Reduction In Mating Research Articles

Seasonal shift in diet affects female reproductive anatomy but not mating behavior.

Females experience considerable environmental variability when breeding seasons are long. Adverse nutritional conditions can result in a reduction in mating and reproduction. However, a return to good nutrition may help animals resume high reproductive investment. I tested the silver spoon hypothesis in which females raised under poor conditions are reproductively limited compared to those raised under good conditions regardless of their adult environment. I used a specialist herbivore, Narnia femorata (Hemiptera: Coreidae), that lives on seasonally changing cacti. I provided juveniles and adults with a cactus pad with fruit (good diet), without fruit (restricted diet), or an improved adult diet (no fruit as juveniles, fruit at adulthood) to simulate a seasonal change in their diets near the end of the breeding season. I found that both ovary size and egg presence were reduced for females fed the restricted diet compared to those fed the good diet. Females fed the improved diet grew large ovaries like those fed the good diet, but few produced any eggs. Interestingly, female mating behavior did not change but females were less attractive to males when fed restricted diets. My results support the silver spoon hypothesis for compensatory growth and suggest that tradeoffs may occur between early survival and future reproduction when females experience a poor early life diet.

Role for nitrate assimilatory genes in virulence of Ustilago maydis

Ustilago maydis can utilize nitrate as a sole source of nitrogen. This process is initiated by transporting nitrate from the extracellular environment into the cell by a nitrate transporter and followed by a two-step reduction of nitrate to ammonium via nitrate reductase and nitrite reductase enzymes, respectively. Here, we characterize the genes encoding nitrate transporter, um03849 and nitrite reductase, um03848 in U. maydis based on their roles in mating and virulence. The deletion mutants for um03848, um03849 or both genes were constructed in mating compatible haploid strains 1/2 and 2/9. In addition, CRISPR-Cas9 gene editing technique was used for um03849 gene to create INDEL mutations in U. maydis mating strains. For all the mutants, phenotypes such as growth ability, mating efficiency and pathogenesis were examined. The growth of all the mutants was diminished when grown in a medium with nitrate as the source of nitrogen. Although no clear effects on haploid filamentation or mating were observed for either single mutant, double Δum03848 Δum03849 mutants showed reduction in mating, but increased filamentation on low ammonium, particularly in the 1/2 background. With respect to pathogenesis on the host, all the mutants showed reduced degrees of disease symptoms. Further, when the deletion mutants were paired with wild type of opposite mating-type, reduced virulence was observed, in a manner specific to the genetic background of the mutant's progenitor. This background specific reduction of plant pathogenicity was correlated with differential expression of genes for the mating program in U. maydis.

An introgressed wing pattern acts as a mating cue.

Heliconius butterflies provide good examples of both homoploid hybrid speciation and ecological speciation. In particular, examples of adaptive introgression have been detected among the subspecies of Heliconius timareta, which acquired red color pattern elements from H. melpomene. We tested whether the introgression of red wing pattern elements into H. timareta florencia might also be associated with incipient reproductive isolation (RI) from its close relative, H. timareta subsp. nov., found in the eastern Andes. No choice experiments show a 50% reduction in mating between females of H. t. subsp. nov. and males of H .t. florencia, but not in the reciprocal direction. In choice experiments using wing models, males of H. timareta subsp. nov. approach and court red phenotypes less than their own, whereas males of H. t. florencia prefer models with a red phenotype. Intrinsic postzygotic isolation was not detected in crosses between these H. timareta races. These results suggest that a color pattern trait gained by introgression is triggering RI between H. timareta subsp. nov. and H. t. florencia.

The Toxicological Properties of Petroleum Gases

To characterize the toxicological hazards of petroleum gases, 90-day inhalation toxicity (Organization for Economic Cooperation and Development [OECD] 413) and developmental toxicity (OECD 414) tests were conducted with liquefied propane gas (LPG) at concentrations of 1000, 5000, or 10,000 ppm. A micronucleus test (OECD 474) of LPG was also conducted. No systemic or developmental effects were observed; the overall no observed adverse effect concentration (NOAEC) was 10,000 ppm. Further, there was no effect of LPG exposure at levels up to 10,000 ppm on micronucleus induction and no evidence of bone marrow toxicity. Other alkane gases (ethane, propane, n-butane, and isobutane) were then evaluated in combined repeated exposure studies with reproduction/development toxicity screening tests (OECD 422). There were no toxicologically important changes in parameters relating to systemic toxicity or neurotoxicity for any of these gases at concentrations ranging from 9000 to 16,000 ppm. There was no evidence of effects on developmental or reproductive toxicity in the studies of ethane, propane, or n-butane at the highest concentrations tested. However, there was a reduction in mating in the high-exposure group (9000 ppm) of the isobutane study, which although not significantly different was outside the range previously observed in the testing laboratory. Assuming the reduction in mating to have been toxicologically significant, the NOAEC for the isobutane reproductive toxicity screening test was 3000 ppm (7125 mg/m(3)). A method is proposed by which the toxicity of any of the 106 complex petroleum gas streams can be estimated from its composition.

Endocrine-disrupting and cytotoxic potential of anticholinesterase insecticide, diazinon in reproductive toxicity of male mice

We evaluated the effects of diazinon (2, 4.1 and 8.2mg/kgbw/day for 4 weeks) in gonadotropins, testosterone and estrogen levels, whether the regulatory interactions in the hypothalamic–pituitary–testicular axis are modified by acetylcholinesterase inhibition and histopathological changes in adult mice testes. Diazinon at doses higher than 2mg/kgbw/day resulted in decreased testis weight, inhibition in acetylcholinesterase activities, decrease in levels of luteinizing hormone and follicle stimulating hormone, following reduction in mating and fertility indices. Diazinon increased testosterone content in 4.1mg/kg group, but decreased testosterone concentration in 8.2mg/kg group. Diazinon increased estrogen, prolactine and decreased levels of acetylcholinesterase activities in 4.1mg/kg group but levels of luteinizing hormone and follicle stimulating hormone remained unmodified. It may be simply postulated a scenario that acetylcholine in the cholinergic neurons has a potential threshold to perform a crucial part in the complex circuitry of neuroendocrine regulatory mechanisms. On overaccumulation, other neurotransmitters can be appropriately recruited to modulate the mechanisms of circuitry.

Differential expression of the putative Kex2 processed and secreted aspartic proteinase gene family of Cryphonectria parasitica

Kex2-silenced strains of Cryphonectria parasitica, the ascomycete causal agent of chestnut blight, show a significant reduction in virulence, reduced sexual and asexual sporulation and reductions in mating and fertility. Due to this and the known involvement of Kex2 in the processing of important proproteins in other systems, we searched the whole C. parasitica genome for putative Kex2 substrates. Out of 1299 open reading frames (ORFs) predicted to be secreted, 222 ORFs were identified as potential Kex2 substrates by this screen. Within the putative substrates we identified cell wall modifying proteins, putative proteinases, lipases, esterases, and oxidoreductases. This in silico screen also uncovered a family of nine secreted aspartic proteinases (SAPs) of C. parasitica. Northern blot analyses of this gene family showed differential expression when exposed to chestnut wood and Cryphonectria hypovirus 1 (CHV1). Due to the reduction in fungal virulence known to be caused upon hypoviral infection of C. parasitica, the differential gene expression observed, and the known involvement of SAPs in virulence in other systems, we conducted deletion analyses of four of these proteinases, representing different expression patterns. Deletion of each of the four SAPs did not affect growth rates, sporulation or virulence, suggesting that none of the considered SAPs is essential for the full development or virulence of C. parasitica under the conditions tested.

Silencing of Kex2 Significantly Diminishes the Virulence of Cryphonectria parasitica

Cryphonectria parasitica is the causal agent of chestnut blight. Infection of this ascomycete with Cryphonectria hypovirus 1 (CHV1) results in reduction of virulence and sporulation of the fungus. The virus affects fungal gene expression and several of the CHV1 downregulated genes encode secreted proteins that contain consensus Kex2 processing signals. Additionally, CHV1 has been shown to colocalize in infected cells primarily with fungal trans-Golgi network vesicles containing the Kex2 protease. We report here the cloning, analysis, and possible role of the C. parasitica Kex2 gene (CpKex2). CpKex2 gene sequence analysis showed high similarity to other ascomycete kexin-like proteins. Southern blot analyses of CpKex2 showed a single copy of this gene in the fungal genome. In order to monitor the expression and evaluate the function of CpKex2, antibodies were raised against expressed protein and Kex2-silenced mutants were generated. Western blots indicate that the Kex2 protein was constitutively expressed. Growth rate of the fungus was not significantly affected in Kex2-silenced strains; however, these strains showed reduced virulence, reduced sexual and asexual sporulation, and reductions in mating and fertility. The reduced virulence was correlated with reduced Kex2 enzymatic activity and reduced relative mRNA transcript levels as measured by real time reverse-transcriptase polymerase chain reaction. These results suggest that secreted proteins processed by Kex2 are important in fungal development and virulence.

Effect of anti‐hail nets on Cydia pomonella behavior in apple orchards

AbstractOver the last 10 years, the use of nets to protect pome fruit from hailstorms has increased. In this study, we investigated the effect of these nets on the behavior of the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), a major pest of apple, Malus domestica Borkh. (Rosaceae). Experiments were carried out in net‐covered and uncovered apple orchards treated with conventional insecticides. The number of codling moth males caught in pheromone‐ and virgin female‐baited traps was significantly reduced in net‐covered compared to uncovered plots. In addition, inhibition of mating by the net was demonstrated by significant reductions in mating of tethered virgin females. Fruit injury was consistently lower in net‐covered plots vs. uncovered plots. Because of the reductions in male trap catch, the reduced female mating frequency, and the lower level of damage, we conclude that flat anti‐hail nets have a disruptive effect on the reproductive behavior of the codling moth.

Gypsy moth mating disruption in open landscapes

Abstract1 Aerial applications of Disrupt II, a plastic laminated flake formulation containing a racemic form of the gypsy moth sex pheromone, disparlure, achieved > 99% reduction of mating among females on individual, isolated trees surrounded by an area cleared of trees.2 These results support the use of mating disruption to eradicate isolated gypsy moth populations in open landscapes, such as parks, residential areas and commercial settings.3 Mating success in both treated and untreated areas varied with the initial distance between males and females. When the initial distance between males and females was < 5 cm in an area receiving a dosage of 37.5 g of racemic disparlure per ha, mating success was reduced by 27% compared with a similar deployment in an untreated area. Mating was eliminated in areas treated at the same dosage when males and females were initially deployed 1 m apart but on separate trees.4 This suggests that mating disruption may not be an effective tactic for gypsy moth eradication in cases where the infestation is concentrated on a small number of trees and males and females are in close proximity in space and time.

Toxic effects of paroxetine on sexual and reproductive functions of rats

This study determined some appropriate parameters to detect male and female reproductive, endocrine, and teratological toxicity besides genotoxic effects of paroxetine. Several parameters concerning fertility were measured in male and female rats given oral doses of paroxetine ( 0.36mg/100g b.wt./day) for a month. In addition, estimation of the drug residues in male, female and fetus were carried out. There were alterations in serum concentration of gonadotraphins: FSH, LH, PRL and in the sex hormones : testosterone, progesterone and estradiol in male and female rats. These alterations were accompanied by sperm reduction, sperm abnormalities, irregular shaped of seminiferous tubules, hypertrophy of geominal cells and structural chromosomal aberrations in male rats. A reduction in mating and fertility indices were observed with an increase in the number of resorbed fetuses, and a decrease in body weight and crown rump length of rat embryos.

Toxic effects of paroxetine on sexual and reproductive functions of rats

This study determined some appropriate parameters to detect male and female reproductive, endocrine, and teratological toxicity besides genotoxic effects of paroxetine. Several parameters concerning fertility were measured in male and female rats given oral doses of paroxetine ( 0.36mg/100g b.wt./day) for a month. In addition, estimation of the drug residues in male, female and fetus were carried out. There were alterations in serum concentration of gonadotraphins: FSH, LH, PRL and in the sex hormones : testosterone, progesterone and estradiol in male and female rats. These alterations were accompanied by sperm reduction, sperm abnormalities, irregular shaped of seminiferous tubules, hypertrophy of geominal cells and structural chromosomal aberrations in male rats. A reduction in mating and fertility indices were observed with an increase in the number of resorbed fetuses, and a decrease in body weight and crown rump length of rat embryos.

Gene flow and inbreeding depression inferred from fine‐scale genetic structure in an endangered heterostylous perennial,Primula sieboldii

We estimated the gene dispersal distance and the magnitude of inbreeding depression from the fine-scale genetic structure in the endangered heterostylous perennial Primula sieboldii. We indirectly estimated the neighbourhood size (Nb) and the standard deviation of gene dispersal distance (sigma(g)) from the detected genetic structure by using 10 microsatellite markers. We also estimated the fitness reduction in mating among neighbouring individuals caused by biparental inbreeding according to the genetic structure. We found clear fine-scale genetic structure (a significantly positive kinship coefficient within 42.3 m), and the indirect estimates of sigma(g) and Nb were 15.7 m and 50.9, respectively. These indirect estimates were similar to the direct estimates (18.4 m and 44.0). The slightly larger indirect estimate of Nb may reflect that inbreeding depression and genetic structure or rare long-distance dispersal that were overlooked in the direct estimate have elongated the long-term average of gene dispersal distance. P. sieboldii is also likely to suffer about 19% fitness reduction in progenies from mating among individuals 5 m apart. Our results suggest that biparental inbreeding and genetic structure can affect the range of gene dispersal and seed reproductive success in P. sieboldii.

Attractancy and Toxicity of an Attracticide for Indianmeal Moth, <I>Plodia interpunctella</I> (Lepidoptera: Pyralidae)

Plodia interpunctella (Hübner) is a serious and widespread postharvest pest on cereal products, dried fruits, candy, and pet food. Due to the strong positive anemotactic flight response of P. interpunctella males to the main component of the female-produced pheromone [(Z,E)-9,12-tetradecadienyl acetate, herein referred to as ZETA], we evaluated the potential of an attracticide for this pest, in which ZETA as attractant was combined with permethrin as the killing agent. Two concentrations of ZETA [0.16 and 0.32% (wt:wt)] and five concentrations of permethrin [0, 3, 6, 12, and 18% (wt:wt)] were incorporated into Last Call gel (10 different permethrin:ZETA combinations). All attracticide gels were evaluated in a toxicity test, in which either the tip of a leg or an antenna of a virgin P. interpunctella male was touched < 3 s into a dot of attracticide gel. These males were subsequently transferred to jars with virgin females. The toxicity test showed that a brief and gentle contact of P. interpunctella males with attracticide gel containing 3-18% permethrin caused a significant reduction in mating and killed males moths within 24 h. A wind tunnel test was conducted to evaluate the flight responses of P. interpunctella males to the same 10 attracticide gels. Male moths displayed significantly higher levels of positive anemotactic flight and more males made contact with the attracticide gel when the ZETA concentration was 0.16% compared with 0.32%. P. interpunctella males showed no signs of repellency to permethrin concentrations within a range of 0-18% in the attracticide gel. Three densities of P. interpunctella pairs were released into small warehouse rooms, and we found that the attracticide gel suppressed oviposition when the moth density was at a low level, but it was ineffective when the moth density exceeded one male-female pair per 11.3 m3.

Comparative efficacy of two controlled‐release gypsy moth mating disruption formulations

AbstractThe effects of aerial applications of the gypsy moth sex pheromone, disparlure, on mating disruption and suppression of growth of populations of the gypsy moth, Lymantria dispar (L.), were investigated. Two formulations of disparlure, plastic laminate flakes applied in a single application and polymethacrylate beads applied in two applications, were compared in two separate tests conducted in 1993 and 1994. The beads were applied in two applications spaced 2 weeks apart because preliminary tests had indicated that they released pheromone too rapidly to maintain adequate emission rates throughout the period of male flight. In 1993, the flakes were applied at a rate of 50 g a.i./ha, and the beads were applied at a rate of 15 g a.i./ha for each application. In 1994, the flakes were applied at a rate of 75 g a.i./ha and the beads were applied at rates of 32.5 and 42.5 g a.i./ha for the two applications. Beads with larger average particle size were used in 1994 to prolong disparlure release. The treatments applied in 1993 resulted in &gt;97% reduction in mating and &gt;82% suppression of population growth in the following year. Because of a 1995 collapse of gypsy moth populations in the vicinity of the tests, reliable population growth data were not available for the treatments applied in 1994, but significant mating disruption did occur under both treatments. Based on measurements of residual disparlure after field aging, the flakes released 32 and 48% of their disparlure content during the 6 weeks of male moth flight in 1993 and 1994, respectively. The smaller beads used in 1993 released 75% of their disparlure content, and the larger beads used in 1994 released 52% of their disparlure content, during the 6 weeks of male flight. The biological efficacy data suggest that the bead and flake formulations, as applied in these tests, have similar effects on gypsy moth mating disruption and subsequent population growth. Based on the observed release rates from both 1993 and 1994, a single application of the beads would provide emission rates equal to or greater than those provided by the flakes when applied at an equal dose.

Effect of hexaflumuron, a chitin synthesis inhibitor, on mating success of three species of vector mosquitoes

The effect of hexaflumuron, a chitin synthesis inhibitor, on the mating success of three species of vector mosquitoes, namely Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi, was investigated. The three species were exposed to concentrations giving 5% and 50% inhibition of emergence (EI5 and EI50, respectively) at the fourth instar and to 0.005 and 0.05 mg /1 hexaflumuron at the pupal stage. Emergent adults were allowed to mate with each other and with their untreated counterparts. Reduction in mating (evaluated as % insemination) was highest in Ae. aegypti exposed at the larval stage. Mosquitoes exposed at the pupal stage to 0.05 mg/1 hexaflumuron showed higher reduction in mating than those exposed to 0.005 mg/1. The effect of hexaflumuron appeared to be cumulative, resulting in a 78–80% reduction in % insemination when treated males were mated with treated females, compared with untreated males mated with untreated females.

Mating Disruption of Diamondback Moth (Lepidoptera: Plutellidae) in Cabbage: Reduction of Mating and Suppression of Larval Populations

An 8.1-ha field of 2-wk-old cabbage within an area of general cabbage production received a single treatment with 8100 m of a continuous-rope formulation of a 70:30 mixture of (Z)-11-hexadecenal and (Z)-11-hexadecen-1-ol acetate, two components of the sex pheromone of the female diamondback moth, Plutella xylostella (L.). Captures of males in synthetic pheromone-baited traps, mating of laboratory-reared sentinel females, and the mated status of native moths taken from the plots demonstrated suppression of mating activity by the pheromone treatment relative to that in the control area for 9 wk. Cabbage in this farm was planted sequentially. Fifteen insecticide treatments were applied during production of the block of cabbage, planted 13 d before the pheromone-treated cabbage, and 13 applications were made to the adjacent (control) block of cabbage planted 3 d after that in the pheromone plot. Two insecticide treatments were applied to plants in the pheromone-treated block to control diamondback moth larvae resident at the time of the pheromone application, and one spray was applied to this block 10 wk later at harvest. Cabbage at the extreme perimeter of the pheromone-treated area was damaged heavily by diamondback larvae; however, larval and pupal counts throughout most of this plot remained comparable to those in the control area. Cabbage at the interior of the pheromone area was graded as U.S. no. 1 quality. The results indicate that mating disruption can be used to protect cabbage from diamondback moth if pheromones are applied to areas of at least 8.1 ha with some supplemental application of insecticide.

Evaluation of Pheromone To Disrupt Mating of Eoreuma loftini (Lepidoptera: Pyralidae) in Sugarcane

The effect of the pheromone of Mexican rice borer, Eoreuma loftini (Dyar), on mating of laboratory-reared females to feral males was tested on mating tables in sugarcane fields. Reductions of 94.3 and 90.5% in mating was obtained using pheromone formulated in cotton wicks and rubber septa, respectively. In three small field plots (≈0.4 ha) treated with 198 g/ha of pheromone in rubber septa, 81.9—95.5% reductions in mating were obtained in the treated areas; 98.6—99.4% reductions in pheromone trap captures were obtained. When (Z)-13-octadecenyl acetate was tested alone, a 63.8% reduction in mating was obtained through 28 d, but this decreased to 6.9% reduction after 43 d.

Influence of nutrition on the reproductive biology of sugarcane pests and their natural enemies

The survival and fecundity of the scale insect,Melanaspis glomerata (Green) varies according to the sugarcane varieties on which they feed. When the sugarcane setts infested with scale insect crawlers were maintained on different nutritional bases, high survival and fecundity were observed in distilled water as the medium. The nutrition of immature stages and adults of the egg parasite,Trichogramma spp. was found to influence the longevity and reproduction. The eggs ofCorcyra reared on groundnut kernels had appreciable quantities of growth promoting amino acids like glysine, analine and tyrosine and this influenced the size of the adult parasites. The higher fecundity of the parasites obtained from the eggs ofCorcyra reared on greengram was attributed to the maximum level of nutrients. The individuals which emerged from superparasitized eggs showed reduction in mating and fecundity because of the sharing of the nutrients. The adult longevity and fecundity increased when fed with different sugars in the presence of host eggs. Increase in the protein content in adult diet decreased the fecundity.

Mating Disruption of a Wild Population of Tobacco Budworm (Lepidoptera: Noctuidae) with Virelure

Virelure [16:1 ratio, (Z)-ll-hexadecenal: (Z)-9-tetradecenal] contained in Hercon flakes (0.64 cm2), Disrupt®, and applied by air at a dosage of 33 g (AI)/ha to cotton significantly reduced mating, and catches in pheromone traps, of tobacco budworms, Heliothis virescens (F.). Mating was reduced between 82 and 95% for 7 nights after treatment. The reduction in mating was 60% 9 nights after treatment and 26% 14 nights after treatment. Mating frequency as well as numbers of single- and multiple-mated females were significantly greater in the check than in the treatment. Numbers of virgin females were greater in the treatment than in the check but the difference was not significant. Catch in pheromone traps was reduced 89 to 98% for 7 nights after treatment. Capture reductions were 89% 14 nights after treatment and 72% 20 nights after treatment. Comparisons of numbers of male moths captured with numbers of matings showed that reduction in numbers captured does not necessarily reflect concomitant reductions in mating. Male population densities were equal in treatment and check plots on the night before treatment, but male densities declined in the treatment plot and increased in the check plot on the night after treatment. Thereafter, male densities remained lower in the treated plot than in the check (32–72% reduction) even though ll.3-fold (1,404:124) more males were being removed from the check plot by pheromone traps. Applications of cypermethrin (Cymbush®) decreased moth density but had no effect on mating frequency.

Pink Bollworms (Lepidoptera: Gelechiidae): Effects of Low Concentrations of Selected Insecticides on Mating and Fecundity in the Laboratory1

Pink bollworm, Pectinophora gossypiella (Saunders), moths treated with low doses of certain insecticides had a lower percentage of mating, laid fewer eggs, and, in some cases, had a reduced number of eggs hatch. The synthetic pyrethroids cyfluthrin, fenpropathrin, fenvalerate, flucythrinate, and permethrin all caused reductions in mating during the first 24-h period after treatment. The insecticides also reduced the number of eggs laid. Reductions in mating and oviposition caused by treatment with azinphosmethyl, methylparathion, trichlorfon, carbaryl, and chlordimeform were usually associated with or were the result of high mortality. Avermectin B1, an experimental compound from Merck, Sharpe and Dohme (MK-936), completely prevented mating and oviposition at the LD10 and LD50 with little mortality among the treated insects. Hatching of eggs was also reduced by these treatment levels of Avermectin B1. These tests show that, in addition to causing mortality, treatments of moths with certain insecticides may cause population suppression through reduced mating, fecundity, and hatching of eggs.