Ultrastructure of the accessory glands of the Mediterranean flour moth

Five regions are recognized in the accessory glands of the Mediterranean flour moth, Anagasta kuehniella (Zeller), on the basis of cellular morphology and aggregates of secretory material in the lumen. Some variation is found in each of the posterior four regions, especially the third one. In the most anterior region (region 1) the epithelium is composed of a single type of cell, while in each of the other regions there are two classes of cells. The cells of region 1 and one class in each of the other four regions are fairly typical exocrine cells with extensive rough endoplasmic reticula. Secretion is primarily via Golgi-derived vesicles. Apocrine secretion in the form of sloughing off of the apical cytoplasm probably also occurs in all regions but is most prominent in the posterior two regions. One class of cells is very similar in morphology in each of the posterior four regions though their secretory products form characteristic aggregates in the lumen. The second class of cells (foliate cells) occurring in the posterior four segments is most notably characterized by elongate apical projections that extend out into the lumen. The apical projections contain large quantities of glycogen, some microtubules, and, in some cases, many minute mitochondria. The membrane content of the projections is also very high. In the anterior regions, the membranes are mostly fused in pairs and typically form multilayered whorls. Fusion and whorl formation decrease in the posterior regions. The cytoplasm of the foliate cells has a high organelle content including many lysosomes and mitochondria. The latter exhibit considerable polymorphism, with particular forms occurring in the different regions of the glands. The apical projections of the foliate cells are detached during copulation, presumably as the result of nervous stimulation, and become a part of the ejaculate. Replenishment of all secretory material, including the apical projections, occurs after copulation.     

Daily cycle of release of sperm from the testes of the Mediterranean flour moth

A daily rhythm of sperm release from the testes was found in young virgin male Mediterranean flour moths, Anagasta kühniella, maintained in a 12 hr light, 12 hr dark regimen. Passage of apyrene sperm from the testes began in the latter half of the light phase and that of eupyrene sperm somewhat later; an apparent peak of release occurred near the end of the light phase. A low level of sperm release continued through the night, but none occurred in the first half of the light phase. Maintenance of pupae and adults in continuous light or decapitation shortly after eclosiion greatly reduced the amount of eupyrene sperm released from the testes. Movement of sperm from the testes was not affected by continuous darkness or by severing the abdominal nerve cord.     

Abdominally entrained periodicities of testis and vas deferens activity in the Mediterranean flour moth

In a light-dark (LD) regimen, sperm, first apyrene and then eupyrene, start moving out of the fused testes of the Mediterranean flour moth, Anagasta kuehniella, toward the beginning of the scotophase. At 27° ± 2°C, the sperm mass remains in the proximal part of the vasa deferentia for 10 to 12 hr and then passes rapidly into the seminal vesicles, remains in these organs for about 5 hr, and is then transported to the ductus ejaculatoris duplex where it becomes available for ejaculation. The phases of sperm movement appear to be closely related to sperm development, and the reproductive activity of the moths. In isolated abdomens there is a significant reduction in the amount of sperm released from the testes, but normal periodicity of sperm release and movement continues in either LD or continuous dark (DD) regimens, and rapid phase shifting occurs when a LD regimen is reversed. All stages of sperm movement are disrupted in continuous light (LL), but normal periodicity is usually resumed when isolated abdomens of the LL moths are placed in LD or DD regimens. Normal periodicity also occurs in moths paralyzed with tetrodotoxin or procaine. Removal of any one of the four abdominal ganglia from LL moths does not prevent increased sperm release when the moths are placed in LD, though with each ganglion there is some disruption of the normal pattern of movement down the vasa deferentia. It is thought that the testes and vasa deferentia down to at least the seminal vesicles represent a semiautonomous complex in which periodicity is maintained by endogenous circadian activity in cells of the testes (and possibly the vasa deferentia) or more probably in a peripheral control center.     

Regulation of Wolbachia density in the Mediterranean flour moth,Ephestia kuehniella,and the almond moth,Cadra cautella

The Mediterranean flour moth, Ephestia kuehniella, is infected with A-group Wolbachia (wKue), and the almond moth, Cadra cautella, is doubly infected with A- and B-group Wolbachia, which are designated as wCauA and wCauB, respectively. In both insects, the Wolbachia populations increased greatly during embryonic and larval stages. The Wolbachia population doubled every 3.6 days on average in E. kuehniella larvae, whereas those of wCauA and wCauB doubled every 2.1 days in C. cautella larvae. The populations of wCauA and wCauB that had been transferred into the E. kuehniella background increased at similar rates to that of wKue in the natural host E. kuehniella, suggesting that the host genetic background influences Wolbachia proliferation. To examine whether the populations of the two Wolbachia variants in double infection is regulated collectively or independently, we measured the infection load in the ovaries of three transfected E. kuehniella lines in different infection states: single infection with wCauA, single infection with wCauB, and double infection. The density of each Wolbachia variant did not differ significantly between the singly and doubly transfected hosts, suggesting independent regulation.     

Comparative toxicity and ecdysone receptor affinity of non-steroidal ecdysone agonists and 20-hydroxyecdysone in Chironomus tentans.

Ecdysone agonists belonging to the bisacylhydrazine class of compounds are a new generation of insecticidal compounds that cause premature lethal molts in susceptible intoxicated insects. While two of the bisacylhydrazines (coded as RH-5992 and RH-2485) are predominantly toxic to lepidopteran pests, RH-5849, which has not been commercialized, has a broader spectrum of toxicity. We have carried out toxicity bioassays with last (4th) instar Chironomus tentans L. larvae, radioligand binding assays using bacterial fusion proteins of C. tentans ecdysone receptor and ultraspiracle (CtEcR, CtUSP), and C. tentans imaginal disc development assays to compare the relative potencies of the three bisacylhydrazine compounds as well as of 20-hydroxyecdysone (20E). In all three assays, the potency of the three bisacylhydrazines was in the order RH-2485>RH-5992>RH-5849. While in toxicity assays 20E was ineffective, most likely due to rapid metabolism, it was more potent than RH-5849 but less so than RH-5992 and RH-2485 in imaginal disc assays. In summary, we compared the potencies of the ecdysone agonists for C. tentans at three levels: whole organism, imaginal discs and the receptor level, and our results indicate that the increased toxicity of the non-steroidal ecdysone agonists for C. tentans has a high correlation to the affinity of these compounds for CtEcR/CtUSP bacterially expressed proteins. Our results, though, do not exclude reasons of metabolic stability of the compounds in C. tentans, which we have not investigated in this report.     

Long-term pheromone-mediated mating disruption of the Mediterranean flour moth, Ephestia kuehniella, in a flourmill

Several studies have indicated that mating disruption (MD) successfully reduces population densities of stored product moths, for example, the Mediterranean flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae). However, practical issues, such as finding control plots, replication, and lack of similarity between replicates, often incur problems in full-scale investigations and often draw focus from the added results. We here present results from long-term monitoring of E. kuehniella populations in two similar flourmills in Poland, one treated with pheromone for MD and one left untreated and used as control. Pheromone-mediated MD was applied during 2 years. Thirty pheromone dispensers (one per 100 m³ factory volume), each releasing about 2 mg ( Z,E )-9,12-tetradecadienyl acetate per day, were used. Pheromone-baited traps were used to monitor the moth populations in the MD mill and in a nearby untreated mill. The reduction in trap catch during the MD treatment was about 90% or more, compared with the untreated mill or pre-treatment periods of the MD mill. The reduction was larger during the 2nd year of MD than during the 1st year. These results contribute to the picture that MD is an effective method to control moth species infesting stored products.     

几种杀虫剂对嗜虫书虱的触杀作用

采用滤纸药膜法比较了常用8种杀虫剂对嗜虫书虱Liposcelis entomophila的触杀作用,在药剂的推荐浓度下有机磷类杀虫剂对嗜虫书虱的急性触杀作用强于其它药剂.同时测定了杀螟硫磷、敌敌畏和溴氰菊酯(含增效醚)3种药剂对嗜虫书虱的触杀毒力,其24h内触杀作用的LC50分别为9.3284、2.1440和7.5007 μg/cm2,但杀螟硫磷的LC95为459.4949 μg/cm2,远高于敌敌畏的8.2453μg/cm2和溴氰菊酯(含增效醚)的14.5274 μg/cm2.此外,48h内敌敌畏等有机磷杀虫剂对嗜虫书虱的毒杀速度较其它供试药剂快.     

3种药剂对广东地区草地贪夜蛾3龄幼虫室内毒力测定及其田间药效评价

为明确几种药剂对广东地区草地贪夜蛾Spodoptera frugiperda幼虫的室内毒杀作用及田间防治效果,合理使用化学农药对草地贪夜蛾进行科学防治提供理论依据.本研究采用浸叶法测定了氯虫苯甲酰胺、高效氯氟氰菊酯和甲氨基阿维菌素苯甲酸盐对草地贪夜蛾3龄幼虫的室内毒杀作用;采用茎叶喷雾法,测定了 200克/升氯虫苯甲酰...     

Infection density of Wolbachia and level of cytoplasmic incompatibility in the Mediterranean flour moth,Ephestia kuehniella

Wolbachia, a causative agent of various reproductive changes in arthropods, induces cytoplasmic incompatibility (CI) in the Mediterranean flour moth, Ephestia kuehniella. Two strains of E. kuehniella, Yokohama and Tsuchiura, harbor closely related Wolbachia, but the Yokohama strain expresses stronger CI than the Tsuchiura strain. A transinfected E. kuehniella strain that harbors the Wolbachia derived from the almond moth Cadra cautella, expresses weak CI at a similar level to the Tsuchiura strain. In the present study, we measured the Wolbachia density in the testis of the three E. kuehniella strains in order to examine the effects of bacterial strain and infection load on the expression of CI. When individuals of the same strain were compared, a correlation of bacterial density to CI level was observed. In addition, the Wolbachia density was higher in the Yokohama strain than the Tsuchiura strain in agreement with the CI levels expressed. However, this relationship did not hold in the comparison between the naturally infected and transinfected strains that carried phylogenetically distant Wolbachia.     

Comparative activity of baculoviruses against the codling moth Cydia pomonella and three other tortricid pests of tree fruit

The granulovirus of Cydia pomonella (L.) (CpGV) offers potential for selective control of codling moth. Two major limitations of CpGV are its narrow host range and lack of persistence in the orchard agroecosystem. The nucleopolyhedroviruses of the alfalfa looper Autographa californica (Speyer) (AcMNPV) and those of the celery looper Anagrapha falcifera (Kirby) (AfMNPV) have broad host ranges. Comparative assays of CpGV, AcMNPV, and AfMNPV against codling moth neonate larvae revealed a 54-93-fold greater susceptibility of codling moth to the granulovirus than to the two nucleopolyhedroviruses based on the LC(50) values for each virus. The LC(50)s for CpGV, AfMNPV, and AcMNPV were 32.7 capsules/mm(2), 1.77 x 10(3) occlusion bodies (OBs)/mm(2), and 3.05 x 10(3)OBs/mm(2), respectively. The LT(50) determined for AfMNPV using an approximate LC(95) of the virus against neonate larvae was 3.6 days. Histological examination of tissues in moribund codling moth larvae that had been treated with AfMNPV revealed the presence of nonoccluded and unenveloped virus rods in midgut tissue. Neither OBs nor signs of infection were detected in other tissues. The activity of AfMNPV was also evaluated in three other tortricid apple pests (obliquebanded leafroller, Choristoneura rosaceana (Harris); Pandemis leafroller, Pandemis pyrusana Kearfott; and the oriental fruit moth, Grapholitha molesta (Busck)). Codling and Oriental fruit moths were significantly more susceptible to AfMNPV than were the two leafroller species.     

室内测定6种化学杀虫剂对草地贪夜蛾幼虫的毒力

2019年草地贪夜蛾Spodoptera frugiperda入侵我国多个省份和地区,对我国农业生产造成重大影响。化学防治是应对入侵害虫的主要措施,因此,本研究测定了6种不同作用机制杀虫剂对草地贪夜蛾初孵和3龄幼虫的生物活性。结果表明,对初孵幼虫具有较高毒力作用的为氯虫苯甲酰胺、多杀菌素、茚虫威、阿维菌素和甲氧虫酰肼;对3龄幼虫具有较高毒力作用的为氯虫苯甲酰胺、多杀菌素和茚虫威;与初孵幼虫相比,阿维菌素、茚虫威、多杀菌素和甲氧虫酰肼的LC 50分别提高了78.06、1.70、11.73和23.09倍。本研究筛选出了对草地贪夜蛾初孵幼虫和3龄幼虫杀虫效果较好的药剂,证明了低龄幼虫对部分农药抵抗力较弱,而3龄后的幼虫抵抗力显著增加,为田间草地贪夜蛾的化学防治提供了科学的用药指导。     

Life stage toxicity and residual activity of insecticides to codling moth and oriental fruit moth (Lepidoptera: Tortricidae)

The codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck), are two key pests of apple (Malus domestica Borkh.) in North Carolina. Growers extensively relied on organophosphate insecticides, primarily azinphosmethyl, for > 40 yr to manage these pests. Because of organophosphate resistance development and regulatory actions, growers are transitioning to management programs that use new, reduced-risk, and OP-replacement insecticides. This study evaluated the toxicity of a diversity of replacement insecticides to eggs, larvae, and adults, as well as an assessment of their residual activity, to codling moth and oriental fruit moth. Laboratory-susceptible strains of both species were used for all bioassays. Fresh field-harvested apples were used as a media for assessing the ovicidal activity of insecticides. For larval studies, insecticides were topically applied to the surface of lima bean-based diet, onto which neonates were placed. Toxicity was based on two measures of mortality; 5-d mortality and development to adult stage. Ovicidal bioassays showed that oriental fruit moth eggs were generally more tolerant than codling moth eggs to insecticides, with novaluron, acetamiprid, and azinphoshmethyl having the highest levels of toxicity to eggs of both species. In contrast, codling moth larvae generally were more tolerant than oriental fruit moth to most insecticides. Methoxyfenozide and pyriproxyfen were the only insecticides with lower LC50 values against codling moth than oriental fruit moth neonates. Moreover, a number of insecticides, particularly the IGRs methoxyfenozide and novaluron, the anthranilic diamide chlorantriliprole, and the spinosyn spinetoram, provided equal or longer residual activity against codling moth compared with azinphosmethyl in field studies. Results are discussed in relation to their use in devising field use patterns of insecticides and for insecticide resistance monitoring programs.     

Chemical induction of mating abnormalities and spermatophore production in the Mediterranean flour moth, Ephestia kühniella

Hexamethyl-melamine (hemel) when injected into male Ephestia kühniella induced mating aberrations expressed as permanent copulation, sterile mating and spontaneous production of spermatophore. Permanent copulation was not caused by blockage or an elongated spermatophore column but probably caused by failure of the male reproductive organs to completely transfer the spermatophore. Spontaneous spermatophore formation was induced by both cholinesterase inhibitors and nerve stimulants, the effect of the former being more pronounced. It was not caused by stress due to poisoning since DDT even at lethal doses did not induce a response. The results suggest involvement of the nervous system in spermatophore production during a normal mating.     

The hairpencils of the flour moth Ephestia kuehniella

The hairpencils of the Mediterranean flour moth, Ephestia kuehniella Zeller, are tufts of modified scales between the seventh and eighth abdominal segments of the adult males. The fine structure and development of a hairpencil organule is described. A process of the trichogen cell secretes the modified scale and then withdraws, and the cell invaginates forming a microvillous lumen into which pheromone is probably secreted. This lumen communicates with the outside via rows of pores in the hollow scale. The opening of these pores when the moth emerges from the pupal cuticle may be a result of the drying out of the membrane that covered them. The socket of the hairpencil scale is secreted by a tormogen cell.
The hairpencils of male Lepidoptera differ in position from family to family, but the organules that compose them seem to share a common structure. Epidermal glands and organules are classified in a scheme that takes account of their mode of development.     

Insecticidal action of Annona coriacea lectin against the flour moth Anagasta kuehniella and the rice moth Corcyra cephalonica (Lepidoptera: Pyralidae)

Annona coriacea lectin (ACLEC) was tested for insecticidal activity against larvae of two pyralid moths, Anagasta kuehniella and Corcyra cephalonica. ACLEC produced approximately 50% mortality and mass loss in A. kuehniella larvae when incorporated into an artificial diet at levels of 1.5% and 1.0% (w/w), respectively. In contrast, the inclusion of up to 2% ACLEC in the diet did not significantly decrease the survival or weight of C. cephalonica larvae. The nutritional indices for A. kuehniella and C. cephalonica suggested that ACLEC had a multi-mechanistic mode of action and was an antifeedant for both insects. The toxicity in A. kuehniella apparently resulted from a change in the gut membrane environment and consequent disruption of digestive enzyme recycling mechanisms. Affinity chromatography showed that ACLEC bound to midgut proteins of A. kuehniella and C. cephalonica. However, the 14 kDa subunit of ACLEC was not digested by midgut proteases of A. kuehniella, but was degraded by the corresponding C. cephalonica proteases within a few hours. These findings suggest the possibility of using ACLEC to engineer crop plants.     

Effects of 20-hydroxyecdysone on sperm release from the testes of the Mediterranean flour moth,Anagasta kuehniella (Zeller)

Abdominal injection of 1 μg aqueous 20-hydroxyecdysone into Anagasta kuehniella, anytime prior to the initiation of sperm release from the testes, prevents the impending release of eupyrene sperm bundles. Apyrene sperm release is not prevented and there is complete recovery of eupyrene release by the following cycle 24 hr later. If 20-hydroxyecdysone is administered on consecutive days, no eupyrene bundles are released and although apryene sperm release continues, it diminishes with time. The effect of 20-hydroxyecdysone in preventing eupyrene release is dose dependent. Administration of decreasing 20-hydroxyecdysone dosages results in increasing numbers of eupyrene bundles released. When a single injection of 20-hydroxyecdysone is administered to isolated abdomens, recovery time of eupyrene sperm release is slower than in whole moths and total recovery is not seen even by 5 days after administration. Apyrene sperm release is also affected to a greater extent than in whole moths, and in some cases, no apyrene release was detected at all. Treatment with 20-hydroxyecdysone prevents cupyrene bundles from passing through the testicular basilar membrane into the vasa efferentia, thus causing a build up of bundles near the basilar membrane but no disintegration of these eupyrene sperm bundles.     

Ultrastructure of the vasa deferentia of the mediterranean flour moth

Each vas deferens of the Mediterranean flour moth, Anagasta kuehniella (Zeller), consists of a short swollen portion immediately below the testis, another swollen portion that forms a seminal vesicle, and an elongate lower portion that empties into one arm of the ductus ejaculatoris duplex. Three types of epithelial cells occur sequentially. Phagocytic cells that engulf debris from the testis form the anterior two-thirds of the first swollen portion. Tall secretory cells form the distal third of the first swollen region and extend to the seminal vesicles. The secretory cells surround a slit-like lumen and appear to function as a valve between the two swollen regions. Many membrane-enclosed secretory granules are stored at the apical ends of the cells and are released into the lumen together with small amounts of the surrounding cytoplasm. The granules remain intact while they are in the male tract. A second type of secretory cell forms the walls of the seminal vesicles and the lower vasa deferentia. These cells produce secretory granules whose contents become dispersed through the semen. PTA-chromic acid staining indicates that the seminal plasma has a high glycoprotein content. A thin muscle layer is basal to the epithelial cells. Both apyrene and eupyrene sperm undergo some development in the vasa deferentia. The epithelial cells, muscle, and stored sperm all undergo extensive changes with age.     

Life tables of Venturia canescens (Hymenoptera: Ichneumonidae) parasitizing the Mediterranean flour moth (Lepidoptera: Pyralidae)

Effects of temperature, adult feeding, and host instar on life table parameters of Venturia canescens Gravenhorst (Hymenoptera: Ichneumonidae) parasitizing larvae of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) were studied in the laboratory. Experimental adults lived under various regimes of temperature (15, 20, 25, and 30 degrees C), food supply (with or without access to honey), and host instar (second, third, fourth, and fifth). Temperature increase resulted in higher values of the intrinsic rate of natural increase (r(m)), the net reproductive rate (R(o)), the finite capacity of increase (lambda), and the gross reproductive rate (GRR), whereas it was followed by decrease of the mean generation time (G) and the doubling time (DT) values. Feeding on honey caused remarkable increase of r(m), R(o), and GRR, whereas r(m) and lambda reached their maximum when full-grown hosts (fifth instar) were parasitized. This is the first time life table parameters of V. canescens have been studied. The findings of the current study are discussed on the basis of improving V. canescens performance as a biological agent against moth pests of stored products.