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

1978 ◽  
Vol 26 (2) ◽  
pp. 305 ◽  
Author(s):  
CM Bull

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.

1983 ◽  
Vol 31 (2) ◽  
pp. 193 ◽  
Author(s):  
MJ Littlejohn ◽  
GF Watson

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.


1976 ◽  
Vol 24 (2) ◽  
pp. 283 ◽  
Author(s):  
MJ Littlejohn

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.


Botany ◽  
2008 ◽  
Vol 86 (3) ◽  
pp. 228-239 ◽  
Author(s):  
E. Tovar-Sánchez ◽  
P. Mussali-Galante ◽  
R. Esteban-Jiménez ◽  
D. Piñero ◽  
D. M. Arias ◽  
...  

Quercus crassifolia H. & B. and Quercus crassipes H. & B. are two common temperate forest species in Mexico that form hybrids when they occur in mixed (sympatric) areas. In this study, we used chloroplast microsatellite haplotypes to infer phylogeographic patterns onto the genetic structure of populations of both parental species, thus defining probable colonization routes throughout Mexico. Haplotype diversity in seven hybrid zones and four allopatric sites with nonmixed (allopatric) populations of both putative parental species was analyzed. To determine the expansion and colonization routes for the two species, we carried out a nested clade phylogeographic analysis that would allow us to infer the haplotype correspondence to a phylogeographical approach. In spite of sharing many common populations, we determined that there is a different genetic historical colonization for Q. crassipes and for Q. crassifolia. Hybrid populations had the highest levels of genetic variation (Gv), Shannon diversity index (H), and haplotype number (nh) in comparison with nonmixed/allopatric populations of their putative parentals. Furthermore, populations of hybrid zones showed the highest values of genetic differentiation FST, RST . Moreover, both species share four distinctive cpDNA haplotypes, which were most likely acquired by introgression through hybrids located in several populations throughout the Eje Neovolcánico area. This last region was confirmed to be a “hot spot” for oak diversity, a place in which different maternal lineages merged.


Evolution ◽  
1998 ◽  
Vol 52 (6) ◽  
pp. 1602 ◽  
Author(s):  
Diane R. Campbell ◽  
Nickolas M. Waser ◽  
Paul G. Wolf

2020 ◽  
Vol 190 (2) ◽  
pp. 757-769
Author(s):  
Imanol Cabaña ◽  
Margarita Chiaraviglio ◽  
Valeria Di Cola ◽  
Antoine Guisan ◽  
Olivier Broennimann ◽  
...  

Abstract Understanding the factors that affect hybridization is an important issue in the study of species evolution. In this work, we analyse the genetic structure of two lizard species, Salvator merianae and Salvator rufescens, at a microscale within a climatic niche analysis framework, to reveal the main factors that contribute to the stability of their hybrid zone. We assess the effect of climate in hybridization by quantifying and decomposing the niche overlap of both species. Using a mitochondrial and a nuclear marker, we find that hybridization is frequent and is not restricted to the sympatric region. The gene flow is mainly from S. rufescens to S. merianae, with introgression into the range of S. merianae. Also, S. merianae would have long been present in the area, while S. rufescens appears to be a recent colonizer. The climate contributes to the population structure of S. merianae, but not to that of S. rufescens. The niches occupied by S. rufescens in the hybrid zone and the non-hybrid zone are similar, while the niches of S. merianae are different. Our results do not fit previous models of hybrid zone stability, suggesting the need to develop new models that consider the evolutionary factors that can differentially affect parental species and hybrids.


1983 ◽  
Vol 25 (4) ◽  
pp. 370-377 ◽  
Author(s):  
Dennis J. Wogaman ◽  
Marvin B. Seiger

Light preferences for ovipositing of the sibling species Drosophila pseudoobscura and D. persimilis were measured in a multichoice chamber. Behavioral differentiation was found among sympatric populations of D. pseudoobscura and D. persimilis and between allopatric populations of D. pseudoobscura. Differences among isofemale lines within populations indicated genetic variability for the behavior. Both D. pseudoobscura populations were less fecund in a uniform light environment than in the multichoice environment while D. persimilis showed no difference in fecundity in the two environments. The patterns for general photoresponse and ovipositional light response were shown to be different for each population. Thus, the motivation to oviposit may affect photopreference differentially in each population.


The Auk ◽  
2000 ◽  
Vol 117 (1) ◽  
pp. 175-183 ◽  
Author(s):  
Scott F. Pearson ◽  
David A. Manuwal

Abstract Hybrid zones between Townsend's Warblers (Dendroica townsendi) and Hermit Warblers (D. occidentalis) in the Pacific Northwest are narrow relative to estimated dispersal distances and appear to be moving, with Townsend's replacing Hermits. We examined whether the habitat-transition and parental-fitness asymmetry models can explain why these zones are narrow and moving by comparing habitat variables associated with warbler territories in the Washington Cascades hybrid zone. Habitat variables did not differ among phenotypes, suggesting that the habitat-transition model cannot explain the narrow and dynamic nature of this hybrid zone. Habitat characteristics of Hermit Warbler territories did not differ inside versus outside the hybrid zone, also suggesting that this zone is not associated with a region of habitat transition. The lack of difference in habitat use could be the result of comparing variables that are not important to pairing success. However, warblers tended to select territories on west-southwest aspects. South aspects in the southern Washington Cascades are dominated by Douglas fir (Pseudotsuga menziesii) and true fir, which is a habitat selected by female warblers when choosing among territories and males. The parental-fitness asymmetry model does not necessarily make predictions about habitat use within the hybrid zone but predicts the superiority of one parental species over the other. However, if significant overlap occurs in habitat use or niche (as in these warblers), then competition between parental species is likely to occur. To determine whether these species compete, we mapped 12 warbler territories and monitored an additional 94 territories throughout the breeding season and found that all males with neighbors compete for and hold exclusive territories. Thus, the pattern of habitat use and territoriality is consistent with the parental-fitness asymmetry model.


1973 ◽  
Vol 62 (4) ◽  
pp. 557-563 ◽  
Author(s):  
T. W. Hogan ◽  
P. G. Fontana

As part of a research project directed at the genetic control of Teleogryllus commodus (Wlk.) in Australia, hybridisation studies have been carried out between T. commodus and the sibling species T. oceanicus (Le Guillou). A cytological examination of a hybrid strain (male progeny of T. commodus × T. oceanicus backcrossed to T. oceanicus) was made in the F4 generation when meiotic stability had been reached. The karyotype was very similar to that of T. oceanicus, suggesting that only those combinations in which the chromosomes were structurally homologous to T. oceanicus survived. But the stridulation pattern of the hybrid males, intermediate between that of the two parental species, and a consistent sex ratio of 2:1 in favour of the males, indicate profound genetic differences from T. oceanicus. These effects are attributed to introgression, with chromosomal material from T. commodus being incorporated in the T. oceanicus genome as an outcome of the initial hybridisation of the two species.


1989 ◽  
Vol 67 (3) ◽  
pp. 579-584 ◽  
Author(s):  
Mrinal K. Das ◽  
Joseph S. Nelson

Hybridization between northern redbelly dace (Phoxinus eos) and finescale dace (Phoxinus neogaeus) was studied in Upper Pierre Grey Lake, Alberta. Sympatric parental and hybrid populations were compared with allopatric populations from Cameron Lake and Tay Lake, Alberta. Canonical variates and principal components analyses, using 31 morphological characters, revealed that the two parental groups were bridged by an intermediate all-female hybrid group in Upper Pierre Grey Lake. Hybrids made up approximately 33% of the individuals of the sympatic population. Neither backcross nor hybrid F2 individuals could be identified from the analyses, although the majority of hybrids were morphologically more similar to P. neogaeus than to P. eos. No clear evidence of introgressive hybridization was found in either of the sympatric parental species.


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