Black Eggs Research Articles

Fungal parasites of the root-knot nematodesMeloidogynespp. in southern Bulgaria

INTRODUCTION Root-knot nematodes are serious pests of many cultivated crops around the word. The Meloidogyne spp. complex is one of the economically most important pests in Bulgaria Damage to tomato by Meloidogyne spp. was first observed in Bulgaria by Malkov (1903). Later research showed that these nematodes are widespread in the country (Stoyanov, 1980). To control the root-knot nematodes resistant varieties and chemicals are used (Stoyanov, 1989; Choleva et al., 2006; Salkova et al., 2006). The root-knot nematodes can be infected by fungi at different stages of their life cycles. Soils are a reservoir for microorganisms that are highly varied in activity and composition. Natural regulation of the soil densities of the root-knot nematodes occurs in monocropping areas. Our review of the literature on fungi associated with cyst and root-knot nematodes revealed that about 160 fungal species belonging to 70 genera had been reported on these nematodes (Qadri, 1989; Qadri & Saleh, 1990; De Leij & Kerry, 1991; Khan & Akram, 2000). Casual observations of populations of Meloidogyne spp. in southern Bulgaria revealed the presence of black eggs in some females. The purpose of the present investigation was to describe and isolate fungi from eggs of Meloidogyne spp. collected from a greenhouse in southern Bulgaria. These studies were conducted to assess the frequency of occurrence of the causative fungus in the nematodo-endemic areas. MATERIALS AND METHODS The experiment was undertaken at the Plant Protection Institute in Kostinbrod in 2002-2004. Monthly root samples were collected from a greenhouse previously identified as infested with Meloidogyne spp. The samples were taken on a zig-zag pattern over the field. Roots were washed free from soil with a fine jet of water. The females were picked off the roots and recorded whether infected or healthy. The egg numbers were determined per 1 g of roots by crushing the females. The healthy and diseased eggs were counted with the aid of a microscope (x400) in three replicates for each sampling time. The effects of parasites upon eggs in females were determined using the following two categories: (1) infested eggs--those developing a fungal colony and eggs that were not identifiable as juveniles or embryos, and (2) normal eggs--those containing embryos or second-stage juveniles (Lopez-Llorca & Boag, 1993). Part of the soil collected from the field was used in a pot experiment. Surface sterilized seeds (0.1 % mercuric chloride for 2 min) of tomato were sown in sterilized soil. Fifteen days after germination the seedlings were thinned to one per pot. Pots were filled with infested soil and planted with tomato seedlings (cv. Ideal) at the end of May. The plants were inoculated with freshly hatched juveniles of Meloidogyne spp. at a rate of 1500/pot. Three pots were removed at monthly intervals and 10 females were randomly chosen from each pot, rinsed several times in sterile water, and preserved at room temperature in sterile sand in glass vials. During January the females were separated from sand, crushed in water, and the numbers of the diseased and healthy eggs were recorded. Part of the soil collected from the infested field was steam-sterilized and put into 24 pots. A second set of 24 pots were filled with infested field soil. Tomato plants were placed in the pots and inoculated with 1500 juveniles/pot in a water suspension pipetted around the roots. From July onward the pots were examined more frequently and when the females emerged they were examined at x400 magnification to ascertain if there was any fungal infection. Weekly counts of healthy and diseased eggs were recorded in both of the sets in three replications. Fungi were isolated from the eggs. The surface of the egg-masses was sterilized by agitation for 3 min in 5 mL of 0.1% NaOCI, then removed and washed twice with sterile distilled water. …

Marine Foraging Birds As Bioindicators of Mercury in the Gulf of Maine

From existing databases, we compiled and evaluated 604 total mercury (Hg) levels in the eggs and blood of 17 species of marine foraging birds from 35 Gulf of Maine islands to provide baseline data and to determine the best tissue, age class, and species for future biomonitoring. While mean Hg levels in most species did not exceed adverse effects thresholds, levels in some individual eggs did; for all species arithmetic mean egg Hg levels ranged from 0.04 to 0.62 (microg/g, wet weight). Piscivorous birds had higher Hg levels than invertivores. Leach's storm-petrel (Oceanodroma leucorhoa), razorbill (Alca torda), and black guillemot (Cepphus grylle) adult blood and egg Hg levels were higher than other species. Our results indicate that adult blood is preferable to chick blood for detecting long-term temporal trends because adult levels are higher and not confounded by metabolic effects. However, since we found that eggs and adult blood are comparable indicators of methylmercury bioavailability, we determined that eggs are the preferred tissue for long-term Hg monitoring because the relative ease in collecting eggs ensures consistent and robust datasets. We suggest specific sampling methods, and based on our results demonstrate that common eider (Somateria mollissima), Leach's storm-petrel, double-crested cormorant, and black guillemot are the most effective bioindicators of Hg of the Gulf of Maine.

Efficiency, intrinsic competition and interspecific host discrimination of Copidosoma desantisi and Trichogramma evanescens, two parasitoids of Phthorimaea operculella

Trichogramma evanescens West. (Hymenoptera: Trichogrammatidae) and Copidosoma desantisi Annecke & Mynhardt (Hymenoptera: Encyrtidae) are potential parasitoids of the potato tuber moth (PTM), Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) in Egypt. Discrimination of a parasitized host from an unparasitized host would prevent wasting of time, eggs and reduce competition with conspecifics or heterospecifics. Therefore, we evaluated interspecific host discrimination, multiparasitism and intrinsic competition between the two wasp species. In a choice test, females of T. evanescens showed high interspecific host discrimination only when they were offered 2-day-old C. desantisi parasitized and unparasitized PTM eggs. In contrast, C. desantisi showed high host discrimination and preferred unparasitized eggs to PTM eggs harboring 2-h- or 2-day-old T. evanescens’ eggs. We also evaluated the effect of different introduction sequences on the efficacy of the two wasps. Dissection data indicated that the two parasitoids had a negative impact on each other. There was a significant reduction in the total number of deposited eggs as well as total number of parasitized hosts by each parasitoid. Regarding the rearing experiment, the total number of T. evanescens-induced black eggs or C. desantisi formed mummies in combined treatments was significantly lower than in single parasitoid treatments (control). Moreover, C. desantisi was inferior and did not develop from any multiparasitized host regardless of oviposition order. It was suggested that combined release of the two wasps would not elevate rate of parasitism over that of single parasitoid treatments and competition between them would reduce their efficacy.

Delusions of Parasitosis of the Eyelids

The authors describe preseptal cellulitis and corneal ulceration due to secondary infection of self- inflicted wounds in a patient with delusions of parasitosis. A 42-year-old man presented with a 3-day history of progressive painful, purulent, periocular erythema. He reported that "little black bugs and whitish eggs" had infiltrated his body including the left eye and eyelids. On examination, he was agitated with superficial wounds covering the majority of his body. Ophthalmic evaluation was notable for markedly erythematous and mildly edematous eyelids resulting in complete blepharoptosis. Excoriations with yellow-brown serous crusting carpeted the periocular region. A 1-mm pericentral corneal ulcer was also noted. No objective evidence of parasites was found and his infection resolved with antibacterial therapy (intravenous ceftriaxone and vancomycin, and topical vancomycin and ceftazidime). Delusions of parasitosis may result in self-mutilation with secondary infection. Appropriate psychiatric care is needed to prevent ongoing destructive behavior.

Physical environmental conditions, spawning and early-life stages of an estuarine fish: climate change implications for recruitment in intermittently open estuaries

Significant variation in the egg and larval survival and juvenile recruitment of estuarine fishes has been linked to fluctuating environmental conditions. This present study compared the distribution and abundance of black bream (Acanthopagrus butcheri) eggs and yolk-sac larvae between two microtidal estuaries of different flow regimes, where the riverine flow into the Glenelg estuary was around eight times the flow volume into the Hopkins estuary. Samples were collected monthly from September to November at sites along each estuary where vertical profiles of temperature, salinity and dissolved oxygen (DO) were measured, and vertically stratified sampling of black bream eggs and yolk-sac larvae was conducted using a Schindler sampler. Salt wedge formation was apparent in both estuaries, with significant de-oxygenation of deeper, saline waters. Eggs occurred in a wide range of DO levels but yolk-sac larvae were less common at the lowest levels. Most eggs and yolk-sac larvae were collected in salinities greater than 10. Results suggested that egg mortality was higher in the Hopkins than the Glenelg estuary, which may be associated with the hypoxic conditions characteristic of low-flow conditions. The results have significant implications in terms of climate change that is predicted to lead to warmer, drier conditions in south-eastern Australia, potentially increasing stratification and subsequent hypoxic zones.

Hypoxia impairs embryo development and survival in black bream ( Acanthopagrus butcheri)

Coastal environments are threatened by the increasing frequency, extent and severity of hypoxic events. Hypoxia affects vast areas around the world and often causes fish kills, reduced abundance, altered distribution, low benthic biomass and declines in fisheries. In Australia, many fisheries are based on sparid fishes and in the southern states black bream ( Acanthopagrus butcheri) is important to both the recreational and commercial sectors. This species completes its entire life cycle in estuaries and annual recruitment is highly variable and very likely influenced by environmental conditions during the spawning season. In a laboratory-based experiment, fertilised black bream eggs (embryos) were exposed to five different levels of dissolved oxygen (DO). The DO levels were maintained in small test wells using nitrogen gas in a novel chamber design. Embryo development was assessed over a 2-day period and hatched larvae were observed until Day 2 post-hatch. Significant differences ( p < 0.05) were observed in embryonic development and survival as a function of DO level. In severely hypoxic conditions (30% saturation) survival to 1 day was reduced and no hatching occurred. In moderately hypoxic conditions (45–55%S), both precocious and delayed hatching was observed and hatch rates were reduced, whilst the number of hatched larvae with deformities increased, resulting in reduced larval lengths. No larvae survived to Day 2 post-hatch when held in hypoxic conditions (<55%S). This study demonstrates the detrimental effect that severe hypoxia can have on the early development of black bream which could result in reduced recruitment and lowered abundance. Other species that share similar early life histories may also be at risk.

Why we should, in Fact, Pay for Egg Donation

In this perspective, I shall argue that women who donate eggs solely for human embryonic stem cell research ought to be compensated. My argument rests on three inter-related principles. First, it is important to recruit the healthiest possible egg donors to minimize the risks of donation. This would relieve pressure to donate on those suffering from diseases that might be treatable with stem cell-based therapies, who are likely to be at greater risk from donation. Second, I believe that it is crucial to be pro-active in building representative stem cell banks, especially in stem cell initiatives paid for, in part, by the public/government. The right of all groups to participate in and benefit from equitable and safe research must be developed for egg donors as for other kinds of research participants. Particular attention should be paid to the opinions and desires of women from historically underserved populations as to how to conduct donations and guide research so as to serve all members of society. Third, reasonable payment would undermine tendencies for domestic and international black and grey egg markets for stem cell research to develop. I then suggest replacing the question of compensation with the question of harm mitigation as the central donor protection issue.

Measuring egg size using digital photography: testing Hoyt's method using Florida Scrub-Jay eggs

Egg volumes are most often estimated using a mathematical model that incorporates length and width measurements and a species-specific shape variable. Although adequate in many respects, this technique does not account for intraspecific variation in egg shape. We developed a computer-automated technique that uses calibrated digital photographs to render precise measurements of several egg-size parameters including length, width, volume, and surface area. The system extracts egg outlines from photographs, and divides each egg into latitudinal slices that are subsequently regarded as simple geometric shapes (cylinders or cone frustra) with volumes and surface areas that can be summed to generate size parameters for the entire egg. We tested this technique using 491 eggs from Florida Scrub-Jay (Aphelocoma coerulescens) nests and compared the resulting egg volumes with volumes calculated using the preeminent method of estimating volume from linear measurements. Our method was highly accurate, and differences between the volumes from our method and the alternative method were strongly associated with variation in egg shape. Advantages of our technique include decreased handling of eggs and increased accuracy. Software resources and additional information regarding the technique are available at http://www.archbold-station.org/abs/data/birddata/Bridge-JFO-eggsize.htm. SINOPSIS. Medidas de huevos utilizando fotograf´ ia digital: poniendo a pruebas el m´ etodo

Modeling egg distribution of Tinocallis kahawaluokalani (Kirkaldy) (Hemiptera: Aphididae) on Lagerstroemia indica L. (Lythraceae)

This is the first record of winter eggs of the holocyclic monoeceous crapemyrtle aphid Tinocallis kahawaluokalani (Kirkaldy) on Lagerstroemia indica L., in Brazil. The shiny black eggs were observed since early autumn, laid on small folds and crevices of the branches. In order to evaluate and model the egg abundance and distribution, four branches from the cardinal points of 10 plants of two age groups, 5-10 and 20-30 years-old, were collected randomly and cut in eight segments of 10 cm and the number of eggs was registered, in the winter 2001. The eggs were laid mainly on the middle portion of the branch, from 40 cm to 60 cm from the apex on the older trees (54%) and on 30 cm to 60 cm on younger ones (58%). The data fit in a longitudinal regression model that expresses the tendency of the egg distribution on the branches. The number of eggs was greater on the 20-30 year-old plants (61%) than on younger ones (39%). The average number (+/- CI 95%) of eggs was 70.5 +/- 9.3 and 47.4 +/- 12.5, respectively, for the older and younger tree groups. There was no correlation between egg distribution and the cardinal positions of the branches.

Functional response ofTrichogramma chilonistoGalleria mellonellaandChilo sacchariphaguseggs

AbstractA biological control programme using inundative releases ofTrichogramma chilonisIschii (Hymenoptera: Trichogrammatidae) reared onGalleria mellonellaL. (Lepidoptera: Pyralidae) is currently underway to reduce infestations ofChilo sacchariphagusBojer (Lepidoptera: Crambidae) in sugarcane,Saccharumspp., on Réunion Island. To assess the potential of the parasitoid as an inundative biocontrol agent, the functional response of threeT. chilonisstrains was tested withG. mellonellaand one strain withC. sacchariphagushost eggs in glass tubes in the laboratory. The shape of the functional response (type II or III) was determined using logistic regression, and attack coefficients and handling times (Th) were determined using non‐linear least‐square regression. The behaviour of all three strains withG. mellonellahost eggs corresponded to a type III response. The St BenoîtT. chilonisstrain had a significantly shorter estimate of Ththan the St Pierre strain (P&lt;0.05) and may, therefore, be more appropriate as a biocontrol agent. The functional response withC. sacchariphagushost eggs was a type II with the St BenoîtT. chilonisstrain. MoreT. chiloniswasps developed per host egg from the largerC. sacchariphagushost eggs (2.9) relative toG. mellonella(1.1). Superparasitism at low host egg densities was, therefore, likely to have been less frequent withC. sacchariphagus. Black eggs were chosen as an estimate of number of eggs parasitized, although they represent the number of eggs where parasitism led to complete pupal development. The low rate of detected parasitism at low host densities withG. mellonellaeggs may be due to incomplete pupal development due to superparasitism rather than lack of parasitism, thus explaining the type III functional response.

Breeding biology, sexually dimorphic development and nestling testosterone concentrations of the classically polyandrous African black coucal, Centropus grillii

Many internal and environmental factors influence the growth of birds. Here we ask whether the reversed sexual dimorphism in the classically polyandrous black coucal is reflected in differential growth and fledging parameters of females and males. We also investigate whether androgen concentrations were higher in females than males during the nestling development, thus, providing a potential mechanism for the ‘behavioural masculinization’ of female black coucals. Furthermore, we give a detailed description of the breeding biology of this little studied and unusual bird species. Black coucal eggs were smaller, and the incubation and nestling periods were shorter than expected for a bird of that size. In absolute terms female black coucals grew faster than males and left the nest with a larger body mass, suggesting that females are the more expensive sex to rear in this species. However, in relation to adult body size, females grew slower and reached a smaller proportion of their adult body size than males upon fledging. ‘Testosterone’ concentrations were significantly higher in male than in female nestlings, hence not supporting a role of circulating androgens in the ontogeny of sex-role reversal. To our knowledge, the early sex differences in ‘testosterone’ levels of black coucals represent the first evidence that such differences exist in nestlings of altricial birds. We present anecdotal evidence that the differences may be related to an early maturation of male reproductive organs in black coucals. In females but not in males, ‘testosterone’ concentrations were related to structural growth rates.

At the Seashore

It was a cool fall day. The sea chopped against the rocks in crisp rhythmic strokes, each time erupting in rolls of foam that furled down the shoreline like cascading dominoes. It was October 1, the first day dogs were allowed on the beach after the summer season. All the vacationers had gone back to their lives in cities to the south. We had the beach once more to ourselves–me and Daisy, my dog, who trotted on ahead. It was low tide. Tangles of seaweed–rippled rubbery gold kelp, knobby bladderwrack, fringed Irish moss, black skate egg cases, fancied by some as mermaid purses–were heaped on the shore like mounds of dark hair. I inspected the jetsam carefully as I walked along, looking for the odd treasure–a scoured lavender-green sea urchin shell with its perfectly symmetrical alignment of spine holes, a peach lobster claw with white teeth shaped like mine, a unique piece of driftwood. All stripped by the sea of pretense, worn down to their bare essence. One couldn’t edit out, however, the contaminating presence of human pollution– the odd bleached coke can caught in the tangle, a plastic spoon, a finished board with rusty nails, flaunting themselves like unwanted ads.

Host color preferences and short‐range searching behavior of the egg parasitoid Trichogramma ostriniae

AbstractThe color of lepidopteran eggs often varies by species or egg condition, and parasitoids that attack lepidopteran eggs could therefore potentially use color to obtain information about host identity or quality. The objective of our study was to determine whether females of the egg parasitoid Trichogramma ostriniae Pang &amp; Chen (Hymenoptera: Trichogrammatidae) showed differential responses to egg color when searching for hosts over short distances and when evaluating the suitability of encountered eggs. We examined the wasps’ host‐selection behavior in a Petri dish arena using white, yellow, green, and black clay beads as egg models presented against a green background (to mimic leaf color). In no‐choice tests, bead color had a significant effect on the proportion of tested wasps that accepted a bead for further examination, on the time it took wasps to find and begin examining a bead, and on the time that wasps spent examining the beads. However, bead color had only a marginally significant effect on the proportion of wasps attempting to drill into a bead with their ovipositors, and no significant effect on the amount of time they spent drilling. The wasps also showed significant color preferences when given a choice between two adjacent beads of different colors. The results of the no‐choice and choice trials taken together indicated a color preference ranking of yellow &gt; white &gt; green &gt; black. The wasps’ higher preference for the yellow and white egg models generally corresponds to the white or yellowish‐white egg color of T. ostriniae's target host, the European corn borer moth, Ostrinia nubilalis Hübner (Lepidoptera: Crambidae). The wasps’ strong rejection of black egg models is likely to be an adaptive response that reflects the fact that eggs that are wholly or partially black are often unsuitable for parasitization due to advanced caterpillar development, damage to the egg, or previous parasitization.

Polybrominated diphenyl ethers and organochlorine compounds in biota from the marine environment of East Greenland

Ten black guillemot eggs, 19 ringed seals, 20 shorthorn sculpins and 20 Arctic chars were collected around Ittoqqortoormiit (Scoresbysund, Central East Greenland) in summer 2001 and analysed for 11 brominated diphenyl ether congeners (BDEs) and organochlorine compounds. Congeners BDE85 and BDE183 were not detected in any sample. ΣBDE was highest in black guillemot eggs, with a median value of 80 ng/g lipid weight. This was approximately three times higher than that found for black guillemot eggs from West Greenland, thus supporting the spatial trend observed for organochlorines in Greenland. The median ΣBDE concentration in ringed seal blubber was 36 ng/g lipid weight. This was clearly higher than ΣBDE concentrations in ringed seal from the Canadian Arctic, but slightly lower than those found in ringed seals from Svalbard collected in 1981 and approximately 10 times lower than levels in seals from the Baltic Sea. Adult ringed seals had significantly higher ΣBDE concentrations than animals less than 5 years old. Shorthorn sculpin liver and Arctic char muscle had similar concentrations of ΣBDE, both with a median value of 7–10 ng/g lipid weight. The levels in shorthorn sculpin were similar to those reported from a previous study in Southwest Greenland. ΣBDE levels correlated with PCB, DDT and chlordane-concentrations in the same samples, indicating similar mechanisms of uptake, bioaccumulation and biomagnification. The summed chlorobiphenyl concentrations in the same samples exceeded the ΣBDE concentrations by a factor of approximately 15–30. The BDE congener patterns in black guillemot eggs and ringed seals were investigated using compound ratios and multivariate data analysis. The intraspecies variance was relatively small for black guillemot eggs and larger for ringed seals. Ringed seals had higher relative levels of the lower BDE congeners, e.g. BDE28 and BDE47 than black guillemots. The reasons for these different accumulation patterns are largely unknown and may reflect species-related differences in pollutant exposure, bioavailablity and metabolism.

Foods and beverages in relation to urothelial cancer: case-control study in Japan.

The roles of several foods and beverages in the development of bladder cancer remain unclear. We undertook a hospital-based case-control study at Aichi Cancer Center Hospital, Japan. Subjects included 124 men and women (bladder cancer cases) with newly diagnosed cancers of the renal pelvis (n = 5), ureter (n = 6) or bladder (n = 113) and 620 age- and sex-matched, cancer-free outpatients (controls) presenting at the hospital in the period from 1994 to 2000. Smoking-adjusted odds ratios (OR) were estimated to assess the strength of associations between self-reported intake of foods or drinks and bladder cancer risk, using conditional logistic models. We found a decreased risk in relation to frequent intake of green-yellow vegetables; the OR for the highest intake score compared with the lowest was 0.54 (95% confidence interval [CI] 0.29-0.99). The OR for carrot intake of >/=5 times/week compared with </=1-3 times/month was 0.41 (95% CI 0.16-1.01) and a decreasing risk with increasing consumption of green vegetables was also detected (P for trend = 0.063). Inverse associations between black tea, eggs and meat and risk were also suggested, whereas moderate drinkers of green tea (5-9 cups/day) showed an elevated risk. Coffee and milk consumption did not appear to exert any influence. Those with an increased risk of bladder cancer, such as smokers, may benefit from increasing their consumption of green-yellow vegetables.

Persistent halogenated compounds in black guillemots ( Cepphus grylle) from Greenland––levels, compound patterns and spatial trends

Twenty-seven black guillemot eggs and 39 livers were analysed for polychlorinated biphenyls (PCBs), chlorinated pesticides including chlordane-related compounds and toxaphene, and polybrominated diphenylethers (PBDEs). The samples were collected at Qeqertarsuaq (Godhavn, West Greenland) and Ittoqqortoormiit (Scoresbysund, East Greenland). The concentrations of halogenated organic compounds in samples from East Greenland were somewhat higher than the corresponding concentrations from West Greenland. Differences in compound patterns were found between West and East Greenland, with higher percentages of the heavier PCB molecules, p, p ′-DDE and α-HCH in the samples from Ittoqqortoormiit. Similarly, different levels and different compositions were observed for eggs and livers. The eggs had generally higher concentrations of all compounds as well as higher percentages of CHB-50, CHB-62 and α-HCH than liver samples from the same area. Dividing the liver samples into age groups revealed increasing concentrations with age.

Fungal parasitism of the cysts and eggs of the Globodera rostochiensis

A survey of Globodera rostochiensis infested field in Velingrad region (South-West Bulgaria) revealed the spread of a black egg disease in the old cysts. The fungus mycelium infected the embryos within the egg shell. The highest egg parasitization by fungi was observed during June (22.2%). The fungus destroyed the new progeny in September. Four species of nematophagous fungi were isolated from cysts and eggs: Botryotrichum piluliferum Sacc. And March, Scolecobasidium constrictum Abbott, Gliocladium roseum and Phoma fineti Brun.

Egg Shell Architecture of the Stink Bug, Eocanthecona furcellata (Wolff.): Ultrastructure of Micropylar Processes and Egg Burster

Scanning electron microscopic examination of the egg shell and associated structures of Eocanthecona furcellata (Wolff.) (Hemiptera: Pentatomidae) reveals a distinct pattern of structural elements, viz. microsculpture of the chorion, pseudoperculum, egg burster and aeromicropylar processes. The egg shell has a highly decorated chorion with a structural difference at both the anterior and posterior ends. A reticulate type of microsculpture with varying sizes of spine-like projections measures 4.02 ± 0.06 to 8.12 ± 0.05 μm and forms an asteroid-like shape at the anterior pole, while the surface at the posterior end has elongated striations over the chorion measuring 72.00 ± 0.074 μm. The pseudoperculum of the egg shell is a circular lid measuring 518 ± 11.43 μm in diameter. During hatching the line of rupture follows the micropylar ring, and this sometimes extends beyond the ring of micropylar processes. An inverted T-shaped black egg burster measures 202 ± 4.63 μm in length, is well developed and can be seen prior to hatching within a thin and transparent egg shell. It is a median sclerotised part of embryonic cuticle. The aeromicropylar processes are situated at the anterior pole of the barrel-shaped eggs. There are 26–28 aeromicropylar processes arranged in a circle at almost equidistance and each micropylar process is slightly curved opposite to the pseudoperculum lid with a bulbous end at the apex. The aeromicropylar processes are 25.40 ± 0.083 μm in length and 3.02 ± 0.07 μm in width. Each micropylar process has a central canal for the passage of sperm whereas the rest of its body is porous, and allows respiratory interchange.

Population Collapses in a Forecasted Outbreak ofLambdina fiscellaria(Lepidoptera: Geometridae) Caused by Spring Egg Parasitism byTelenomusspp. (Hymenoptera: Scelionidae)

A major outbreak of the hemlock looper, Lambdina fiscellaria (Guenee), predicted for 1997 on the Gaspe Peninsula in Quebec, collapsed due to egg parasitism by Telenomus spp. Only 3,857 ha of balsam–spruce forest were defoliated from the forecasted 130,000-ha outbreak area. This represents only 3% of the anticipated outbreak area. We present data that indicate highly efficient natural control by Telenomus spp. The L. fiscellaria population also collapsed due to egg parasitism by Telenomus spp. on Anticosti Island in the same year. In the past, L. fiscellaria egg parasitism has usually been estimated from egg samples collected in the fall or early spring surveys and was based mostly on the eggs’ black coloration. However, our observations indicate that entirely black and opaque eggs result from parasitism by Trichogramma spp., those attacked by Telenomus spp. varying from translucent to dark brown but always showing a single dark spot on the chorion. Moreover, our data on seasonal egg parasitism showed important and rapid increases in parasitism by Telenomus spp. in late spring. Therefore, similar unexplained L. fiscellaria outbreak collapses that occurred in the past might have also been caused by egg parasitism by Telenomus spp. There are several species in the Telenomus complex attacking L. fiscellaria and the most abundant one might be a “keystone species” in the population dynamics of this defoliator. The spring activity of Telenomus spp. may lead to errors when forecasting L. fiscellaria populations based only on fall egg surveys.

Induced Gynogenesis in Black Crappie

Abstract This study reports the results of initial experiments on induced diploid gynogenesis in black crappie Pomoxis nigromaculatus. White bass Morone chrysops were an effective sperm donor for gynogenetic experiments with black crappies. White bass spermatozoa fertilized black crappie eggs, but hybrid larvae were not viable and died after hatching. In a series of experiments, we determined the ultraviolet (UV) light dose required to inactivate the sperm genome and the heat shock parameters needed to restore diploidy. Black crappie eggs were inseminated with white bass sperm irradiated with UV dosages ranging from 25 to 2,500 J/m2. A typical “Hertwig effect” in the yield of hatched larvae was observed with dosages greater than 100 J/m2. The genetic inactivation of paternal chromosomes was confirmed by flow cytometry measurement of DNA content in larval cells. Larvae resulting from sperm irradiated at a dose of 1,000 J/m2 were haploid. Time durations of mitotic interval (τ0) at different temperatures for...