scholarly journals Parental Photoperiod Affects Egg Diapause in a Montane Population of Mormon Crickets (Orthoptera: Tettigoniidae)

2020 ◽  
Vol 49 (4) ◽  
pp. 895-901 ◽  
Author(s):  
Robert B Srygley
Keyword(s):  
Life Cycles ◽  
Hedging Strategy ◽  
Egg Diapause ◽  
Fitness Measures ◽  
Unpredictable Environment ◽  
Prolonged Diapause ◽  
Anabrus Simplex ◽  
Adult Mass ◽  
Humidity Profiles ◽  
Bighorn Mountains

Abstract Insect diapause is a state of arrested development persisting when conditions are favorable for growth. Prolonged diapause, which occurs when insects remain in diapause for multiple years, is uncommon. Mormon crickets Anabrus simplex Haldane, a katydid and pest of rangeland forage and crops, were thought to be biennial in the Bighorn Mountains of Wyoming, but they are able to prolong diapause in the egg stage for multiple years. To test whether parental photoperiod serves as a cue to prolong diapause, mating pairs from the Bighorn Mountains were set in the same daily temperature and humidity profiles with 20 pairs on short daylength (12:12 [L:D] h) and 20 on long daylength (15:9 [L:D] h). Almost every parental pair had some undeveloped eggs after two warm periods. Females in short daylength were not more likely to have eggs with a biennial life cycle, but they were more likely than those in long daylength to lay eggs with multi-annual life cycles. Parents on short daylength were more likely to lay inviable eggs. Other fitness measures, such as hatchling mass, nymphal survivorship, and adult mass were not different between parental treatments. Diapause termination distributed over multiple years probably constitutes a bet-hedging strategy in an unpredictable environment.

scholarly journals “Indirect development” increases reproductive plasticity and contributes to the success of scyphozoan jellyfish in the oceans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Isabella D’Ambra ◽  
Louise Merquiol ◽  
William M. Graham ◽  
John H. Costello
Keyword(s):  
Reproductive Mode ◽  
Life Cycles ◽  
Direct Development ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Indirect Development ◽  
Polyp Stage ◽  
Evolutionary Success ◽  
Reproductive Plasticity ◽  
Scyphozoan Jellyfish

AbstractEcologists and evolutionary biologists have been looking for the key(s) to the success of scyphomedusae through their long evolutionary history in multiple habitats. Their ability to generate young medusae (ephyrae) via two distinct reproductive strategies, strobilation or direct development from planula into ephyra without a polyp stage, has been a potential explanation. In addition to these reproductive modes, here we provide evidence of a third ephyral production which has been rarely observed and often confused with direct development from planula into ephyra. Planulae of Aurelia relicta Scorrano et al. 2017 and Cotylorhiza tuberculata (Macri 1778) settled and formed fully-grown polyps which transformed into ephyrae within several days. In distinction to monodisk strobilation, the basal polyp of indirect development was merely a non-tentaculate stalk that dissolved shortly after detachment of the ephyra. We provide a fully detailed description of this variant that increases reproductive plasticity within scyphozoan life cycles and is different than either true direct development or the monodisk strobilation. Our observations of this pattern in co-occurrence with mono- and polydisk strobilation in Aurelia spp. suggest that this reproductive mode may be crucial for the survival of some scyphozoan populations within the frame of a bet-hedging strategy and contribute to their long evolutionary success throughout the varied conditions of past and future oceans.

scholarly journals Comparing fitness measures and the influence of age of first reproduction in Columbian ground squirrels

2020 ◽  
Vol 101 (5) ◽  
pp. 1302-1312
Author(s):  
Kristin K Rubach ◽  
F Stephen Dobson ◽  
Bertram Zinner ◽  
Jan O Murie ◽  
Vincent A Viblanc
Keyword(s):  
Reproductive Success ◽  
Population Growth ◽  
Life Cycles ◽  
Ground Squirrels ◽  
Relative Fitness ◽  
Age At First Reproduction ◽  
Individual Fitness ◽  
First Reproduction ◽  
Fitness Measures ◽  
Columbian Ground Squirrels

Abstract The timing of life-history traits may have strong influences on the evolution of life cycles and on population demography. This is especially true of the age at which females first reproduce (Cole’s principle). We examined whether the age at which females first reproduce influences fitness in Columbian ground squirrels (Urocitellus columbianus), for which females varied in the age at which they initially produce weaned offspring, from ages 1 through 5 years. With 148 females with complete known life spans in a 28-year data set, we examined four fitness measures: individual fitness (λ ind), individual fitness relative to the pattern of growth of the population (λ rel), lifetime reproductive success (LRS), and LRS relative to the total LRS for each female’s cohort (LRSrel). These metrics were calculated for offspring produced at the time of weaning and offspring that survived to emerge after their first hibernation period. Individual fitness (λ ind) was significantly associated with population growth during a female’s lifetime (λ Leslie; R2 = 0.523, P < 0.0001), indicating the need to adjust individual fitness for demonstrated changes in population growth and thus producing a relative individual fitness index (λ rel). We regressed λ rel on age at first reproduction, and found significant selection favoring earlier reproductive success (β ± SE = −0.20 ± 0.06; R2 = 0.306, P < 0.0001). When using an earlier (offspring at weaning) versus later (those that survived their first hibernation) measure of fecundity, we found that the latter introduced considerable variation, likely environmental, into the estimate of selection. This greatly weakened the regression of relative fitness on the age at first successful reproduction. LRS and LRSrel exhibited nonsignificant changes with age at first reproduction. Finally, those females that reproduced successfully at younger ages had similar litter sizes but significantly shorter life spans than females that matured when older, perhaps reflecting costs to early reproduction.

scholarly journals Ecology ofPeltoperla arcuataandTallaperla maria(Plecoptera: Peltoperlidae) at the Fernow Experimental Forest, Tucker County, West Virginia

1995 ◽  
Vol 102 (3-4) ◽  
pp. 151-168 ◽  
Author(s):  
Kevin A. Yokum ◽  
Ted R. Angradi ◽  
Donald C. Tarter
Keyword(s):  
Life History ◽  
West Virginia ◽  
Life Cycles ◽  
Base Flow ◽  
Order Stream ◽  
Egg Diapause ◽  
Specific Distribution ◽  
Stream Size ◽  
Species Specific ◽  
Fernow Experimental Forest

We examined the abundance, life history, and production of the stonefliesPeltoperla arcuataandTallaperla maria(Plecoptera: Peltoperlidae) in four forested headwater streams at the Fernow Experimental Forest, Tucker County, West Virginia.Peltoperla arcuatawas most abundant in the smallest watersheds (<100 ha), and was present at all sites.Tallaperla mariawas most abundant in watersheds >200 hectares (ha), was restricted to sites with a base-flow alkalinity of >2 mg L-1CaCO3, and was the dominant peltoperlid only at sites with an alkalinity >15 mg L-1. We conclude that water chemistry overrides stream size as a determinant of species-specific distribution of Fernow peltoperlids. Both taxa had semi-voltine life cycles with an 18-month naiadal period following a 6-month egg diapause. Emergence was during May-July for both species.Peltoperla arcuatahad about 15 instars;T. mariahad about 14 instars. Peltoperlid production was highest (509 mg m-2y-1) in a 128 ha watershed where onlyP. arcuatawas collected;P. arcuataproduction was lowest (17 mg m-2y-1) in a 4th order stream (1536 ha).Taltaperla mariaproduction was highest (271 m-2y-1) in a 257 ha watershed partially underlain by limestone. Production across streams was higher forP. arcuata(205 mg m-2y-1) than forT. maria(91 mg m-2y-1).

Fitness Trade-Offs and Environmentally Induced Mutation Buffering in Isogenic C. elegans

Science ◽  
2011 ◽  
Vol 335 (6064) ◽  
pp. 82-85 ◽  
Author(s):  
M. Olivia Casanueva ◽  
Alejandro Burga ◽  
Ben Lehner
Keyword(s):  
Stress Resistance ◽  
Reproductive Fitness ◽  
Stress Signaling ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Induced Mutation ◽  
C Elegans ◽  
Trade Offs ◽  
Environmental Responses ◽  
Unpredictable Environment

Mutations often have consequences that vary across individuals. Here, we show that the stimulation of a stress response can reduce mutation penetrance in Caenorhabditis elegans. Moreover, this induced mutation buffering varies across isogenic individuals because of interindividual differences in stress signaling. This variation has important consequences in wild-type animals, producing some individuals with higher stress resistance but lower reproductive fitness and other individuals with lower stress resistance and higher reproductive fitness. This may be beneficial in an unpredictable environment, acting as a “bet-hedging” strategy to diversify risk. These results illustrate how transient environmental stimuli can induce protection against mutations, how environmental responses can underlie variable mutation buffering, and how a fitness trade-off may make variation in stress signaling advantageous.

scholarly journals Staying in touch: how highly specialised moth pollinators track host plant phenology in unpredictable climates

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jonathan T. D. Finch ◽  
Sally A. Power ◽  
Justin A. Welbergen ◽  
James M. Cook
Keyword(s):  
Host Plant ◽  
Plant Phenology ◽  
Hedging Strategy ◽  
Egg Diapause ◽  
Nursery Pollination ◽  
Pupal Diapause ◽  
Early Instar ◽  
Female Host ◽  
Male Flowers ◽  
Female Flowers

Abstract Background For specialised pollinators, the synchrony of plant and pollinator life history is critical to the persistence of pollinator populations. This is even more critical in nursery pollination, where pollinators are obligately dependant on female host plant flowers for oviposition sites. Epicephala moths (Gracillariidae) form highly specialised nursery pollination mutualisms with Phyllanthaceae plants. Several hundred Phyllanthaceae are estimated to be exclusively pollinated by highly specific Epicephala moths, making these mutualisms an outstanding example of plant–insect coevolution. However, there have been no studies of how Epicephala moths synchronise their activity with host plant flowering or persist through periods when flowers are absent. Such knowledge is critical to understanding the ecology and evolutionary stability of these mutualisms. We surveyed multiple populations of both Breynia oblongifolia (Phyllanthaceae) and it’s Epicephala pollinators for over two years to determine their phenology and modelled the environmental factors that underpin their interactions. Results The abundance of flowers and fruits was highly variable and strongly linked to local rainfall and photoperiod. Unlike male flowers and fruits, female flowers were present throughout the entire year, including winter. Fruit abundance was a significant predictor of adult Epicephala activity, suggesting that eggs or early instar larvae diapause within dormant female flowers and emerge as fruits mature. Searches of overwintering female flowers confirmed that many contained pollen and diapausing pollinators. We also observed diapause in Epicephala prior to pupation, finding that 12% (9/78) of larvae emerging from fruits in the autumn entered an extended diapause for 38–48 weeks. The remaining autumn emerging larvae pupated directly without diapause, suggesting a possible bet-hedging strategy. Conclusions Epicephala appear to use diapause at multiple stages in their lifecycle to survive variable host plant phenology. Furthermore, moth abundance was predicted by the same environmental variables as male flowers, suggesting that moths track flowering through temperature. These adaptations may thereby mitigate against unpredictability in the timing of fruiting and flowering because of variable rainfall. It remains to be seen how widespread egg diapause and pre-pupal diapause may be within Epicephala moths, and, furthermore, to what degree these traits may have facilitated the evolution of these highly diverse mutualisms.

THE CONCEPT OF AUTONOMOUS SYSTEMS IN INDUSTRY 4.0

2019 ◽  
Vol 12 (1) ◽  
pp. 77-87
Author(s):  
György Kovács ◽  
Rabab Benotsmane ◽  
László Dudás
Keyword(s):  
Industry 4.0 ◽  
Intelligent Systems ◽  
Autonomous Systems ◽  
Essential Element ◽  
Industrial Sector ◽  
Life Cycles ◽  
Multi Agent Systems ◽  
New Paradigm ◽  
Intelligent Machines ◽  
Digital Network

Recent tendencies – such as the life-cycles of products are shorter while consumers require more complex and more unique final products – poses many challenges to the production. The industrial sector is going through a paradigm shift. The traditional centrally controlled production processes will be replaced by decentralized control, which is built on the self-regulating ability of intelligent machines, products and workpieces that communicate with each other continuously. This new paradigm known as Industry 4.0. This conception is the introduction of digital network-linked intelligent systems, in which machines and products will communicate to one another in order to establish smart factories in which self-regulating production will be established. In this article, at first the essence, main goals and basic elements of Industry 4.0 conception is described. After it the autonomous systems are introduced which are based on multi agent systems. These systems include the collaborating robots via artificial intelligence which is an essential element of Industry 4.0.

Strategi Pengelolaan Risiko dan Peningkatan Kualitas Pengelolaan Kas Negara

2017 ◽  
Vol 2 (2) ◽  
pp. 43-54
Author(s):  
Agung Mulyono
Keyword(s):  
Interest Rates ◽  
Financial Risk ◽  
Vector Autoregression ◽  
Secondary Market ◽  
Key Factors ◽  
Bond Price ◽  
Hedging Strategy ◽  
Foreign Loan ◽  
Term Operation ◽  
Loan Interest Rates

Cash management is  one of treasury’s main functions in which has a potential financial risk. A potential financial risk emerges when State Treasurer manages cash surplus and or/ shortages in order to maintain optimum liquidity. By applying Vector Autoregression (VAR) system on empirical data provided by Bank Indonesia and the Ministry of Finance of Indonesia, we found that currency value  flunctuation is a significant factor for repayment value of foreign loan. Interest rates and amount of government’s bond held by foreign investors are also variables impacted on government’s bond price movement in secondary market. Currency value  flunctuation and price of government’s bond in secondary market are the key factors that have to be considered by State Treasurer (BUN) in managing state’s money. Hedging strategy by using derivatif product is possible to be utilized by State Treasurer (BUN) due to it’s flexibility for short-term operation.   Abstrak Pengelolaan kas negara merupakan salah satu fungsi pokok perbendaharaan yang dalam proses pelaksanaannya menyimpan potensi berbagai risiko keuangan. Risiko keuangan, khususnya dalam investasi berpotensi muncul ketika Bendahara Umum Negara (BUN) melakukan kegiatan pengelolaan kelebihan dan/ kekurangan kas dalam rangka menjamin ketersediaan dan optimalisasi kas. Dengan menggunakan analisis Vector Autoregression (VAR) atas data empiris yang diperoleh dari Bank Indonesia dan Kementerian Keuangan Indonesia, penulis menemukan bahwa fluktuasi nilai tukar mata uang merupakan faktor yang signifikan terhadap besaran pembayaran utang luar negeri pemerintah. Tingkat suku bunga acuan dan pergerakan besaran kepemilikan SUN oleh investor asing juga merupakan variabel yang berpengaruh terhadap pergerakan harga SUN di pasar sekunder. Fluktuasi nilai tukar mata uang dan pergerakan harga SUN di pasar sekunder menjadi faktor penting dalam pelaksanaan investasi yang dilakukan BUN dalam rangka pengelolaan kelebihan dan/ kekurangan kas. Berdasarkan hasil tersebut, strategi pengelolaan risiko atau hedging dengan menggunakan produk-produk derivatif dalam pengelolaan kelebihan dan/ kekurangan kas jangka pendek – menengah sangat dimungkinkan karena sifat instrumen derivatif yang fleksibel.

Multiple-source Record Linkage in a Rural Industrial Community, 1680–1820

1994 ◽  
Vol 6 (3) ◽  
pp. 133-142 ◽  
Author(s):  
Steve King
Keyword(s):  
Early Modern ◽  
Large Scale ◽  
Social Economic ◽  
Life Cycles ◽  
Multiple Source ◽  
Demographic Analysis ◽  
Ordinary People ◽  
Industrial Community ◽  
The Social ◽  
Broad Outline

Re-creating the social, economic and demographic life-cycles of ordinary people is one way in which historians might engage with the complex continuities and changes which underlay the development of early modern communities. Little, however, has been written on the ways in which historians might deploy computers, rather than card indexes, to the task of identifying such life cycles from the jumble of the sources generated by local and national administration. This article suggests that multiple-source linkage is central to historical and demographic analysis, and reviews, in broad outline, some of the procedures adopted in a study which aims at large scale life cycle reconstruction.

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