Life Sciences Commons^™

Antipredator Behavior And Physiology Determine Lestes Species Turnover Along The Pond-Permanence Gradient, Robby Stoks, Mark A. Mcpeek

Dartmouth Scholarship

Identifying key traits that shape trade-offs that restrict species to only a subset of environmental gradients is crucial to understanding and predicting species turnover. Previous field experiments have shown that larvae of Lestes damselfly species segregate along the entire gradient of pond permanence and predator presence and that differential predation risk and life history constraints together shape their distribution. Here, we report laboratory experiments that identify key differences in behavior and physiology among species that structure their distributions along this gradient. The absence of adaptive antipredator behavioral responses against large dragonfly larvae and fish of Lestes dryas, the only species …

G03-1523 Low Toxic Cockroach Control, Barbara P. Ogg, Clyde L. Ogg

University of Nebraska-Lincoln Extension: Historical Materials

This NebGuide describes how to identify common cockroach species, what they need to survive, and effective, low-toxic alternatives to traditional chemical control options.

Some people see a cockroach and immediately grab a can of bug spray, but a quick spray from an aerosol can won't provide long-term control. Ingredients in most aerosol and "bomb" treatments repel cockroaches. Using these products can cause the cockroaches to hide deeper inside walls and be more difficult to control later. To make the most of your efforts to control cockroaches, use a multiple tactic approach. First, you need to understand a little about the …

Multistate Estimates Of Survival And Movement In Relation To Colony Size In The Sociable Weaver, Charles R. Brown, Rita Covas, Mark D. Anderson, Mary Bomberger Brown

School of Biological Sciences: Faculty Publications

We estimated survival and movement probabilities in relation to breeding-colony size in the sociable weaver (Philetairus socius) by using multistate statistical methods, in which survival and movement to time t + 1 is conditional on an individual’s colony size at time t. The sociable weaver is a colonial, cooperatively breeding species that builds a massive communal nest, with colony size ranging from fewer than 20 to more than 500 individuals in some areas. We conducted an 8-year capture/mark/re-capture study of sociable weavers near Kimberley, South Africa. By comparing the fit of different multistate models to our data, we found evidence …

Properties Of The Residuals From Two Tag-Recovery Models, Robert J. Latour, John M. Hoenig, Kenneth H. Pollock

VIMS Articles

No abstract provided.

Nf02-543 Ascochyta Blight Of Chickpeas, Robert M. Harveson

University of Nebraska-Lincoln Extension: Historical Materials

The chickpea (Cicer arietinum) ranks among the world's three most important pulse (legume) crops. It is an important source of protein in many parts of central Asia, Africa and the Mediterranean and among the food legumes, is the most effective in reducing blood ocholesterol levels. The crop is antive to western Asia and the Middle East, and is usually grown as a rainfed cool-weather crop or as a dry climate crop in semi-arid regions.

Although chickpeas are reported to be susceptible to over 50 pathogens, few diseases are currently recognized as significant economic constraints to production. Ascochyta blight …

Changes In Thermotolerance And Hsp70 Expression With Domestication In Drosophila Melanogaster, R. A. Krebs, S. (Stephen) P. Roberts, B. R. Bettencourt, M. E. Feder

Biological Sciences Faculty Research & Creative Works

To Examine How the Duration of Laboratory Domestication May Affect Drosophila Stocks Used in Studies of Thermotolerance, We Measured Expression of the Inducible Heat-Shock Protein Hsp70 and Survival after Heat Shock in D. Melanogaster Strains Recently Collected from Nature and Maintained in Laboratory Culture for Up to 50 or More Generations. after an Initial Increase in Both Hsp70 Expression and Thermotolerance Immediately after Transfer to Laboratory Medium, Both Traits Remained Fairly Constant over Time and Variation among Strains Persisted through Laboratory Domestication. Furthermore, Variation in Heat Tolerance and Hsp70 Expression Did Not Correlate with the Length of Time Populations Evolved …

The Effect Of Littermate Weight On Survival, Weight Gain, And Suckling Behavior Of Low-Birth-Weight Piglets In Cross-Fostered Litters, Barry N. Milligan, David Fraser, Donald L. Kramer

Ontogeny Collection

Objective: To determine whether low-birth-weight piglets show better survival, weight gain, and suckling behavior when grouped with other small piglets by cross-fostering.

Methods: We manipulated the number and size of foster littermates for low-birth-weight piglets in 31 small (eight or nine piglets) and 22 large (11 or 12 piglets) litters. Experimental litters were composed of four to six piglets of lowest birth weight and either four to six slightly heavier or four to six much heavier piglets from two combined litters.

Results: Low-birth-weight piglets raised with much heavier littermates had somewhat lower survival rates, but showed no tendency towards lower …

Restoration Of Aspen-Dominated Ecosystems In The Lake States, Douglas M. Stone, John D. Elioff, Donald V. Potter, Donald B. Peterson, Robert Wagner

Aspen Bibliography

A reserve tree method (RTM) of harvesting was installed in six 70 to 75 year old aspen dominated stands to determine if retaining 10 to 15 dominant aspen per acre would decrease sucker density to facilitate restoration of a conifer component. A reserve shelterwood cut was applied to three additional stands to evaluate performance of white pine planted under 50% crown cover. After the first full growing season following harvest, 96% of the RTM harvested areas were stocked; sucker density averaged 27000 per acre versus 38.2 k per acre on a clearcut control, 41% greater. Basal diameter of dominant suckers …

Permeabilization Of Cochliomyia Hominivorax (Diptera: Calliphoridae) Embryos, Dennis Berkebile, Jan Chirico, Roger A. Leopold

Department of Entomology: Faculty Publications

Embryos of the primary screwworm, Cochliomyia hominivorax (Coquerel), were successfully permeabilized for use in subsequent cryopreservation studies. Mortality was greater for eggs incubated for<5 h before treatment. The mean survival of embryos to first instars was 55.7, 61.1, and 62.6% when the embryos were incubated for 5, 5.5, and 6 h before treatment, respectively. The survival to the pupal and adult stages was low. An improved media for culturing the embryos during and immediately after treatment needs to be devised and the procedure for rearing the larval stages also needs to be altered to improve survival for emerging adults.

The Cost Of Limited Attention In Blue Jays, Reuven Dukas, Alan Kamil

Papers in Behavior in Biological Sciences

Experiments with fish and birds suggest that animals are unable to simultaneously allocate sufficient attention to tasks such as the detection of an approaching predator while searching for cryptic prey. We quantified the effects of limited attention on performance in controlled laboratory settings and report here the first direct evidence that attending to a difficult central task simulating foraging deters a bird’s ability to detect a peripheral target, which could be a predator. Our results fill a gap between ecological and neurobiological studies by illustrating that, although attention is an efficient filtering mechanism, limited attention may be a major cause …

Growth And Survival Of Colorado Squawfish In The Upper Colorado River, D. B. Osmundson, Ronald J. Ryel, T. E. Mourning

Wildland Resources Faculty Publications

Growth and adult survival rates were estimated for the endangered Colorado squawfish Ptychocheilus lucius inhabiting the upper Colorado River by using data from fish captured during 1990–1995. Mean annual growth rates of fish aged 3–6 years ranged from 32.2 (age 6) to 82.0 (age 3) mm/year. Growth rates for older fish were highest for fish 400–449 mm total length, TL, (42.7 mm/year) and declined to 19.8 mm/year for fish 500–549 mm TL. Fish 550 mm and longer grew an average 9.5 mm/year. Survival rates for fish 550 mm and longer were estimated by comparing measured size distributions with simulated stable …

Particle Size And Temperature Affect Fecal Bacteria Survival In Sediment, Mark S. Coyne, J. M. Howell, P. L. Cornelius

Agronomy Notes

When cattle have direct access to streams, fecal bacteria concentrations in stream sediments increase. If these bacteria persist, and if the sediments are resuspended, fecal bacteria may also appear in surrounding water for extended periods. Why do fecal bacteria persist, since dry conditions, high acidity or alkalinity, sunlight, competition from native microbes, and extreme temperatures all diminish their populations in soil? The effects of these environmental factors are much reduced in sediment. Water protects fecal bacteria from desiccation and ultraviolet light. High temperatures can promote their regrowth in wet environments. Fecal bacteria also survive on fine-sized sediments in streams because …

Environmental Effects On Neonatal Mortality Of Beef Calves, S. M. Azzam, J. E. Kinder, Merlyn K. Nielsen, L. A. Werth, K. E. Gregory, Larry V. Cundiff, R. M. Koch

Department of Animal Science: Faculty Publications

Calving records from 1969 to 1989 from the Roman L. Hruska U.S. Meat Animal Research Center were used to investigate how climatic conditions, in addition to dystocia, age of dam, size of calf, and sex affect calf survival from birth to 1 wk of age. Data were analyzed separately for cows calving with (n = 11,094) or without (n = 72,187) dystocia. Neonatal mortality was described by a logit model and parameters were estimated by maximum-likelihood procedures. Calves born to cows with dystocia were five times as likely to die neonatally than calves born without assistance. Of all calves that …

Temperature, Activity And Lizard Life Histories, Stephen C. Adolph, Warren P. Porter

All HMC Faculty Publications and Research

Lizard life-history characteristics vary widely among species and populations. Most authors seek adaptive or phylogenetic explanations for life-history patterns, which are usually presumed to reflect genetic differences. However, lizard life histories are often phenotypically plastic, varying in response to temperature, food availability, and other environmental factors. Despite the importance of temperature to lizard ecology and physiology, its effects on life histories have received relatively little attention. We present a theoretical model predicting the proximate consequences of the thermal environment for lizard life histories. Temperature, by affecting activity times, can cause variation in annual survival rate and fecundity, leading to a …

Estimates Of Genetic Parameters For Direct And Maternal Effects On Embryonic Survival In Swine, Luis T. Gama, Keith G. Boldman, Rodger K. Johnson

Department of Animal Science: Faculty Publications

Survival of 16,838 potential embryos was determined by counting corpora lutea and fetuses at 50 d of gestation for 1,081 litters by 225 sires. These data, coded as 1 or 0 depending on whether an ovulation was represented by a fetus, were used to estimate direct and maternal additive genetic variances and their covariance for embryonic survival. Data were from fist-parity gilts of a Large White-Landrace composite population subdivided into two lines, one selected for an index of ovulation rate and embryonic survival for seven generations and a contemporary control line. Variance components were obtained by ANOVA and expectations of …

Twinning In Cattle: 111. Effects Of Twinning On Dystocia, Reproductive Traits, Calf Survival, Calf Growth And Cow Productivity, K. E. Gregory, S. E. Echternkamp, G. E. Dickerson, Larry V. Cundiff, R. M. Koch, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

An evaluation of natural twinning in beef cattle revealed that cows birthing twins had shorter (P < .0l) gestation lengths, more (P < .0l) retained placentas, more (P < .01) dystocia, more (P < .0l) days to estrus, lower (P < .0l) conception rates and more (P < .01) days to pregnancy than cows birthing singles. Days to estrus, conception rate and days to pregnancy were not affected by number of calves reared (1 vs 2) in cows birthing twins. Survival at birth was greater (P < .0l) for single- than for twin-born calves, but twins and singles did not differ (P > .05) in postnatal survival. When dystocia was experienced, calf survival at birth was 95% vs 73% for singles vs twins compared with 99% vs 92% when no dystocia was experienced. Calves born twins were lighter (P < .01) at birth, 100 d and 200 d, but twins and singles did not differ in postweaning gains. Total calf weights at 100 d per cow calving were 12% greater (P < .01) in cows birthing twins vs singles when twin calves reared by foster dams were! excluded. The potential increase in cow productivity for total calf weight at 100 d is 40% if calf survival rates of twins with dystocia relative to survival rates of twins without dystocia were comparable to survival rates of singles with and without dystocia, and if cows birthing twins were fed and managed to obtain conception rates equal to those of cows birthing singles. Identification of cows gestating twins to provide for their higher prepartum nutritive requirements and calving assistance at parturition is necessary to make twinning in cattle an economically viable technology.

Influence Of Planting Depth And Interval To Initial Harvest On Yield And Plant Response Of Asparagus, Dale T. Lindgren

West Central Research and Extension Center, North Platte

Four planting depths and two time intervals ( l or 2 years) between transplanting and initial year of harvest of asparagus (Asparagus officinalis L.) yield were compared for 4 years. Spear emergence and initial spring harvest date were delayed and susceptibility to spring frost injury was decreased with increasing planting depth (from S.O to 20.0 cm). Over years, crown depth increased for the shallowest planting and decreased for the deepest planting. Harvesting after 1 year vs. 2 years from planting reduced yield. There were no significant interactions between year of initial harvest and depth of planting.

The Effects Of Seed Size, Shell Bags, Crab Traps, And Netting On The Survival Of The Northern Hard Clam Mercenaria Mercenaria (Linne), John N. Kraeuter, Michael Castagna

VIMS Articles

Seed size at planting is the dominant factor affecting hard clam survival to marketable size when field grow-out techniques are used. The use of plastic mesh nets, crab traps, and wire mesh bags (filled with oyster shells) alone or in combination can be used to increase survival of hard clams of ~ 6 to 8-mm shell height. These techniques do not provide sufficient protection for 2-mm seed. The combination of net + crab trap + shell bag was nearly twice as effective as the net alone when 10 to 14-mm seed was used and over five times as effective as …

Effects Of Chemical Weed Control And Seedling Planting Depth On Survival And Growth Of Aspen, G.L. Reighard, G. Howe, J.W. Hanover

Aspen Bibliography

No abstract provided.

Preweaning Survival In Swine: Heritability Of Direct And Maternal Effects, William R. Lamberson, R. K. Johnson

Department of Animal Science: Faculty Publications

The heritabilities of direct and maternal effects on litter survival to weaning (LS) were estimated from records of 1,243 litters of pigs from the Nebraska Gene Pool population born from 1968 to 1981. Heritabilities were estimated by: (1) weighted least-squares regressions of average survival for litters of sons on average survival for litters of their sire, (2) nested analysis of variance with LS fitted to a model including year-line and sire of litter, (3) weighted least-squares regression of average survival for the litter of daughters on the survival of the litter of their dam and (4) nested analysis of variance …

Method For Improving The Metabolic Stability And Survival Of Neonatal Pigs, Tim S. Stahly

Animal and Food Sciences Faculty Patents

A method of improving the metabolic stability of neonatal pigs and increasing their survival rate by administering to the pregnant sow during its latter stages of gestation up to about 80 days prior to parturition an effective amount of a material selected from the group consisting of a dihydroxy alkanol having 3 to 10 carbon atoms; a triglyceride of glycerol and fatty acids wherein at least one of the fatty acid moieties containing 8 to 12 carbon atoms with the remaining acid moieties containing 13 to 20 carbon atoms; the mono and diol esters of said alkanols and said fatty …

Method For Improving The Metabolic Stability And Survival Of Newborn Pigs, Tim S. Stahly

Animal and Food Sciences Faculty Patents

The disclosed invention concerns improving the metabolic stability of newborn pigs and increasing their survival rate by administering to a pregnant sow during its late stages of gestation an effective amount of a material selected from the group consisting of a dihydroxy alkanol having 3 to 10 carbon atoms, a triglyceride of glycerol and fatty acids containing 8 to 12 carbon atoms and the mono-and diol esters of said alkanols and said fatty acids.

Survival Factors Of Plant Pathogenic Bacteria, M. L. Schuster, D. P. Coyne

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The research works discussed in this review were selected to provide a cross section of the phenomenon of survival of plant pathogenic bacteria.

Genetic Studies Of Winter Hardiness In Barley, C. R. Rohde, C. F. Pulham

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

An important obstacle toward the development of winter barley varieties with a higher level of winter hardiness has been the deficiency of genetic information on this character. The primary objective of these studies was to obtain information on the genetics of the winter hardiness of a group of 18 winter barley varieties which originated from widely different geographic areas of the world. It was hoped that this information might be helpful in determining whether or not it would be possible for barley breeders to combine different genetic sources of winter hardiness and attain a higher level of hardiness than presently …