Sex chromosome pairing and sex chromatin bodies in W-Z translocation strains of Ephestia kuehniella (Lepidoptera).

Structure and pairing behavior of sex chromosomes in females of four T(W;Z) lines of the Mediterranean flour moth, Ephestia kuehniella, were investigated using light and electron microscopic techniques and compared with the wild type. In light microscopic preparations of pachytene oocytes of wild-type females, the WZ bivalent stands out by its heterochromatic W chromosome strand. In T(W;Z) females, the part of the Z chromosome that was translated onto the W chromosome was demonstrated as a distal segment of the neo-W chromosome, displaying a characteristic non-W chromosomal chromomere-interchromomere pattern. This segment is homologously paired with the corresponding part of a complete Z chromosome. In contrast with the single ball of heterochromatic W chromatin in highly polyploid somatic nuclei of wild-type females, the translocation causes the formation of deformed or fragmented W chromatin bodies, probably owing to opposing tendencies of the Z and W chromosomal parts of the neo-W. In electron microscopic preparations of microspread nuclei, sex chromosome bivalents were identified by the remnants of electron-dense heterochromatin tangles decorating the W chromosome axis, by the different lengths of the Z and W chromosome axes, and by incomplete pairing. No heterochromatin tangles were attached to the translocated segment of the Z chromosome at one end of the neo-W chromosome. Because of the homologous pairing between the translocation and the structurally normal Z chromosome, pairing affinity of sex chromosomes in T(W;Z) females is significantly improved. Specific differences observed among T(W;Z)1-4 translocations are probably due to the different lengths of the translocated segments.     

Structural mutants of the W chromosome in Ephestia (Insecta,Lepidoptera)

In a search for genetic markers of W-chromosome-autosome fusions in Ephestia, two closely linked autosomal markers, ml and Us, were found to show sex linkage in several families of chromosome mutant strains. In these families, the wild-type allelomorphs, ml ⁺ and US ⁺, label the autosome that is translocated to the W chromosome. With ml (musterlos) a sex dimorphic strain could be established in which males (ml/ml) have patternless wings and females (ml ⁺/ml) have the normal wing pattern.—Using these genetic markers, stability of the fusion chromosome was studied. Recurrence to autosomal inheritance of the marker occurs at a considerable rate. In two chromosome fusion strains, a cytogenetically detectable breakage of the fusion giving rise to a wild-type-like W chromosome was the predominant cause for the recurrence of the marker to autosomal inheritance. In a third strain a more complicated chromosome rearrangement was the predominant cause: the translocated autosome was replaced by a non-homologous one, presumably after a cytogenetically undetectable breakage event of the original fusion. — The high rate of breakage suggests that the fusion chromosomes are dicentrics, a situation not compatible with a typical holokinetic organization of Lepidoptera chromosomes.     

Sex chromatin and sex chromosome systems in nonditrysian Lepidoptera (Insecta)

Eleven representatives of the superorder Amphiesmenoptera (Trichoptera + Lepidoptera) were examined for sex chromatin status. Three species represent stenopsychoid, limnephiloid and leptoceroid branches of the Trichoptera; eight species belong to the primitive, so-called nonditrysian Lepidoptera and represent the infra-orders Zeugloptera, Dacnonypha, Exoporia, Incurvariina, Nepticulina and Tischeriina. The female-specific sex chromatin body was found in the interphase somatic nuclei of Tischeria ekebladella (Bjerkander 1795) (Lepidoptera, Tischeriina). The sex chromatin was absent in all investigated Trichoptera species as well as in all representatives of the nonditrysian Lepidoptera except Tischeria ekebladella . The sex chromosome mechanism of Limnephilus lunatus Curtis 1834 (Trichoptera, Limnephilidae) is Z/ZZ. The sex chromosome mechanism of Tischeria ekebladella (Lepidoptera, Tischeriina) is ZW/ZZ including the W chromosome as the largest element in the chromosome set. The data obtained support the hypothesis that the Z/ZZ sex chromosome system, the female heterogamety and the absence of the sex chromatin body in interphase nuclei are ancestral traits in the superorder Amphiesmenoptera. These ancestral characters are probably kept constant in all the Trichoptera and in the most primitive Lepidoptera. The W sex chromosome and the sex chromatin evolved later in the nonditrysian grade of the Lepidoptera. It is proposed that the sex chromatin is a synapomorphy of Tischeriina and Ditrysia.     

The structure of Verson's cells in Ephestia kuehniella Z. (Pyralidae,Lepidoptera)

Summary Testis follicles of Lepidoptera contain a large somatic cell termed Verson's cell. The present study focuses on the structure of Verson's cells and neighbouring germ cells in the Mediterranean mealmoth, Ephestia kuehniella (Pyralidae), using electron microscopy, antitubulin immunofluorescence, and phalloidin incubation for the visualization of microfilaments. Verson's cells of young larvae are connected with the follicle boundary and show large areas containing packages of glycogen particles, whereas Verson's cells of pupae lie freely within the testis follicle and are largely devoid of glycogen. Both developmental stages of Verson's cells have in common the presence of a dense cytoplasmic network of microtubules. A juxtanuclear subset of the cytoplasmic microtubule array is recognized by an antibody against acetylated microtubules. This indicates that more stable microtubules exist in this region. Microfilaments are arranged parallel to the cytoplasmic microtubules. The microtubule-microfilament-complex forms a cytoskeleton that may keep larger organelles, such as mitochondria and lysosomes, in a juxtanuclear position. Chromatin within the nuclei of Verson's cells is largely decondensed and nuclear pores are abundant. This indicates a high synthetic activity within the cells. The development of cells directly attached to Verson's cells, viz. prespermatogonia, may be controlled by the Verson's cells. Prespermatogonia, which differ in cytoplasmic density from spermatogonia further away from Verson's cells, may represent stem cells that give rise to spermatogonia and somatic cyst cells upon detachment from Verson's cells. This suggestion is compatible with the low division rate of prespermatogonia.     

Der Feinbau des Auges der Mehlmotte,Ephestia kuehniella Zeller (Lepidoptera,Pyralididae)

Zusammenfassung Die Retinula im Ommatidium der Mehlmotte besteht aus einer wechselnden Anzahl (9–12, meist 11) langgestreckter, prismatischer Sinneszellen. Außerdem enthält jede Retinula nahe der Basalmembran im Zentrum zwischen diesen distalen Retinulazellen noch eine basale Retinulazelle. Die Längsachse der Retinula wird von der Achsenstruktur eingenommen, die aus Mikrovilli besteht. Ihr distaler Teil ist der Achsenfaden, der breitere, proximale Teil bildet das Rhabdom. Dieses erscheint im Querschnitt meist vierstrahlig gelappt, da seine Außenseite in Längsrichtung tief gekehlt ist. Der Rhabdomquerschnitt gliedert sich in mehrere Schöpfe parallel angeordneter Mikrovilli (Rhabdomsektoren); jeder Rhabdomsektor besteht aus 1 oder 2 Rhabdomeren. Die basale Retinulazelle entsendet einen kleinen Schopf von Mikrovilli in die proximale Spitze des Rhabdoms. Die distalen Retinulazellen setzen sich proximal in Neuriten fort, welche sich in Einkehlungen der basalen Retinulazelle bzw. der Tracheenendzelle einschmiegen. Jeweils eine Tracheole durchbricht zusammen mit dem Neuritenstrang einer Retinula die Basalmembran; sie verzweigt sich distal zu ca. 30 Tracheolen, die die Retinula umhüllen.Die Kristallkegelzellen grenzen distal an die Cornea; proximal laufen die Kristallkegelzellen eines Ommatidiums in einen gemeinsamen Fortsatz aus, der zwischen den Retinulazellen unmittelbar am Achsenfaden endet. — Nur das helladaptierte Auge wurde untersucht. Hierbei erscheint im distalen Teil der Retinula nur der Achsenfaden lichtdurchlässig, das Cytoplasma der Retinulazellen hingegen von Pigmentgrana durchsetzt und für Licht undurchlässig.

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Fine structure of the eye of the meal moth, Ephestia kuehniella Zeller (Lepidoptera, Pyralididae)

Summary In each ommatidium of the meal moth a retinula is formed from a varying number (9–12, mostly 11) of elongated, prismatic sense cells. In addition, a basal retinular cell is situated near the basement membrane in the center of the other (distal) retinular cells. The axis of the retinula is occupied by many microvilli forming the axial structure, the distal section of which is the slender axial thread. Proximally, the axial structure widens (to 8.5 m instead of 1 m in diameter) and is now called rhabdom. Cross sections of the rhabdom mostly look like a petaloid with four petals; this figure is due to longitudinal infoldings along the length of the rhabdom surface. The rhabdom cross section is subdivided into several brushes of microvilli (rhabdom sectors), each one being characterized by an approximately parallel arrangement of its microvilli. One rhabdom sector may be composed of one or two rhabdomeres respectively.The basal retinular cell participates in rhabdom formation through a small brush of microvilli at the proximal end of the rhabdom. Proximally, the distal retinular cells taper into slender neurites which are embedded in grooves at the surface of the basal retinular cell and the tracheal end cell respectively. One tracheole piercing the basement membrane together with the neurites of one retinula branches into about 30 tracheoles surrounding the retinula.The crystalline cone cells touch the cornea; proximally, their cytoplasm forms a point which eventually terminates amongst the distal tips of the retinular cells, immediately at the axial thread.—Our work was restricted to light adapted eyes; in this condition, light transmission in the distal part of the retinula seems to be blocked by retinular cell pigment except inside the axial thread.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Distribution of gamma-tubulin differs in primary and secondary oocytes of Ephestia kuehniella (Pyralidae,Lepidoptera)

In a previous study, barrel-shaped spindles were found in metaphase I oocytes of Ephestia kuehniella (Pyralidae, Lepidoptera). Aster microtubules (MTs) were missing (Wolf, 1993: Cell Motil Cytoskeleton 24:200-204). This points to an acentriolar organization of the spindle apparatus. The present study was aimed at the question of whether gamma-tubulin, a newly detected member of the tubulin superfamily that has often been identified in microtubule-organizing centers, plays a role in the nucleation of MTs in meiotic spindles of the moth. To this end, the distribution of gamma tubulin was examined in oocytes of E. kuehniella using an antibody against gamma-tubulin in combination with indirect immunofluorescence. The antibody evenly decorated spindle MTs in metaphase I oocytes of the moth. Enhanced staining of the spindle poles was not detectable In subsequent stages of meiosis, gamma-tubulin was gradually lost from spindle MTs and was then found at the surface of the so-called elimination chromatin. Female meiosis in Lepidoptera is achiasmatic. The elimination chromatin, i.e., modified and persisting synaptonemal complexes, is believed to keep homologous chromosomes linked until the onset of anaphase I. In meiosis I of female Lepidoptera, the elimination chromatin persists at the spindle equa or between the segregating chromatin masses. It is plausible to assume that gamma-tubulin is involved in spindle organization in the absence of canonical centrosomes. In MTs of metaphase II spindles of E. kuehniella, gamma-tubulin was no longer detectable with our immunological approach. This points to a far-reaching change in spindle organization during transition from meiosis I to meiosis II. © 1996 Wiley-Liss, Inc.     

Connections between adjacent retinula cell columns in the eye of Ephestia kuehniella Zeller (Lepidoptera,Pyralididae)

Summary Connections were found between retinula cells of adjacent retinula cell columns in the eye of Ephestia. The connections occur most frequently at the level of the retinula cell nuclei and may involve two or more retinula columns simultaneously. The absence of specialized structural modifications of the membranes and the presence of pigment granules at the level of the connections or distal to them indicates that these connections are probably not involved in selective chemical or electrical communication nor in light transmission. It is suggested that the connections may serve tactily to coordinate cytoplasmic movement in adjacent retinula columns during light-dark adaptation.Senior U. S. Scientist Awardee of the Alexander von Humboldt Foundation. Thanks to Prof. Dr. A. Fischer for his suggestions and assistance.     

Ultrastructure of distal flagellar swellings in spermatocytes and spermatids of Ephestia kuehniella Z. (Pyralidae,Lepidoptera)

Summary Development of flagella was investigated by transmission electron microscopy in spermatocytes and spermatids of the Mediterranean mealmoth, Ephestia kuehniella Z. Growing flagella displayed voluminous distal swellings. In short flagella the apical portion of the swellings contained an amorphous, dense accumulation. In more developed flagella a less dense proximal extension of the apical accumulation was formed, which in turn was in contact with the elongating flagellar microtubules. The material of the flagellar tip is interpreted as being a precursor of the axoneme containing mainly tubulin. The material may be converted into the axoneme.     

Effect of diallyl disulfide on physiological performance of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

Ephestia kuehniella Zeller is a key pest by severe deficiencies on quantity and quality of stored products. Due to concerns made by synthetic insecticides, use of natural products (like botanical insecticides) is of great importance as an alternative pest management. In the current study, the effect of diallyl disulfide was determined on digestive enzymes and those involved in intermediary metabolism of E. kuehniella. Concentration of 0.31% was obtained as LC₅₀ of diallyl disulfide followed by bioassay experiments. Activities of α-amylase, proteases, alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase significantly decreased in the treated larvae, while the adverse effects were observed in case of triacylglyceride-lipase, aspartate aminotransferase, γ-glutamyl transferase, aldolase and acid phosphatase. Results confirmed that diallyl disulfide interrupted larval digestion by lower activities of digestive enzymes indicating significant effect on intermediary metabolism.     

Immunocytochemical Evidence of a Tubulin Reserve at the Tip of Growing Flagella in Spermatogenesis of the Mediterranean Mealmoth,Ephestia kuehniella Z. (Pyralidae,Lepidoptera, Insecta)

Abstract The distal swellings of growing flagella in spermatocytes of Ephestia kuehniella Z. contain dense material associated with the ends of axonemal microtubules. In order to define the nature of this material, spermatocytes were lysed under microtubule-stabilizing conditions, spun onto cover-slips, probed with an antibody against β-tubulin and processed for indirect immunofluorescence. Whereas the dense material was lost from the cells when untreated spermatocytes were used, a block of stained material was visible in cold-treated spermatocytes. Most probably, cold-treatment alters the dense material and guarantees its survival during preparation of the cells for anti-tubulin immunofluorescence. The positive reaction with the antibody indicates the presence of β-tubulin. Flagellar outgrowth in spermatogenesis of the moth starts in late prophase I and continues throughout both meiotic divisions. Therefore, spindles and flagella compete for tubulin monomers. A tubulin reserve, deposited early in development at the elongating tip of axonemes, may ensure their uninterrupted growth, independent of tubulin-consuming cytoplasmic events. In order to test this hypothesis, flagellar outgrowth was studied in the spermatocytes of a long-horned beetle, Agapanthia villosoviridescens de Geer (Cerambycidae, Coleoptera) using electron microscopy. In this species, flagella begin to elongate only in telophase II, when the second meiotic spindle is just disassembling. The absence of dense material at the tip of flagellar stubs in the beetle corroborates the hypothesis formulated above.     

Chromosomal principle of radiation-induced F1 sterility in Ephestia kuehniella (Lepidoptera: Pyralidae).

A dose-response analysis of chromosomal aberrations was performed in male progeny of gamma-irradiated males in the flour moth, Ephestia kuehniella. For comparison, several female progeny from each dose level were examined. Aberrations were detected on microspread preparations of pachytene nuclei in the electron microscope and classified according to pairing configurations of synaptonemal complexes (SCs). Fragmentation and various translocations were the most numerous aberrations, whereas interstitial deletion and inversion were rare. At 100 Gy, relatively simple multiple translocations were found. Multiple translocations showing complicated configurations occurred at 150 and 200 Gy, and their number increased with the dose. In males, the mean number of chromosomal breaks resulting in aberrations linearly increased with the dose from 8.4 to 16.2 per nucleus. In females, this value achieved a maximum of 11.2 breaks/nucleus at 200 Gy. Three factors were suggested to contribute to the reported higher level of F1 sterility in males than females: (i) survival of males with high numbers of breaks, (ii) crossing-over in spermatogenesis but not in the achiasmatic oogenesis, and (iii) a higher impact of induced changes on the fertility of males than females. It was concluded that translocations are most responsible for the production of unbalanced gametes resulting in sterility of F1 moths. However, F1 sterility predicted according to the observed frequency of aberrations was much higher than the actual sterility reported earlier. This suggests a regulation factor which corrects the predicted unbalanced state towards balanced segregation of translocated chromosomes.     

Spatiotemporal clustering and association of Ephestia kuehniella (Lepidoptera: Pyralidae) and two of its parasitoids in bulk-stored wheat

To assess the spatiotemporal distribution of insects in a flat storage containing wheat (Triticumn spp.), probe traps were suspended in the wheat bulk and inspected for captured insects at 15-d intervals, from June 2001 to August 2002. The grain bulk was 1 m in height, and traps were placed at the upper and the lower 0.5 m of the bulk. During the entire trapping period, 17 insect taxa were recorded. The most abundant species were Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and its larval parasitoids Harbobracon hebetor (Say) (Hymenoptera: Braconidae) and Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae). Most individuals were found in the upper bulk part. The highest E. kuehniella trap catches were found between August and November 2001 and during June and July 2002. Of the two parasitoids, H. hebetor was more abundant than V. canescens, with the exception of winter and early spring, when both species occurred at low numbers, especially H. hebetor. Spatial analysis by distance indices (SADIE) spatiotemporal analysis showed significant clustering of species, especially during summer and autumn. Early in the season and during spring 2002, at low host numbers, V. canescens occupied the locations where E. kuehniella mainly aggregated, but with the increase of E. kuehniella population, H. hebetor occupied these host groups and replaced V canescens. Although the two parasitoids competed for the same host species, both species coexisted in the storage facility during the entire trapping period.     

Effect of temperature and humidity on insecticidal effect of SilicoSec against Ephestia kuehniella (Lepidoptera: Pyralidae) larvae

Laboratory experiments were carried out to assess the insecticidal effect of the diatomaceous earth formulation SilicoSec against larvae of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), in stored wheat (Triticum durum Desf.). Larvae were exposed to wheat treated with SilicoSec at 400 and 800 ppm and held at 20, 25, and 30 degrees C and 55 and 75% RH. Larval mortality was assessed after 24 h, 48 h, 7 d, and 14 d of exposure in the treated wheat. At both dose rates, mortality increased with temperature, but this increase varied with the exposure interval. At short (< or = 48-h) exposures, larval mortality was significantly higher at 30 degrees C than at the other two temperatures. In contrast, no significant differences were noted between 20 and 25 degrees C. At longer exposures (> or = 7 d), the increase of temperature increased mortality at 800 ppm, but no significant differences were noted between 25 and 30 degrees C at 400 ppm. Furthermore, significant differences in larval mortality were noted between the two humidity levels, but only at exposures > or = 7 d. After 14 h of exposure, at both dose rates examined, the increase of temperature significantly decreased mortality. The results of the current study indicate that E. kuehniella is susceptible to SilicoSec, but temperature and relative humidity should be taken into consideration.     

The restructuring of the flagellar base and the flagellar necklace during spermatogenesis of Ephestia kuehniella Z. (Pyralidae,Lepidoptera)

Summary Transmission electron microscopy was used to study the development of the flagellar base and the flagellar necklace during spermatogenesis in a moth (Ephestia kuehniella Z.). Until mid-pachytene, two basal body pairs without flagella occur per cell. The basal bodies, which contain a cartwheel complex, give rise to four flagella in late prophase I. The cartwheel complex appears to be involved in the nucleation of the central pair of axonemal microtubules. In spermatids, there is one basal body; this is attached to a flagellum. At this stage, the nine microtubular triplets of the basal body do not terminate at the same proximal level. The juxtanuclear triplets are shifted distally relative to the triplets distant from the nuclear envelope. Transition fibrils and a flagellar necklace are formed at the onset of axoneme elongation. The flagellar necklace includes Y-shaped elements that connect the flagellar membrane and the axonemal doublets. In spindle-containing spermatocytes, the flagellar necklace is no longer detectable. During spermatid differentiation, the transition fibrils move distally along the axoneme and a prominent middle piece appears. Our observations and those in the literature indicate certain trends in sperm structure. In sperms with a short middle piece, we expect the presence of a flagellar necklace. The distal movement of the transition fibrils or equivalent structures is prevented by the presence of radial linkers between the flagellar membrane and the axonemal doublets. On the other hand, the absence of a flagellar necklace at the initiation of spermiogenesis enables the formation of a long middle piece. Thus, in spermatozoa possessing an extended middle piece, a flagellar necklace may be missing.     

Inheritance of a temperature-modified phenotype of the short antennae (sa) mutation in a moth, Ephestia kuehniella (Lepidoptera: Pyralidae).

The autosomal recessive mutation short antennae (sa) causes considerable shortening of antennae in male and female Mediterranean flour moths (Ephestia kuehniella Zeller). However, the sa phenotype can be suppressed by several physical factors, making sa moths indistinguishable from wild-type moths (sa(WT)). This can be done by subjecting larva and pupa to a higher temperature (25 degrees C), to lithium ions, or to an alternate electric field. The first half of pupal development was found to be the sensitive period for the sa(WT) phenotype. The sa(WT) phenotype is stable and cannot be reverted to the original sa type by physical or chemical factors. The sa(WT) phenotype is transmitted to future generations. When crossed with typical sa moths, the sa(WT) phenotype is inherited either as a dominant character if carried by males or a semidominant character if carried by females. We compared proteins of the ejaculate, accessory gland secretions, and spermatophore in sa, sa(WT), and wild-type males and found considerable differences between sperm proteins of sa(WT), sa, and wild-type males. The sa(WT) phenotype influences the mating success of males: sa(WT) males mated successfully with any females, whereas typical sa males were less successful in mating and then mainly with females of the same phenotype.     

Effect of temperature on parasitism and host-feeding of Trichogramma turkestanica (Hymenoptera: Trichogrammatidae) on Ephestia kuehniella (Lepidoptera: Pyralidae)

The egg parasitoid Trichogramma turkestanica Meyer is being evaluated as a biological control agent against the Mediterranean flour moth, Ephestia kuehniella Zeller, in flour mills. The longevity, parasitism and host-feeding of the parasitoid at four constant temperatures (15-30 degrees C) has been determined in the laboratory. The highest fecundity occurred at intermediate temperatures. The number of host eggs killed by host-feeding per female was highest at the two lower temperatures. A very conservative estimate of host-feeding showed that it accounts for approximately half of the mortality of host eggs at 20 and 25 degrees C and thus could constitute a major mortality factor for the flour moth population.     

Development of Geocoris varius and G. proteus (Hemiptera: Geocoridae) provided with Ephestia kuehniella (Lepidoptera: Pyralidae) eggs

We studied the development of Geocoris varius (Uhler) and Geocoris proteus Distant reared on Ephestia kuehniella Zeller eggs at 20, 24, 26, 30, 33, or 36?°C. The lower developmental thresholds (T ₀) and the thermal constants (K) of eggs and nymphs of G. varius were 13.3?°C, 151.1 degree-days and 13.4?°C, 433.0 degree-days, respectively; those of G. proteus were 16.1?°C, 98.3 degree-days and 16.9?°C, 226.9 degree-days, respectively. The hatch rate of G. varius eggs was significantly lower at 33?°C than at ??30?°C, and no eggs hatched at 36?°C. That of G. proteus was lowest at 20?°C and did not decline significantly at 36?°C. The survival rate throughout the nymphal period increased with temperature up to 30?°C in G. varius, and it was lowest at 20?°C in G. proteus. Thus, the optimal rearing temperatures for immature stages appear to be about 24?C30?°C for G. varius and 26?C33?°C for G. proteus. It might be possible to improve the efficiency of their mass production by controlling the rearing temperature in the above ranges. This would also make the developmental stages of nymphs more uniform and so prevent cannibalism in mass rearing.     

Virulence of Candida albicans mutants toward larval Galleria mellonella (Insecta, Lepidoptera, Galleridae)

Culture medium affected the virulence of a strain of Candida albicans toward Galleria mellonella larvae, but the yeast growth rates in yeast extract - peptone - dextrose broth and synthetic Galleria serum were not correlated with yeast virulence. Virulent C. albicans grew rapidly in larval serum, whereas, it limited nodulation and continued development in vivo, producing toxins that damaged the hemocytes and fat body. Nonpathogenic yeast-phase cells grew slowly in larval serum but induced extensively melanized nodules in vivo and developed no further. There was no discernible relationship in 14 exo-enzymes between the virulent and avirulent yeast strains and virulence. The avirulent myosin-I-defective yeast cells were rapidly removed from the hemolymph in vivo because of lysozyme-mediated yeast agglutination and the possible binding of the yeast cells by lysozyme and apolipophorin-III. Both lysozyme and apolipophorin-III are proteins that bind beta-1,3-glucan. Finally, insects with nonpathogenic C. albicans exhibited induced immunity and were more resistant to candidiasis from the wild-type yeast cells than were noninduced insects.     

Effect of different cold storage periods on parasitization performance of Trichogramma cacoeciae (Hymenoptera,Trichogrammatidae) on eggs of Ephestia kuehniella (Lepidoptera,Pyralidae)

The parasitism rates by Trichogramma cacoeciae Marchal (Hymenoptera, Trichogrammatidae) using Ephestia kuehniella Zell. (Lepidoptera, Pyralidae) eggs held at 0, 4 and 8°C and for up to 31 days was measured. Parasitism was lowest on eggs held at 8°C and highest on eggs held at 0°C. The highest parasitism, 97.8%, was measured for parasitoids attacking eggs held for 3 days and stored at 0°C. Parasitism of eggs stored at all three temperatures decreased with increasing duration of storage. The number of T. cacoeciae successfully developing and emerging as adults after storage in E. kuehniella eggs held at 0, 4 and 8°C was measured. Parasitoid emergence was >83% from E. kuehniella eggs stored at 8°C for 3 weeks. Storage at 0°C caused a significant decline in parasitoid emergence after 2 weeks (P<0.05). Storage at 0°C for more than 4 weeks reduced fecundity by 50%. T. cacoeciae parasitized the highest number of E. kuehniella eggs 1 day after adult emergence. The oviposition period lasted 6–7 days, although the parasitoids lived up to 13–14 days. Impact of storage time and temperature on parasitism rates by T. cacoeciae stored while in E. kuehniella eggs was measured. As storage time and temperature increased, subsequent parasitism rates of resulting adult T. cacoeciae decreased. Eggs of E. kuehniella can be stored at 0°C for up to 31 days. Trichogramma cacoeciae developing in eggs of E. kuehniella can be stored at 4°C for up to 5 weeks prior to release.