Alterations in the reproductive performance of habrobracon females following combined treatments with ethylurea and sodium nitrate or nitrite

Reproductive performance and mutagenic response of the wasp Bracon hebetor following treatment with the antibiotic bleomycin

Bleomycin (BM) induced dominant-lethal genetic lesions in the gametes of both sexes of adult Bracon hebetor wasps following ingestion. This effect was demonstrated by decreased fertility in the unfertilized eggs of treated females as well as in eggs fertilized by mature sperm derived from treated males. Death in the unhatched eggs occurred prior to blastoderm formation indicating BM caused chromosome breakage. Affected ovarian cells were limited to those exposed to BM between the developmental stages of vitellogenesis and early metaphase I. Sperm-associated fertility reductions were temporary in duration with substantial reductions being observed starting on the second day following the initiation of oviposition. BM lowered general egg-formation capacity in treated females but, unlike the fertility effects, decreased fecundity was caused by somatic debility. Although the BM-induced genetic damage observed in B. hebetor was radiomimetic in nature, the time of appearance and duration of the effects did not correspond with previous patterns found when B. hebetor adults were exposed to X-rays. While the differences could be due to the BM detoxification or the repair of BM-induced chromosome damage, further investigation would be required to demonstrate the presence of such systems in this hymemopteran.

Toxic and reproductive effects of the soluble organic fraction from diesel particulate emissions on the parasitoid wasp, Bracon hebetor

The soluble organic fraction of diesel particulate emissions was tested for physiological and genotoxic effects on the parasitoid wasp, Bracon hebetor. Adult female survival after topical treatment was significantly decreased at the higher concentrations of SOF. Daily egg production, a sensitive assay for genotoxic and physiological effects, was not significantly affected at any concentration. Egg hatchability on Days 1-5, representing vitellogenic oocytes at the time of treatment, was decreased, but this effect lacked consistency and dose dependence. An extensive dominant lethal test was performed with negative results. Possible explanations for these findings and comparisons with in vitro tests such as the Ames test and sister chromatid exchange are discussed.

The pattern of damage to the oogenetic series of cells after a single feeding of cis-diamminedichloroplatinum to Habrobracon females

A single meal of cis-diamminedichloroplatinum (DDP) fed to virgin braconid wasps decreased drastically the number of eggs derived from oogonia. In contrast, most of the larger oocytes completed oogenesis even after a dose which shortened average lifespan to 1/3 its normal length. Temporary infecundity resulted from the destruction of the germarial cells which produced the 32 cystocytes per follicle (1 oocyte and 31 trophocytes) by mitosis. As determined by egg hatchability, oogonia were the most vulnerable cell type to DDP in the ovariole sequence. Therefore, oogonial vulnerability to DDP was demonstrated by failure to complete both gametogenesis and embryogenesis. In combination with gamma radiation, DPP reduced egg production and hatchability below the values obtained from either agent used alone. However, the decreases were moderate, as expected from additivity of effect. A difference from the results from either radiation or several types of alkylating agents appeared in the proportion of early embryonic deaths. Deaths during cleavage predominated in every daily sample of eggs treated with DDP as oocytes. Usually only the eggs laid the first 2 days after treatment are characterized by a large number of 'stage 1' deaths.