Academic literature on the topic 'Cotesia flavipes complex'

AbstractMating behaviour, sex pheromone attraction and reciprocal breeding of Cotesia flavipes Cameron (Hymenoptera: Braconidae), C. sesamiae (Cameron) and C. chilonis (Matsumura) were studied. These three putative species comprise the Cotesia flavipes complex. Wing fanning and antennal vibration were the initial courtship signals from the males. Antennal stroking by the male was also an important contact signal and a prerequisite to successful mounting and copulation. Interspecific crosses revealed that males of C. flavipes exhibited courtship behaviour, and mounted and copulated with females of C. chilonis and C. sesamiae; the males transferred sperm but progeny from these crosses did not include females. Males of C. sesamiae copulated with females of C. chilonis and the progeny included viable females. The progeny backcrosses of the hybrid females to male parents also included viable females. Sex pheromone experiments were conducted in a Y-tube olfactometer and in large field cages. Males and females of C. flavipes perceived and responded to odours emitted by the opposite sex. There was no significant response to odours from conspecific individuals of the same sex in any of the three species. Pheromone bioassays in field cages using sticky traps baited with live virgin C. flavipes females attracted conspecific males.

The Australian species Cotesia nonagriae Olliff stat. rev. (Hymenoptera: Braconidae) is redescribed and formally removed from synonymy with C. flavipes based on molecular, morphological and biological differences. The taxonomic history and phylogenetic relationships of C. nonagriae with other members of the C. flavipes complex are presented and underscore the importance of molecular-based identification within this group. The biology of C. nonagriae on the native noctuid stemborer host, Bathytricha truncata (Walker), is compared with previously recorded C. flavipes life history traits. The implications of this taxonomic study relative to biological control and importation of stemborer parasitoids into Australia are discussed.

AbstractMorphometric studies of allopatric populations of the Cotesia flavipes species complex representing three putative species; C. flavipes Cameron, C. sesamiae (Cameron) and C. chilonis (Matsumura), were conducted. Sixteen characters were measured. Principal component analysis separated the complex into three somewhat overlapping groups that corresponded well with previous concepts of the species. Canonical variate analysis separated the complex into three distinct clusters with populations from Africa together, populations from Asia and the Neotropics forming a second cluster, and material from China and Japan forming a third cluster. The Mahalanobis squared distances between the three clusters were nearly equal. Results support recognition of three species in the C. flavipes complex.

AbstractLocal parasitoid populations may be adapted to their sympatric major plant host complex. Parasitoid strains may thus differ in their propensity to search for a particular micro-habitat or host or they may differ in their physiological compatibility with particular plant or host species. Cotesia flavipes Cameron, a larval parasitoid used worldwide in biological control against tropical stemborers, has a wide host range in diverse habitats. The existence of plant and/or host specific strains in C. flavipes has been postulated. To provide insight into the existence of strains in C. flavipes, we compared the plant/host complex selection behaviour, and physiological compatibility with different stemborers, of six different geographic strains of C. flavipes that differed in the plant/host complex they were obtained from. The results of the host selection experiments indicate that there is no intraspecific variation in host selection behaviour among C. flavipes strains. However, our comparative experiments show variation in reproductive success among strains. The most significant result was that the strain with the longest period of co-existence with the new host Diatraea saccharalis Fabricius had the highest reproductive success on this host species. We argue that the reported existence of C. flavipes strains is based not on differences in host selection behaviour, but on differences in physiological compatibility between local parasitoid and host population.

Nutritional and physiological interactions depend on the evolutionary history of the host-parasitoid interaction considering that the host’s regulation by the parasitoid is species-specific. Cotesia flavipes Cameron was introduced in Brazil in the 70’s to be used in the control of Diatraea sugarcane borer complex; however, Diatraea flavipennella Box is restricted to Brazil. Thus, this study investigated the possible nutritional changes in the hemolymph and fat body, and cytochemistry of D. flavipennella hemocytes parasitized by Cotesia flavipes. The levels of nutrients were quantified using colorimetric tests in the hemolymph and fat body. Levels of acidic polysaccharides, mucin, and lipids were investigated only in hemocytes using cytochemical techniques. In addition, histological sections of parasitized and non-parasitized caterpillars were prepared to observe volume changes and the presence of glycogen in the fat body. The results showed a reduction in protein and lipid concentration in the hemolymph of parasitized caterpillars. The parasitism reduced the levels of total carbohydrate, glycogen, and protein in the fat body and almost completely consumed the perivisceral fat body. It changed the cytochemistry of hemocytes and reduced acidic glycans in prohemocytes and oenocytoids, mucin in plasmatocytes and granulocytes, and lipids in adipohemocytes, granulocytes, and prohemocytes. We concluded that the presence of the parasitoid leads to different changes in D. flavipennella hemolymph and fat body and alters the cytochemistry of hemocytes causing a significant reduction in the reserve tissue. The results from this study contribute to consolidating the use of C. flavipes in biological control programs targeting D. flavipennella in sugarcane crops.

Orientador: Eleni Gomes
Coorientador: Éder Antônio Giglioti
Banca: Fernando Barbosa Noll
Banca: Marcia Maria de Souza Moretti
Banca: José Eduardo Marcondes de Almeida
Banca: Jeferson Gross
Resumo: A broca da cana-de-açúcar é considerada a principal praga da cultura, cujo controle químico não tem sido eficaz. O controle biológico com Cotesia flavipes, em função da expansão do plantio, não será suficiente para o controle em áreas de alta infestação. O clima quente e úmido das regiões Noroeste e Centro-Oeste do Estado de São Paulo potencializam a utilização dos fungos Beauveria bassiana e Metarhizium anisopliae para o controle desta praga. O presente trabalho teve como objetivos estudar as variações genéticas dentre uma população pré-selecionada de 20 isolados de Metarhizium spp. associada ao controle de Diatraea saccharalis para identificar espécies e isolados com potencial de uso como agentes para o controle desta praga e a compatibilidade dos mesmos com o parasitoide Cotesia flavipes para serem utilizados em programas de manejo integrado dessa praga-MIP. Neste sentido, foram realizados testes para determinação da agressividade desse grupo de isolados de Metarhizium spp. previamente selecionados sobre D. saccharalis. Os isolados foram inicialmente caracterizados quanto ao potencial de patogenicidade, posteriormente foi realizada a seleção de cepas com alta eficiência de infecção sobre a D. saccharalis através da TL90. Também foi realizada a avaliação da compatibilidade dos isolados selecionados de Metarhizium spp. com o parasitoide C. flavipes para serem utilizados juntamente em programas de Manejo de Pragas - MIP. Os resultados do presente estudo demonstraram que todos...
Abstract: The sugarcane borer is considered as a major crop pest, whose chemical control has not been very effective. The biological control by Cotesia flavipes, due to the expansion of the plan, are not enough to control in areas of high infestation. The hot and humid climate of the Northwest and Miwest regions of São Paulo state potentiate the utilization of the fungi Beauveria bassiana and Metarhizium anisopliae to control this pest. The present work aims to study the genetic variations among a pre-selected population of 20 isolates of Metarhizium spp. associated to the control of Diatraea saccharalis to identify species and isolates with potential of use as agents for the control of this pest and their compatibility with the Cotesia flavipes parasitoid to be used in Integrated Pest Management (IPM) programs. In this sense, the tests were carried out to aggressiveness determination of this Metarhizium spp isolate groups previously selected on Diatraea saccharalis. The isolates were initially characterized for the pathogenicity potential, later the strain selection was made of highly efficient of infection on D. saccharalis through TL90. Also was made the evaluation of Metarhizium spp selected isolates compatibility with the Cotesia flavipes parasitoid to be used together in Integrated Pest Management (IPM) programs. The results of the present study demonstrated that all the isolates evaluated showed high virulence against D. saccharalis caterpillars, and being possible to prove the efficiency of these isolates in the control of this pest, but they showed differences in mortality distribution over time, and the estimate of the lethal time to kill 90% of insect population (TL90) ranged from 5.39 days for M13 to 7.49 days for M20. Moreover, the results of the compatibility tests showed that most of the isolates of the Metarhizium spp. fungus presented some toxicity degree to C. flavipes, ...
Doutor

The Cotesia flavipes species complex of parasitoid wasps are economically important worldwide for the biological control of lepidopteran stemborers. The complex currently comprises three species: Cotesia flavipes Cameron, C. sesamiae (Cameron) and C. chilonis (Matsumura), which appear morphologically similar. Despite their economic importance, considerable confusion surrounds the identity of species and host-associated biotypes. Differences in the biology and variation in host range of geographic populations have generally been interpreted as genetic divergence among strains, but direct genetic evidence is lacking. In Australia, several stemborer pests in neighbouring countries have been identified as significant threats to the sugar industry. However, the status of C. flavipes in Australia is unknown. To examine the genetic variation among worldwide populations of the C. flavipes complex and investigate the status of the Australian C. flavipes-like species, a pilot study based on 21 geographic populations of the complex and four outgroups was carried out using partial sequence data generated for mitochondrial gene regions, 16S rRNA and COI. Phylogenetic analyses supported the monophyly of the complex and the existence of genetically divergent populations of C. flavipes and C. sesamiae. The geographically isolated Australian haplotypes formed a distinct lineage within the complex and were ~3.0% divergent from the other species. Based on molecular, morphological and preliminary investigations into biological differences, the Australian species Cotesia nonagriae Olliff stat. rev. was redescribed and formally removed from synonymy with C. flavipes. Investigations of biology and behaviour of C. nonagriae on the native stem borer host, Bathytricha truncata (Walker) (Noctuidae) revealed that duration of the larval stages and adult longevity of C. nonagriae were longer than previously recorded for other members of the species complex. In addition, C. nonagriae oviposited an average of over 100 eggs into each host, almost three times more than for other species in the C. flavipes complex (30-40). During microhabitat location, both naïve and experienced females demonstrated a strong response towards the plant host complex, with experienced wasps benefiting by having a more rapid response time to infested than noninfested plants. Genetic variation and relationships among the complex were further studied by generating nucleotide sequence data for two partial mtDNA gene regions (COI, 16S) and three anonymous nuclear loci (CfBN, CfCN, CfEN) among 42 worldwide populations within the C. flavipes complex and three outgroups. Phylogenetic reconstructions provided strong support for the monophyly of the complex and the presence of at least four species, C. chilonis (from China and Japan), C. sesamiae (from Africa), C. flavipes (originating from the Indo-Asia region but introduced into Africa and the New World), and C. nonagriae (from Australia and PNG). Although there was geographic variation within species, the analyses did not support the overall separation and monophyly of clades associated with different host species. Members of the complex habour polydnavirus (PDV) symbionts, which play a key role in determining host range by host immune suppression during the course of parasitoid development. A worldwide phylogeny of the C. flavipes complex PDV CrV1 locus was determined to investigate cophylogeny between wasps and their PDV symbionts. The results showed that there were numerous PDV CrV1 haplotypes within worldwide populations. However, not all coevolutionary analyses supported the cophylogeny between wasp and PDV trees. Phylogenetic incongruence was most likely a result of the ability of PDVs to coevolve with host resistance through a process of natural selection, whereas the wasp genes were not under selection. The most important result of this study was the implication for the use of the CrV1 locus as a virulence marker in biological control.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2010