Molecular technologies to improve the effectiveness of the sterile insect technique.

The application of the Sterile Insect Technique (SIT) in area-wide integrated pest management (AW-IPM) programmes continues to increase. However, programme efficiency can still be considerably enhanced when certain components of the technology are improved, such as the development of improved strains for mass rearing and release. These include strains that (1) produce only male insects for sterilization and release and (2) carry easily identifiable markers to identify released sterile insects in the field.

Mitotic and polytene chromosomes analysis of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae).

The Oriental fruit fly, Batrocera dorsalis s.s. (Hendel) is one of the most destructive agricultural pests, belonging to a large group of difficult to distinguish morphologically species, referred as the B.

Total body nitrogen and total body carbon as indicators of body protein and body lipids in the melon fly Bactrocera cucurbitae: effects of methoprene, a juvenile hormone analogue, and of diet supplementation with hydrolyzed yeast.

The application of methoprene, and providing access to diet including hydrolyzed yeast, are treatments known to enhance mating success in the male melon fly Bactrocera cucurbitae Coquillett (Diptera: Tephritidae), supporting their use in mass rearing protocols for sterile males in the context of sterile insect technique (SIT) programmes. The objective of the present laboratory study was to investigate the effect of methoprene application and diet supplementation with hydrolyzed yeast (protein) on the turnover of body lipids and protein to confirm the feasibility of their application in melon fly SIT mass-rearing programmes. While females had access to a diet that included hydrolyzed yeast (protein), males were exposed to one of the following treatments: (1) topical application of methoprene and access to diet including protein (M+P+); (2) only diet including protein (M-P+); (3) only methoprene (M+P-) and (4) untreated, only sugar-fed, control males (M-P-).

Effects of the juvenile hormone analogue methoprene and dietary protein on male melon fly Bactrocera cucurbitae (Diptera: Tephritidae) mating success.

The effect of access to dietary protein (P) and the topical application of a juvenile hormone analogue (methoprene (M)) on mating behaviour of male melon fly Bactrocera cucurbitae was assessed in the laboratory and in field cages. Age, dietary protein and methoprene application increased the mating success and influenced the mating behaviour. Treatment with methoprene (M+) to protein-deprived (P-) males had only a modest effect on the acceleration of sexual maturity, but application of methoprene (M+) to protein-fed (P+) males greatly accelerated sexual maturity.

Dynamics of the salivary gland hypertrophy virus in laboratory colonies of Glossina pallidipes (Diptera: Glossinidae).

Many species of tsetse flies are infected by a virus that causes salivary gland hypertrophy (SGH) and the virus isolated from Glossina pallidipes (GpSGHV) has recently been sequenced. Flies with SGH have a reduced fecundity and fertility. To better understand the impact of this virus in a laboratory colony of G.

Colonisation and mass rearing: learning from others.

Mosquitoes, just as other insects produced for the sterile insect technique (SIT), are subjected to several unnatural processes including laboratory colonisation and large-scale factory production. After these processes, sterile male mosquitoes must perform the natural task of locating and mating with wild females. Therefore, the colonisation and production processes must preserve characters necessary for these functions.

Historical applications of induced sterilisation in field populations of mosquitoes.

Research on sterile mosquito technology from 1955 to the 1980s provided a substantial body of knowledge on propagation and release of sterile mosquitoes. Radiation sterilisation and chemosterilisation have been used effectively to induce dominant lethality and thereby sterilise important mosquito vectors in the laboratory. Experimental releases of chemosterilised males provided complete control of Anopheles albimanus in a small breeding population (14-15 sq km) in El Salvador.

Conceptual framework and rationale.

The sterile insect technique (SIT) has been shown to be an effective and sustainable genetic approach to control populations of selected major pest insects, when part of area-wide integrated pest management (AW-IPM) programmes. The technique introduces genetic sterility in females of the target population in the field following their mating with released sterile males. This process results in population reduction or elimination via embryo lethality caused by dominant lethal mutations induced in sperm of the released males.

Two viruses that cause salivary gland hypertrophy in Glossina pallidipes and Musca domestica are related and form a distinct phylogenetic clade.

Glossina pallidipes and Musca domestica salivary gland hypertrophy viruses (GpSGHV and MdSGHV) replicate in the nucleus of salivary gland cells causing distinct tissue hypertrophy and reduction of host fertility. They share general characteristics with the non-occluded insect nudiviruses, such as being insect-pathogenic, having enveloped, rod-shaped virions, and large circular double-stranded DNA genomes. MdSGHV measures 65x550 nm and contains a 124 279 bp genome (approximately 44 mol% G+C content) that codes for 108 putative open reading frames (ORFs).

Quantitative PCR analysis of the salivary gland hypertrophy virus (GpSGHV) in a laboratory colony of Glossina pallidipes.

Many species of tsetse flies can be infected by a virus that causes salivary gland hypertrophy (SGH) and virus isolated from Glossina pallidipes (GpSGHV) has recently been sequenced. Flies having SGH have a reduced fecundity and fertility. To better understand the impact of this virus in a laboratory colony of G.

High levels of genetic differentiation between Ugandan Glossina fuscipes fuscipes populations separated by Lake Kyoga.

Background: Glossina fuscipes fuscipes is the major vector of human African trypanosomiasis, commonly referred to as sleeping sickness, in Uganda. In western and eastern Africa, the disease has distinct clinical manifestations and is caused by two different parasites: Trypanosoma brucei rhodesiense and T. b.

Genome analysis of a Glossina pallidipes salivary gland hypertrophy virus reveals a novel, large, double-stranded circular DNA virus.

Several species of tsetse flies can be infected by the Glossina pallidipes salivary gland hypertrophy virus (GpSGHV). Infection causes salivary gland hypertrophy and also significantly reduces the fecundity of the infected flies. To better understand the molecular basis underlying the pathogenesis of this unusual virus, we sequenced and analyzed its genome.

Transgenic mosquitoes and the fight against malaria: managing technology push in a turbulent GMO world.

Genetic modification (GM) of mosquitoes (which renders them genetically modified organisms, GMOs) offers opportunities for controlling malaria. Transgenic strains of mosquitoes have been developed and evaluation of these to 1) replace or suppress wild vector populations and 2) reduce transmission and deliver public health gains are an imminent prospect. The transition of this approach from confined laboratory settings to open field trials in disease-endemic countries (DECs) is a staged process that aims to maximize the likelihood of epidemiologic benefits while minimizing potential pitfalls during implementation.

Development of genetic sexing strains in Lepidoptera: from traditional to transgenic approaches.

The sterile insect technique (SIT) is currently being used for the control of many agricultural pests, including some lepidopteran species. The SIT relies on the rearing and release of large numbers of genetically sterile insects into a wild population. The holokinetic chromosomes of Lepidoptera respond differently to radiation than do species where there is a localized centromere.

Insect transgenesis and its potential role in agriculture and human health.

The ability to genetically engineer insects other than Drosophila melanogaster has further extended modern genetic techniques into important insect pest species ranging from fruit fly pests of horticulture to mosquito vectors of human disease. In only a relatively short period of time, a range of transgenes have been inserted into more than 10 insect pest species. Genetic transformation of these pest species has proven to be a very important laboratory tool in analyzing gene function and effects on phenotype however the full extension of this technology into the field is yet to be realized.

The first releases of transgenic mosquitoes: an argument for the sterile insect technique.

Potential applications for reducing transmission of mosquito-borne diseases by releasing genetically modified mosquitoes have been proposed, and mosquitoes are being created with such an application in mind in several laboratories. The use of the sterile insect technique (SIT) provides a safe programme in which production, release and mating competitiveness questions related to mass-reared genetically modified mosquitoes could be answered. It also provides a reversible effect that would be difficult to accomplish with gene introgression approaches.

Mutations and their use in insect control.

Traditional chemically based methods for insect control have been shown to have serious limitations, and many alternative approaches have been developed and evaluated, including those based on the use of different types of mutation. The mutagenic action of ionizing radiation was well known in the field of genetics long before it was realized by entomologists that it might be used to induce dominant lethal mutations in insects, which, when released, could sterilize wild female insects. The use of radiation to induce dominant lethal mutations in the sterile insect technique (SIT) is now a major component of many large and successful programs for pest suppression and eradication.