The effect of multiple mating on female reproductive success in the simultaneously hermaphroditic land snail Arianta arbustorum

1993 ◽  
Vol 71 (12) ◽  
pp. 2431-2436 ◽  
Author(s):  
Xiaofeng Chen ◽  
Bruno Baur
Keyword(s):  
Reproductive Success ◽  
Hatching Success ◽  
Multiple Mating ◽  
Reproductive Traits ◽  
Land Snail ◽  
First Year ◽  
Female Reproductive Success ◽  
Female Function ◽  
Arianta Arbustorum ◽  
Second Year

The simultaneously hermaphroditic land snail Arianta arbustorum mates several times in the course of a reproductive season. Repeated matings might be adaptive for the male function of A. arbustorum to inseminate several "females." We designed an experiment to evaluate the effects of repeated mating on the female reproductive success of this hermaphrodite. Reproductive traits and survival were examined over 2 years in individuals that copulated several times per year (snails were kept in pairs), in individuals that copulated twice (once at the beginning of each year) or once (at the beginning of the first year only), and in individuals prevented from copulating (they were kept isolated). Copulations were not always reciprocally successful: 3 of 57 snails (5.3%) failed to produce fertile eggs, although their mates reproduced successfully. Similarly, 2 of 15 pairs (13.3%) failed to reproduce successfully. Snails allowed to mate repeatedly within each season tended to lay more eggs than snails that mated once per year. However, the numbers of hatchlings did not differ significantly between the two treatment groups, because eggs laid by snails allowed to mate repeatedly had a lower hatching success. Snails that remated in the second year laid more eggs that had higher hatching success, and thus produced more hatchlings than snails that mated once at the beginning of the first year only. Snails that were prevented from mating produced a few hatchlings (by self-fertilization) in the second year; their reproductive success was less than 1% of that of mated snails. Our results suggest that multiple mating is also adaptive for the female function of A. arbustorum by increasing female fecundity and fertility and serving as a hedge against unsuccessful copulations.

scholarly journals Space use and its effects on reproductive success of anadromous Atlantic salmon

2016 ◽  
Vol 73 (10) ◽  
pp. 1461-1471 ◽  
Author(s):  
Cédric Tentelier ◽  
Nicolas Larranaga ◽  
Olivier Lepais ◽  
Aurélie Manicki ◽  
Jacques Rives ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Atlantic Salmon ◽  
Home Range ◽  
Space Use ◽  
Parentage Analysis ◽  
First Year ◽  
Radio Tracking ◽  
Female Reproductive Success ◽  
Second Year ◽  
Individual Features

We combined habitat mapping, radio tracking of adults, redd mapping, and genetic parentage analysis on juveniles for 2 consecutive years to test eight predictions on the reproductive payoffs and individual features associated with space use tactics of anadromous Atlantic salmon (Salmo salar) in a natural population. Regarding payoffs, we found that (1) males settled in better habitat, visited more redds, and tended to get more mates than males settled in poorer habitat; (2) they also sired more offspring; (3) the latter effect was stronger in the first year, when redds were more aggregated; and (4) female reproductive success increased with habitat quality in their home range, especially in the first year. For individual features, (5) individuals that settled earlier in their home range had better habitat for juvenile production, but only in the first year; (6) females were less mobile than males, especially in the second year; (7) larger males did not settle in better habitats than smaller males; and (8) smaller males were not more mobile than larger males.

scholarly journals Lifetime reproductive success of Greylag Geese Anser anser breeding in south Sweden

Ornis Svecica ◽  
2018 ◽  
Vol 28 (1) ◽  
Author(s):  
Leif Nilsson ◽  
Hakon Kampe-Persson
Keyword(s):  
Reproductive Success ◽  
Life Time ◽  
Breeding Population ◽  
Lifetime Reproductive Success ◽  
First Year ◽  
Anser Anser ◽  
South West ◽  
South Sweden ◽  
Second Year ◽  
Greylag Geese

During 1984–2009, 664 adults and 1,944 goslings of Greylag Geese Anser anser were neck-banded in south-west Scania, Sweden. After hatching the area was carefully searched for marked geese, giving more than 100,000 re-sightings. Of those marked as goslings 71% survived the first year, 52% the second year, and the oldest bird recorded was 25 years. About 50% of the survivors were recruited into the breeding population when two to three years old. Of 1,187 geese that survived for at least two years, 25% produced at least one brood of small young, and 18% at least one fledged young. The maximum life-time number of broods with fledged young was nine, but 50% of the geese known to have bred successfully produced only one brood of fledged young. Ten percent of the geese seen with small goslings produced 47% of all fledged young. The maximum number of fledged young for a goose of known age was 32 (age 15 years), but two geese marked as adults and followed for 16 and 17 years produced 40 fledglings each.

scholarly journals Polyandrous females benefit by producing sons that achieve high reproductive success in a competitive environment

2011 ◽  
Vol 278 (1719) ◽  
pp. 2823-2831 ◽  
Author(s):  
Renée C. Firman
Keyword(s):  
Reproductive Success ◽  
Sperm Competition ◽  
Multiple Mating ◽  
Female Mate Choice ◽  
Good Genes ◽  
House Mice ◽  
Embryo Viability ◽  
Female Reproductive Success ◽  
Selection History ◽  
Free Ranging

Females of many taxa often copulate with multiple males and incite sperm competition. On the premise that males of high genetic quality are more successful in sperm competition, it has been suggested that females may benefit from polyandry by accruing ‘good genes’ for their offspring. Laboratory studies have shown that multiple mating can increase female fitness through enhanced embryo viability, and have exposed how polyandry influences the evolution of the ejaculate. However, such studies often do not allow for both female mate choice and male–male competition to operate simultaneously. Here, I took house mice (Mus domesticus ) from selection lines that had been evolving with (polygamous) and without (monogamous) sperm competition for 16 generations and, by placing them in free-ranging enclosures for 11 weeks, forced them to compete for access to resources and mates. Parentage analyses revealed that female reproductive success was not influenced by selection history, but there was a significant paternity bias towards males from the polygamous selection lines. Therefore, I show that female house mice benefit from polyandry by producing sons that achieve increased fitness in a semi-natural environment.

scholarly journals Development and reproduction in Bulimulus tenuissimus (Mollusca: Bulimulidae) in laboratory

2008 ◽  
Vol 25 (2) ◽  
pp. 220-223 ◽  
Author(s):  
Lidiane C. Silva ◽  
Liliane M. O. Meireles ◽  
Flávia O. Junqueira ◽  
Elisabeth C. A. Bessa
Keyword(s):  
Reproductive Success ◽  
Incubation Period ◽  
Laboratory Study ◽  
Hatching Success ◽  
Land Snail ◽  
Reproductive Period ◽  
Egg Laying ◽  
Reproductive Patterns ◽  
Self Fertilization ◽  
Hatch Success

Bulimulus tenuissimus (d'Orbigny, 1835) is a land snail of parasitological importance with a poorly understood biology. The goal of this laboratory study was to determine development and reproductive patterns in B. tenuissimus. Recently hatched individuals in seven groups of 10 were maintained in the laboratory for two years. To test for self-fertilization, 73 additional individuals were isolated. After 180 days the isolated snails showed no signs of reproduction. Subsequently, 30 of these snails were paired to test fertility. We noted the date and time of egg-laying, the number of eggs produced, the number of egg-layings per individual, the incubation period and hatch success. This species shows indeterminate growth. Individuals that were maintained with others, as compared to isolated individuals, laid eggs sooner, laid more eggs and had a greater hatching success. This species can self-fertilize, however, with lower reproductive success. Bulimulus tenuissimus has a well-defined reproductive period that is apparently characteristic for this species.

An inevitable crisis? From first to second year in counsellor training

2020 ◽  
Vol 5 (1) ◽  
pp. 74-89
Author(s):  
Hugh Crago
Keyword(s):  
Right Hemisphere ◽  
Training Programme ◽  
First Year ◽  
Training Experience ◽  
Counsellor Training ◽  
Student Dropout ◽  
Second Year ◽  
Neurological Research ◽  
First Year Of Life ◽  
And Control

In a seminal 1973 paper, Robert Clark described the very different “cultures” of the first and second year students in a four year clinical psychology PhD programme. The author applies Clark’s template to his own experiences as trainee or trainer in five different counsellor education programmes, one in the US and four in Australia. Each of the programmes, to varying degrees, demonstrates key features of the pattern identified by Clark, where the first year is “therapeutic” and other-oriented, the second is “professional” and self-focused. The author concludes that all the surveyed programmes exhibited some level of “second year crisis”, in which a significant number of students felt abandoned, dissatisfied, or rebellious. The author extends and refines Clark’s developmental analogy (first year = childhood; second year = adolescence) to reflect recent neurological research, in particular, the shift from a right hemisphere-dominant first year of life, prioritising affiliative needs, to a left hemisphere-dominant second year, prioritising autonomy and control. This shift is paralleled later by a more gradual move from a protective, supportive childhood to necessary, but sometimes conflictual, individuation in adolescence. The first two years of a counsellor training programme broadly echo this process, a process exacerbated by the second year internship/placement, in which students must “leave home” and adjust to unfamiliar, potentially less nurturing, authority figures. Finally, the author suggests introducing more rigorous “academic holding” into the first year, and greater attention to “therapeutic holding” of dissident students in the second, hopefully decreasing student dropout, and achieving a better balanced training experience.

Implementation of the Second-year course in an Engineering Professional Spine

2018 ◽  
Author(s):  
Umar Iqbal ◽  
Deena Salem ◽  
David Strong
Keyword(s):  
Learning Outcomes ◽  
Research University ◽  
Engineering Students ◽  
Employability Skills ◽  
First Year ◽  
Computer Engineering ◽  
Core Courses ◽  
Second Year ◽  
First Time ◽  
Academic Year

The objective of this paper is to document the experience of developing and implementing a second-year course in an engineering professional spine that was developed in a first-tier research university and relies on project-based core courses. The main objective of this spine is to develop the students’ cognitive and employability skills that will allow them to stand out from the crowd of other engineering graduates.The spine was developed and delivered for the first time in the academic year 2010-2011 for first-year general engineering students. In the year 2011-2012, those students joined different programs, and accordingly the second-year course was tailored to align with the different programs’ learning outcomes. This paper discusses the development and implementation of the course in the Electrical and Computer Engineering (ECE) department.

Exploring the Implementation of Early Math Assessments in Kindergarten Classrooms: A Research-Practice Collaboration

2020 ◽  
Author(s):  
Jennifer McDonald ◽  
Rebecca Merkley ◽  
Jacqueline Mickle ◽  
Lisa Collimore ◽  
Daniel Ansari
Keyword(s):  
Mathematical Thinking ◽  
Math Education ◽  
Kindergarten Students ◽  
First Year ◽  
Research Practice ◽  
Early Numeracy ◽  
Future Directions ◽  
Collaborative Project ◽  
Practice Gap ◽  
Second Year

Research in cognitive development has highlighted that early numeracy skills are associated with later math achievement, suggesting that these skills should be targeted in early math education. Here we tested whether tools used by researchers to assess mathematical thinking could be useful in the classroom. This paper describes a collaborative project between cognitive scientists and school board researchers/educators implementing numeracy screeners with kindergarten students over the course of three school years. The Give-A-Number task (Wynn, 1990) was used with first-year kindergarten students and the Numeracy Screener [BLINDED] with second-year kindergarten students. Results indicated that educators (N = 59) found the tools feasible to implement and helpful for exploring their students’ thinking and targeting instruction. The Educators’ feedback also helped inform improvements to the implementation of the tools and future directions for both the schools and the researchers. This work emphasizes the importance of transdisciplinary collaboration to address the research-practice gap.

Influence of abiotic factors and hosts on seasonal dynamic of green lacewing, Chrysoperla carnea (Stephens)

2016 ◽  
Vol 3 (3) ◽  
Author(s):  
ARVIND KUMAR ◽  
POOJA KHULBE
Keyword(s):  
Abiotic Factors ◽  
Host Population ◽  
Maximum Temperature ◽  
First Year ◽  
Green Lacewing ◽  
Larval Population ◽  
Correlation Studies ◽  
Helianthus Annus ◽  
Sunflower Crop ◽  
Second Year

Influence of abiotic factors and hosts on population dynamics of green lacewing, Chrysoper lacarnea (Stephens) was studied in sunflower, Helianthus annus (Linn.).The maximum number of C. carnea population was found during mid March –mid April in the first year and mid April – mid May in the second year in sunflower crop. The maximum number of host population viz. egg and larva of Helicoverpa armigera and Myzuspe rsicae population were found during mid March –mid April in both the year and correlation studies revealed the positive and significant correlation between larval population of H. armigera, M. persicae and predator C. carnea. While there was no significant relationship found between eggs of H. armigera and C. carnea. The C. carnea population on H. annus during both the year was positively correlated with maximum temperature and found significant,while negatively correlated with relative humidity.However, no significant correlation of C. carnea was found with minimum temperature in both the year.

Effects of Cutting First Year Red Clover on Stand and Yield in the Second Year 1

1955 ◽  
Vol 47 (5) ◽  
pp. 224-228 ◽  
Author(s):  
James H. Torrie ◽  
Earle W. Hanson
Keyword(s):  
Red Clover ◽  
First Year ◽  
Second Year
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