Fernando L. Cônsoli

Two genomes of highly polyphagous lepidopteran pests (Spodoptera frugiperda, Noctuidae) with different host-plant ranges

Emergence of polyphagous herbivorous insects entails significant adaptation to recognize, detoxify and digest a variety of host-plants. Despite of its biological and practical importance - since insects eat 20% of crops - no exhaustive analysis of gene repertoires required for adaptations in generalist insect herbivores has previously been performed. The noctuid moth Spodoptera frugiperda ranks as one of the world’s worst agricultural pests. This insect is polyphagous while the majority of other lepidopteran herbivores are specialist. It consists of two morphologically indistinguishable strains (“C” and “R”) that have different host plant ranges. To describe the evolutionary mechanisms that both enable the emergence of polyphagous herbivory and lead to the shift in the host preference, we analyzed whole genome sequences from laboratory and natural populations of both strains. We observed huge expansions of genes associated with chemosensation and detoxification compared with specialist Lepidoptera. These expansions are largely due to tandem duplication, a possible adaptation mechanism enabling polyphagy. Individuals from natural C and R populations show significant genomic differentiation. We found signatures of positive selection in genes involved in chemoreception, detoxification and digestion, and copy number variation in the two latter gene families, suggesting an adaptive role for structural variation.

Do new Access and Benefit Sharing procedures under the Convention on Biological Diversity threaten the future of biological control

Under the Convention on Biological Diversity (CBD) countries have sovereign rights over their genetic resources. Agreements governing the access to these resources and the sharing of the benefits arising from their use need to be established between involved parties [i.e. Access and Benefit Sharing (ABS)]. This also applies to species collected for potential use in biological control. Recent applications of CBD principles have already made it difficult or impossible to collect and export natural enemies for biological control research in several countries. If such an approach is widely applied it would impede this very successful and environmentally safe pest management method based on the use of biological diversity. The CBD is required to agree a comprehensive Access and Benefit Sharing process in 2010, in preparation for which the IOBC (International Organization for Biological Control of Noxious Animals and Plants) Global Commission on Biological Control and Access and Benefit Sharing has prepared this position paper. Here, we first describe the practice of biological control in relation to the principles of ABS, illustrated extensively by case studies and successes obtained with biological control. Next, we emphasise the very limited monetary benefits generated in biological control when compared to other fields of ABS such as the collection of germplasm for development of human drugs, chemical pesticides or crop cultivars. Subsequently, we inform the biological control community of good ABS practice and challenges, and we hope to make clear to the community involved in ABS under the CBD the special situation with regard to biological control. Finally, based on the non-commercial academic research model, we make recommendations which would facilitate the practice of collection and exchange of biological control agents, propose a workable framework to assist policy makers and biological control practitioners, and urge biological control leaders in each country to get involved in the discussions with their national ABS contact point to take their needs into consideration.

Side‐effects of insecticides used in tomato fields on the egg parasitoid Trichogramma pretiosum Riley (Hym., Trichogrammatidae), a natural enemy of Tuta absoluta (Meyrick) (Lep., Gelechiidae)

Abstract: Trichogramma pretiosum Riley is an important natural enemy used for the biological control of Tuta absoluta in tomato fields in several countries in South America. The side‐effects of insecticides on T. pretiosum was tested by dipping parasitized host eggs (Ephestia kuehniella Zeller) at three different development stages (egg‐larvae, pre‐pupae and pupae) in pesticide solution at recommended concentrations. The insecticides varied in their toxicity and significantly affected the development time of the immature stages, emergence, parasitism and longevity of the adult parasitoid. Cartap and phenthoate were harmful and caused total mortality in all the experiments in the three stages of development tested. Lambda‐cyhalothrin was not detrimental but caused a significant increase in mortality, prolonged development of the immature stages and decreased the capacity of parasitism of the emerged females. Tebufenozide, teflubenzuron and abamectin had sublethal effects. They reduced the time of development, especially when applied during the pupae stage. The capacity of parasitism of emerged females decreased and was affected by the stage of development treated. With abamectin treatments, parasitism decreased as the development of the parasitoid advanced and the mortality of the emerged adults from host eggs treated during the pupae stage was significantly higher. Tebufenozide reduced parasitism when applied during the egg‐larval and pre‐pupae stages. The results showed that cartap and phenthoate were harmful, lambda‐cyalothrin and abamectin were intermediate, tebufenozide and teflubenzuron were harmless to slightly harmful. Nearly all the chemicals tested had significant sublethal effects.

Selectivity of insecticides to the egg parasitoid Trichogramma galloi Zucchi, 1988, (Hym., Trichogrammatidae)

Trichogramma galloi Zucchi is an efficient biological control agent against the sugarcane borer, Diatraea saccharalis (F.) in sugarcane fields in Brazil. This parasitoid is also a candidate to be used in pest management programmes in corn, as D. saccharalis has become a serious pest of this crop in some areas in Brazil. However, there is no data on the side‐effects of chemicals on this species. The side‐effects of promising chemicals to control the sugarcane borer in corn were tested by dipping eggs of the factitious host into the insecticidal solutions. Two different treatments were tested. First, dipping parasitized host eggs at different stages of immature development (egg‐larva, prepupa and pupa); and second, by offering treated eggs to newly emerged females. The toxicity of the chemicals tested were dependent on the age of the parasitoid, affecting the immature survival, developmental time from egg to adult, parasitization capacity, adult longevity and the development of the filial generation. Spinosad, tebufenozide, triflumuron and lufenuron delayed adult eclosion of T. galloi when used to treat the host egg during the pupal stage. Spinosad was harmful when tested against any immature stage and adults of T. galloi. Lufenuron and triflumuron were harmful only when applied during the egg‐larval development of the parasitoid. Although they did not affect the parasitization capacity, they caused almost 100% mortality of the immatures when used to treat eggs prior to parasitization. Tebufenozide was harmless to T. galloi causing a very slight immature mortality if used during the prepupal development.

Egg parasitoids in agroecosystems with emphasis on Trichogramma

1. Reproduction and Immature Development of Egg Parasitoids Guy Boivin.- 2. Nutritional Ecology of Insect Egg Parasitoids S. Bradleigh Vinson.- 3. Antennal Structures Used in Communication by Egg Parasitoids Roberto Romani, Nunzio Isidoro, Ferdinando Bin.- 4. Host Searching by Egg Parasitoids: Exploitation of Host Chemical Cues Stefano Colazza, Ezio Peri, Gianandrea Salerno, Eric Conti.- 5. Genetics of the Behavioral Ecology of Egg Parasitoids Eric Wajnberg.- 6. Sex Ratio Modulators of Egg Parasitoids James Russell, Richard Stouthamer.- 7. Systematics of the Trichogrammatidae (Hymenoptera: Chalcidoidea) with a Focus on the Genera Attacking Lepidoptera Ranyse B Querino, Roberto A Zucchi, John D. Pinto.- 8. Diversity and hosts of Trichogramma in the New World, with emphasis in South America Roberto A Zucchi, Ranyse B Querino, Renata C Monteiro.- 9. Species Diversity and Host Associations of Trichogramma in Eurasia Andrew Polaszek.- 10. Mass Rearing of Egg Parasitoids for Biological Control Programs Jose Roberto Postali Parra.- 11. In vitro Rearing of Egg Parasitoids Fernando L Consoli, Simon Grenier.- 12. Quality Control of Mass Reared Egg Parasitoids Joop C. van Lenteren, Franz Bigler.- 13. Biological Control with Egg Parasitoids other than Trichogramma - the Citrus and Grape Cases Jorge E. Pena, Josep A. Jacas, Serguei Tryapsin, Bryan J. Ulmer, R. E. Duncan.- 14. Egg Parasitoid Commercialization in the New World Jose Roberto Postali Parra.- 15. Egg Parasitoids in Biological Control and Integrated Pest Management Nick Mills.- 16. Risk Assessment and Non-Target Effects of Egg Parasitoids in Biological Control Franz Bigler, Dirk Babendreier, Joop C. van Lenteren.- 17. Genetically Modified Crops and Biological Control with Egg Parasitoids Julio S Bernal.

Ultrastructure of the natural and factitious host eggs of Trichogramma galloi Zucchi and Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

Abstract The surface and structure of the chorion of eggs of Diatraea saccharalis (F.) (Lepidoptera: Crambidae), Anticarsia gemmatalis (Huebner), Heliothis virescens F., Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), Sitotroga cerealella (Oliver) (Lepidoptera: Gelechiidae), Ephestia kuehniella Zeller and Corcyra cephalonica Stainton (Lepidoptera: Pyralidae), that are hosts of Trichogramma galloi Zucchi and Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) were studied on SEM and TEM. Other characteristics of these eggs, such as changes in their color during embryonic development, size and volume were also recorded. Sculpturing and texture of the surface of the chorion greatly varied among the species studied, as well as the number of layers of the chorion and their thickness. Eggs of the factitious hosts were among the smallest and their volume was very close to each other. All these characteristics would provide basic information for a better understanding of the host selection behavior and are useful for the development of a suitable artificial host egg for the in vitro rearing of these egg parasitoids.

Isolation and characterization of actinobacteria ectosymbionts from Acromyrmex subterraneus brunneus (Hymenoptera, Formicidae)

The ectosymbiont actinobacterium Pseudonocardia was isolated from the integument of Acromyrmex leaf-cutter ants and seems to play a crucial role in maintaining asepsis of the nest. Currently, there has been an intensive search for Pseudonocardia associated with several attine species, but few studies have indicated that other actinobacteria may be associated with these ants as well. We therefore characterized the culturable actinobacteria community associated with the integument of the fungus-growing ant Acromyrmex subterraneus brunneus Forel, 1893 (Hymenoptera: Formicidae). Ectosymbionts were isolated using four different media and characterized by morphological and molecular (16S rDNA) methods. A total of 20 strains were isolated, of which 17 were characterized as Streptomyces spp., and one isolate each as Pseudonocardia, Kitassatospora and Propionicimonas. Unlike other Acromyrmex species, A. subterraneus brunneus is associated with a diversity of actinobacteria. Even though Pseudonocardia is present on this leaf-cutting ants integument, the number and diversity of Streptomyces spp. found differs from those of previous studies with other attine ants and suggest that different culturing approaches are needed to characterize the true diversity of microbes colonizing the integument of attine ants. Moreover, understanding the diversity of the culturable actinobacteria associated with A. subterraneus brunneus should increase our knowledge of the evolutionary relationship of this intricate symbiotic association.

Effects of constant and alternating temperatures on Trichogramma galloi Zucchi (Hym., Trichogrammatidae) biology. I. Development and thermal requirements

This work was carried out in order to study the effects of constant and alternating temperatures on the development and thermal requirements of Trichogramma galloi, the most common egg parasitoid of the sugarcane borer in Brazil. T. galloi developmental time was shorter when reared at alternating temperatures. The emergence rate of T. galloi decreased at constant 18°C, and the sexual ratio was affected only at 32°C. T. galloi degree‐days and threshold temperatures were similar when estimated using constant or alternating temperatures.

Trans-bergamotenes-male pheromone of the ectoparasitoid Melittobia digitata.

The first male-produced sex attractant pheromone in the parasitic Hymenoptera has been identified. The elaborate courtship behavior of Melittobia digitata, an idiobiont that parasitizes the last larval instar or the pupal stage of solitary bees and wasps, involves a series of coordinated movements of legs, wings, and antennae, initiated after the female is attracted to the blind, flightless male. We identified α- and β-trans-bergamotene as the active compounds of the male M. digitata sex attractant. Variation in the release of the sex pheromone by males and the pheromone load during aging is also described.

Clutch size, development and wing morph differentiation of Melittobia digitata

Melittobia digitata Dahms (Hymenoptera, Eulophidae) is a wing polymorphic, gregarious ectoparasitoid of bees and wasps. In nature, females of this wasp start to produce their progeny after feeding on the host. The first adults to develop will emerge as short wing morphs (SWM). Mother and daughters will lay eggs in the same hosts, and the following females to develop will emerge as long wing morphs (LWM). We evaluated the effects of the clutch size on the development, egg load, and wing morph differentiation of M. digitata. Developmental time was shorter when insects developed in small clutches, and immature survivorship was reduced in the largest clutch (400 eggs/host). Morph differentiation was also affected by the clutch size. SWMs developed in small clutches (5 and 25 eggs/host) while LWMs in large clutches (200 and 400 eggs/host). However, both morphs developed in intermediate clutches (50 and 100 eggs/clutch), with a decreasing number of SWMs developing with the increase in the clutch. The size and egg load of each morph was affected with the increase in the clutch size, although the forewing length/hind‐tibia length ratio was kept constant for each morph developing from different clutch sizes. Egg load of LWMs was also reduced when compared to the SWMs that developed from the same clutch, although LWMs females were larger (longer tibia length). We discuss the possible mechanisms inducing the morph differentiation in M. digitata, as well as the physiological, behavioral, and ecological changes facing each morph.