INTERSPECIFIC CROSSES AND FERTILE HYBRIDS AMONG THE CONIFEROPHAGOUS CHORISTONEURA (LEPIDOPTERA: TORTRICIDAE)

1997 ◽  
Vol 129 (3) ◽  
pp. 519-536 ◽  
Author(s):  
George T. Harvey
Keyword(s):  
North American ◽  
Mating Success ◽  
Parental Species ◽  
Interspecific Crosses ◽  
Laboratory Studies ◽  
Low Level ◽  
Parental Type ◽  
Host Type ◽  
Fertile Hybrids ◽  
Harsh Conditions

AbstractLaboratory studies of seven North American Choristoneura species and two subspecies from widely distributed locations demonstrate the low level of genetic separation among them. No differences were found in numbers (n = 30) or morphology of chromosomes among members of the group or in any of the hybrids examined. High levels of mating success were obtained in all inter se matings as well as in crosses and back-crosses. However, mating success was greater for crosses within host type and within pheromone type than for crosses between types. Viability and fertility were similar in all the hybrids and close to those of the inter se progenies. Mean weights of initial eggs varied by a factor of 2 from the lowest (C. pinus Freeman) to the highest (C. lambertiana ponderosana Obraztsov). Mean weights of initial eggs produced by hybrids were generally close to those of the parental species. However, when one parent was C. fumiferana (Clem.), mean weights of initial eggs were either much larger (male C. fumiferana) or much smaller (female C. fumiferana) than either parental type. These differences could affect survival of some progeny under harsh conditions. This evidence supports other studies in indicating that C. fumiferana is genetically distinct from other species in this group.

Hybrids in Marsupial Research

1989 ◽  
Vol 37 (3) ◽  
pp. 259 ◽  
Author(s):  
RL Close ◽  
PS Lowry
Keyword(s):  
Gene Mapping ◽  
Genetic Markers ◽  
Chromosome Numbers ◽  
Growth And Development ◽  
Parental Species ◽  
Interspecific Crosses ◽  
Personal Communications ◽  
In Captivity ◽  
Morphological Differences ◽  
Fertile Hybrids

Many species from the superfamily Macropodoidea hybridise in captivity despite chromosomal and/or morphological differences. Details of such hybrids were collected from the literature or by personal communications from researchers or breeders of macropods. A Table of known hybrids and notes on their fertilities is presented, which includes the chromosome numbers and differences in gross and C-banded karyotypes of each parental species. Also included in the table are the numbers of proteins known to differ in electrophoretic mobility between each pair of parental species, and the number of proteins which are polymorphic in either of the two parental species. This table, therefore, can be used in gene mapping studies for assessing which hybrids carry suitable chromosomal and genetic markers and might be fertile. Four different interspecific crosses have already been reported as fertile, and artificial methods of increasing fertility could increase the likelihood of producing fertile hybrids. Moreover, the variety of hybrids and their different degrees of fertility show that they are potentially valuable for studying the effects of genic and chromosomal heterozygosity on growth and development, meiotic processes and spermatogenesis.

Acoustic Communication and Mating Behaviour in the Muellerianella Complex (Homoptera - Delphacidae)

Behaviour ◽  
1985 ◽  
Vol 94 (1-2) ◽  
pp. 183-201 ◽  
Author(s):  
S. Drosopoulos
Keyword(s):  
Mating Behavior ◽  
Acoustic Communication ◽  
Parental Species ◽  
Mating Behaviour ◽  
Interspecific Crosses ◽  
Bisexual Species ◽  
Duration Of Copulation ◽  
Isolating Mechanisms ◽  
Copulation Behavior ◽  
Biological Differences

AbstractSome data on acoustic communication and mating behavior of two biparentally reproducing species and the clonally reproducing pseudogamous "species" of the genus Muellerianella are reported. Although bioacoustic differences were found in the calling songs between the species, these did not prevent pairforming. Also, differences in mating behavior, such as pre-copulation behavior, courtship activities, frequency and duration of copulation were not sufficient to prevent successful hybridization between both the two biparentally reproducing species and between each of these two species and the pseudogamous "species". The data reported here are related to other biological differences reported previously. According to these data there is some evidence that differences in acoustic communication and mating behavior between the two species are established by ecological influences which in turn have established analogous physiological requirements. These differences are rather weak isolating mechanisms. Regarding the behavioral relation of the pseudogamous species with males of the two parental species it was found that these females behave exactly as the females of M. fairmairei with which they coexist in the field. In interspecific crosses mechanical barriers to copulation are more efficient than courtship differences. Finally it is assumed that pseudogamy is a strong isolation mechanism between the not yet fully genetically differentiated bisexual species of Muellerianella.

Intraseasonal Teleconnection between North American and Western North Pacific Monsoons with 20-Day Time Scale

2008 ◽  
Vol 21 (11) ◽  
pp. 2664-2679 ◽  
Author(s):  
Xianan Jiang ◽  
Ngar-Cheung Lau
Keyword(s):  
United States ◽  
North American ◽  
North Pacific ◽  
Time Scale ◽  
Western North Pacific ◽  
Wave Train ◽  
Eastern Pacific ◽  
Southwestern United States ◽  
Low Level ◽  
The North

Abstract Based on a recently released, high-resolution reanalysis dataset for the North American region, the intraseasonal variability (ISV; with a time scale of about 20 days) of the North American monsoon (NAM) is examined. The rainfall signals associated with this phenomenon first emerge near the Gulf of Mexico and eastern Pacific at about 20°N. They subsequently migrate to the southwestern United States along the slope of the Sierra Madre Occidental. The rainfall quickly dissipates upon arrival at the desert region of Arizona and New Mexico (AZNM). The enhanced rainfall over AZNM is accompanied by strong southeasterly low-level flow along the Gulf of California. This pattern bears strong resemblance to the circulation related to “gulf surge” events, as documented by many studies. The southeasterly flow is associated with an anomalous low vortex over the subtropical eastern Pacific Ocean off California, and a midlatitude anticyclone over the central United States in the lower troposphere. This flow pattern is in broad agreement with that favoring the “wet surges” over the southwestern United States. It is further demonstrated that the aforementioned low-level circulations associated with ISV of the NAM are part of a prominent trans-Pacific wave train extending from the western North Pacific (WNP) to the Eastern Pacific/North America along a “great circle” path. The circulation anomalies along the axis of this wave train exhibit a barotropic vertical structure over most regions outside of the WNP, and a baroclinic structure over the WNP, thus suggesting the important role of convective activities over the WNP in sustaining this wave train. This inference is further substantiated by an analysis of the pattern of wave-activity–flux vectors. Variations in the WNP convection are correlated with the ISV of the monsoons in both North American and East Asian (EA)/WNP sectors. These relationships lead to notable teleconnections between NAM and the EA/WNP monsoon on 20-day time scales.

scholarly journals Low-Level Jets in the North American Regional Reanalysis (NARR): A Comparison with Rawinsonde Observations

2014 ◽  
Vol 53 (9) ◽  
pp. 2093-2113 ◽  
Author(s):  
Claudia K. Walters ◽  
Julie A. Winkler ◽  
Sara Husseini ◽  
Ryan Keeling ◽  
Jovanka Nikolic ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
North American ◽  
Low Level ◽  
The North ◽  
Central United States ◽  
North American Regional Reanalysis ◽  
Low Level Jets ◽  
Regional Reanalysis ◽  
Wind Profiles ◽  
Fine Resolution

AbstractClimatological analyses of low-level jets (LLJs) can be negatively influenced by the coarse spatial and temporal resolution and frequent changes in observing and archiving protocols of rawinsonde observations (raobs). The introduction of reanalysis datasets, such as the North American Regional Reanalysis (NARR), provides new resources for climatological research with finer spatial and temporal resolution and potentially fewer inhomogeneities. To assess the compatibility of LLJ characteristics identified from NARR wind profiles with those obtained from raob profiles, LLJs were extracted using standard jet definitions from NARR and raobs at 12 locations in the central United States for four representative years that reflect different rawinsonde protocols. LLJ characteristics (e.g., between-station differences in relative frequency, diurnal fluctuations, and mean speed and elevation) are generally consistent, although absolute frequencies are smaller for NARR relative to raobs at most stations. LLJs are concurrently identified in the NARR and raob wind profiles on less than 60% of the observation times with LLJ activity. Variations are seen between analysis years and locations. Of particular note is the substantial increase in LLJ frequency seen in raobs since the introduction of the Radiosonde Replacement System, which has led to a greater discrepancy in jet frequency between the NARR and raob datasets. The analyses suggest that NARR is a viable additional resource for climatological analyses of LLJs. Many of the findings are likely applicable for other fine-resolution reanalysis datasets, although differences between reanalyses require that each be carefully evaluated before its use in climatological analyses of wind maxima.

Simulations of the 2004 North American Monsoon: NAMAP2

2009 ◽  
Vol 22 (24) ◽  
pp. 6716-6740 ◽  
Author(s):  
D. S. Gutzler ◽  
L. N. Long ◽  
J. Schemm ◽  
S. Baidya Roy ◽  
M. Bosilovich ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
North American ◽  
Warm Season ◽  
North American Monsoon ◽  
Regional Models ◽  
Global Models ◽  
Low Level ◽  
The Core ◽  
The North ◽  
Low Level Jet

Abstract The second phase of the North American Monsoon Experiment (NAME) Model Assessment Project (NAMAP2) was carried out to provide a coordinated set of simulations from global and regional models of the 2004 warm season across the North American monsoon domain. This project follows an earlier assessment, called NAMAP, that preceded the 2004 field season of the North American Monsoon Experiment. Six global and four regional models are all forced with prescribed, time-varying ocean surface temperatures. Metrics for model simulation of warm season precipitation processes developed in NAMAP are examined that pertain to the seasonal progression and diurnal cycle of precipitation, monsoon onset, surface turbulent fluxes, and simulation of the low-level jet circulation over the Gulf of California. Assessment of the metrics is shown to be limited by continuing uncertainties in spatially averaged observations, demonstrating that modeling and observational analysis capabilities need to be developed concurrently. Simulations of the core subregion (CORE) of monsoonal precipitation in global models have improved since NAMAP, despite the lack of a proper low-level jet circulation in these simulations. Some regional models run at higher resolution still exhibit the tendency observed in NAMAP to overestimate precipitation in the CORE subregion; this is shown to involve both convective and resolved components of the total precipitation. The variability of precipitation in the Arizona/New Mexico (AZNM) subregion is simulated much better by the regional models compared with the global models, illustrating the importance of transient circulation anomalies (prescribed as lateral boundary conditions) for simulating precipitation in the northern part of the monsoon domain. This suggests that seasonal predictability derivable from lower boundary conditions may be limited in the AZNM subregion.

The bearing of Phoxinus (Cyprinidae) hybridity on the classification of its North American species

1970 ◽  
Vol 48 (6) ◽  
pp. 1167-1177 ◽  
Author(s):  
Pierre Legendre
Keyword(s):  
Chromosome Number ◽  
Discriminant Function ◽  
North American ◽  
Parental Species ◽  
North American Species ◽  
Discriminant Functions

Three populations of Phoxinus eos × P. neogaeus were found to form single Mendelian populations, by comparison with the parental species through a discriminant function. The hybrids of one of these populations were found to be fertile. A fourth hybrid collection, studied by three discriminant functions, was found to contain Semotilus margarita, P. eos × P. neogaeus, and hybrids of S. margarita with at least P. eos, but possibly P. eos × P. neogaeus. The presence of this hybrid, when related to the chromosome number of the species concerned, suggests the transfer of S. margarita to the genus Phoxinus.

The adaptive significance of paedogenesis in North American species of Ambystoma (Amphibia: Caudata): an hypothesis

1974 ◽  
Vol 52 (3) ◽  
pp. 393-400 ◽  
Author(s):  
W. Gary Sprules
Keyword(s):  
Life History ◽  
North America ◽  
North American ◽  
Genetic Basis ◽  
Temperature Fluctuations ◽  
Adaptive Significance ◽  
Supporting Evidence ◽  
Low Humidity ◽  
Ambystomatid Salamanders ◽  
Harsh Conditions

Paedogenesis in varying degrees is exhibited by many species of North American salamanders, particularly of the genus Ambystoma. On the basis of a consideration of the ecology of these species, it is proposed that paedogenesis is evolutionarily adaptive and the following hypothesis is presented. In most habitats where ambystomatid salamanders occur, they exhibit the typical amphibian life history, consisting of aquatic larvae and terrestrial adults. However, where unusually harsh conditions, such as severe temperature fluctuations, lack of suitable cover or food, and low humidity, exist on land then the adjacent aquatic habitat is more suitable for salamanders provided it is permanent and provided fish are rare or absent. Under these circumstances paedogenesis will evolve because salamanders which spend their whole lives as larvae in the water have an adaptive advantage over those which metamorphose and become primarily terrestrial. Supporting evidence for the hypothesis is based primarily on patterns of similarity in the ecology of paedogenetic species of Ambystoma. It is suggested that paedogenesis is most commonly reported from the western mountains because this area contains more permanent fish-free ponds than any other area of North America. Exceptions to the hypothesis are discussed and some speculation on the genetic basis of paedogenesis is offered.

scholarly journals Spawning behaviour and mating success in hybrids of silver bream (Blicca bjoerkna L.) and rudd (Scardinius erythrophthalmus L.) in an experimental environment

2013 ◽  
Vol 63 (2) ◽  
pp. 119-130 ◽  
Author(s):  
Billy Nzau Matondo ◽  
Michaël Ovidio ◽  
Jean Claude Philippart ◽  
Pascal Poncin
Keyword(s):  
Food Consumption ◽  
Mating Success ◽  
Parental Species ◽  
Mating Behaviour ◽  
Survival Rates ◽  
Spawning Ground ◽  
Scardinius Erythrophthalmus ◽  
Experimental Fish ◽  
Spawning Behaviour ◽  
Dry Food

The egg-release, mating, courting and aggressive acts for the spawning behaviour as well as the survival rates after spawning at stages of eyed embryos, viable hatchlings, and larvae to dry food consumption for the mating success were studied in cultured silver bream Blicca bjoerkna × rudd Scardinius erythrophthalmus hybrids at their first sexual maturity. Experiments were conducted in experimental environments simulating natural reproductive conditions of the parental species. Spawning behaviour was analysed over 1 day from 8.00 to 18.00 hours using a remote-controlled video. Mating success was assessed from eggs and hatched embryos collected on the spawning ground. The results showed that these hybrids exhibited all the reproductive behaviours of the parental species with significantly more courtship than mating. Each egg-release act was accompanied by mating behaviour, involving all the experimental males. A surprising aggressive behaviour was observed in one male which attacked all other experimental fish. Successful mating resulted in the presence of fertilized eggs, the production of hatched embryos in experiments, and the survival of larvae at the dry food consumption stage. However, the low viable hatchling rate observed could indicate a very low chance of survival for these hybrids in rivers in which the occurrence of post-F1 individuals may be more possible by backcrossing.

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