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Full-Text Articles in Life Sciences

Phenotypically Plastic Responses To Predation Risk Are Temperature Dependent, Thomas M. Luhring, Janna M. Vavra, Clayton E. Cressler, John Delong Oct 2019

Phenotypically Plastic Responses To Predation Risk Are Temperature Dependent, Thomas M. Luhring, Janna M. Vavra, Clayton E. Cressler, John Delong

School of Biological Sciences: Faculty Publications

Predicting how organisms respond to climate change requires that we understand the temperature dependence of fitness in relevant ecological contexts (e.g., with or without predation risk). Predation risk often induces changes to life history traits that are themselves temperature dependent. We explore how perceived predation risk and temperature interact to determine fitness (indicated by the intrinsic rate of increase, r) through changes to its underlying components (net reproductive rate, generation time, and survival) in Daphnia magna. We exposed Daphnia to predation cues from dragonfly naiads early, late, or throughout their ontogeny. Predation risk increased r differentially across temperatures …


Status Of The Plains Harvest Mouse (Reithrodontomys Montanus Griseus) In Eastern Nebraska, Keith Geluso, Greg D. Wright Mar 2019

Status Of The Plains Harvest Mouse (Reithrodontomys Montanus Griseus) In Eastern Nebraska, Keith Geluso, Greg D. Wright

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

In eastern Nebraska, current status of the Plains Harvest Mouse (Reithrodontomys montanus griseus) is not well understood. Infrequent captures during the last century have led to a paucity of information regarding this taxon, and some researchers postulate that its distribution has contracted in the state. In 2008, we conducted a field survey for R. m. griseus in eastern Nebraska, amassed prior specimen records, and examined most of the specimens for this subspecies from the state to better understand its distribution, natural history, and subspecific status. In our field efforts, we only captured a single individual despite …


Biotic Potential And Reproductive Parameters Of Spodoptera Frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), Debora G. Montezano, Alexandre Specht, Embrapa Soja, Daniel R. Sosa-Gomez, Vania F. Roque-Specht, Juaci V. Malaquias, Silvana V. Paula-Moraes, Julie A. Peterson, Thomas E. Hunt Jan 2019

Biotic Potential And Reproductive Parameters Of Spodoptera Frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), Debora G. Montezano, Alexandre Specht, Embrapa Soja, Daniel R. Sosa-Gomez, Vania F. Roque-Specht, Juaci V. Malaquias, Silvana V. Paula-Moraes, Julie A. Peterson, Thomas E. Hunt

Department of Entomology: Faculty Publications

The fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), a native to the Americas and recently reported in Africa, Germany, the Netherlands and India, is a significant pest of many crop species. Although a widespread and important pest, information on its biology and development are incomplete and require detailed study. In this study, the biotic potential and reproductive parameters of S. frugiperda were evaluated under controlled conditions (25±1 °C, 70±10% RH and 14 hour photophase). The longevity, pre-, postand oviposition periods, fecundity, and fertility of 30 pairs were evaluated. The longevity of females (10.87 days) was not significantly …


Temperature Dependent Development Of Sugarcane Aphids Melanaphis Sacchari, (Hemiptera: Aphididae) On Three Different Host Plants With Estimates Of The Lower And Upper Threshold For Fecundity, Michael A. De Souza, J. Scott Armstrong, W. Wyatt Hoback, Phillip G. Mulder, Sulochana Paudyal, John E. Foster, Mark E. Payton, Josephine Akosa Jan 2019

Temperature Dependent Development Of Sugarcane Aphids Melanaphis Sacchari, (Hemiptera: Aphididae) On Three Different Host Plants With Estimates Of The Lower And Upper Threshold For Fecundity, Michael A. De Souza, J. Scott Armstrong, W. Wyatt Hoback, Phillip G. Mulder, Sulochana Paudyal, John E. Foster, Mark E. Payton, Josephine Akosa

Department of Entomology: Faculty Publications

The sugarcane aphid, Melanaphis sacchari (Zehntner) is a serious economic threat to grain sorghum across the U.S. sorghum belt. It can develop on multiple grass hosts but only appears to survive winter temperatures in Texas near the Mexican border, Florida and Louisiana. Because survival and reproduction of aphids is dependent on access to appropriate nutrition and temperatures at which metabolic processes are maintained, we evaluated the growth, reproduction and survival of sugarcane aphids at constant temperatures (5°C,10°C,15°C,20°C,25°C,30°C,35°C) on three known hosts, sorghum, Johnsongrass, and Columbus grass. Longevity, fecundity, number of female nymphs/d, reproductive period in d, and intrinsic rate of …


The Impact Of Heat Load On Cattle, Angela M. Lees, Veerasamy Sejian, Andrea L. Wallage, Cameron C. Steel, Terry L. Mader, Jarrod C. Lees, John B. Gaughan Jan 2019

The Impact Of Heat Load On Cattle, Angela M. Lees, Veerasamy Sejian, Andrea L. Wallage, Cameron C. Steel, Terry L. Mader, Jarrod C. Lees, John B. Gaughan

Department of Animal Science: Faculty Publications

Heat stress and cold stress have a negative influence on cattle welfare and productivity. There have been some studies investigating the influence of cold stress on cattle, however the emphasis within this review is the influence of heat stress on cattle. The impact of hot weather on cattle is of increasing importance due to the changing global environment. Heat stress is a worldwide phenomenon that is associated with reduced animal productivity and welfare, particularly during the summer months. Animal responses to their thermal environment are extremely varied, however, it is clear that the thermal environment influences the health, productivity, and …


Developmental And Reproductive Characteristics Of Beef Heifers Classified By Number Of Estrous Cycles Experienced By Start Of First Breeding, Andy Roberts, Jaclyn N. Ketchum, Richard N. Funston Jan 2019

Developmental And Reproductive Characteristics Of Beef Heifers Classified By Number Of Estrous Cycles Experienced By Start Of First Breeding, Andy Roberts, Jaclyn N. Ketchum, Richard N. Funston

West Central Research and Extension Center, North Platte

A retrospective analysis was conducted to evaluate the effect of number of estrous cycles exhibited before breeding on growth and reproductive performance of replacement beef heifers fed ad-libitum or restricted by 20% less than ad-libitum during postweaning development over a 9-yr period. Progesterone concentration in blood samples collected at 9- to 11-d intervals were used to assign heifers into groups by number of estrous cycles exhibited before the start of breeding: 0 (nonpubertal; n = 395), 1 (n = 205), 2 (n = 211), 3 (n = 116), or >3 (n = 249). Heifers (P …