnxG and vnxQ2, using recombinant baculoviruses in susceptible host, the caterpillar Heliothis virescens. Following intrahemocoelic injections, we observed >90% of hemocytes (blood cells) were infected, producing recombinant protein. Larvae infected with a vinnexin-recombinant baculovirus exhibited significantly reduced molting rates relative to larvae infected with a control recombinant baculovirus and mock infected larvae. Similarly, larvae infected with vinnexin-recombinant baculoviruses were less likely to molt relative to controls, and showed reduced ability to encapsulate chromatography beads in an immune assay. In most assays, the VnxG protein was associated with more severe pathology than VnxQ2. These results, in light of previous findings, support that Polydnavirus Vinnexin gene family members may provide complementary, rather than redundant, effects. This in turn indicates a need to test gene family member functionality across infected hosts for effects to determine member contribution to host range.2.ImportancePolydnaviruses are obligate mutualistic associates of highly speciose wasp taxa that parasitize caterpillars. Expression of Polydnavirus-encoded genes in hosts parasitized by wasps is necessary for successful parasitization, and an unusual genome structure including multiple-membered gene families is hypothesized to contribute to host manipulation. We have tested this hypothesis by in vivo expression of two members of a family of Polydnavirus homologues of Innexins, or insect gap junction proteins. Previous findings demonstrated that the two Vinnexins induce different physiological alterations in heterologous systems. Here, in host caterpillars, we observed differential alteration by the two proteins of host immune cell (hemocyte) bioelectrical physiology and the immune response of encapsulation. Not only do our data suggest a linkage between cellular bioelectricity and immunity in insects, but they support that gene family expansion has functional consequences to both Polydnavirus and host wasp success.


2020 ◽  
Author(s):  
Árpád Szentesi

Abstract Background The host specificity of the dry bean weevil, Acanthoscelides obtectus Say (Coleoptera: Bruchinae), a seed predator of beans, is not properly known. Occasional use of leguminous seeds other than beans is reported, however the sphere of possible wild and cultivated hosts is uncertain. Female oviposition preference and larval performance relationship is complicated by the respective importance of seed coat and cotyledon, because paradoxically, females must exercise oviposition preference on the basis of stimuli provided by the seed coat alone, without directly being able to assess the quality of cotyledon’s suitability for larval development.Results Host specificity and host range investigations carried out on seeds of 62 grown and naturally occurring legume species and 82 cultivars of Phaseolus, Pisum, Glycine, Lens and others in Hungary, using no-choice tests for egg-laying, and intact or pierced seed coat for larval development in seeds, showed that there were 18 plant species (35% of them Lathyrus) that supported larval development to adults, however, only nine species (4 of 17 Glycine max accessions, Vigna unguiculata, V. angularis, Phaseolus vulgaris, Ph. coccineus, Cicer arietinum, Vicia faba, Lathyrus sativus and 13 of 27 Pisum sativum accessions) allowed it if the seed coat was intact. Furthermore, there was no overall positive correlation between oviposition preference and larval performance, with the exception for the so-called acceptable non-hosts (Kendall’s τ = 0.3088). Bean weevil females also demonstrated an ovipositional hierarchy of legume species even in no-choice tests.Conclusions Host range expansion is not probable with the bean weevil, primarily because it would require the recognition of basically different oviposition substrates (pods) among outdoor conditions.


Author(s):  
Kondwani R. Msangosoko ◽  
Mark A. Boetel ◽  
Robert J. Dregseth ◽  
Allen J. Schroeder

2019 ◽  
Vol 19 (6) ◽  
Author(s):  
Shihai Chu ◽  
Shengbo Cong ◽  
Ruhai Li ◽  
Youming Hou

Abstract Alternanthera philoxeroides (Mart.) Griseb. is an invasive herbaceous amphibious weed species in China. A pyralid moth Herpetogramma basalis (Walker) was discovered feeding on A. philoxeroides through field surveys and may be a potentially useful biocontrol agent. To determine the host range of H. basalis and evaluate its potential to control A. philoxeroides, no-choice and multiple-choice tests were conducted. Herpetogramma basalis fed on target weeds and 29 nontarget plant species. In addition to the target weed A. philoxeroides, H. basalis developed to adult on eight other nontarget species. Herpetogramma basalis survived to adulthood successfully on A. philoxeroides and less successfully on several other Amaranthaceae species. In multiple-choice studies, H. basalis showed a strong oviposition preference for A. philoxeroides over Amaranthus tricolor L. (Centrospermae: Amaranthaceae). Amaranthus tricolor was the only crop plant that supported the complete development of H. basalis. We cautiously recommend H. basalis for the biological control of A. philoxeroides in China.


2020 ◽  
Vol 113 (3) ◽  
pp. 1279-1289 ◽  
Author(s):  
Gamal E A Idriss ◽  
Hannalene du Plessis ◽  
Fathiya M Khamis ◽  
Sunday Ekesi ◽  
Chrysantus M Tanga ◽  
...  

Abstract Tuta absoluta (Meyrick) is one of the most devastating pests of tomato in both open field and greenhouse production settings that significantly reduce yield and quality of the fruit. Being a new invasive pest, information on the pest bio-ecology, including host-rage and effects of plant species on its various fitness traits are virtually lacking. This study involved a field survey to establish the realized host range and laboratory experiments to evaluate the preference for, and fitness effects of T. absoluta on different plant species. In the field, T. absoluta was recovered from only four solanaceous plant species: tomato (Solanum lycopersicum L.), eggplant (S. melongena L.), black nightshade (S. nigrum L.), and gubbain (S. dubium Fr.). In choice and no-choice tests, tomato was the most preferred host of T. absoluta having the highest number of eggs deposited, followed by black nightshade, French bean Phaseolus vulgaris L., and chilli pepper Capsicum frutescens. Larvae developed quickest on tomato followed by black nightshade and French bean. The percentage survival to adulthood was significantly higher on tomato, compared to survival on black nightshade and French bean. Rearing of T. absoluta on tomato or black nightshade had no significant effect on pupal mass and length as well as adult size for both sexes. Fecundity and longevity, as well as oviposition preference of T. absoluta, were not affected by rearing on different plants. These findings confirm the oligophagous nature of the pest with high preference to tomato.


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