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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.


Ovipositor length relative to body size (pronotal width) in females.
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f5-insects-02-00195: Ovipositor length relative to body size (pronotal width) in females.

Mentions: At the time that Bill Cade and I started our character displacement study, there were no known morphological means of distinguishing between these two species. That situation is unchanged for males, however during our work we observed that female G. rubens appeared to have longer ovipositors relative to body size than did female G. texensis. To confirm this, we measured ovipositor length and pronotal width, and we found that females were in fact quite strongly divergent in relative ovipositor length [67]. In particular, if we make a histogram of ovipositor length divided by pronotal width, we see imperfect but bimodal separation (Figure 5). Ovipositor length in crickets is clearly an ecologically linked trait; effects of phylogenetic history, latitude, egg size, oviposition behavior, diapause strategy, and soil type have all been described [68–73]. G. rubens and G. texensis share their deeper phylogenetic history, are found at similar latitudes, and both have facultative nymphal diapause with no egg diapause observed. Egg size, oviposition strategy, and soil preferences have not been examined, but G. rubens, in Florida and the southeastern coastal areas especially, experiences sandier soils than elsewhere throughout the species' ranges. Sandy soils drain and dry quickly compared to more loamy or clay-laden soils, and crickets are known to oviposit deeper in dryer sandy soil [73]. The congeneric species pair, G. firmus (known as the ‘sand field cricket’) and G. pennsylvanicus show a similar pattern: both have recent shared evolutionary history, both are egg diapausing species, but G. firmus has a considerably longer ovipositor than the more inland G. pennsylvanicus [71,74]. Ovipositor length thus appears to be an indicator of adaptive ecological divergence between G. rubens and G. texensis. This would be especially true for G. rubens populations in the southeastern US coastal areas, including peninsular Florida.


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

Gray DA - Insects (2011)

Ovipositor length relative to body size (pronotal width) in females.
© Copyright Policy
Related In: Results  -  Collection

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

f5-insects-02-00195: Ovipositor length relative to body size (pronotal width) in females.
Mentions: At the time that Bill Cade and I started our character displacement study, there were no known morphological means of distinguishing between these two species. That situation is unchanged for males, however during our work we observed that female G. rubens appeared to have longer ovipositors relative to body size than did female G. texensis. To confirm this, we measured ovipositor length and pronotal width, and we found that females were in fact quite strongly divergent in relative ovipositor length [67]. In particular, if we make a histogram of ovipositor length divided by pronotal width, we see imperfect but bimodal separation (Figure 5). Ovipositor length in crickets is clearly an ecologically linked trait; effects of phylogenetic history, latitude, egg size, oviposition behavior, diapause strategy, and soil type have all been described [68–73]. G. rubens and G. texensis share their deeper phylogenetic history, are found at similar latitudes, and both have facultative nymphal diapause with no egg diapause observed. Egg size, oviposition strategy, and soil preferences have not been examined, but G. rubens, in Florida and the southeastern coastal areas especially, experiences sandier soils than elsewhere throughout the species' ranges. Sandy soils drain and dry quickly compared to more loamy or clay-laden soils, and crickets are known to oviposit deeper in dryer sandy soil [73]. The congeneric species pair, G. firmus (known as the ‘sand field cricket’) and G. pennsylvanicus show a similar pattern: both have recent shared evolutionary history, both are egg diapausing species, but G. firmus has a considerably longer ovipositor than the more inland G. pennsylvanicus [71,74]. Ovipositor length thus appears to be an indicator of adaptive ecological divergence between G. rubens and G. texensis. This would be especially true for G. rubens populations in the southeastern US coastal areas, including peninsular Florida.

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.