population ecology of the Australian frog Crinia signifera: egg-laying patterns and egg mortality

1994 ◽  
Vol 21 (6) ◽  
pp. 621 ◽  
Author(s):  
I Williamson ◽  
CM Bull
Keyword(s):  
Population Ecology ◽  
Water Body ◽  
Significant Variation ◽  
Hatching Success ◽  
Egg Laying ◽  
Egg Mass ◽  
Egg Mortality ◽  
Different Depths ◽  
Small Clusters ◽  
Overall Mortality

There are few studies of embryo mortality in anurans, and most of these studies deal with anurans that deposit clutches as one egg mass. In this study, egg mortality in Crinia signifera, an anuran that distributes its clutches in small clusters of eggs, was examined with the aims of: (i) determining overall mortality levels, and (ii) determining whether there was significant variation in success between clutches laid by different females. Hatching success varied significantly between years and between habitats, and was as low as 2% in some habitats in some years. Fungal infection caused most mortality, and hatching success was higher in temporary pools than in a permanent water body. Although significant variation in clutch success between females could occur if clutches were laid in different habitats or at different times, it was not clear whether there would be significant variation in clutch success between females laying simultaneously in the same water body. Differences in success of clutches might occur if females distributed eggs at different depths or in different-sized clusters. However, information on inter-female variation in these components of egg-laying behaviour in C. signifera is currently unavailable.

Multiple clutches, egg mortality and mate choice in the mid-wife toad, Alytes obstetricans

1988 ◽  
Vol 9 (4) ◽  
pp. 357-364 ◽  
Author(s):  
R.T. Clarke ◽  
C.J. Reading
Keyword(s):  
Mate Choice ◽  
Egg Production ◽  
Hatching Success ◽  
Egg Laying ◽  
Central Spain ◽  
Egg Survival ◽  
Small Reservoir ◽  
Egg Mortality ◽  
Alytes Obstetricans

AbstractEgg laying, clutch brooding, egg survival and mate choice were investigated in the mid-wife toad, Alytes obstetricans (Lataste) at a small reservoir in central Spain during 1986 and 1987. Females divided their total egg production into at least three separate clutches. The majority of males brooded between one and three clutches of eggs, though one may have brooded four. First clutches received by males were 24-34% larger than subsequent clutches. No significant differences were found in egg fertilisation, survival and hatching success between individual clutches. The results show that females prefer to spawn with non-brooding males rather than brooding males but that they will spawn with brooding males. When spawning with brooding males they lay smaller clutches than with non-brooding males.

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 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.

scholarly journals Does the vicinity of the Black-Headed Gull colony (Chroicocephalus ridibundus) increase the breeding success of the Common Tern (Sterna hirundo) on the islands of the middle Vistula?

2018 ◽  
Vol 16 (4) ◽  
pp. 43-50
Author(s):  
Dariusz Bukackiński ◽  
Monika Bukacińska ◽  
Milena Grabowska
Keyword(s):  
Hatching Success ◽  
Single Species ◽  
Common Tern ◽  
Egg Mass ◽  
Chick Survival ◽  
Effective Protection ◽  
Vistula River ◽  
Nesting Site ◽  
The Common ◽  
The City

We conducted our study in the Common Tern colony (STH) located on an island in the middle Vistula River course, at the height of the city of Dęblin (km 393–394 of the waterway), in 2017. Our goal was to investigate some aspects of the biology and reproductive ecology of this species. Due to the fact that STH breeds both in single-species as well as in two- or multi-species colonies, in associations with Little Terns (Sternula albifrons), Black-Headed Gulls (Chroicocephalus ridibundus) (LAR) and/or Mew Gulls (Larus canus), we wanted to investigate whether the neighborhood of other species (in this case LAR) affected hatching success and chick survival in STH. Our results clearly show that the presence of breeding terns in the neighborhood of the LAR colony was not accidental and/or caused by the lack of space on the island and/or the possibility of nesting elsewhere. The height of nesting site, type of nesting habitat, clutch size, mean egg volume and mean egg mass of these STH pairs did not differ significantly from those that formed a single species colony, on the same island but several hundred meters away. However, STH nests in the neighborhood of the LAR colony were established much earlier and both the hatching success and chick survival of STH during the early-chick stage were twice as high. Thus, we can conclude that the LAR colony could provide an effective protection against predation of crows, magpies and gulls, dangers which accounted for the vast majority of STH nest failures in the year of our study.

scholarly journals Effects of constant incubation regimes on eggs and hatchlings of the egg-laying skink, Oligosoma suteri

2021 ◽  
Author(s):  
◽  
Kelly Maree Hare
Keyword(s):  
Hatching Success ◽  
Incubation Temperature ◽  
Unit Length ◽  
Condition Index ◽  
Egg Laying ◽  
Maternal Influence ◽  
Temperature Dependent ◽  
Sprint Speed ◽  
Fitness Traits ◽  
Incubation Temperatures

<p>The conditions under which reptilian eggs are incubated affect survival probability and physiological attributes of the progeny. The egg-laying skink, Oligosoma suteri, is the only endemic oviparous lizard in New Zealand. No controlled laboratory incubation had previously been undertaken, and thus no information was available on the requirements for successful captive incubation. I studied the effects of incubation regime on the eggs and hatchlings of O. suteri to four months of age. Oligosoma suteri eggs (n = 174) were randomly distributed among three constant incubation temperatures (18°C, 22°C and 26°C) and two water potentials (-120 kPa and -270 kPa). Hatching success and hatchling survival were greatest at 22°C and 26°C, with hatchlings from 18°C incubation suffering from physical abnormalities. Incubation regime and maternal influence did not affect sex of individuals, with equal sex ratios occurring from each incubation treatment. Hatchlings from the 22°C and -120 kPa incubation treatments were larger, for most measurements, and warmer incubation temperatures resulted in increased growth rates. Juveniles from 22°C and 26°C and individuals with greater mass per unit length (condition index) sprinted faster over 0.25 m. Sprint speed was positively correlated with ambient temperature. At four months of age sprint speed decreased in 18°C individuals and individuals incubated at 26°C and -270 kPa compared to their performance at one month. The results suggest that the most successful captive incubation regime for O. suteri is 22°C and -120 kPa. This study also shows that temperature-dependent sex determination does not occur in O. suteri, but that fitness traits are influenced by incubation temperature.</p>

An ultrastructural study of oogenesis, fertilization, and egg laying in a nemertean ectosymbiont of crabs, Carcinonemertes epialti (Nemertea, Hoplonemertea)

1986 ◽  
Vol 64 (6) ◽  
pp. 1256-1269 ◽  
Author(s):  
Stephen A. Stricker
Keyword(s):  
Ultrastructural Study ◽  
Gravid Female ◽  
Somatic Cells ◽  
Egg Laying ◽  
Egg Mass ◽  
Stages Of Development ◽  
Endocytotic Vesicles ◽  
Brachyuran Crabs ◽  
Germinal Cells ◽  
Sexually Mature

The nemertean worm Carcinonemertes epialti occurs ectosymbiotically on brachyuran crabs and becomes sexually mature while feeding on the eggs of its host. Gravid worms possess numerous saccular ovaries that lie among serially arranged diverticula of the intestine. The epithelium surrounding the lumen of each ovary contains germinal cells at various stages of development and somatic cells. Previtellogenic oocytes are typically situated in the subepidermal region of the ovarian epithelium, whereas vitellogenic oocytes tend to occur toward the intestine. The presence of numerous synthesizing organelles in vitellogenic oocytes indicates that at least some yolk constituents are produced within the ooplasm by an autosynthetic method. A supplemental form of heterosynthetic vitellogenesis may also occur, since somatic cells situated next to yolk-forming oocytes possess putative endocytotic vesicles that might help to transport yolk components derived from ingested crab eggs to the developing oocytes. Fully formed primary oocytes in the lumen of the ovary lack extracellular coats and typically measure 70–75 μm in diameter. Following fertilization, several egg strings that characteristically contain about 200 developing embryos are deposited by each gravid female in the egg mass of the crab.

scholarly journals Costs of Egg Punctures and Parasitism by Shiny Cowbirds (Molothrus Bonariensis) at Creamy-Bellied Thrush (Turdus Amaurochalinus) Nests

The Auk ◽  
2006 ◽  
Vol 123 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Andrea A. Astié ◽  
Juan C. Reboreda
Keyword(s):  
Reproductive Success ◽  
Hatching Success ◽  
Nest Survival ◽  
Egg Laying ◽  
Chick Survival ◽  
Egg Survival ◽  
Lower Survival Rate ◽  
Molothrus Bonariensis ◽  
Primary Determinant ◽  
The Cost

AbstractMost studies on cowbird parasitism have focused on its effects on parasitized nests, whereas few have considered the costs at nests that cowbirds visit but at which they do not lay eggs. Shiny Cowbirds (Molothrus bonariensis) peck and puncture host eggs both in nests where they lay eggs and in unparasitized nests. We analyzed the effect of egg punctures in unparasitized and parasitized nests of a large host, the Creamy-bellied Thrush (Turdus amaurochalinus; hereafter “thrush”), as well as the costs of Shiny Cowbird eggs and chicks in this host’s nests. We determined thrush egg survival, hatching success, and chick survival in successful nests, and nest survival during the egg and nestling stages. Frequency of parasitism was 60%, and its intensity 1.6 ± 0.1 eggs nest−1. Number of host eggs punctured was positively associated with intensity of parasitism. The host’s eggs were frequently punctured in parasitized nests (71%) and in unparasitized nests (42%). Egg punctures reduced the number of eggs at hatching in 23% and 49% of unparasitized and parasitized nests, respectively. Nests with egg punctures had a lower survival rate than nests without them, but nest survival was not associated with parasitism. Presence of a Shiny Cowbird egg was associated with a decrease in the hatching success of host eggs, but presence of a Shiny Cowbird chick did not have any detrimental effect on either the survival and growth rate of host chicks in successful nests or the survival of the whole nest. Our results show that egg punctures were the primary determinant of thrush reproductive success. Consequently, comparison of unparasitized and parasitized nests gives an incomplete estimation of the effects of Shiny Cowbirds on host reproductive success, because the cost of egg punctures is also important in nests where there is no Shiny Cowbird egg laying.Costos de la Perforación de Huevos y el Parasitismo por Molothrus bonariensis en Nidos de Turdus amaurochalinus

Laboratory hybridization in green lacewings (Neuroptera: Chrysopidae: Chrysoperla): evidence for genetic incompatibility

1993 ◽  
Vol 71 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Marta Martínez Wells
Keyword(s):  
Hatching Success ◽  
Biological Species ◽  
Egg Laying ◽  
Postzygotic Isolation ◽  
Separate Species ◽  
Genetic Incompatibility ◽  
Second Stage ◽  
Behavioral Isolation ◽  
Two Generations ◽  
Chrysoperla Plorabunda

Courtship songs are an important reproductive barrier in lacewings of the genus Chrysoperla, so heterotypic matings should occur less readily than homotypic matings. In addition, if song morphs have become separate species, there may be some postzygotic isolation between song morphs. Two generations of crosses using sympatric P1 and P3 morphs of Chrysoperla plorabunda provide evidence for both hypotheses. In the first stage of the experiment, egg laying (an indication of mating success) was delayed by a week in heterotypic crosses compared with homotypic crosses, and hatching success of eggs from hybrid crosses was 16% lower than that from control crosses. In the second stage of the experiment, backcrosses involving P3 morph males or females were the least successful in mating. When pairs did mate, they did so a week later than in the other crosses. Thus, behavioral isolation delays heterotypic matings when females are not given a choice of mates. These results provide some genetic evidence that the song morphs of the C. plorabunda complex are biological species.

scholarly journals Reproductive traits of the gray ratsnake Ptyas korros from three geographically distinct populations

2012 ◽  
Vol 58 (6) ◽  
pp. 820-827 ◽  
Author(s):  
Long-Hui Lin ◽  
Fei Mao ◽  
Ce Chen ◽  
Xiang Ji
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
Egg Laying ◽  
Laying Date ◽  
Egg Mass ◽  
Size Number ◽  
Female Reproductive Traits ◽  
Clutch Mass

Abstract We collected gravid gray rat snakes Ptyas korros from three geographically distinct populations in China, Chenzhou (CZ), Jiangshan (JS) and Dinghai (DH), to study geographical variation in female reproductive traits. Egg-laying dates differed among the three populations such that at the most northern latitude egg-laying was latest, and earliest at the most southern lati-tutde. Clutch size, clutch mass, egg mass, egg shape, within clutch variability in egg sizes and relative clutch mass differed among the three populations, whereas post-oviposition body mass did not. Except for egg-laying date, none of the traits examined varied in a geographically continuous trend. CZ and DH females, although separated by a distance of approximately 1100 km as the crow flies, were similar in nearly all traits examined. JS females were distinguished from CZ and DH females by their higher fecundity (clutch size), greater reproductive output (clutch mass) and more rounded eggs. Our data do not validate the prediction that larger offspring should be produced in colder localities. The absence of an egg size-number trade-off in each of the three populations presumably suggests that P. korros is among species where eggs are well optimized for size within a population.

The effects of ice cover over the colony site on reproductive activities of herring gulls

1985 ◽  
Vol 63 (3) ◽  
pp. 607-611 ◽  
Author(s):  
Ralph D. Morris ◽  
John W. Chardine
Keyword(s):  
Lake Erie ◽  
Hatching Success ◽  
Thick Layer ◽  
Egg Laying ◽  
Larus Argentatus ◽  
Herring Gull ◽  
Herring Gulls ◽  
The Mean ◽  
Colony Site ◽  
Reproductive Activities

The substrate at a herring gull (Larus argentatus) colony on Lake Erie near Port Colborne, Ontario (Lighthouse), was completely covered by a thick layer of ice throughout April and early May 1982. Egg laying normally begins at this location in mid-April. An adjacent herring gull colony (Canada Furnace) was ice free. Herring gull pairs at the Lighthouse colony defended territories on top of the ice but only 3 of about 90 pairs built nests on the ice. Birds neither deserted the colony nor moved within it to ice-free areas as these became available. The mean date of egg laying at the Lighthouse colony in 1982 was about 2 weeks later than in the previous year. At the adjacent Canada Furnace colony, there was no difference in the mean date of egg laying between the 2 years. There were no differences in the distribution of clutch sizes, mean clutch sizes, or hatching success of three-egg clutches laid within ± 1 SD of the mean date of egg laying at either colony in the 2 years. By these measures, the ice-induced delay in breeding chronology of birds at the Lighthouse colony in 1982 did not adversely effect reproductive performance in that year.

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