Effects of interactions with older males on behavior and reproductive development in first-year male red-winged blackbirdsAgelaius phoeniceus

1976 ◽  
Vol 196 (2) ◽  
pp. 231-242 ◽  
Author(s):  
R. Haven Wiley ◽  
Sue A. Hartnett
Keyword(s):  
Reproductive Development ◽  
First Year ◽  
Older Males

scholarly journals Trill consistency is an age-related assessment signal in banded wrens

2009 ◽  
Vol 276 (1665) ◽  
pp. 2315-2321 ◽  
Author(s):  
Selvino R. de Kort ◽  
Erin R.B. Eldermire ◽  
Sandra Valderrama ◽  
Carlos A. Botero ◽  
Sandra L. Vehrencamp
Keyword(s):  
Sexual Selection ◽  
Competitive Advantage ◽  
Phenotypic Trait ◽  
First Year ◽  
Repertoire Size ◽  
Song Repertoire ◽  
Age Related ◽  
Related Trait ◽  
Structural Aspects ◽  
Older Males

Older males tend to have a competitive advantage over younger males in sexual selection. Therefore, it is expected that signals used in sexual selection change with age. Although song repertoire size in songbirds is often mentioned as an age-related trait, many species, including the banded wren ( Thryothorus pleurostictus ), do not increase their repertoires after the first year. Here, we show that banded wrens reproduce the trill notes in their songs with less variability between them (i.e. more consistently) when they grow older. In a playback experiment, we also show that banded wrens discriminate between younger and older birds based on structural aspects of their song. In a second experiment, banded wrens also respond differentially to natural songs versus songs with artificially enhanced consistency. We argue that consistency in trill note reproduction may be achieved through practice. Sexual selection in the form of male–male competition may therefore operate on a phenotypic trait, the expression of which is enhanced by practice.

scholarly journals Effects of Timing and Intensity of Summer Pruning on Reproductive Traits of Two Southern Highbush Blueberry Cultivars

HortScience ◽  
2015 ◽  
Vol 50 (10) ◽  
pp. 1486-1491 ◽  
Author(s):  
Alisson P. Kovaleski ◽  
Rebecca L. Darnell ◽  
Bruno Casamali ◽  
Jeffrey G. Williamson
Keyword(s):  
Interspecific Hybrid ◽  
Reproductive Traits ◽  
Reproductive Development ◽  
First Year ◽  
Highbush Blueberry ◽  
Southern Highbush ◽  
Main Effects

Blueberry (Vaccinium spp.) summer pruning can increase yield by promoting healthy fall foliage to support the reproductive development. However, there has been little research to examine the effects of timing and intensity of summer pruning in subtropical conditions. The objective of this study was to determine the effects of summer pruning timing and intensity on reproductive traits of mature ‘Jewel’ and ‘Emerald’ southern highbush blueberry (SHB) plants (V. corymbosum L. interspecific hybrid) in subtropical Florida. The effect of pruning time was evaluated by removing 30% of the canopy in June or July. The effect of intensity was evaluated by pruning either 30% or 60% of the canopy in June, followed by removal of the upper 5 cm of regrowth (“tipping”) in July. Both timing and intensity used nonpruned plants as a control. The same plants were evaluated over three consecutive seasons (June 2011–May 2014). Main effects of pruning time, intensity, and tipping were evaluated. Tipping did not affect the reproductive traits evaluated. ‘Emerald’ reproductive traits were unaffected by either summer pruning time or intensity over the 3-year study. ‘Jewel’ yield was unaffected in the first year, but was increased by 48% and 65% in years 2 and 3, respectively, in the 30% pruning treatment compared with the nonpruned control. Lack of pruning in ‘Jewel’ decreased inflorescence bud number compared with moderate pruning likely due to more diseased foliage that increased defoliation. Thus, pruning effects on reproductive traits were cultivar dependent. Leaving ‘Jewel’ plants unpruned for two or more seasons reduced inflorescence bud number and yield.

scholarly journals The Effect of Macronutrient Availability on Pomegranate Reproductive Development

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 963
Author(s):  
Silit Lazare ◽  
Yang Lyu ◽  
Uri Yermiyahu ◽  
Yehuda Heler ◽  
Gershon Kalyan ◽  
...  
Keyword(s):  
Fruit Set ◽  
System Development ◽  
Reproductive Development ◽  
Dry Weight ◽  
Nutrient Concentrations ◽  
First Year ◽  
Limited Information ◽  
Severe Deficiency ◽  
Irrigation Solution ◽  
Positive Effect

Pomegranate cultivation has expanded significantly in the last two decades. However, there is limited information on its fertilization requirements and the effect of macronutrient availability on its reproductive development. Two commercial pomegranate cultivars—“Wonderful” and “Emek”—were grown in 500-L containers for 3 years, using a fertigation system. Development and reproduction indices were measured to explore the trees’ responses to elevated levels of nitrogen (N), phosphorus (P) and potassium (K) in the irrigation solution. Andromonoecy rate was affected by nutrient levels only in the first year of the experiment, with higher levels of N and P leading to a greater proportion of hermaphrodites out of total flowers. P level had a positive effect on the total number of hermaphrodites per tree in both varieties. Differences recorded between hermaphroditic and staminate flowers included nutrient concentrations and dry weight. Fruit set and aril number were positively affected by N concentration in the irrigation solution. We conclude that only a severe deficiency of N and P affects the andromonoecy trait, and that at the levels examined in this study, K hardly influences pomegranate reproduction.

First-Year Common Nightingales (Luscinia megarhynchos) Have Smaller Song-Type Repertoire Sizes Than Older Males

Ethology ◽  
2006 ◽  
Vol 112 (12) ◽  
pp. 1217-1224 ◽  
Author(s):  
Sarah Kiefer ◽  
Anne Spiess ◽  
Silke Kipper ◽  
Roger Mundry ◽  
Christina Sommer ◽  
...  
Keyword(s):  
First Year ◽  
Song Type ◽  
Luscinia Megarhynchos ◽  
Older Males

The influence of desert temperature cycles on the reproductive biology of Pseudodiplorchis americanus (Monogenea)

Parasitology ◽  
1991 ◽  
Vol 103 (1) ◽  
pp. 111-120 ◽  
Author(s):  
K. Tocque ◽  
R. C. Tinsley
Keyword(s):  
Reproductive Biology ◽  
Laboratory Data ◽  
Reproductive Development ◽  
Optimal Growth ◽  
First Year ◽  
Effective Period ◽  
Temperature Regimes ◽  
Soil Temperatures ◽  
Abiotic Control ◽  
Summer Temperatures

Pseudodiplorchis americanus has an extremely brief opportunity for transmission, restricted to less than 24 h in the year when the host (Scaphiopus couchii) enters water to breed. This strict annual cycle means that invading worms have 1 year to complete reproductive development. Despite this, a large proportion of the parasite suprapopulation is not prepared for transmission at the time of host breeding. The present study correlates detailed soil temperatures for one field site in S.E. Arizona, spanning 3·5 years, with laboratory data on parasite growth and reproductive development at a series of controlled temperatures. Development is totally inhibited at 16°C. Optimal growth and development occurs at 25°C and is slower at both 20°C and a diurnal cycle fluctuating between 20 and 34°C (mean 27°C) (simulating summer temperatures experienced by host and parasite). The effective period for accumulation of infective stages by P. americanus in any one season varies according to the timing of the summer rains in consecutive years. Between 1985 and 1988, the interval between host breedings varied from 11 to 13 months and the period when temperatures were above 20°C varied from 4 to 5·5 months per year. Since the first month post-infection (p.i.) consists of pre-reproductive development, first-year worms have only 3–4·5 months to produce infective larvae. In the shortest seasons, these worms may not be able to complete reproductive preparation in time for the first opportunity for transmission. In different parts of the geographical distribution of S. couchii, different cycles of temperature, rainfall and host breeding occur; varying temperature regimes represent an important abiotic control of P. americanus reproductive biology and transmission.

Reproduction in captive and wild dingoes (Canis familiaris dingo) in temperate and arid environments of Australia

1992 ◽  
Vol 19 (2) ◽  
pp. 195 ◽  
Author(s):  
PC Catling ◽  
LK Corbett ◽  
AE Newsome
Keyword(s):  
Canis Familiaris ◽  
Social Constraints ◽  
Breeding Period ◽  
First Year ◽  
Reproductive Pattern ◽  
Arid Environments ◽  
Reproductive Response ◽  
Males And Females ◽  
June July ◽  
Older Males

The dingo (Canis familiaris dingo) had one breeding period per year. Most matings took place in April/May and most births in June/July. All males in their first year exhibited a testis response similar to that in older males, but the peak in that response was reached two months later and the prostate reached only half the weight of the prostate of old males. Some older females did not produce young and only a small percentage of females bred in their first year. Crossbreed canids [dingo xferal dog (Canis familiaris familiaris)] did not follow the same reproductive pattern as the dingo. Several testis parameters did not show the marked seasonal variation seen in the dingo. Also, crossbreeds had larger litters than dingoes and some bred throughout the year. A major difference in reproductive response was detected between flush and drought periods in arid central Australia. Males and females responded one month later during drought periods. During drought, fewer older females and no first-year females bred and males demonstrated a reduced and delayed reproductive response. Social constraints on reproduction have been shown in young dingoes, but in this study a lack of food due to drought may have had a greater influence.

A comparison of first and second cropping years of Nova Scotia lowbush blueberries (Vaccinium angustifolium) Ait.

1995 ◽  
Vol 75 (3) ◽  
pp. 703-707 ◽  
Author(s):  
W. Christopher Jordan ◽  
Leonard J. Eaton
Keyword(s):  
Management System ◽  
Crop Yields ◽  
Reproductive Development ◽  
Crop Plants ◽  
First Year ◽  
Flower Buds ◽  
Vaccinium Angustifolium ◽  
Crop Fields ◽  
Lowbush Blueberry ◽  
Lower Productivity

Traditional lowbush blueberry (Vaccinium angustifolium Ait.) production is based on a biennial management system with vegetative growth occurring the first year and fruit development and harvest in the second. An alternative to this management system is the 3-yr system (second-cropping) which is characterized by 2 cropping years/cycle. This study was initiated to quantify differences in vegetative and reproductive development between first and second cropping years of the lowbush blueberry and to determine why there are lower second crop yields. Second crops averaged 70% of first crop yields. Second crop plants had longer stems and higher branch numbers than first crop plants. Although both cropping years produced equal numbers of flower buds/stem, second crops had fewer blossoms/bud, blossoms/stem, set fruit, and berries/stem, resulting in lower fresh and dry weights of fruit/stem in second crop fields. Slower growth rate, fewer blossoms/bud, smaller leaf area/stem, and lower productivity of the second cropping year suggest that second crop stems have fewer resources available to achieve the same production level as first crop stems. Key words: Lowbush blueberry, Vaccinium angustifolium, 3-year management, second-cropping

Changes in role perceptions by first-year dental students

1977 ◽  
Vol 41 (8) ◽  
pp. 507-510 ◽  
Author(s):  
AC Rosen ◽  
M Marcus ◽  
N Johnson
Keyword(s):  
Dental Students ◽  
First Year ◽  
Role Perceptions
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