The reproductive rates of yearling and older Ipswich Sparrows, Passerculus sandwichensis princeps

1980 ◽  
Vol 58 (9) ◽  
pp. 1557-1563 ◽  
Author(s):  
Howard A. Ross
Keyword(s):  
Nova Scotia ◽  
Reproductive Rate ◽  
Parental Age ◽  
Passerculus Sandwichensis ◽  
The Mean ◽  
Reproductive Rates ◽  
Older Males

The mean reproductive rates (number of 7-day-old nestlings raised per year per individual) of yearling and older Ipswich Sparrows breeding on Sable Is., Nova Scotia in 1977 and 1978 were the following: yearling males 3.3, older males 4.2, yearling females 3.9, and older females 4.7. The mates of older males began nesting earlier, laid larger clutches, and renested more quickly after each brood than did the mates of yearling males, thereby laying slightly more clutches and significantly more eggs. Older females laid slightly more and slightly larger clutches than did yearling females, resulting in a significantly greater production of eggs. The number of nestlings aged 7 days (i.e., the age immediately before nest leaving) raised per egg laid varied only slightly with parental age. Consequently, the reproductive rate increased with age because parental abilities must have increased by the same proportion as did the production of eggs.

Reproductive Rates of Harp Seals, Pagophilus groenlandicus (Erxleben)

1966 ◽  
Vol 23 (5) ◽  
pp. 757-766 ◽  
Author(s):  
D. E. Sergeant
Keyword(s):  
Sexual Maturity ◽  
Reproductive Rate ◽  
First Year ◽  
Published Data ◽  
Age Class ◽  
Adult Females ◽  
Pagophilus Groenlandicus ◽  
The Mean ◽  
Reproductive Rates ◽  
Lower Population

In less than a decade the mean age at sexual maturity of female harp seals of the Front, or northeastern Newfoundland population, decreased to 4 from [Formula: see text] years. Exploitation was heavy during this period and included a high proportion of seals older than 1 year. Females of the Gulf of St. Lawrence herd declined in mean age at sexual maturity over the same decade to 5 from nearly 6 years. Exploitation of this herd was lower, especially for animals older than their first year. Fertility of the adult females was likely higher in the more heavily exploited population. Published data on the White Sea population, which was reduced to low numbers, show reproduction at a lower mean age than for the present Front herd; for the Jan Mayen herd, of uncertain population status, about the same reproductive rate as the present Gulf herd. In most of the populations, samples of adult, whelped females showed the greatest number in the age-class about 1 year older than that first showing 100% of the females mature, as would be expected; however, samples from the Front herd showed dominance of an older age-class, suggesting that young adult females may to some extent segregate into separate groups. The immediate factors leading to increased reproductive rates at lower population densities were not elucidated.

PREDATION BY INSECTS AND SPIDERS INHABITING COLONIAL WEBS OF HYPHANTRIA CUNEA

1972 ◽  
Vol 104 (8) ◽  
pp. 1197-1207 ◽  
Author(s):  
R. F. Morris
Keyword(s):  
Population Dynamics ◽  
Nova Scotia ◽  
North America ◽  
Population Density ◽  
New Brunswick ◽  
Numerical Response ◽  
Initial Number ◽  
Hyphantria Cunea ◽  
The North ◽  
The Mean

AbstractThe number of predators inhabiting nests of Hyphantria cunea Drury was recorded annually for 13 years in four areas in New Brunswick and two areas on the coast of Nova Scotia. The most common groups were the pentatomids and spiders, which sometimes reproduced within the nests, but the mean number per nest was low in relation to the number of H. cunea larvae in the colonies. The rate of predation on fifth-instar larvae was low. Small or timid predators appeared to prey largely on moribund larvae or small saprophagans during the principal defoliating instars of H. cunea.No relationship could be detected between the number of larvae reaching the fifth instar and the number of predators in the colony; nor could any functional or numerical response of the predators to either the initial number of larvae per colony or the population density of colonies be found. It is concluded that the influence of the nest-inhabiting predators is small and relatively stable, and may be treated as a constant in the development of models to explain the population dynamics of H. cunea.H. cunea is a pest in parts of Europe and Asia, where it has been accidentally introduced from North America. The introduction to other continents of the North American predator, Podisus maculiventiis (Say), is discussed briefly.

scholarly journals Biological performance of the predatory mite Neoseiulus idaeus (Phytoseiidae): a candidate for the control of tetranychid mites in Brazilian soybean crops

2016 ◽  
Vol 77 (2) ◽  
pp. 361-366 ◽  
Author(s):  
M. B. Reichert ◽  
M. Toldi ◽  
P. A. Rode ◽  
J. J. Ferla ◽  
N. J. Ferla
Keyword(s):  
Adult Development ◽  
Predatory Mite ◽  
Reproductive Rate ◽  
Agricultural Crop ◽  
Net Reproductive Rate ◽  
Glycine Max L ◽  
The Mean ◽  
Neoseiulus Idaeus ◽  
Biological Performance ◽  
Northwest Region

Abstract The soybean (Glycine max (L.): Fabaceae) is considered the most important agricultural crop in Brazil. Phytophagous tetranychid mites as Mononychellus planki McGregor, Tetranychus ludeni Zacher and T. urticae Koch have been considered pest in soybean crops. Neoseiulus idaeus Denmark & Muma (Phytoseiidae) is a predatory mite of T. ludeni and T. urticae. The aim of the present study was to evaluate the biological performance of N. idaeus when fed on T. urticae, T. ludeni and M. planki, coming from the Northwest region of Rio Grande do Sul state, Brazil. The study was conducted in the laboratory with individual predators supplied with different preys. The mean duration (days) of N. idaeus egg-adult development was similar independently of supplied prey (T. ludeni - 5.29±0.03; M. planki - 5.34±0.05 and T. urticae - 5.23±0.03 days). Female viability was 90% when fed on M. planki and 100% when fed on T. ludeni and T. urticae. Mean fecundity of N. idaeus was lower when fed on M. planki (4.6±1.58 eggs/female) and higher when fed on T. ludeni (21.8±3.22) and T. urticae (26.2±2.41). The mean generation time (T) was lower when N. idaeus fed on M. planki than when fed on T. ludeni and T. urticae. The net reproductive rate (Ro) was 4.42±0.49 on M. planki, 17.77±0.55 on T. ludeni and 20.59±0.48 on T. urticae. The innate capacity for increase (rm) was lower when N. idaeus was fed on M. planki (0.09) and higher when such predator was fed on T. ludeni (0.20) and T. urticae (0.22 females/females/day). These results demonstrated that N. idaeus is able to reach the complete development feeding on all the three tetranychid species. Mononychellus planki demonstrated to provide a sub-optimal diet if compared to T. ludeni and T. urticae.

scholarly journals Life Tables of Two-Spotted Spider Mite Tetranychus urticae Koch (Acari: Tetranychidae) and its Predator Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae)

1970 ◽  
Vol 16 ◽  
pp. 1-10 ◽  
Author(s):  
M Fazlul Hoque ◽  
W Islam ◽  
M Khalequzzaman
Keyword(s):  
Tetranychus Urticae ◽  
Generation Time ◽  
Development Time ◽  
Phytoseiulus Persimilis ◽  
Reproductive Rate ◽  
Finite Capacity ◽  
Net Reproductive Rate ◽  
Wide Range ◽  
The Mean ◽  
Capacity For Increase

Life table of Tetranychus urticae and Phytoseiulus persimilis on bean leaflets were studied under laboratory conditions in three seasons. For T. urticae the development time from egg to adult varied from 7 to 24 days and the highest immature mortality was 78.70 % in winter. Eggs laid by females were 88.1 eggs in autumn and 70.6 eggs in summer season. The gross reproductive rate (GRR) was the highest (65.51) in autumn and 52.50 in summer. The net reproductive rate (Ro) was the highest (15.862) in autumn and 8.916 in summer. The intrinsic rates of increase (rm) and finite capacity for increase (λ) reached maximal values (0.1873 and 1.206) in autumn, whereas minimal values (0.056 and 1.058) were in winter season. The mean generation time (T) was the shortest in summer and double (3.701) days in autumn. The development time of P. persimilis from egg to adult varied from 5 to 14 days. The highest immature mortality was 60% in summer. Eggs laid by females were 39.4 eggs in autumn and 30.2 eggs in summer. The gross reproductive rate (GRR) was the highest (31.4) in autumn and 24.0 in summer. The net reproductive rate (Ro) was the highest (10.573) in autumn and 8.460 in winter. The intrinsic rates of increase (rm) and finite capacity for increase (λ) reached maximal values (0.1823 and 1.200) in summer, whereas minimal values (0.1025 and 1.108) were in winter. The mean generation time (T) was the shortest in summer. The results suggested that P. persimilis could develop and reproduce within a wide range of temperatures. Key words: Tetranychus urticae, Phytoseiulus persimilis, immature mortality, intrinsic rates of increase, reproductive rate, Survival  DOI:10.3329/jbs.v16i0.3733 J. bio-sci. 16: 1-10, 2008

scholarly journals Effects of imidacloprid and thiamethoxam on the development and reproduction of the soybean aphid Aphis glycines

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0250311
Author(s):  
Aonan Zhang ◽  
Lin Zhu ◽  
Zhenghao Shi ◽  
Tianying Liu ◽  
Lanlan Han ◽  
...  
Keyword(s):  
Treatment Group ◽  
Reproductive Rate ◽  
Soybean Aphid ◽  
Aphis Glycines ◽  
Intrinsic Rate Of Increase ◽  
Control Group ◽  
Net Reproductive Rate ◽  
Treatment Groups ◽  
Rate Of Increase ◽  
The Mean

The soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) is a primary pest of soybeans and poses a serious threat to soybean production. Our studies were conducted to understand the effects of different concentrations of insecticides (imidacloprid and thiamethoxam) on A. glycines and provided critical information for its effective management. Here, we found that the mean generation time and adult and total pre-nymphiposition periods of the LC50 imidacloprid- and thiamethoxam-treatment groups were significantly longer than those of the control group, although the adult pre-nymphiposition period in LC30 imidacloprid and thiamethoxam treatment groups was significantly shorter than that of the control group. Additionally, the mean fecundity per female adult, net reproductive rate, intrinsic rate of increase, and finite rate of increase of the LC30 imidacloprid-treatment group were significantly lower than those of the control group and higher than those of the LC50 imidacloprid-treatment group (P < 0.05). Moreover, both insecticides exerted stress effects on A. glycines, and specimens treated with the two insecticides at the LC50 showed a significant decrease in their growth rates relative to those treated with the insecticides at LC30. These results provide a reference for exploring the effects of imidacloprid and thiamethoxam on A. glycines population dynamics in the field and offer insight to agricultural producers on the potential of low-lethal concentrations of insecticides to stimulate insect reproduction during insecticide application.

scholarly journals Biology and life-table of Typhlodromus (Anthoseius) athenas (Acari: Phytoseiidae) fed with the Old World Date Mite, Oligonychus afrasiaticus (Acari: Tetranychidae)

Acarologia ◽  
2018 ◽  
Vol 58 (1) ◽  
pp. 52-61
Author(s):  
Samah Ben Chaaban ◽  
Brahim Chermiti ◽  
Serge Kreiter
Keyword(s):  
Life Table ◽  
Intrinsic Rate ◽  
Phoenix Dactylifera ◽  
Reproductive Rate ◽  
Intrinsic Rate Of Increase ◽  
Net Reproductive Rate ◽  
Old World ◽  
Rate Of Increase ◽  
Wide Range ◽  
The Mean

The old world date mite Oligonychus afrasiaticus is an important spider mite pest of the date palms Phoenix dactylifera L. mostly in North Africa and the Middle East. A population of the predaceous mite Typhlodromus (Anthoseius) athenas has been recently found in Tunisia in association with a decrease of O. afrasiaticus densities. The objective of this paper was to assess the development and reproduction abilities of T. ( A.) athenas on O. afrasiaticus under laboratory conditions at two temperatures: 27 and 32 °C. The results obtained show that females of T. (A.) athenas develop in 5 days at 27 °C and 4.1 days at 32 °C. The mean fecundity of T. (A.) athenas was 32.1 and 23.2 eggs per female at 27 and 32 °C, respectively. Life table parameters were stimated: the net reproductive rate (Ro) 27.9 and 17.9 eggs/female, the intrinsic rate of increase (rm) 0.322 and 0,344 female/female/day and the mean generation time (T) 10.3 and 8.4 days at 27 and 32 °C, respectively. At both temperatures tested, T. (A.) athenas intrinsic rate of increase was greater than that of O. afrasiaticus (rm = 0.213 at 32 °C,against rm = 0.166 day1 at 27 °C). Typhlodromus (A.) athenas would be able to develop at a wide range of temperatures feeding on O. afrasiaticus and seems to be able to potentially control it.

scholarly journals Phytophagy of the predator Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae) fed on prey and Brassicaceae

2017 ◽  
Vol 77 (4) ◽  
pp. 703-709 ◽  
Author(s):  
J. F. J. Grigolli ◽  
M. M. Kubota Grigolli ◽  
D. G. Ramalho ◽  
A. L. Martins ◽  
A. M. Vacari ◽  
...  
Keyword(s):  
Generation Time ◽  
Reproductive Rate ◽  
Egg Mass ◽  
Reproductive Parameters ◽  
Net Reproductive Rate ◽  
Laboratory Rearing ◽  
Males And Females ◽  
The Mean ◽  
Heteroptera Pentatomidae ◽  
Alternative Diet

Abstract The purpose of this study was to investigate the development and reproduction of the zoophytophagous predator Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) fed kale, broccoli and cabbage affects its. Nymphs and adults of this predator were fed on larvae of Plutella xylostella (L.) (Lepidoptera: Plutellidae) as prey with kale, cabbage, or broccoli. In the nymph period, the duration and prey consumption were similar with all the Brassicacea cultivar. However, nymph viability was higher for predators with broccoli leaves. The mean weight of 5th-instar nymphs, newly emerged females and the sex ratio were similar among the Brassicacea cultivars, while newly emerged males were heavier with kale and broccoli leaves. The supply of broccoli leaves resulted in greater oviposition, higher number of eggs per egg mass and longer longevity of P. nigrispinus males and females. Furthermore, the consumption of P. xylostella larvae by adult predators was higher with these cultivars. The net reproductive rate (R0) and mean generation time (T) were highest for predators with prey and broccoli leaves. The reproductive parameters of P. nigrispinus were enhanced when fed on P. xylostella larvae with and broccoli leaves, which can be an alternative diet in laboratory rearing of this predator.

scholarly journals The Relationship Between Habitat Characteristics and Demographic Performance of Northern Spotted Owls in Southern Oregon

The Condor ◽  
2005 ◽  
Vol 107 (4) ◽  
pp. 863-878 ◽  
Author(s):  
Katie M. Dugger ◽  
Frank Wagner ◽  
Robert G. Anthony ◽  
Gail S. Olson
Keyword(s):  
Winter Precipitation ◽  
Reproductive Rate ◽  
Habitat Characteristics ◽  
Forest Types ◽  
Apparent Survival ◽  
Breeding Experience ◽  
Old Growth Forest ◽  
Strix Occidentalis Caurina ◽  
Demographic Performance ◽  
Reproductive Rates

Abstract We used data from Northern Spotted Owl (Strix occidentalis caurina) territories to model the effects of habitat (particularly intermediate-aged forest stand types), climate, and nonhabitat covariates (i.e., age, sex) on owl reproductive rate and apparent survival in southwestern Oregon. Our best model for reproductive rate included an interaction between a cyclic, annual time trend and male breeding experience, with higher reproductive rates in even years compared to odd, particularly for males with previous breeding experience. Reproductive rate was also negatively related to the amount of winter precipitation and positively related to the proportion of old-growth forest near the owl territory center. Apparent survival was not associated with age, sex, climate or any of the intermediate-aged forest types, but was positively associated with the proportion of older forest near the territory center in a pseudothreshold pattern. The quadratic structure of the proportion of nonhabitat farther from the nest or primary roost site was also part of our best survival model. Survival decreased dramatically when the amount of nonhabitat exceeded ∼50%. Habitat fitness potential estimates (λ̂h) for 97 owl territories ranged from 0.29–1.09, with a mean of 0.86 ± 0.02. Owl territories with habitat fitness potentials <1.0 were generally characterized by <40%–50% old forest habitat near the territory center. Our results indicate that both apparent survival and reproductive rate are positively associated with older forest types close to the nest or primary roost site. We found no support for either a positive or negative direct effect of intermediate-aged forests on either survival or reproductive rate.

scholarly journals Mitochondrial DNA Variation, Species Limits, and Rapid Evolution of Plumage Coloration and Size in the Savannah Sparrow

The Condor ◽  
2005 ◽  
Vol 107 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Robert M. Zink ◽  
James D. Rising ◽  
Steve Mockford ◽  
Andrew G. Horn ◽  
Jonathan M. Wright ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Nova Scotia ◽  
San Diego ◽  
Baja California ◽  
Rapid Evolution ◽  
Plumage Coloration ◽  
Phylogeographic Structure ◽  
Species Status ◽  
Passerculus Sandwichensis ◽  
Savannah Sparrows

Abstract We compared sequences from two mitochondrial DNA (mtDNA) genes (ND2, ND3) in Savannah Sparrows (Passerculus sandwichensis; n = 112) sampled from Baja California (five sites), coastal Sonora and the continental range (eight sites). Populations from Baja California, San Diego and Sonora formed a clade within which there was no phylogeographic structure; this clade merits species status (Passerculus rostratus). The other clade, consisting of phenotypically “typical” savannah sparrows, should be classified as P. sandwichensis. Among the typical sparrows, there was no phylogeographic structure, although two major clades were discovered. Representatives of each of the two main clades occurred at most sampling localities, excluding Suisan Bay, California and Sable Island, Nova Scotia, Canada. Haplotypes found on Sable Island, representing the “Ipswich Sparrow,” were not distinctive, thereby failing to support species status for this taxon. On Isla San Benito, a single haplotype was found, which also occurred in other Mexican localities. The results for Sable Island and Isla San Benito show that size and plumage coloration can evolve rapidly. Variación en ADN Mitocondrial, Límites entre Especies y Evolución Rápida de la Coloración del Plumaje y el Tamaño en Passerculus sandwichensis Resumen. En este estudio comparamos secuencias de dos genes mitocondriales (ND2 y ND3) entre individuos de la especie Passerculus sandwichensis (n = 112) muestreados en Baja California (5 sitios), la costa de Sonora y el rango de distribución continental (8 sitios). Las poblaciones de Baja California, San Diego y Sonora formaron un clado, al interior del cual no existió estructura filogeográfica; este clado merece estatus de especie (Passerculus rostratus). El otro clado, conformado por individuos fenotípicamente “típicos”, debe clasificarse como P. sandwichensis. Entre los individuos típicos no existió estructura filogeográfica, aunque se descubrieron dos clados principales. Individuos representativos de cada uno de estos dos clados se encontraron en la mayoría de las localidades, excepto Suisan Bay, California y Sable Island, Nova Scotia. Los haplotipos encontrados en Sable Island, correspondientes al “gorrión de Ipswich” no fueron distintivos, lo que no apoya el estatus de especie para este taxón. En Isla San Benito se encontró un solo halpotipo, el cual también se encontraba en otras localidades mexicanas. Los resultados de Sable Island e Isla San Benito muestran que el tamaño y la coloración del plumaje pueden evolucionar rápidamente.

Caloric Content of the Standing Crop of Benthic and Epibenthic Invertebrates of St. Margaret's Bay, Nova Scotia

1968 ◽  
Vol 25 (9) ◽  
pp. 1803-1811 ◽  
Author(s):  
V. M. Brawn ◽  
D. L. Peer ◽  
R. J. Bentley
Keyword(s):  
Nova Scotia ◽  
Standing Crop ◽  
Caloric Content ◽  
Wet Weight ◽  
The Common ◽  
The Mean ◽  
Epibenthic Invertebrates

The benthos of St. Margaret's Bay at depths of 28–62 m was sampled quantitatively during the summer and the caloric contents of the common invertebrates determined. The shrimps, amphipods, and the polychaete Lumbrinereis with caloric contents between 1000 and 1300 cal/g wet weight had the highest caloric content of those tested. The mean caloric content of the standing crop was 76 kcal/m2 with the highest values occurring where the sand and silt–clay fractions of the sediment were nearly equal and the lowest where either sand or silt–clay predominated. Annelids and echinoderms together accounted for more than three-quarters of the caloric content of the standing crop.

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