Terahertz radiation influence on number and development dynamics of offspring F1 of fruit fly females under stress

Virgin fruit fly females were stressed by placement into a confined space without food for 2.5 hours. Some flies were subjected to terahertz radiation (0.1–2.2 THz) for the last 30 min. Then females were copulated with males. Offspring F1 from oocytes which were mature or immature at exposure (oviposition in 1–2 or 9–10 days after irradiation) was studied. Stress induces a rejection of the offspring maturation dynamics to imago from external control (offspring of flies which was maintained in standard conditions). In offsping from mature oocytes of irradiated flies the dynamics of male maturation to imago was different from internal control (offspring of stressed unirradiated flies). The number of imago males decreased. The dynamics of female maturation to imago coincides with laboratory control. In offsping from immature oocytes of irradiated flies the dynamics of female and male maturation and the number of flies were not significantly different from the internal control. It was concluded that only mature oocytes are sensitive to THz radiation influence.     

Terahertz radiation improves adaptation characteristics in <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

An investigation into the effect of nonionizing terahertz radiation (0.1–10 THz) on living organisms is urgent due to the recent development of modern technologies employing such radiation. The aim of this study was to establish the impact of terahertz radiation on successive generations of fruit flies. The effects of terahertz radiation on the survival ability and lifespan of the Oregon-R strain of Drosophila melanogaster proved to be diverse: they were negative or neutral at early life stages and positive at late stages. The female flies exposed to the radiation showed increased survival rate during the second half of the life of imago. The males demonstrated low sensitivity to the radiation. There were no significant differences noted in the dynamics of maturation and total number of offspring between the female flies that were exposed to the radiation and those that were not. The results of the study practically did not depend on the sex and maturity stage of the oocytes irradiated.     

Dynamics of reaching imago stage by F1 animals after terahertz irradiation of parental <Emphasis Type="Italic">Drosophila</Emphasis>

Terahertz radiation (0.1–10 THz) is increasingly becoming a factor of human habitat. The study of the consequences of radiation allows one to estimate its possible biological danger. Our data indicate that the terahertz irradiation of parental Drosophila shortens the period of embryonic development of their first generation descendants. Significant deviations of data from the control were found, when both females and males were experimental parents. The highest portion of animals with accelerated hatching as compared with the control was found in progenies from irradiated females. The shift of maximal hatching peak to an earlier period was found in descendants of both sexes. Thus, it was for the first time found on the model object (Drosophila) that the terahertz irradiation of parents can have positive or negative consequences in the first generation descendants.     

Mutability of the germ cells of the progeny of irradiated male Drosophila

The increased frequency of random and radiation-induced mutation was registered in germ cells of drosophila irradiated male descendants of the first generation. The effect observed depended on of radiation dose delivered to parent males, test dose to progeny, type of mutation registered, and sex of the descendants under study.     

Effect of irradiation on Mexican leafroller (Lepidoptera: Tortricidae) development and reproduction

The effects of irradiation on egg, larval, and pupal development, and adult reproduction in Mexican leafroller, Amorbia emigratella Busck (Lepidoptera: Tortricidae), were examined. Eggs, neonates, early instars, late instars, early pupae, and late pupae were irradiated at target doses of 60, 90, 120, or 150 Gy, or they were left untreated as controls in replicated factorial experiments. Survival to the adult stage was recorded. Tolerance to radiation increased with increasing age and developmental stage. A radiation dose of 90 Gy applied to neonates and early instars prevented adult emergence. A dose of 150 Gy was not sufficient to prevent adult emergence in late instars or pupae. The effect of irradiation on sterility was examined in late pupae and adult moths. For progeny produced by insects treated as late pupae, a total of three out of 3,130 eggs hatched at 90 Gy, 0 out of 2,900 eggs hatched at 120 Gy, and 0 out of 1,700 eggs hatched at 150 Gy. From regression analysis, the dose predicted to prevent egg hatch from the progeny of irradiated late pupae was 120 Gy, with a 95% confidence interval of 101-149 Gy. The late pupa is the most radiotolerant stage likely to occur with exported commodities; therefore, a minimum absorbed radiation dose of 149 Gy (nominally 150 Gy) has potential as a quarantine treatment. Reciprocal crosses between irradiated and unirradiated moths demonstrated that males were more radiotolerant than females. Irradiation of female moths at a target dose of 90 Gy before pairing and mating with irradiated or unirradiated males resulted in no viable eggs, whereas irradiated males paired with unirradiated females produced viable eggs at 90 and 150 Gy.     

Terahertz radiation influence on stressed drosophila life span

Virgin fruit fly females and males were stressed by placement into a confined space without food for 3 h. Part of stressed flies were subjected to terahertz irradiation (0.1–2.2 THz) during 30 min. Life span of individual flies was evaluated. Terahertz radiation had some positive influence on male survival during the stage of monotonic decrease in flies number and negative effect during the stage of relatively stable number of flies. The survival of irradiated females on the stage of sharp decline in the number of flies was higher than in stressed and control females. Authors propose that terahertz radiation has an indirect effect on gene expression and signaling pathways which control the survival and life span of Drosophila.     

Effect of low intensity pulsed laser radiation of basic parameters of aging in Drosophila melanogaster

The effect of the low-intensive impulse laser radiation (LILR) on the life span of Drosophila melanogaster has been studied. The flies at various stages of their life (larvae and imago) were exposed to LILR. The estimation of the effect of LILR was carried out on the basis of the analysis of the basis parameters of aging. We found out increasing as well as shortening effects of the life span. The direction of the effect depends on parameters of radiation, stage of development of irradiated individuals and their sex.     

Radiation induction of mutations affecting sperm morphology in mice

To investigate the basis of the sperm abnormality assay, studies have been made of the frequency of sperm abnormalities in the genital tracts of the progeny of irradiated males. Male C57BL/6 mice were irradiated (75-600 rad X-rays to the testes) and were then bred in the pre-sterile period to untreated C57BL/6 females. The sperm of their male progeny were examined for the frequency of sperm abnormalities. Variant males with clearly elevated levels of sperm abnormalities were more frequently seen amongst the progeny of irradiated fathers than with the progeny of sham-irradiated controls (10 in 170 compared with 2 in 188; P less than 0.02). Although no clear dose-response relation could be discerned with the number of animals studied, similar differences were observed with irradiated male SWR, C3H/He in inbred crosses and with C57BL/6 in hybrid crosses with C3H/He females. In contrast, matings of males made at longer times following irradiation did not lead to a significant increase in the number of affected progeny for the number tested. Breeding experiments with the affected F1 males showed that the sperm morphology defect could be transmitted in 7 of 19 cases. Parallel cytogenetic studies showed that 3 of the initial affected progeny had detectable reciprocal translocations and that in 2 of these cases the translocation was transmitted with the sperm defect. The studies thus showed that radiation can induce mutations that affect the levels of sperm abnormalities and that these mutations can be associated with reciprocal translocations.     

Reproduction of Japanese quail after microwave irradiation (2.45 GHz CW) during embryogeny

Japanese quail (Coturnix coturnix japonica) embryos were irradiated continuously in ovo with 2.45-GHz continuous wave radiation during the first 12 days of embryogenesis at an incident power of 5 mW/cm2 and a specific absorption rate of 4.03 mW/g. The internal temperature of irradiated and nonirradiated (sham) eggs was 37.5 +/- 0.3 degrees C, which is the optimum temperature for incubating quail eggs. At 35 days after hatching irradiated and sham-irradiated males were paired with irradiated or sham-irradiated females and daily records of reproductive performance were collected through 224 days of age. Progeny were hatched from each of the male-female pairs, and progeny reproductive performance was measured from 35 through 168 days of age. Hatchability was not affected by irradiation during embryogeny. Mortality after hatching, egg production, egg weight, fertility, hatchability of eggs produced, and reproductive performance of the progeny were not affected by irradiation during embryogeny. These observations indicate that irradiation of quail embryos with low-level microwave radiation does not affect the reproductive capacity of the hatchlings or of progeny produced from quail irradiated during incubation.     

Induced sterility of Glossina pallidipes Austen males after irradiation in a nitrogen atmosphere

The sterile insect technique relies on sterilization of males using ionizing radiation. Life cycle stage, and the environmental conditions under which irradiation is carried out are crucial to the provision of good‐quality insects. To identify an optimal radiation strategy for Glossina pallidipes Austen, 1903, 13‐day‐old males were irradiated at different doses in a nitrogen atmosphere. The following day the males were mated with 8‐day‐old virgin females. Pupal production of mated females was monitored for 6 weeks, and induced sterility was determined by probit analysis. Survival of the males that mated was also monitored. At least 95% sterility of irradiated males was achieved with a 158 Gy dose in nitrogen and a 125 Gy in air. Irradiation significantly lowered the probability of survival between 30 and 100 days of age (especially flies irradiated in air), but probabilities of survival were similar outside this period for irradiated and unirradiated flies. Exposure of 2‐ or 13‐day‐old males to sterilizing radiation induced similar levels of sterility in both air and nitrogen.     

Cryptic maternal effects in Hippodamia convergens vary with maternal age and body size

Maternal effects can mold progeny phenotypes in various ways and may constitute ecological adaptations. By examining the effect of oviposition sequence on progeny produced by different size classes of female ladybird beetles (produced by controlling larval access to food), we show that maternal signals can change through adult life and alter the developmental programs of progeny, ostensibly to synchronize their life histories with predictable resource dynamics, thus maximizing maternal fitness. We also show that female body size, as determined by larval food supply, interacts with female age to influence progeny fitness. When fed ad libitum as adults, small females reared with limited food access laid fewer, smaller eggs than large females reared with ad libitum food access. Maternal body size interacted with oviposition sequence to influence progeny development, but the latter had greater impact. Eggs laid later by medium and large females hatched faster than those laid earlier, larvae fed longer in the fourth instar, their pupation period was shorter, total developmental time was reduced, and adults emerged with greater mass, most notably daughters. Oviposition sequence effects on progeny from small mothers were non‐significant for total developmental time and progeny mass. Only large mothers increased egg size over time and egg mass was not consistently correlated with developmental parameters, indicating that progeny phenotype was impacted by other, more cryptic, maternal signals. Such signals appear costly, as food limitation during development constrained not only fecundity and egg size but also maternal ability to manipulate progeny phenotype. The production of faster‐developing offspring that mature to larger sizes late in the oviposition cycle may be adaptive for exploitation of ephemeral aphid outbreaks with predictable dynamics of prey abundance and competition.     

Reduced productivity in adult yellowfever mosquito (Diptera: Culicidae) populations

Male and female Aedes aegypti (L.) mosquitoes of the laboratory strain ROCK were irradiated with 130 mw of argon 514.5 nm laser microbeams for 0.04, 0.25, 0.4, and 0.5 s, respectively. Egg production, percentage hatch, and productivity (average number of adults surviving after 3 wk) were used to assess mutagenic effects. Mortality was high for males in all laser radiation groups and increased with time of exposure. Except for the group treated for 0.25 s, significant reductions in total F1 progeny also were demonstrated for all other experimentals when male parents were exposed to laser radiation. Females showed a high mortality when subjected to 0.4- and 0.5-s laser radiation. No F1 progeny were produced when parental females were exposed for 0.25, 0.4, and 0.5 s. Numbers of F1 progeny from females exposed to 0.04 s of laser radiation were significantly reduced. A comparison of weekly mean number of progeny showed that the important differences in productivity occurred during the first and second week, respectively, when either male or female adult parents were subjected to laser radiation.     

Biology of Leipothrix dipsacivagus (Acari: Eriophyidae), a candidate for biological control of invasive teasels (Dipsacus spp.)

The present study describes key aspects of the biology of Leipothrix dipsacivagus, an eriophyid mite that is under study as a biological control candidate of Dipsacus fullonum and D. laciniatus (Dipsacaceae). Preliminary host-specificity tests have shown that it can develop and reproduce only on Dipsacus spp. (teasels). Studies were conducted in a laboratory at 26 ± 2^oC with 16 h of light per day. Mites for the stock colony were collected from D. laciniatus in Klokotnitsa, Bulgaria and reared on rosettes of D. laciniatus in the laboratory. Unfertilized L. dipsacivagus females reared in isolation from the juvenile stage produced male offspring only, while progeny of fertilized females were of both sexes, suggesting arrhenotokous parthenogenesis with haplodiploid sex determination. Experiments were designed to compare male progeny from fertilized females to males from unfertilized females and to compare males and females from fertilized females. Male progeny of virgin mothers had significantly longer durations of active immature stages and total egg-to-adult period than male progeny of fertilized females. Female progeny had significantly longer durations of egg incubation, active immature stages and egg-to-adult period than male progeny from fertilized mothers. Adult longevity was significantly greater in females than in males. Fertilized females produced significantly more eggs per day and overall than virgin females. The results of this study suggest that fertilization status of L. dipsacivagus females can affect both their own fecundity and the development of their male progeny.     

Effects of radiation (Cobalt-60) on the elimination of Brevipalpus phoenicis (Acari: Tenuipalpidae) Cardinium endosymbiont

Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) is a polyphagous mite with worldwide distribution and it is also a vector of several plant viruses. In citrus, B. phoenicis transmits Citrus leprosis virus (CiLV), the causal agent of leprosis, a disease that costs millions of dollars per year for its prevention and control. Brevipalpus phoenicis mites reproduce through thelytokous parthenogenesis, producing haploid females. This characteristic is attributable to the presence of an endosymbiont bacterium of the genus Cardinium; however, very little is known about the biological and ecological implications of the presence of this endosymbiont in Brevipalpus mites. In order to investigate the role of Cardinium in the transmission of CiLV to citrus plants, our goal was to eliminate the bacterium from the mite. We assessed the effectiveness of different doses of radiation from a Cobalt-60 source to cure B. phoenicis populations from Cardinium sp. The efficiency of irradiation on the elimination of the endosymbiont was determined by counting the number of females and males obtained in the F(1) generation after irradiation and confirming the presence of the endosymbiont by PCR. Both radiation treatments influenced the oviposition period and the number of eggs laid by irradiated females. Also, irradiation eliminated the Cardinium endosymbiont and increased the number of males in progeny of the exposed populations. Although macroscopic morphological abnormalities were not observed among the treated mites, the mortality was higher compared to the non-irradiated control group.     

Influence of ionizing radiation on the formation of adult antennae in large fruit-tree tortrix <Emphasis Type="Italic">Archips podana</Emphasis> Scop. (Lepidoptera,Tortricidae)

The influence of sterilizing doses of X-radiation on the formation of adult antennae during the pupa period of development of Archips podana was studied. We found a change in the number of coeloconic and auriculate sensilla in those imago whose pupae were exposed to radiation. A slow-down in the process of antennae formation at the pupal stage was registered after the irradiation of instar five larvae and newly formed pupae.     

Effect of weak electromagnetic radiation on larva development and metamorphosis of grain beetle Tenebrio molitor

The effect of weak electromagnetic radiation (36 GHz, 100 mu W/cm2) on the development of the grain beetle Tenebrio molitor was studied. Insects were irradiated in different larval instars and at the pupal stage. It was found that weak electromagnetic radiation stimulated the molting and pupation of larvae and the metamorphosis of pupae. The stimulating effect of radiation was weak when animals were exposed in the initial period of the instar and the pupal stage and was more pronounced if the irradiation was carried out in the second half of the current instar and the pupil stage. The effect of weak electromagnetic radiation on the development of beetle can be related to the function of the hormones of metamorphosis.     

Genetic consequences of irradiation of one or both parents (results of experiments on Wistar rats) Exitus lethalis in Wistar rat's progeny after irradiation of one or both parents

Examination of 2563 offsprings of Wistar rats after irradiation of one or both parents with doses of 0.25, 0.5, 1, 2, 3 and 4 Gy was carried out; the manifestation of lethal effects in the progeny of the first generation in ontogenesis was studied. The level of embryonic death was the highest after irradiation of germ cells of parents at stages of spermatids, spermatozoids and matured oocytes. Following irradiation of both parents with doses of 0.25, 0.5 and 1 Gy at these stages of gametogenesis and 4 Gy at the stage of spermatids and matured oocytes there was a trend of increasing radiation effects caused by the participation of two irradiated germ cells. After irradiation of both parents with doses of 2, 3 and 4 Gy the embryonic death F1 was essentially the same as rates for irradiated females and non-irradiated males. The F1 death rate in early postnatal development exceeded the control only after irradiation with doses of 2, 3 and 4 Gy. The increase in radiation effects in the F1 due to the mating of two irradiated parents appears to be associated with a mechanism demonstrating additivity or synergism.     

The influence of X-rays on reproduction in Pseudeucoila bochei (Hymenoptera Cynipidae), a parasite of Drosophila melanogaster

The parasitic wasp Pseudeucoila bochei was the subject in experiments designed to detect a reliable method of mutation induction. Radiation doses of 360, 720, 1080, 1440, 1800 and 2160 R were given to pupae 15 or 18 days old or to freshly eclosed male and female wasps. The irradiation did not influence the survival of pupae. Dose-action responses were established and appeared to be dependent on the stage of development of the wasps at the moment of irradiation. The production of sons by virgin females showed that the germ cells of the adults were the most sensitive to irradiation. In contrast, the sperms of the male wasps irradiated as adults were the most resistant. Irradiation of males as pupae with 1880 or 2160 R on the 15th day or as adults led to a high frequency of amle progeny. The elimination of sperm cells from fertilization is discussed. Comparisons with Habrobracon, Nasonia and Drosophila showed that the germ cells of Pseudeucoila are more sensitive to irradiation. In the progeny from irradiated females and males 2 types of mutant were found, with yellow eye colour and with aberrations in the antennae.     

AP-PCR assay of DNA alterations in the progeny of male mice exposed to low-level gamma-radiation

By comparative analysis of fingerprints of arbitrarily primed polymerase chain reaction (AP-PCR) products, DNA alterations in somatic cells of the progeny (F1 generation) of male mice chronically exposed to low-doses of gamma-radiation was investigated. Male BALB/c mice exposed to 10-50 cGy were mated with unirradiated females 15 days after irradiation. DNA was isolated from biopsies taken from tail tips of 2-month-old progeny. Preliminary AP-PCRs were carried out with 17 primers representing core sequences of micro- and/or minisatellites or their flanking oligonucleotides. Best quantitatively reproduced AP-PCR fingerprints of genomic DNA were obtained with one of these primers, a 20-mer oligonucleotide flanking the micro-satellite locus Atplb2 on mouse chromosome 11. Comparative analysis of individual fingerprints of AP-PCR products obtained on DNA templates from the progeny of irradiated and intact males revealed an increased variability of micro-satellite-associated sequences and an increased frequency of "non-parental bands" in DNA-fingerprints from the progeny of males chronically exposed to gamma-radiation 15 days before mating (at the postmeiotic stage of spermatogenesis). The results show that increased micro-satellite instability can be initiated by irradiation of the male parent to subsequently arise or be transmitted to the soma of the F1 generations.     

Chromosome aberrations in spermatocytes and oocytes of mice irradiated prenatally

5 pregnant mice were exposed to a single dose of 150 R whole body γ-irradiation on the 12th day of gestation. The ocytes and spermatocytes, collected from the F₁ progeny at ages 10–12 weeks, were examined for chromosome aberrations in metaphase I and compared with those of the progeny of non-irradiated controls. No differences were found in the type and frequency of aberrations between irradiated and controls nor between the sexes. It appears, therefore, that either primordial germ cells of both males and females are fairly resistant to radiation or an efficient selection or repair mechanism has eliminated the aberrant cells.