The effects of brood stock size on the economy of catfish (Clarias anguillaris) fry production using the hormone induced natural breeding technique

89 ripe female brooders of the catfish, Clarias anguillaris (Body wt. Range 150g-1, 200g) were induced to spawn by hormone (Ovaprim) induced natural spawning technique over a period of 10 weeks. Matching ripe males were used for pairing the females at the ratio of two males to a female. Six ranges of brood stock body weights were considered as follows; <200g; 200g-399g; 400g-599g; 600-799g; 800g-999g; > 1000g and the number of fry produced by each female brooder was scored/recorded against the corresponding body weight range. The number of fry per unit quantity of hormone and the cost of production a fry based on the current price of Ovaprim (hormon) were determined so as to ascertain most economic size range. The best and most economic size range was between 400g-599g body weight with about 20,000 fry per ml of hormone and N0.028 per fry, while the females above 1000g gave the poorest results of 9,519 fry per ml of hormone and N0.059 per fry. For optimum production of Clarias anguillaris fry and maximum return on investment female brooders of body weights ranging between 400g-599g are recommended for hormone induced natural breeding exercises

The effects of brood stock size on the economy of catfish (Clarias anguillaris) fry production using the hormone induced natural breeding technique

89 ripe female brooders of the catfish, Clarias anguillaris (Body wt. Range 150g-1, 200g) were induced to spawn by hormone (Ovaprim) induced natural spawning technique over a period of 10 weeks. Matching ripe males were used for pairing the females at the ratio of two males to a female. Six ranges of brood stock body weights were considered as follows; <200g; 200g-399g; 400g-599g; 600-799g; 800g-999g; > 1000g and the number of fry produced by each female brooder was scored/recorded against the corresponding body weight range. The number of fry per unit quantity of hormone and the cost of production a fry based on the current price of Ovaprim (hormon) were determined so as to ascertain most economic size range. The best and most economic size range was between 400g-599g body weight with about 20,000 fry per ml of hormone and N0.028 per fry, while the females above 1000g gave the poorest results of 9,519 fry per ml of hormone and N0.059 per fry. For optimum production of Clarias anguillaris fry and maximum return on investment female brooders of body weights ranging between 400g-599g are recommended for hormone induced natural breeding exercises

Studies on hymenopteran parasitism of Drosophila

Studies on Hymenopteran Parasitism of Drosophila

Flies of the genus Drosophila are subject to attack by a number of parasitic forms. Sturtevant (1921) has listed records of parasitism by protozoa (Leptomonas), fungi (Muiaria and Stigmatomyces), nematodes, mites and v~rious hymenoptera. According to Sturtevant, Perkins (1913) has bred at least five species of hymenoptera, belonging to the proctotrupoid, cynipoid and chalcidoid groups, upon Drosophiline flies. H.S. Smith has bred an unidentified proctotrupoid and a chalcidoid, Pachy crepoideus dubius Ashmead* from both Drosophila melanogaster ani D. hydei. Kieffer ( 1913) has described three species of hymenoptera from Africa collected by Silvestri and stated by him to be parasitic on Drosophila, species not given. They are Trichopria (Planopria) rhopalica (Diapriidae), Ashmeadopria drosophilae (Diapriidae), and the insect which forms the subject matter of the present investigation, Eucoila drosophilae (Figitidae).

There are in addition a number of predacious enemies among wasps, spiders, flies and beetles.

The present account is concerned with parasitism of various species of Drosophila by Eucoila drosophilae Kieff. The wasps were found b y Dr. w. P. Spencer who exposed traps in an effort to collect Drosophila at Long Lake, Ohio, in Sept. 1934 . Drosophila larvae from the trap gave a large number of pupae from which wasps emerged in considerable proportions. Since that time stock s have been maintained in culture on Drosophila melanogaster.

Reprodução e parasitismo em Melanoides tuberculata (Müller, 1774) (Gastropoda, Thiaridae) da Vila do Abraão, Ilha Grande, Angra dos Reis, RJ

Melanoides tuberculata (Müller, 1774), molusco exótico límnico de origem afroasiática, foi registrado pela primeira vez na Vila do Abraão, Ilha Grande, Angra dos Reis, Rio de Janeiro, em 2005. Atua como primeiro hospedeiro intermediário de diversos trematódeos de importância médica. As populações são compostas majoritariamente por fêmeas partenogenéticas que possuem um marsúpio onde se desenvolvem os juvenis. Os objetivos foram verificar: a presença de machos; se existem flutuações na produção de ovos e juvenis ao longo do tempo; quando a maturidade sexual é atingida e, a existência de parasitos relacionando sua presença com o número de ovos e juvenis. Para a contagem de ovos e juvenis, foram utilizadas fêmeas coletadas bimestralmente de setembro/07 a outubro/10, separadas em quatro classes de tamanho, segundo o diâmetro da concha: Classe I: < 3mm; Classe II: 3 a 5,99mm; Classe III: 6 a 8,99mm; Classe IV: > 9mm. Separamos cinco fêmeas/classe, totalizando 20 fêmeas/coleta, exceto nas amostras de setembro/07 (16 exemplares), abril/09 (19 exemplares) e de abril/10 (13 exemplares), totalizando 348 fêmeas. Para observação dos parasitos, ovos e juvenis o teto da cavidade palial foi retirado e o marsúpio dissecado. Classificamos os juvenis em classes de acordo com o número de voltas: com menos de duas; com duas a quatro e com mais de quatro. Os dados foram analisados utilizando Excel e SYSTAT 12. Para a histologia da gônada e do marsúpio, utilizamos cinco exemplares coletados mensalmente de setembro/12 a fevereiro/13, de cada classe de tamanho, totalizando 20 espécimes/coleta, exceto em outubro/12, quando 16 espécimes foram usados, pois somente um espécime da Classe IV foi encontrado. Os espécimes foram fixados em formalina Millonig de Carson, descalcificados em EDTA, incluídos em parafina e corados em hematoxilina e eosina. Foram encontrados 16 machos. Quantificamos 24.694 ovos e 31.474 juvenis, com as seguintes médias: Classe I: 0 ovos e 0,31 juvenis; Classe II: 24,19 ovos e 47,56 juvenis; Classe III: 114,84 ovos e 155,78 juvenis; Classe IV: 146,76 ovos e 158,41 juvenis. O teste de Kruskal-Wallis mostrou que existe variação significativa no número de ovos e juvenis ao longo do ano (p < 0,01 para ambos) e entre o número de ovos e juvenis entre as diferentes classes de tamanho de concha (p <0,01 para ambos). Foram contabilizados 27.877 juvenis com menos de duas voltas, 3.251 juvenis com duas a quatro voltas e 346 juvenis com mais de quatro voltas. Dentre 348 fêmeas, 111 estavam parasitadas (32% do total) por Centrocestus formosanus (Nishigori, 1924). O Teste de Mann-Whitney, levando em consideração todas as fêmeas, demonstrou que fêmeas parasitadas apresentaram menor número de ovos e juvenis que as não parasitadas ( p<0,01). Excluindo as fêmeas da Classe 1, o resultado do teste foi o mesmo (p< 0,01). Concluímos que: a população de M. tuberculata da Vila do Abraão não é formada somente por fêmeas; as fêmeas se reproduzem o ano todo, pois foram encontrados ovos e juvenis em todas as coletas; que quanto maior a fêmea há mais ovos e, em média, há mais juvenis no marsúpio; que a maturidade sexual é alcançada com aproximadamente 3 mm de diâmetro de concha, devido a presença de ovócitos vitelogênicos tardios e, que o parasitismo afeta negativamente M. tuberculata, reduzindo o número de ovos e juvenis formados

Morphometric studies in Penaeus merguiensis from Ratnagiri waters for selection of the brood stock in genetic improvement programmes

Studies on genetic improvement of penaeid prawns for the character higher tail weight using methods of selective breeding were undertaken. Prior to the actual breeding experiments it was necessary to find out the quantum of available variability in the character tail weight amongst the natural populations of Penaeus merguiensis from the Indian waters. Thirteen morphometric variables were measured and various statistical analyses were carried out. The tail weight showed almost double values of coefficient of variation in the females than the males (C.V. 20.37 and 11.08 respectively). The combination of the characters viz. sixth segment length (SSL), sixth segment depth (SSD) and posterior abdominal circumference (PAC) gave the highest R super(2) values. These variables were easy to measure and gave maximum variation in the character tail weight without sacrificing the breeders in the brood stock. The quantitative character tail weight was influenced by both genetic and environmental factors was statistically ascertained by applying 2-Factor analysis.

Early and better maturity in carp brood stock with control of environment and feeding

Available of carp breeders in their prim state of maturity is a major constraint in hypophysation. Experiments conducted in a fish farm at Naihati, West Bengal, for two consecutive years, 1983-84 and 1984-85, clearly prove that by manipulation of environmental parameters such as metabolites, dissolved oxygen, running water conditions, as also of stock densities and quality and quantity of feed. Catla catla, Hypophythalmichthys molitrix, Labeo rohita, Cirrhina mrigala and Ctenopharyngodon idella can be made to attain better maturity and spawning stage much earlier than normal i.e. even in summer months and the entire stock spawned during the period from March to September. Percentage of successful breeding, quantities of eggs released and fertilised in relation to the body weight of all the species, were also found to be more in comparison to the brood stock raised through the conventional methods.

Effect of brood source on the growth of rohu (Labeo rohita Ham.) fingerlings reared in glass tanks with formulated diets

A 60 day long feeding trial was conducted in an indoor static water system with rohu fingerlings (Labeo rohita Ham.) originating from wild brood, private and public hatcheries (denoted as A B and C respectively). They were fed on formulated diet having 34% crude protein level using indigenous ingredients. The effect of brood source on growth as well as their responses to formulated diet was observed. On the basis of the observed growth rate, food conversion ratio, protein efficiency ratio, apparent net protein utilization and apparent protein digestibility, fingerling source A showed significantly (p<0.05) higher growth, while the sources B and C produced no significantly different (p>0.05) in terms of these parameters. The results of the present study demonstrated that the fingerlings of wild source were of best quality in terms of growth and food utilization in comparison to those had the sources from hatcheries.

Effect of high and low cost brood feeds on gonado-somatic index and fecundity of freshwater prawn Macrobrachium rogenbergii de Man

Studies were conducted to observe the effects of different types of feeds on the gonado-somatic index (GSI) and fecundity of freshwater prawn Macrobrachium rogenbergii. Three different treatments (T1 T2 and T3) were designed with three types of feed as follows: (i) Saudi-Bangla Prawn feed 100% - T1 (ii) SaudiBangla prawn feed 50%+ local feed 50%- T2 and (iii) local feed 100%- T3. The results showed that the average value of gonado-somatic index (GSI) was 14.39, 14.35 and 14.36 and the average fecundity of M. rogenbergiiwas 99,741, 98,125 and 97,911 in T1 T2 and T3 respectively. No significant difference (p>00.5) was between gonado-somatic indices (GSI) and fecundities of M. rogenbergii among different feeding trails. The price of Saudi-Bangla prawn feed was very high (Tk. 23/kg) than the local feed (Tk. 14/kg). So, use of local feed was recommended for M. rogenbergii brood rearing.

Study of distribution, growth and reproduction polychaetes Nereidae in intertidal zone of Bandar Abbas and effect dominant species on white Indian shrimp brood stocks (Fenneropenaeus indicus)

Distribution of polychaetes worms Nereidae in intertidal zone of Bandar Abbass indicated that distribution rate of worms from the west to east for the reason status of seabed type, habitat and feeding substrate used to worms increased. Also investigation description that last-mentioned worms are belong to Nereididae family, Perinereis genus and species of Perinereis nuntia. By viewpoint seabed soil types experiments implement indicated Nereididae worms have higher survival with sandy clay loam soil texture. Statistical analysis showed positive relation coefficient correlation of Pearson between substrate type to frequency of worms and too substrate type with soil organic matter value (P<0.05). By viewpoint feeding also experiments with different feed treatment indicated that Nereid worms is Omnivore but in natural condition more utilized algae substrate special Entermorpha and survival rate had the worms last-mentioned in dietary treatments on this algae 93/3% different significant with other treatments (P<0.05). In this project pond-reared white Indian shrimp (Fenneropenaeus indicus) were used in four maturation and spawning trials lasting 60 days. one group of shrimps was fed a formulated pelleted special of broodstock diet only, a second group was fed squid meat diet; a third group of shrimps with mollusca (Solen vagina) meat diet and fourth group was fed polychaete worms Nereidae family, collected in intertidal zone of Bandar Abbass. Four types of dietary treatments (M1, M4) were given to separate batches that were run in three duplicate. Results of experiments demonstrate that more grew rate and maturation and spawning rate and we found that shrimps fed with polychaete worms have the best condition and then shrimps fed with solen. This is demonstrate furthermore environmental circumstance, endocrine hormone, types of feed important of maturation and spawning of shrimps and in polychaete worms used HUFA help to maturation ovarian in shrimp.

Occurrence of double parasitism on black-barred halfbeak fish from the southeast coast of India

A double parasitism (isopod Cymothoidae and copepod Pennellidae) on black-barred halfbeak fish, Hemiramphus far, was recorded from Pazhayar coastal waters (southeast coast of India) during September 2008. This is the first report from this region and the infection is discussed in relation to environmental and biological parameters.

Behavioural reaction of root vole (Microtus oeconomus pallas) males of different social ranks to familiar and novel odour of conspecific males

In this experiment, we tested the hypothesis that males of root voles (Microtus oeconomus Pallas) of different social ranks display different behavioural strategies. To document behavioural differences between social ranks, we investigated patterns in the behavioural responses to urine cues from familiar and novel individu in a choice maze. Ten pairs of male voles were efectively used in this experiment. All behaviour was recorded with OBSERVER 5.0. When experiment was finished, video tapes were transformed into digital data. Then all data were analyzed by SPSS. The results showed that the approach latency of subordinates was shorter for familiar odours than novel ones, dominant individuals preferentially entered the strange odourant box, subordinates preferred familiar odours over novel ones, subordinates spent more time visiting familiar odours compared to the novel odours, dominants preferred novel odours to familiar ones, subordinates approached familiar odours more frequently than novel ones and self-groomed more often in the familiar odourant box than in the novel box, and dominant and subordinate individuals showed significantly different countermarking behaviours to familiar and novel odours. In conclusion, the dominants and subordinates displayed different behaviour patterns when faced to familiar and novel conspecific males' urine cues. The data support our hypothesis that differences in social rank induce differences in behavioural patterns.

Victims of infanticide and conspecific bite wounding in a female-dominant primate: a long-term study.

The aggression animals receive from conspecifics varies between individuals across their lifetime. As poignantly evidenced by infanticide, for example, aggression can have dramatic fitness consequences. Nevertheless, we understand little about the sources of variation in received aggression, particularly in females. Using a female-dominant species renowned for aggressivity in both sexes, we tested for potential social, demographic, and genetic patterns in the frequency with which animals were wounded by conspecifics. Our study included 243 captive, ring-tailed lemurs (Lemur catta), followed from infancy to adulthood over a 35-year time span. We extracted injury, social, and life-history information from colony records and calculated neutral heterozygosity for a subset of animals, as an estimate of genetic diversity. Focusing on victims rather than aggressors, we used General Linear Models to explain bite-wound patterns at different life stages. In infancy, maternal age best predicted wounds received, as infants born to young mothers were the most frequent infanticide victims. In adulthood, sex best predicted wounds received, as males were three times more likely than females to be seriously injured. No relation emerged between wounds received and the other variables studied. Beyond the generally expected costs of adult male intrasexual aggression, we suggest possible additive costs associated with female-dominant societies - those suffered by young mothers engaged in aggressive disputes and those suffered by adult males aggressively targeted by both sexes. We propose that infanticide in lemurs may be a costly by-product of aggressively mediated, female social dominance. Accordingly, the benefits of female behavioral 'masculinization' accrued to females through priority of access to resources, may be partially offset by early costs in reproductive success. Understanding the factors that influence lifetime patterns of conspecific wounding is critical to evaluating the fitness costs associated with social living; however, these costs may vary substantially between societies.

The effect of spatial scale on interactions between two weevils and their parasitoid

1. The effect of spatial scale on the interactions between three hymenopteran parasitoids and their weevil hosts was investigated. The parasitoid Mesopolobus incultus (Walker) parasitised Gymnetron pascuorum Gyll.; the parasitoids Entodon sparetus (Walker) and Bracon sp. parasitised Mecinus pyraster Herbst. Both of these weevils develop inside the seedhead of Plantago lanceolata L. but occupy different niches. Seedheads were sampled annually from 162 plants at each of two experimental sites consisting of a series of habitat patches of two distinct sizes. Data were analysed from three site-years. 2. Parasitoid densities at each site-year were closely related to the abundance of their respective weevil hosts. The overall proportion of hosts parasitised was more variable for M. incultus than for E. sparetus and Bracon sp. 3. Changes in spatial scale affected the variability of parasitoid densities. For M. incultus, there was generally a greater degree of additional heterogeneity for all increases of scale; for E. sparetus, this was true only at the largest scales; for Bracon sp., all components of variance were negative. 4. The rate of parasitism was related to host density in different ways at different spatial scales. Mesopolobus incultus exhibited inverse density dependence at the finest (seedhead) scale, direct density dependence at the intermediate (plant) scale, and density independence at the large (habitat area 729 m2) scale. Entodon sparetus showed no response to variation in host density at any spatial scale. Bracon sp. showed direct density dependence only at the intermediate and largest scales. 5. Parasitoids E. sparetus and Bracon sp. seemed able to detect more than one M. pyraster individual in seedheads with multiple host occupancy; a greater incidence of conspecific parasitoids than expected emerged from such seedheads.