Complete Breeding Cycle Research Articles

Applying machine learning to understand the relationship between body weight and beak and nail dimensions in broiler chickens

The aim of this research was to determine whether body weight could be used as a reliable indicator of beak and claw length in broiler chickens during the production cycle. Sixty broiler chickens were evaluated individually and evaluated weekly (1, 7, 14, 21, 28, 35 and 42 days) throughout the production cycle. The following variables were measured: body weight, length of nails and beaks (maxillary mandible and beak area considering the presence of the nostril). The evaluation of body weight was performed using a digital scale. Nail lengths (U1, U2 and U3) were obtained using a digital calliper. The biomechanical analysis of the length of the beaks of the birds was carried out through photographs, using a digital camera and the analysis of the images carried out through the ImageJ software. It is concluded that the correlations between body weight x maxila, body weight x area of the beak with nostril and body weight x nails (U1, U2 and U3), can be a reliable indicator of dependence between the variables if we consider the complete breeding cycle of broiler chickens. However, when the correlations are evaluated weekly separately, they are not a reliable indicator. The first two main components revealed 94.7% of the data variation, with all morphological variables being important, as the communalities were greater than 0.93. The factorial analysis biplot revealed that nail characteristics, especially Nail1 and Nail 3, are strongly associated with the body weight of birds considering the complete cycle (42 days), i.e. nail characteristics are the main phenotypic predictors of body weight. The morphological traits of the nail and beak are predictors of body weight when evaluating the complete cycle (42 days), especially nail 1 and nail 3.

Validation of Diets with Tomato Pomace in Complete Cycle Breeding of Tenebrio molitor (L.) (Coleoptera: Tenebrionidae).

By-product-based diets have the potential to improve the environmental and economic sustainability of Tenebrio molitor (Linnaeus, 1758) production. However, evaluations of the efficacy of new diets are generally focused on larval performance, while the effect on adults is poorly understood. This aim of this study was to evaluate diets enriched with tomato pomace over a complete breeding cycle. The results showed that when used as an oviposition substrate, all the tested diets, including tomato pomace (T), outperformed the control bran-yeast diet (WY, 95:5 ratio), possibly due to the presence of cholesterol and linoleic acid. The adults fed with the bran-tomato pomace-brewer's spent grain diet (WTB, 50:27:23 ratio), the bran-tomato pomace-yeast diet (WTY, 50:41:9 ratio), and the bran-tomato pomace diet (WT, 50:50 ratio) produced significantly more larvae than those fed with the WY diet. The WTB diet (despite being yeast-free) performed similarly to the WY control diet during the subsequent larval growth phase, making it suitable for the entire production cycle. In conclusion, the results show that tomato pomace can be used a valid by-product in the formulation of efficient diets for the breeding of T. molitor and also provide an alternative to expensive yeast.

THE EFFECT OF ROSEMARY (SALVIA ROSMARINUS) SUPPLEMENTED DIET ON REPRODUCTIVE AND PRODUCTIVE TRAITS OF LIBYAN LOCAL PIGEON

The objective of this study was to investigate the effect of rosemary leaves powder supplement on reproductive and productive performance of local pigeon. Thirty pairs of Libyan local pigeons were randomly allocated into three groups, each with 10 replicates. Rosemary leaves powder (RLP) was added to isonitrogenous and isoenergetic ration at 0 % (control, C), 0.5 % (T1) or 1 % (T2). The experiment lasted for a complete breeding cycle. RLP did not affect egg weight, egg number or incubation period. Egg volume (13.82, 10.73 and 11.42 cm3), egg hatchability (100, 55.56 and 50.00 %) and hatching weight (16.63, 14.91 and 14.89 g) were higher in C group in comparison with T1 and T2, respectively (p < 0.05). Egg surface area (30.25, 26.30 and 27.74 cm2) and egg width (2.67, 2.44 and 2.53 cm) were higher in C than in T1 (p < 0.05) and tended to be higher than T2 (p > 0.05). Egg length, egg shape index, fertility rate and pre-weaning survival rate tended to decrease with the increased RLP inclusion rate; however, these differences were not significant (p > 0.05). Squab weight at weaning was lower in C than in T2 group, (310.35, 312.08, 337.98 g for C, T1, and T2, respectively) (p < 0.05). Peroxide value of fresh meat tended to decrease in T2 compared to T1 or C groups (0.6, 0.49, 0.37 meq/kg for C, T1 and T2, respectively) (p > 0.05). Malondialdehyde (MDA) concentration in fresh meat (0.16, 0.16, 0.09 mg MDA/kg) and blood (1.66, 0.83, 0.61 mg MDA/L) for C, T1 and T2, respectively, was lower in T2 compared to C group (p < 0.05). In conclusion, adding RLP to feed negatively affected the reproductive performance despite expected improvement of the productive performance and oxidative status in pigeons.

Influence of wheat-rye translocations on yield and productivity elements of soft winter wheat in southern Ukraine

Topicality. The level of genetic yield potential and adaptive properties of modern bread winter wheat varieties at this stage of breeding development is at a fairly high level. So breeding, improve-ment of bread winter wheat is becoming increasingly difficult. For this purpose, the creation and identification of new genetic sources of valuable traits and creation of genetic diversity, evaluation and selection of desired genotypes is extremely relevant. Issues. Introduction of alien translocations into the gene pool of bread winter wheat can serve as one of such sources of new original genetic material. However, the effects of these translocations are manifested to varying degrees depending on the genetic environment of hybrids and agroclimatic conditions of genotype selection. Aim. To compare the changes in the yield of recombinant lines and plant productivity elements based on their drought and heat tolerance depending on their genetic effects of wheat-rye translocations (WRT) 1AL.1RS and 1BL.1RS. To determine the use effectiveness of each WRT in order to create more perfect varieties of bread winter wheat under the conditions of soil-air drought in the Steppe zone of Ukraine. Materials and Methods. In 2010-2020, field trials were carried out on the Institute’s fields on the by black fallow as the annual predecessor with the optimal agricultural background for breeding work. During the analysis of experimental data, all changes in meteorological conditions over the years of research were taken into account. In general, weather conditions were arid, which is typical for the Steppe zone. The studies of 112 lines (9.2 %) were carried out in the Department of Genetic Basis of Breeding of the Plant Breeding and Genetics Institute at the National Center of Seeds and Cultivar In-vestigation led by A. I. Rybalka, the rest 1093 lines (90.8 %) were studied in the Institute of Plant Pro-tection NAAS led by N. A. Kozub and I. O. Sozinov. The material of competitive variety trials was tested on the presence of translocations and their state by DNA markers in the Department of General and Molecular Genetics of the the Plant Breeding and Genetics Institute at the National Center of Seeds and Cultivar Investigation led by V. I. Fait. Mathematical processing and analysis of the study results were performed using the methods of B. A. Dospekhov and P. F. Rokitskyi, and with Microsoft Excel 2007. Results. It was established that genetic effects of the most widespread in the world breeding practice wheat-rye translocations 1АL.1RS and 1ВL.1RS are considerably modified by features of their interaction in genetic environment and depending on agroclimatic conditions of growing introgressive genotypes. The positive effect of 1AL.1RS on the yield, total and productive tillering, and head productivity elements was significantly revealed due to simultaneous positive effect of translocation on drought and heat tolerance of plants. As a result of complete breeding cycle, a series of bread winter wheat varieties was developed on the material of 1AL.1RS, such as Zhytnytsia Odeska, Oktava Odeska, Liha Odeska, Duma Odeska, Versiia Odeska, which provided 10–15 % increase in yield to standards according to the station and state variety testing. These varieties are listed in the State Register of Ukraine and Moldova. Conclusions. The use of WRT 1AL.1RS is perspective for further bread winter wheat breeding, and in the the Plant Breeding and Genetics Institute at the National Center of Seeds and Cultivar Inves-tigation as one of the next stages of improvement of bread winter wheat varieties for arid conditions of the South of Ukraine. The use of 1ВL.1RS in wheat breeding in the region is less promising method, but does not exclude the possibility of obtaining a positive result in a favorable combination with highly adapted local varieties. Keywords: bread winter wheat, recombinant lines, yield, wheat-rye translocations 1AL.1RS and 1BL.1RS.

Long-Term Measurement of Piglet Activity Using Passive Infrared Detectors.

Measuring animal activity is useful for monitoring animal welfare in real time. In this regard, passive infrared detectors have been used in recent years to quantify piglet activity because of their robustness and ease of use. This study was conducted on a commercial farm in Northwest Spain during six complete breeding cycles. The hourly average activity of weaned piglets with a body mass of 6-20 kg was recorded and further analyzed by using a multiplicative decomposition of the series followed by a wavelet analysis. Finally, the real series were compared to the theoretical models of activity. Results showed a high level of movement immediately after weaning and a sustained level of activity throughout the cycles. The daily behavior of the piglets followed a clear circadian pattern with several peaks of activity. No differences in behavior were observed between spring-summer cycles and autumn-winter cycles. Single-peak models achieved the best predictive results. In addition, the installed sensors were found to underestimate mild activity.

Assessment of Heavy Metal Pollution in the Water, Sediment and Fish during a Complete Breeding Cycle in the Pond of the Pearl River Delta, China

The paper aimed to investigate the concentration variations and evaluate the bioaccumulation as well as the health risk of Cr, Ni, Cu, Zn, As, Cd and Pb in the aquaculture pond ecosystem during a complete breeding cycle. The samples of water, sediment and aquatic organisms were collected from the pond of gull island in the Pearl River Delta, China. In the breeding cycle, the results revealed the metal concentration in the water increased, while the sediment metal concentration showed no significant difference. The heavy metal concentrations in the water were higher than the background values (December 2017) which related to the input of feeds. Sediment metal concentrations (Cr, Ni, Cu, Zn, As and Cd) in the sediment were higher than the background values of Guangdong Province, China, indicating these metal pollutions came from anthropogenic activities. While the concentration of Pb was comparable to the background value, implying that the Pb was mainly from the earth crust. In addition, various metals showed different affinity to fish organs (muscle, skin, bladder, gill, heart, kidney and liver). Zinc was abundant in skin, while As and Cd concentrations were highest in kidneys; Cu was accumulated highest in liver; Cr concentrations was highest in hearts; and Ni was mainly found in bladders, and the Pb was most commonly found in gills. The distribution of heavy metals in the tissues organs was in the sequence of: Zn > Cu > Cr > Ni > Pb > As > Cd. As the fish ages, the Cu and Zn concentration in tissue organs declined, while the Cr, Ni, As, Cd and Pb increased slightly. Estimations of health risks showed no evidence of potential threats to consumers.

Rearing a virulent common cuckoo is not extra costly for its only cavity-nesting host.

Virulent brood parasites refrain from arduous parental care, often kill host progeny and inflict rearing costs upon their hosts. Quantifying the magnitude of such costs across the whole period of care (from incubation through to parasite fledgling independence) is essential for understanding the selection pressures on hosts to evolve antiparasitic defences. Despite the central importance of such costs for our understanding of coevolutionary dynamics, they have not yet been comprehensively quantified in any host of any avian brood parasite. We quantified parasite-rearing costs in common redstarts Phoenicurus phoenicurus raising either parasitic common cuckoo Cuculus canorus or their own chicks throughout the complete breeding cycle, and used multiple cost parameters for each breeding stage: incubation, brooding and feeding effort; length of parental/host care; parent/host body condition; and heterophil/lymphocyte ratio (stress-level indicator). Contrary to traditional assumptions, rearing the parasite per se was not associated with overall higher physiological or physical costs to hosts above the natural levels imposed by efforts to rear their own progeny. The low parasite-rearing costs imposed on hosts may, in part, explain the low levels of known host counter-defences in this unusually frequently parasitized cuckoo host.

Genomic selection in soybean: accuracy and time gain in relation to phenotypic selection

Genomic selection (GS) can potentially accelerate genetic improvement of soybean [Glycine max L. (Merrill)] by reducing the time to complete breeding cycles. The objectives of this study were to (1) explore the accuracy of GS in soybean, (2) evaluate the contribution of intrapopulational structure to the accuracy of GS, and (3) compare the efficiencies of phenotypic selection and GS in soybean. For this, phenotypic and genotypic data were collected from 324 soybean genotypes (243 recombinant inbred lines and 81 cultivars) and GS was performed for five yield related traits. BayesB methodology with a 10-fold cross-validation was used to compute accuracies. The GS accuracies were evaluated for grain yield, plant height, insertion of first pod, days to maturity, and 1000-grain weight at eight locations. We found that GS can reduce the time required to complete a selection cycle in soybean, which can lead to increased production of this commercially important crop. Furthermore, genotypic accuracy was similar regardless of population structure correction.

Evaluation of Toyocerin®, a probiotic containing Bacillus toyoi spores, on the health status and performance of sows and their litters

The aim of this study was to assess the efficacy of Toyocerin®, a probiotic containing l x l09Bacillus toyoi spores per gram, on the health status and productivity of sows and their litters. Eighty gilts and sows were allocated into four experimental groups as follows: TOYO - 0 = control, TOYO - 0.5 = 0.5xl09 Bacillus toyoi spores/kg of feed, TOYO - 1 = l.0xl09Bacillus toyoi spores/kg of feed, TOYO - 2 = 2.0x109Bacillus toyoi spores/kg of feed. The treatments started at the day of service and covered two complete breeding cycles. Toyocerin® supplementation of the feed improved gilt/sow performance by: increasing (P<0.05) the mean body weight from service to farrowing, decreasing (P<0.05) the mean weight loss from farrowing to weaning and decreasing (P<0.05) the mean weaning-to-conception interval. Toyocerin® also showed a positive effect on litter characteristics in terms of: higher (P<0.05) mean number of piglets born alive at each birth, higher (P<0.05) mean number of piglets weaned, a higher (P<0.05) mean piglet body weight at each weaning and lower (P<0.05) mean diarrhoea score. Finally, Toyocerin® tended to improve the health status and fertility of sows demonstrating: a tendency for lower percentages of sows with abnormal clinical signs and a similar effect on the percentages of sows returning to oestrus. These beneficial effects of Toyocerin® were more pronounced in the TOYO - 1 and the TOYO – 2 groups.

Breeding ecology of buff-breasted babbler (Pellorneum tickelli) at Doi Chiang Dao Wildlife Research Station, Chiang Mai province, Thailand

The behavior of the buff-breasted babbler (Pellorneum tickelli) was recorded from April 2010 to May 2012 along creeks in Doi Chiang Dao Wildlife Research Station, Chiang Mai, Thailand. Fifteen nests of the buff-breasted babbler were found on four creeks: Maeka, Maemard, Ong and Sikrobkrua. The general behavior of birds included foraging, excretion, locomotion, preening and vigilance. The complete breeding cycle of the buff-breasted babbler in this study was almost 1 mth. Egg clutch size was in the range 3–4 and the nestlings hatched almost simultaneously. The eggs were incubated by both the males and the females. After hatching, both parents invested in intensive parental care. As well as providing food, they also protected their nestlings. This information can be used to help with conservation planning in the area and elsewhere.

Gene Expression Networks Underlying Ovarian Development in Wild Largemouth Bass (Micropterus salmoides)

BackgroundOocyte maturation in fish involves numerous cell signaling cascades that are activated or inhibited during specific stages of oocyte development. The objectives of this study were to characterize molecular pathways and temporal gene expression patterns throughout a complete breeding cycle in wild female largemouth bass to improve understanding of the molecular sequence of events underlying oocyte maturation.MethodsTranscriptomic analysis was performed on eight morphologically diverse stages of the ovary, including primary and secondary stages of oocyte growth, ovulation, and atresia. Ovary histology, plasma vitellogenin, 17β-estradiol, and testosterone were also measured to correlate with gene networks.ResultsGlobal expression patterns revealed dramatic differences across ovarian development, with 552 and 2070 genes being differentially expressed during both ovulation and atresia respectively. Gene set enrichment analysis (GSEA) revealed that early primary stages of oocyte growth involved increases in expression of genes involved in pathways of B-cell and T-cell receptor-mediated signaling cascades and fibronectin regulation. These pathways as well as pathways that included adrenergic receptor signaling, sphingolipid metabolism and natural killer cell activation were down-regulated at ovulation. At atresia, down-regulated pathways included gap junction and actin cytoskeleton regulation, gonadotrope and mast cell activation, and vasopressin receptor signaling and up-regulated pathways included oxidative phosphorylation and reactive oxygen species metabolism. Expression targets for luteinizing hormone signaling were low during vitellogenesis but increased 150% at ovulation. Other networks found to play a significant role in oocyte maturation included those with genes regulated by members of the TGF-beta superfamily (activins, inhibins, bone morphogenic protein 7 and growth differentiation factor 9), neuregulin 1, retinoid X receptor, and nerve growth factor family.ConclusionsThis study offers novel insight into the gene networks underlying vitellogenesis, ovulation and atresia and generates new hypotheses about the cellular pathways regulating oocyte maturation.

Human‐induced eutrophication enhances reproductive success through effects on parenting ability in sticklebacks

Human‐induced processes are altering habitats at an unprecedented rate and scale. This has changed the biodiversity and biomass in many areas, but also led to phenotypic and genetic alterations of populations. Here we investigated the effects of the ongoing eutrophication in the Baltic Sea on the reproductive success of threespine stickleback males Gasterosteus aculeatus, through effects on reproductive behaviour and parenting ability. We allowed males to complete breeding cycles in a competitive setting under increased macro algae cover or increased turbidity caused by phytoplankton growth. Both environmental factors improved the parenting ability of the males and enhanced reproductive output. Increased alga growth and turbidity reduced aggressive interactions between males during the parental phase, probably due to reduced visibility, which slowed down a deterioration of condition. This increased the reproductive lifespan of the males and enabled them to complete more breeding cycles, as found when males were allowed to complete as many breeding cycles as they could under increased algae cover. In addition, increased turbidity improved oxygen conditions, which enhanced hatching success and reduced the need for vigorous fanning behaviour. Increased turbidity, however, relaxed selection on male size. Together with earlier results on relaxed sexual selection under changed environmental conditions, this suggests that the effect of eutrophication on stickleback populations is complex. It increases the reproductive output of populations, since more individuals are spawning within eutrophicated areas and their hatching success is increased, but it relaxes sexual and natural selection at the reproductive stage. Whether this will shift selection and population regulation to other life stages, such as the juvenile stage, deserves further investigations.

Objetivos de seleção e valores econômicos em sistemas de produção de gado de corte no Brasil

A importância econômica de possíveis características biológicas a serem incluídas em objetivos de seleção para diferentes sistemas de produção de bovinos da raça Nelore, mediante o cálculo dos seus valores econômicos foi avaliada nesta pesquisa. Com base em informações de desempenho e parâmetros biológicos e econômicos, foram simulados diferentes sistemas de produção (ciclos de cria e completo) para dois rebanhos. O rebanho 1, com ciclo de cria (Ccr), ciclo completo (Cco) e ciclo completo com venda de reprodutores (CcoR), é um rebanho elite no qual é desenvolvido um programa seleção. Parte deste rebanho é também destinada à produção de animais comerciais. O rebanho 2 é um rebanho exclusivamente comercial, com Ccr e Cco. Os valores econômicos foram calculados usando-se um modelo bio-econômico, para as seguintes características: peso (PD) e taxa de desmama (TD), peso da vaca adulta (PVA), ganho médio diário no confinamento (GMD), pesos ao abate (PA) e de carcaça (PC), peso final dos tourinhos (PFT), rendimento de carcaça (RC) e consumo alimentar no confinamento (CAc) e em pastagem (CAp). Para os sistemas de ciclo completo e de ciclo completo com venda de reprodutores e CcoR (Cco e CcoR), os valores econômicos variaram de R$ 0,34 a R$ 0,40 para PD, R$ 3,51 a R$ 10,15 para TD, -R$ 0,16 a R$ 0,09 para PAV, R$ 0,32 a R$ 0,76 para GMDc, R$ 1,09 a R$ 1,17 para PA; R$ 2,03 a R$ 2,19 para PC, R$ 23,89 a R$ 28,61 para RC, e R$ 11,85 para PFT, - R$0,45 para CAc e - R$ 0,03 para CAp. A taxa de desmama e o rendimento de carcaça foram as características de maior impacto no lucro anual dos dois rebanhos. As análises de sensibilidade demonstraram que, de modo geral, possíveis mudanças nos preços de insumos e produtos influenciariam de forma mais significativa os valores econômicos nos sistemas de produção nos quais esses preços eram mais elevados nas situações básicas.

Vitamin A requirements of alipochromatic (‘recessive-white’) and coloured canaries (Serinus canaria) during the breeding season

Six pairs of alipochromatic (‘recessive-white’) canaries (Serinus canaria) and six pairs of coloured canaries were kept through a complete breeding cycle while being fed a diet providing 12,000 iu vitamin...

Modelo bioeconômico para cálculo de custos e receitas em sistemas de produção de gado de corte visando à obtenção de valores econômicos de características produtivas e reprodutivas

Foi desenvolvido um modelo bioeconômico para o cálculo do desempenho, dos custos e das receitas para obtenção de valores econômicos de características de interesse econômico em sistemas de produção de gado de corte no Brasil. As informações de desempenho e de parâmetros biológicos e econômicos foram obtidas em uma propriedade de gado Nelore que realiza ciclo completo com venda de reprodutores. O modelo é determinístico e estático e foram usadas planilhas Excel para a realização dos cálculos. Com base nas informações originais, foram simulados dois sistemas de produção, um fazendo o ciclo completo com venda de reprodutores (CcoR) e o outro, de cria (Cc). Foram calculados os custos e as receitas para esses dois sistemas e, a partir disto, foram obtidos seus lucros anuais. Para o cálculo dos valores econômicos foram escolhidas as características peso à desmama (PD), peso adulto da vaca (PAV), taxa de prenhez (TP) e taxa de desmama (TD), que são de interesse nos dois sistemas de produção. Para avaliar o impacto das mudanças no desempenho das características sobre o lucro anual do sistema de produção, os valores iniciais das características foram aumentados em 1%. Esse aumento resultou em mudanças positivas no lucro, observando-se que a TD foi a característica que apresentou maior impacto nos dois sistemas. Para o CcoR, os valores econômicos para PD, PAV, TP e TD foram, respectivamente, R$ 0,40/kg, R$ 0,09/kg, R$ 3,20/1% e R$ 10,15/1%. Para Cc, estes valores foram, respectivamente, de R$ 1,31/kg, R$ 0,09/kg, R$ 2,41/1% e R$ 3,36/1%. O modelo foi capaz de reproduzir satisfatoriamente o sistema de produção de gado de corte estudado e pode ser adaptado para outras circunstâncias de produção.

Predation on burrowing petrels by the brown skua (Catharacta skua lönnbergi) at Mayes Island, Kerguelen

AbstractThe diet of the brown skua (Catharacta skua lönnbergi) was studied at Mayes Island, Kerguelen archipelago, by collection of prey remains on 11 territories during the complete breeding cycle of the species there. In nine territories, collections were daily or every two days for a quantitative investigation of the diet. The blue petrel (Halobaena caerulea) and thin‐billed prion (Pachyptila belcheri) accounted for, respectively, 72.9 and 19% of the remains. Differences in diet and prey capture rate were analysed according to territory size, local abundance of prey inferred from the vegetation cover of territories, colony attendance patterns of prey, and according to the breeding timing and success of skuas. Skuas holding large territories caught more prey, and especially more blue petrels than those with small territories. Diet reflected local abundance of blue petrel and thin‐billed prion but the blue petrel was apparently preferred to other available prey. Failure to breed was not significantly related to hunting performance of the skua or to food availability, but sample size was small. Variations over time of prey capture rates reflected the colony attendance patterns of the main prey. Captures of blue petrel and thin‐billed prion were most numerous during their respective laying, incubation and hatching periods, decreasing during chick‐rearing. Prey capture rates were greatest when brown skuas were hatching, and decreased during chick‐rearing to a minimum when young skuas were fledged. Capture rate patterns differed according to laying date of skuas: early breeding skuas caught more prey and were well synchronized with the breeding cycle of the blue petrel and late breeders exhibited more dependence on the thin‐billed prion for some periods. Finally, this study has allowed us to assess the impact of the brown skuas upon the burrowing petrels on this locality.

Seasonal Effects of Timing and Reproduction in the King Penguin: A Unique Breeding Cycle

There was a seasonal biomodality in the distribution of breeding activities of King Penguins Aptenodytes patagonicus, studied from 1991 to 1994 at South Georgia, with peaks of courtship and egg-laying 2-3 months apart. The late peak was of birds that bred successfully the previous year, whereas the early peak was of birds that had failed. Successful birds were delayed because the median time for a complete breeding cycle, including moult, was > 14 month. Although most birds made a breeding attempt each year, none bred successfully in two consecutive seasons. Hence, in practice the cycle was biennial. The egg-laying period spanned four months but only pairs that laid within the first quarter of this period were successful. Parental quality, rather than laying date, strongly influenced the outcome of first quarter breeding attempts. No late breeding attempt was successful and why they are undertaken is unclear. At least they posed no measurable cost, either by delaying subsequent breeding or by increasing mortality; this may be important for balancing the low benefit. After the over-wintering fast the chick could be fledged by a single parent; but no sex-specific difference in invested time in the chick near to fledge was observed.

The Breeding System of the Three-Spined Stickleback, Gasterosteus Aculeatus (Forma Leiura) With Reference To Spatial and Temporal Patterns of Nesting Activity

Abstract1) The breeding succes of three-spined stickleback (Gasterosteus aculeatus L., forma leiura) males in a small stream of the Tsuya River, Gifu Prefecture, Central Japan, was studied with reference to timing of nesting initiation, use of space for nesting and social interactions. The observations were made almost daily during March to early July 1988 along the shore at a distance of 1-2 m from the fish and nests. 2) All the males in an enclosed study pool were individually marked (99 males). Furthermore, a total of 67 females were marked and observed weekly. The males were individually observed and their agonistic, courtship and parental behaviour as well as their reproductive success were quantified. Reproductive success of individual male was measured as the number of nests built, the number of successful nests, the number of hatched fry per nest. Nest sites were categorized in six types (A-F) on the basis of the proportion of vegetation cover around the nest and distance from the shore. 3) Body size and environmental factors (water temperature, water depth, changes in water level) were not correlated with reproductive success. Flooding was not a major cause of unsuccessful nesting. The brightness of nuptial colouration at the onset of breeding correlated significantly with individual success. Individual variation in the development of secondary sexual characteristics such as a nuptial colouration may have an important consequence for the lifetime reproductive success of the individuals. There was no relationship between fish density and reproductive success. 4) All males that nested more than once had begun breeding early in the season. The sooner a male started nest-building, the more opportunities he had to complete breeding cycles. 5) After an unsuccessful nest, males were significantly more likely to move their nest sites than after a successful nest. The subsequent nesting cycle was not always successful. 6) There was variation in nest-sitc location. The spatial pattern of nest distribution was strongly related to the temporal pattern, because the first males which settled, more often built their nests at sites along the shore where the nest was covered on one or two sides by vegetation. The location of nest site was significantly correlated with reproductive success. When males nested in partly concealed places along the shore, they could sometimes obtain a high reproductive success irrespective of the date of breeding initiation. Thus, reproductive success was largely determined by the timing of nest-building and nest position.

The Symbiosis of Acarid Mites, Genus Ctenocolletacarus (Acarina, Acariformes), and Stenotritid Bees, Genus Ctenocolletes (Insecta, Hymenoptera)

Details of the life history of acarid mites of the genus Ctenocolletacarus have emerged from studies of nests of their hosts, Ctenocolletes albomarginatus and Ce. nicholsoni, and from rearing mites in the laboratory. The mites are closely associated with their hosts at all stages and their complete breeding cycle occurs in the hosts' sealed brood cells. Only the phoretic deutonymph leaves the cells. The mites, like their hosts, are univoltine. One to a few hypopi dismount from nesting females into each new brood cell and rapidly transform through non-mobile tritonymphs to adults of both sexes. Female mites oviposit on the ceiling of the cell during the host larva's early instars, giving rise to hundreds of larvae and then protonymphs by the time the host larva has completed feeding. Protonymphs metamorphose to hypopi once the host larva has defaecated and entered the prepupal phase. Hypopi remain with the dormant prepupa until the following season when they secrete themselves beneath the terga of the newly emerged adult bee. Circumstantial evidence, suggesting that hypopi are transmitted venereally between adult bees, is discussed. Adult, larval and protonymphal mites ingest pollen and the late protonymphal stage invades the faeces of the larval host. Sanitary control is a possible pay-off for the hosts.

The role of nest-building activity in gonadotropin secretions and the reproductive success of ring doves (Streptopelia risoria).

This study was undertaken to investigate the intricate relations between prelaying nest-building activity and preovulatory hormonal changes, and the effects of these events on breeding success. Pairs of ring doves were allowed to go through a complete breeding cycle under four conditions of nest-building opportunity. Nest were self-made, pre-made, pre-made and covered, or removed daily to generate various levels of building activity. Behavioral and hormonal changes were observed throughout the cycle. Blood levels of gonadotrophins were monitored by daily measurements with the method or radioimmunoassay. A depression of follicle-stimulating hormone (FSH) typically was associated with every preovulatory surge of luteinizing hormone (LH); an LH surge not accompanied by a FSH dip was not followed by ovulation. Moreover, the FSH depression was significantly correlated with the level of nest-building activity. These findings led to the proposal that nest-building activity stimulated preovulatory FSH change and, hence, ovulation. The constructed nest in turn appeared to promote incubation behavior. These results are discussed in the context of breeding success.