Patterns of composition and abundance in macroinvertebrate egg masses from temperate Australian streams

2004 ◽  
Vol 55 (1) ◽  
pp. 39 ◽  
Author(s):  
P. Reich
Keyword(s):  
Water Surface ◽  
Egg Laying ◽  
Maximum Diameter ◽  
Egg Mass ◽  
Egg Masses ◽  
Eastern Australia ◽  
The Common ◽  
Substrate Size ◽  
High Degree ◽  
Sampling Times

Quantitative samples of lotic invertebrate egg masses were collected on two occasions from three riffles along two rivers within the Acheron River catchment, south-eastern Australia. Sampling was stratified to compare the abundance and composition of egg masses on submerged rocks with rocks that protruded above the water surface within each of three substrate size classes. The egg mass fauna of both rivers was found to be both species rich and abundant. Egg masses belonging to Diptera and Trichoptera represented the majority of material collected, with approximately 70% of all taxa common to both rivers. In particular, egg masses of Chironomidae, Hydrobiosidae, Hydroptilidae and Hydropsychidae dominated most samples numerically. Descriptions of the egg masses belonging to 17 taxa are provided, as well as preliminary estimates of hatching times and observations of egg-laying and post-hatching behaviour for some species. Large rocks (> 30 cm maximum diameter) that protruded above the water surface consistently yielded the highest number of egg masses for all common taxa. For common taxa, between 74% and 100% of all egg masses were found on large emergent rocks. Of the common taxa, little variation in egg mass abundance was detected between sampling times or between sites within each river. Exceptions were hydroptilids and chironomids, which were completely absent from some time/site combinations, suggesting a degree of synchrony in egg-laying behaviour. For all common taxa, the greatest source of variation in egg mass numbers appeared at the level of individual rocks, where a high degree of spatial aggregation was apparent (as described by Lloyd's index of patchiness).

scholarly journals Something Darwin didn't know about barnacles: spermcast mating in a common stalked species

2013 ◽  
Vol 280 (1754) ◽  
pp. 20122919 ◽  
Author(s):  
Marjan Barazandeh ◽  
Corey S. Davis ◽  
Christopher J. Neufeld ◽  
David W. Coltman ◽  
A. Richard Palmer
Keyword(s):  
Egg Mass ◽  
Free Living ◽  
Single Nucleotide ◽  
Egg Masses ◽  
Pollicipes Polymerus ◽  
Alternative Hypotheses ◽  
Gooseneck Barnacle ◽  
Self Fertilization ◽  
The Common ◽  
First Time

Most free-living barnacles are hermaphroditic, and eggs are presumed to be fertilized either by pseudo-copulation or self-fertilization. Although the common northeast Pacific intertidal gooseneck barnacle, Pollicipes polymerus , is believed only to cross-fertilize, some isolated individuals well outside penis range nonetheless bear fertilized eggs. They must therefore either self-fertilize or—contrary to all prior expectations about barnacle mating—obtain sperm from the water. To test these alternative hypotheses, we collected isolated individuals bearing egg masses, as well as isolated pairs where at least one parent carried egg masses. Using 16 single nucleotide polymorphism markers, we confirmed that a high percentage of eggs were fertilized with sperm captured from the water. Sperm capture occurred in 100 per cent of isolated individuals and, remarkably, even in 24 per cent of individuals that had an adjacent partner. Replicate subsamples of individual egg masses confirmed that eggs fertilized by captured sperm occurred throughout the egg mass. Sperm capture may therefore be a common supplement to pseudo-copulation in this species. These observations (i) overturn over a century of beliefs about what barnacles can (or cannot) do in terms of sperm transfer, (ii) raise doubts about prior claims of self-fertilization in barnacles, (iii) raise interesting questions about the capacity for sperm capture in other species (particularly those with short penises), and (iv) show, we believe for the first time, that spermcast mating can occur in an aquatic arthropod.

Reproductive cycles and fecundities of two species of Siphonaria (Mollusca : Pulmonata) in south-eastern Australia

1980 ◽  
Vol 31 (1) ◽  
pp. 37 ◽  
Author(s):  
RG Creese
Keyword(s):  
Breeding Season ◽  
Egg Mass ◽  
Egg Masses ◽  
Rocky Substratum ◽  
South Eastern ◽  
Eastern Australia ◽  
Reproductive Cycles ◽  
South Eastern Australia

The reproductive cycles of Siphonaria denticulata and S. virgulata were determined by measuring the length or weight of the spawn of each species. S. denticulara lays a typical. coiled, gelatinous egg ribbon, cemented to the rocky substratum. S. virgulata lays a globular egg mass which is released directly into the water. This latter form of spawning is apparently unique amongst pulmonate molluscs. S. denticulata has a long breeding season, extending from November-December to the following April-May. Spawning usually occurs every 2 weeks for large adults, but smaller (i.e. younger) limpets spawn less frequently. Periods of spawning correspond to periods of full or new moons. The exact length of the breeding season of S. virgulata is unknown. Estimates of fecundity were obtained from counts of eggs within egg masses. There were differences in the fecundity of S. denticulata between localities, but S. denticulata and S. virgulata from the same locality had similar fecundities for similar-sized animals. Egg ribbons of S. denticulata experimentally placed high on the shore were found to suffer higher mortality from desiccation than those lower on the shore. This may explain why S. virgulata, which generally lives higher on the shore than its congener, has pelagic egg masses.

Relation of the Saccasa?khepa??k? Called S?ratthas?lin? to the Vinayavinicchaya??k? Called Vinayas?ratthasand?pan?

2018 ◽  
Vol 35 (1-2) ◽  
pp. 189-223
Author(s):  
Petra Kieffer-Pülz
Keyword(s):  
Thirteenth Century ◽  
Present Contribution ◽  
The Common ◽  
Literary Histories ◽  
High Degree ◽  
Parallel Texts

The present contribution suggests the common authorship of three P?li commentaries of the twelfth/thirteenth centuries CE, namely the Vinayavinicchaya??k? called Vinayas?ratthasand?pan? (less probably Vinayatthas?rasand?pan?), the Uttaravinicchaya??k? called L?natthappak?san?, and the Saccasa?khepa??k? called S?ratthas?lin?. The information collected from these three commentaries themselves and from P?li literary histories concerning these three texts leads to the second quarter of the thirteenth century CE as the period of their origination. The data from parallel texts explicitly stated to having been written by V?cissara Thera in the texts themselves render it possible to establish with a high degree of probability V?cissara Thera as their author.

Probiotics in the diets of laying quails

2020 ◽  
pp. 60-66
Author(s):  
O. Merzlyakova ◽  
V. Rogachyev ◽  
V. Chegodaev
Keyword(s):  
Bacillus Subtilis ◽  
Bacillus Licheniformis ◽  
Egg Production ◽  
Positive Impact ◽  
Hematological Parameters ◽  
Economic Effect ◽  
Egg Laying ◽  
Control Group ◽  
Egg Mass ◽  
The Cost

The efficiency of introducing probiotics based on strains of Bacillus subtilis, Bacillus licheniformis and their consortium in the amount of 150 g/t of feed into the diets of laying quails has been studied. The experiment lasting 182 days has been carried out on four groups of quails with 30 heads in each. The quails have been housed in the broiler battery in compliance with the required microclimate conditions. Quails of all groups have been received the main diet (compound feed) developed taking into account their age and physiological characteristics. The quails of the 1st, 2nd and 3rd experimental groups in addition to the main diet received probiotics (150 g/t compound feed) based on strains Bacillus subtilis, Bacillus licheniformis and their consortium, respectively. It has been found that feeding the laying quails of the consortium of strains Bacillus subtilis and Bacillus licheniformis had the most significant positive impact on their productive performance, it allowed to increase egg production by 7,81 %, egg laying intensity by 5,0 %, egg mass yield by 9,77 %, while reducing feed expenditures for 10 eggs by 13,35 %. The yield of hatching eggs has been increased by 7,03 %, hatchability of chickens from laid and fertilized eggs by 8,33 and 8,35 %, brooding waste decreased by 21,74 %. Hematological parameters of quails during the whole experiment were within the physiological norm. The economic effect calculated on the basis of data on the cost of compound feed, probiotics and the cost of sold eggs of quail laying was 14,56 % in the 3rd experimental group (in relation to the control group).

scholarly journals New terpenoid metabolites from the skin extracts, an egg mass, and dietary sponges of the Northeastern Pacific dorid nudibranch Cadlinaluteomarginata

1997 ◽  
Vol 75 (6) ◽  
pp. 773-789 ◽  
Author(s):  
Eric J. Dumdei ◽  
Julia Kubanek ◽  
John E. Coleman ◽  
Jana Pika ◽  
Raymond J. Andersen ◽  
...  
Keyword(s):  
Structure Elucidation ◽  
Egg Mass ◽  
The Novel ◽  
Egg Masses ◽  
Northeastern Pacific ◽  
First Time

Chemical investigations of Cadlinaluteomarginata skin extracts, egg masses, and dietary sponges have led to the identification of the novel terpenoids cadlinaldehyde (30), spongian 32, seco-spongian 35, 20-acetoxy-12-marginatone (38), and lutenolide (39) from the nudibranch skin extracts, the new drimane sesquiterpenoid 1α,2α-diacetoxyalbicanyl acetate (40) from the nudibranch's egg mass, and the new sesquiterpenoids O-methyl-9-oxofurodysininlactone (47), 2-oxomicro-cionin-2-lactone (48), and O-methyl-2-oxomicrocionin-2-lactone (49), from the dietary sponge Pleraplysilla sp. The known terpenoids furodysinin (1), furodysin (16), marginatafuran (21), and 9,11-dihydrogracillin A (37), which have been frequently isolated from C. luteomarginata skin extracts, were found for the first time in extracts of the dietary sponges Pleraplysilla sp. and Aplysilla sp. One of the new terpenoids, cadlinaldehyde (30), has an unprecedented degraded sesterterpenoid skeleton. Keywords: nudibranch, sponge, terpenoids, structure elucidation.

GROUND RELEASES OF TRICHOGRAMMA MINUTUM RILEY (HYMENOPTERA: TRICHOGRAMMATIDAE) AGAINST THE SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE)

1987 ◽  
Vol 119 (3) ◽  
pp. 251-263 ◽  
Author(s):  
S.M. Smith ◽  
M. Hubbes ◽  
J.R. Carrow
Keyword(s):  
Optimal Strategy ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Egg Mass ◽  
Northern Ontario ◽  
Inundative Release ◽  
Egg Masses ◽  
Trichogramma Minutum ◽  
Spruce Stands ◽  
Natural Parasitism

AbstractDuring 1982 and 1984, ground releases of Trichogramma minutum Riley were assessed for control of the spruce budworm, Choristoneura fumiferana (Clemens), on 12- to 20-year-old, white spruce stands in northern Ontario. Maximum parasitism of susceptible egg masses was 16 and 87% following the release of 480 000 and 12 million female T. minutum per hectare, respectively. Releases at intervals of 1 week maintained parasitism of susceptible egg masses at constant levels throughout the oviposition period of spruce budworm. When parasitism of susceptible egg masses was maintained above 78.2% during the ovipositional period, total egg mass parasitism averaged 58.0% and resulted in an 80.3% reduction of overwintering 2nd-instar larvae. The optimal strategy for reducing spruce budworm was two releases of T. minutum at an interval of 1 week in the ovipositional period. This allowed a second generation of parasitoids to emerge from the spruce budworm eggs that were more efficient in maintaining high levels of parasitism than those emerging from the standard rearing host. Natural parasitism of spruce budworm egg masses was less than 4% and there was no carryover of parasitism in the years following inundative release. The rate of T. minutum release necessary to achieve effective mortality of spruce budworm during outbreak populations is discussed briefly.

scholarly journals Reproductive suppression in female cooperatively breeding cichlids

2008 ◽  
Vol 4 (6) ◽  
pp. 606-609 ◽  
Author(s):  
Dik Heg
Keyword(s):  
Clutch Size ◽  
Group Living ◽  
Egg Laying ◽  
Alloparental Care ◽  
Large Female ◽  
Egg Mass ◽  
Small Female ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Female Subordinate

Suppression by dominants of female subordinate reproduction has been found in many vertebrate social groups, but has rarely been shown experimentally. Here experimental evidence is provided for reproductive suppression in the group-living Lake Tanganyika cichlid Neolamprologus pulcher . Within groups of three unrelated females, suppression was due to medium- and small-sized females laying less frequently compared with large females, and compared with medium females in control pairs. Clutch size and average egg mass of all females depended on body size, but not on rank. In a second step, a large female was removed from the group and a very small female was added to keep the group size constant. The medium females immediately seized the dominant breeding position in the group and started to reproduce as frequently as control pairs, whereas clutch size and egg mass did not change. These results show that female subordinate cichlids are reproductively capable, but apparently suppressed with respect to egg laying. Nevertheless, some reproduction is tolerated, possibly to ensure continued alloparental care by subordinate females.

A comparison of bryophyte species diversity and niche structure of montane streams and stream banks

1987 ◽  
Vol 65 (9) ◽  
pp. 1824-1837 ◽  
Author(s):  
Janice M. Glime ◽  
Dale H. Vitt
Keyword(s):  
New York ◽  
Species Diversity ◽  
Water Surface ◽  
Niche Overlap ◽  
Niche Width ◽  
Vertical Distance ◽  
Substrate Size ◽  
Species Cover ◽  
Montane Streams ◽  
Stream Substrate

Eleven alkaline western Canadian montane streams were sampled by transects to compare the bryophyte species cover, diversity, frequency, richness, niche width, and niche overlap in three vertical zones (relative to water level) with the same parameters in four acidic streams on Slide Mountain in the Adirondack Mountains of New York. Resources for niche width and overlap include vertical distance from water surface, aspect in stream, substrate size, and percent bare substrate. Species cover, richness, and diversity increase from the submerged zone 1 (< −5 cm) to the terrestrial zone 3 (10–30 cm). Brillouin species diversity increases from 1.98 to 3.03 (means per stream) along the same gradient. All species except one from zone 1 also occur in zone 3. The niche widths for aspect in stream, substrate size, and vertical distance from water surface are all negatively correlated with their chi-square values, indicating that the width values are most reliable for small widths and become increasingly less reliable for large niche widths. Niche overlap is high among most species for at least one resource parameter.

Sexual reproduction and larval development of Rhaphidrilus nemasoma Monticelli, 1910 (Polychaeta: Ctenodrilidae)

1989 ◽  
Vol 67 (10) ◽  
pp. 2345-2351 ◽  
Author(s):  
Pei-Yuan Qian ◽  
Fu-Shiang Chia
Keyword(s):  
British Columbia ◽  
Sexual Reproduction ◽  
Larval Development ◽  
Intertidal Zone ◽  
Vancouver Island ◽  
Benthic Diatoms ◽  
Egg Mass ◽  
High Fecundity ◽  
Egg Masses ◽  
Trochophore Stage

Adult specimens and egg masses of Rhaphidrilus nemasoma were collected in the low intertidal zone from Execution Rock, Bamfield, Vancouver Island, British Columbia, in June of 1986. Each egg mass contained about 1000 eggs. The eggs were green, spherical, and measured 125–145 μm in diameter. Larval development took place within the egg mass until the three-or four-setiger stage, at which time they emerged from the egg mass. Newly emerged larvae crawled on the bottom of the culture beakers and fed on benthic diatoms. Metamorphosis took place soon after emergence and was completed within 2 weeks. Paddle cilia were observed at the early trochophore stage, and their possible function, and the extremely high fecundity of this polychaete, are discussed.

Invasion, development, growth and egg laying by Meloidogyne javanica in Brassicaceae crops

Nematology ◽  
2001 ◽  
Vol 3 (5) ◽  
pp. 463-472 ◽  
Author(s):  
John Kirkegaard ◽  
Rod McLeod ◽  
Christopher Steel
Keyword(s):  
Intermediate Host ◽  
Subterranean Clover ◽  
Meloidogyne Javanica ◽  
Mature Female ◽  
Egg Laying ◽  
Field Pea ◽  
Crop Species ◽  
Egg Masses ◽  
Brassicaceae Species ◽  
Host Status

AbstractInvasion, development and egg laying by Meloidogyne javanica in 11 Brassicaceae and four non-Brassicaceae crop species/subspecies was investigated. At 10 to15 and 15 to 20°C, fodder rape cv. Rangi was invaded less than the good hosts tomato cv. Grosse Lisse and field pea cv. Dun but more than the poor host oat cv. Cooba. With an inoculum of 50 second stage juveniles (J2), invasion of Rangi, and the intermediate host subterranean clover cv. Trikkala, were similarly invaded when inoculated with 50 and 100 J2, cv. Rangi was invaded less than tomato. The intermediate host subterranean clover cv. Trikkala and Rangi were similarly invaded when inoculated with 50 and 100 J2 but cv. Trikkala was less invaded with 200 J2. Oat cv. Cooba was always less invaded than the other hosts. Invasion of 3-week-old seedlings of cv. Rangi and 12 cultivars of seven other Brassicaceae crop species/subspecies were similar. Three weeks after inoculation, more M. javanica had developed to the mature female stage in tomato than in the eight Brassicaceae species/subspecies. Females growing in tomato and field pea were always larger than those in rape cv. Rangi. Females in Rangi were larger but those in oilseed radish cv. Adagio were smaller than in 11 other cultivars of seven Brassicaceae, except in plants grown in winter. Egg masses from four Brassicaceae species contained fewer eggs than egg masses from tomato at 6 weeks after inoculation, but at 7 and 8 weeks only those from fodder rape cv. Korina had consistently fewer than tomato. Results are discussed in relation to host status, glucosinolates and potential use of Brassicaceae for control of Meloidogyne.

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