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Speciation, Divergence, and the Origin of Gryllus rubens: Behavior, Morphology, and Molecules.

Gray DA - Insects (2011)

Bottom Line: This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions.This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule.The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than 'sister' species we should consider these taxa as 'mother-daughter' species with G. rubens derived from within a subset of ancestral G. texensis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330, USA. dave.gray@csun.edu.

ABSTRACT
The last 25 years or so has seen a huge resurgence of interest in speciation research. This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions. Here I review about a decade of work on the sister species of field crickets Gryllus texensis and G. rubens. This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule. The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than 'sister' species we should consider these taxa as 'mother-daughter' species with G. rubens derived from within a subset of ancestral G. texensis.

No MeSH data available.


Waveform (amplitude versus time) representative courtship songs of G. rubens (Figure 2a) and G. texensis (Figure 2b).
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f2-insects-02-00195: Waveform (amplitude versus time) representative courtship songs of G. rubens (Figure 2a) and G. texensis (Figure 2b).

Mentions: Given that males and females may encounter one another without calling song, we conducted several studies to examine divergence in male courtship song, and in male and female close-range mating behaviors. Courtship song in G. rubens and G. texensis is composed of a series of quieter mostly pure tone lower-frequency ticks (ca. 5 kHz) with louder broader spectrum higher-frequency ticks (most sound energy 11–14 kHz) at regular intervals (Figure 2). Just by recording and analyzing male courtship songs, we were able to show that G. rubens and G. texensis differ in their courtship song rates in a manner that mirrors their calling song pulse rates: G. texensis has faster courtship song than G. rubens [50], and experimental manipulation of the diet showed that courtship song features did not appear to reflect male nutritional condition [51]. Based on this, my lab conducted two separate studies of close-range courtship and mating behavior with these species. The first [52], used muted males with virgin females of both species. Males that courted females, although themselves mute, were accompanied by a synthetic species average courtship song played via a tweeter directly under the pair of crickets. Thus males had the opportunity to court females, or not, and females had two experimentally separated sources of information about male species identity (1) from their cuticular hydrocarbons (unmanipulated) and (2) from the accompanying courtship song (manipulated). I replicated the entire experiment with crickets from allopatry and sympatry, using G. texensis from Austin, Texas and Tuscalloosa, Alabama, and G. rubens from Gainesville, Florida, and from Tuscallosa, Alabama. In short, the results showed separate significant effects of male species identity and courtship song played on the likelihood of female mounting; there was no difference in either species between the behaviors of crickets from sympatry and allopatry (Figure 3). Although these results show divergence in close-range courtship mating behaviors, they also notably show that despite significant species effects, the potential for hybridization is not trivial—on the assumption of no prior female phonotaxis to male calling song.


Speciation, Divergence, and the Origin of Gryllus rubens: Behavior, Morphology, and Molecules.

Gray DA - Insects (2011)

Waveform (amplitude versus time) representative courtship songs of G. rubens (Figure 2a) and G. texensis (Figure 2b).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4553458&req=5

f2-insects-02-00195: Waveform (amplitude versus time) representative courtship songs of G. rubens (Figure 2a) and G. texensis (Figure 2b).
Mentions: Given that males and females may encounter one another without calling song, we conducted several studies to examine divergence in male courtship song, and in male and female close-range mating behaviors. Courtship song in G. rubens and G. texensis is composed of a series of quieter mostly pure tone lower-frequency ticks (ca. 5 kHz) with louder broader spectrum higher-frequency ticks (most sound energy 11–14 kHz) at regular intervals (Figure 2). Just by recording and analyzing male courtship songs, we were able to show that G. rubens and G. texensis differ in their courtship song rates in a manner that mirrors their calling song pulse rates: G. texensis has faster courtship song than G. rubens [50], and experimental manipulation of the diet showed that courtship song features did not appear to reflect male nutritional condition [51]. Based on this, my lab conducted two separate studies of close-range courtship and mating behavior with these species. The first [52], used muted males with virgin females of both species. Males that courted females, although themselves mute, were accompanied by a synthetic species average courtship song played via a tweeter directly under the pair of crickets. Thus males had the opportunity to court females, or not, and females had two experimentally separated sources of information about male species identity (1) from their cuticular hydrocarbons (unmanipulated) and (2) from the accompanying courtship song (manipulated). I replicated the entire experiment with crickets from allopatry and sympatry, using G. texensis from Austin, Texas and Tuscalloosa, Alabama, and G. rubens from Gainesville, Florida, and from Tuscallosa, Alabama. In short, the results showed separate significant effects of male species identity and courtship song played on the likelihood of female mounting; there was no difference in either species between the behaviors of crickets from sympatry and allopatry (Figure 3). Although these results show divergence in close-range courtship mating behaviors, they also notably show that despite significant species effects, the potential for hybridization is not trivial—on the assumption of no prior female phonotaxis to male calling song.

Bottom Line: This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions.This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule.The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than 'sister' species we should consider these taxa as 'mother-daughter' species with G. rubens derived from within a subset of ancestral G. texensis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330, USA. dave.gray@csun.edu.

ABSTRACT
The last 25 years or so has seen a huge resurgence of interest in speciation research. This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions. Here I review about a decade of work on the sister species of field crickets Gryllus texensis and G. rubens. This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule. The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than 'sister' species we should consider these taxa as 'mother-daughter' species with G. rubens derived from within a subset of ancestral G. texensis.

No MeSH data available.