The litoria ewingi complex (Anura : Hylidae) in south-eastern Australia IV. Variation in mating-call structure across a narrow hybrid zone between L. ewingi ad L.paraewingi

1976 ◽  
Vol 24 (2) ◽  
pp. 283 ◽  
Author(s):  
MJ Littlejohn
Keyword(s):  
Hybrid Zone ◽  
Parental Species ◽  
Character Displacement ◽  
Pulse Repetition ◽  
Reproductive Character Displacement ◽  
Genetic Incompatibility ◽  
Call Structure ◽  
Mating Call ◽  
Eastern Australia ◽  
Mating Calls

The presence of mating calls characteristic of both parental species, and of intermediate calls, within the zone of contact between L. ewingi and L. paraewingi supports the earlier interpretation that the interaction is an overlap with hybridization. Pulse repetition rates are similar throughout the transect, and there are no clear indications of reproductive character displacement within the hybrid zone, even though marked one-way genetic incompatibility is present. However, calls from close allopatry are more distinctive than those from distant allopatry, mainly in pulses per repeated note (a meristic character reflecting differences in note duration), suggesting that the effects of reinforcing selection may be accumulating in the proximity of the zone of interaction.

The litoria ewingi complex (Anura : Hylidae) in south-eastern Australia V. Interactions between northern L. ewingi and adjacent taxa

1978 ◽  
Vol 26 (1) ◽  
pp. 175 ◽  
Author(s):  
GF Watson ◽  
MJ Littlejohn
Keyword(s):  
Small Area ◽  
Character Displacement ◽  
Reproductive Character Displacement ◽  
Genetic Compatibility ◽  
Natural Interaction ◽  
Call Structure ◽  
Environmental Features ◽  
Mating Call ◽  
Eastern Australia ◽  
High Level

A small area of overlap with hybridization characterizes the interaction between northern L. ewingi and L. paraewingi. Although significant levels of postmating isolation exist between the taxa, no evidence of reproductive character displacement in mating-call structure is apparent within the contact zone. No obvious environmental features appear to correlate with the position of the zone. Northern L. ewingi and L. verreauxi alpina also form a hybrid zone where their ranges meet, and the position of the zone appears to be correlated with altitude. The taxa are characterized by a high level of genetic compatibility and no mating-call differentiation is evident. However, despite hybridization with adjacent taxa, the distinctness of northern L. ewingi is maintained away from the areas of interaction, and hence it is considered specifically distinct from L. paraewingi and L. v. alpina. No natural interaction between northern L. ewingi and L. ewingi has been located. However, they are considered to be conspecific because of: their morphological resemblance; the high level of genetic compatibility between them; and, the similarity of each of their interactions with L. paraewingi and with L. v. alpina.

The Litoria ewingi Complex (Anura: Hylidae) in South-Eastern Australia VII.* Mating Call Structure and Gentic Compatibility across a Narrow Hybrid Zone between L. ewingi and L. parawingi

1983 ◽  
Vol 31 (2) ◽  
pp. 193 ◽  
Author(s):  
MJ Littlejohn ◽  
GF Watson
Keyword(s):  
Hybrid Zone ◽  
Parental Species ◽  
Allopatric Population ◽  
Minimum Width ◽  
Call Structure ◽  
Allopatric Populations ◽  
South Eastern ◽  
Mating Call ◽  
Eastern Australia

On the basis of the number of pulses per repeated note and of repeated notes per call for individual males, the interaction between Litoria ewingi and L. paraewingi in the region of the Tallarook (northern) transect is interpreted as a transitional hybrid zone, with populations consisting of hybrids and individuals of only one or other parental species. The Tallarook transect thus differs from the Glenburn (southern) transect, which is considered to be an overlap of both parental species together with recombination products. The minimum width of the zone in the area of the Tallarook transect is estimated to be 25 km, compared with 5 km for the Glenburn transect. Levels of partial and total anophthalmia were assessed in progeny from in vitro crosses involving a total of 27 males from both transects whose calls had been recorded and analysed, and females of L. ewingi from adjacent allopatry (a measure of the genetic representation of L. paraewingi). The results are, with one exception, consistent with the mating-call structure of these males. As was found with the Glenburn transect, calls of males of L. paraewingi from an allopatric population on the Tallarook transect close to the zone of interaction are more distinctive from calls of L. ewingi in pulses per repeated note than are those of distant allopatric populations of L. paraewingi. This finding is consistent with the suggestion that the products of reinforcing selection may be accumulating near the zone of interaction.

Acoustic analysis of an intergrade zone between two call races of the Limnodynastes tasmaniensis complex (Anura : Leptodactylidae) in south-eastern Australia

1975 ◽  
Vol 23 (1) ◽  
pp. 113 ◽  
Author(s):  
MJ Littlejohn ◽  
JD Roberts
Keyword(s):  
Acoustic Analysis ◽  
Secondary Contact ◽  
Ecological Gradient ◽  
North Central ◽  
Call Structure ◽  
Central Victoria ◽  
South Eastern ◽  
Eastern Australia ◽  
Mating Calls ◽  
South Eastern Australia

Mating calls of the northern and southern call races of the L. tasmaniensis complex are described. Analysis of call structure along a transect across the main contact between these allopatric forms in north central Victoria indicates that there is a zone of intergradation between 90 and 135 km wide, about 215 km long and with a north-westerly orientation. The interaction is interpreted as a secondary contact in which there is hybrid or recombinant superiority along a subtle ecological gradient.

scholarly journals POSITIVE FEEDBACK BETWEEN ECOLOGICAL AND REPRODUCTIVE CHARACTER DISPLACEMENT IN A YOUNG AVIAN HYBRID ZONE

Evolution ◽  
2011 ◽  
Vol 66 (4) ◽  
pp. 1167-1179 ◽  
Author(s):  
Niclas Vallin ◽  
Amber M. Rice ◽  
Richard I. Bailey ◽  
Arild Husby ◽  
Anna Qvarnström
Keyword(s):  
Hybrid Zone ◽  
Positive Feedback ◽  
Character Displacement ◽  
Reproductive Character Displacement ◽  
Reproductive Character

A natural hybrid between Hyla arborea and Hyla meridionalis detected by mating calls

1991 ◽  
Vol 12 (1) ◽  
pp. 15-20 ◽  
Author(s):  
E.G. Crespo ◽  
M. Paillette ◽  
H.D. Rosa ◽  
M.E. Oliveira
Keyword(s):  
Allozyme Variation ◽  
Tree Frog ◽  
Natural Hybrid ◽  
Call Structure ◽  
Hyla Arborea ◽  
Testis Histology ◽  
Mating Call ◽  
Mating Calls

AbstractA tree-frog with unusual mating calls was found in an area of sympatry between H. arborea and H. meridionalis. This individual was studied by analysis of mating call structure and allozyme variation. The structure of the testes was also examined. The intermediate characteristics of the mating calls, the heterozygosity of all discriminative loci examined, and the apparent sterility, as shown by testis histology, all corroborate the identification of this hybrid.

Contact hybridization in the Crinia laevis complex (Anura : Leoptodactylidae)

1971 ◽  
Vol 19 (1) ◽  
pp. 85 ◽  
Author(s):  
MJ Littlejohn ◽  
GF Watson ◽  
JJ Loftus-Hills
Keyword(s):  
Environmental Factors ◽  
Hybrid Zone ◽  
Acoustic Analysis ◽  
Backcross Progeny ◽  
Geographic Ranges ◽  
Call Structure ◽  
Mating Call ◽  
High Level ◽  
Western Victoria ◽  
Different Parts

Mating-call structure was used to determine the nature and extent of an interaction between the two morphologically indistinguishable taxa, C. laevis and C. victoriana, where their geographic ranges contact in south-western Victoria. Intermediacy of mating-call structure was detected in a zone about 115 km long and less than 2 km wide. Acoustic analysis of call samples from six localities indicated that hybrids, backcross progeny, and one or both parental types were present in this zone. Results of reciprocal artificial hybridization tests between allopatric individuals of the two taxa showed that there was a high level of interfertility in both combinations, but with slightly reduced survival to metamorphosis. Presumed backcrosses using males from the hybrid zone resulted in a higher level of survival to metamorphosis. The zone does not coincide with any conspicuous ecotone and presumably represents a complex balance point with various environmental factors contributing to a greater or lesser extent in different parts of the contact. In spite of this lack of reproductive isolation, the narrowness of the zone and the presumed antiquity of the contact demonstrate that the taxa will continue to maintain their distinctness, and should retain their specific status.

The Litoria ewingi complex (Anura : Hylidae) in south-eastern Australia III. Blood protein variation across a narrow hybrid zone betweeen L. ewingi and L. Paraewingi

1972 ◽  
Vol 20 (4) ◽  
pp. 435 ◽  
Author(s):  
DF Gartside
Keyword(s):  
Hybrid Zone ◽  
Molecular Forms ◽  
Direct Selection ◽  
Blood Protein ◽  
Electrophoretic Study ◽  
Genetic Incompatibility ◽  
Protein Variation ◽  
Eastern Australia ◽  
Selection For ◽  
High Level

An electrophoretic study of transferrin distribution across a narrow hybrid zone between L. ewingi and L. paraewingi revealed seven molecular forms of transferrin. The transferrin frequencies and distribution may be an incidental product of the high level of genetic incompatibility between the taxa, or the result of direct selection for different transferrin types, or both. Haemoglobin variation was found only in L. ewingi samples. In most cases haemoglobins of L. ewingi and L. paraewingi were electrophoretically identical. The position and width of the hybrid zone, based on the biochemical data, generally agree with dimensions based on other criteria, although one transferrin cline is wider than those for other characteristics.

Studies in Australian amphibia III. The limnodynastes dorslis complex (Anura : Leptodactylidae)

1972 ◽  
Vol 20 (2) ◽  
pp. 165 ◽  
Author(s):  
AA Martin
Keyword(s):  
Western Australia ◽  
Hybrid Zone ◽  
Adult Male ◽  
Dominant Frequency ◽  
The Other ◽  
Hybrid Zones ◽  
Species Status ◽  
Call Structure ◽  
Mating Call ◽  
Male Morphology

The L. dorsalis complex is distributed extensively through coastal Australia, the Dividing Range, and parts of the western slopes and plains. Six subspecies have been described in the complex. Four of these are raised to species status and two additional subspecies are described. The complex thus comprises eight taxa in all: L. dorsalis, L. dumerili dumerili, L. d. insularis, L. d. grayi, L. d. variegatus, L, d. fryi, L. interioris, and L. terraereginae. The taxa were compared using two main criteria: adult male morphology and mating-call structure. Topotypic or near-topotypic samples of each form were obtained to ensure that comparisons were valid. L. dorsalis is restricted to Western Australia and is disjunctly allopatric to all the other forms in the complex. The eastern taxa have mainly parapatric distributions with several areas of contact between them. Where the range of L. d. dumerili comes into contact with those of L. d. insularis and L. d. variegatus, broad hybrid zones (up to 240 km wide) are formed. L. d. dumerili and L. d, grayi also appear to hybridize extensively. Where the range of L. d. dumerili contacts that of L. interioris a narrower hybrid zone (25-32km wide) is formed. Both L. d, dumerili and L. interioris have achieved sympatry with L, termereginae without any evidence of hybridization. The types of contact interactions can be related to the levels of divergence, particularly in mating-call structure, between the forms. Thus the calls of L, d. dumerili, L. d. insularis, L. d, grayi, and L. d. variegatus are all very similar. The call of L. interioris is quantitatively different to that of L. d. dumerili, with a lower dominant frequency,

Dispersal of the Australian Reptile Tick Aponomma Hydrosauri by Host Movement.

1978 ◽  
Vol 26 (2) ◽  
pp. 305 ◽  
Author(s):  
CM Bull
Keyword(s):  
Hybrid Zone ◽  
Sibling Species ◽  
Parental Species ◽  
Tape Recording ◽  
Call Structure ◽  
Allopatric Populations ◽  
High Modulation ◽  
Host Movement

Tape recordings of calls of males in allopatric populations of the sibling species Ranidella insignifera and R. pseudinsignifera show non-overlapping ranges of call modulation. Laboratory-raised hybrids have a call structure falling between the high modulation of the three- or four-pulsed call of R. pseudinsignifera and the low modulation of the almost unpulsed call of R. insignifera. However, hybrid calls could not always be distinguished from some calls of the parental species. The largely allopatric distributions of the two species meet along the scarp of the Darling Ranges. In two areas examined in detail, west of Perth and north of Bullsbrook, populations sampled by ear and by tape recording confirmed earlier studies which suggested that there is a very steep cline, over less than 3 km, from populations with mostly R. pseudinsignifera-like calls, to populations with mostly R. insignifera-like calls. Populations with calls of both parental species as well as intermediate calls were detected in this zone, but the extent of introgression could not be judged on the basis of call structure alone. The evidence suggests that the hybrid zone is stable in time.

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