Sexual isolation between two newt species, Triturus vulgaris and T. montandoni (Amphibia, Urodela, Salamandridae)

Abstract

Riolqpical~r/ournal ofthe Linnenn Socie!v (1 999), 67: 343 352.Article ID: bijl. 1998.0306, available online at http://~w.idealibra r)...com o n I D E b b 0 c Sexual isolation between two newt species, -Triturus vulgaris and T montandoni (Amphibia, Urodela, Salamandridae)In the present study we investigated sexual isolation between TrituruJ vulgaris and 7: montandoni in mating experiments run under semi-natural conditions. The two newt species offer a suitable model for studying evolution of reproductive isolation and mating preferences because they arc genetically the most similar species within the genus and readily hybridize in nature. Separate experiments were conducted in which groups of virgin females were placed together (in artificial pools) with groups of homospecific, heterospecific or both types of males. T h r estimates of reproductive isolation and mating propensity were based on the numbers of females producing hybrids and/or non-hybrid progeny. The levels of reproductive isolation, isolation asymmetry (IA) and propensity asymmetry (PA) were significant only for experiments in which females were given a choice between conspecific and heterospecific males. This implies that mating experiments with no interspecific choice may reduce discrimination and affect patterns of IA and PA. Asymmetry in reproductive isolation was also significant when the analysis was confined to just inseminated females. Differences in habitat preferences and condition of females possibly contributed to the relativcly high values of PA. 0 1999 The 1,innean Society of I.ondon

Differential introgression across newt hybrid zones: Evidence from replicated transects

“…Such hierarchical sampling should allow us to disentangle systematic differences between zones from random variation between transects (Janoušek et al, ). Overall, all transects were similar—allele frequency clines were narrow compared to the dispersal capabilities of newts (Smith & Green, ) and hybrids were uncommon, indicating strong reproductive isolation, due to assortative mating (Babik, Szymura, & Rafiński, ; Michalak & Rafiński, ) and possibly low fitness of hybrids. Local variation in environmental factors had some modulating effect on the characteristics of individual transects, but environmental associations were relatively weak compared to spatial position within the transect.…”

Nuclear markers, mitochondrial DNA and male secondary sexual traits variation in a newt hybrid zone (Triturus vulgaris × T. montandoni)

“…Previous studies on mating behaviour in T. vulgaris and T. montandoni (Michalak et al . 1997) in laboratory and garden pond experiments (Michalak & Rafiński 1999) showed strong behavioural isolation between newts from allopatric populations. Some asymmetry in isolation was also detected, with the montandoni females being more discriminating.…”

“…In heterospecific matings T. montandoni females appear to be more discriminating than T. vulgaris females (Michalak et al . 1997; Michalak & Rafiński 1999).…”

Molecular and morphological evidence of hybridization between newts Triturus vulgaris and T. montandoni (Caudata: Salamandridae) in Slovakia

“…Hybrids of intermediate phenotype were recorded in Ukraine by Hofmann (1908), Kushniruk (1963) and Bannikov (1969), in Romania by Fuhn (1963) and Fuhn et al (1975), in Poland by SzeligaMierzeyewski & Ulasiewicz (1931), Juszczyk &Świerad (1984, Rafiński (1985Rafiński ( , 1988, Pecio & Rafiński (1985), Rafiński & Pecio (1989) and Babik et al (2003), and in the Czech Republic described by Rehák (1992Rehák ( , 1993, Zwach (1992), Šálek (1993), Kotlík et al (1997), Kotlík & Zavadil (1999) and Zavadil et al (2003Zavadil et al ( , 2004. Besides hybrids in nature, hybrids in captivity were obtained during laboratory experimental crosses (Wolterstorff 1925;Geyer 1953Geyer , 1954Macgregor et al 1990;Cogȃlniceanu 1992Cogȃlniceanu , 1994Michalak & Rafiński 1999). A detailed survey of T. vulgaris and T. montandoni hybrid zone in Poland exhibits its mosaic pattern, i.e., genetic composition of populations is only weakly associated with their geographic position (Babik et al 2003).…”