The ways in which abiotic factors contribute to parallel evolution – the evolution of similar, derived phenotypes in independent, closely related lineages – remain understudied. Australian blaberid cockroaches of the subfamilies Panesthiinae (‘wood feeders’) and Geoscapheinae (‘soil burrowers’) are two closely related groups that provide a striking example of parallel evolution of burrowing behaviour. The ancestral wood-feeding panesthiines migrated from Asia ~20 million years ago before soil burrowing was independently acquired multiple times in the derived geoscapheines.
We investigated whether specific abiotic factors were associated with the parallel evolution of soil burrowing behaviour, and whether divergence events of geoscapheines from panesthiine ancestors are consistent with niche conservatism or diversification. These analyses were paired with statistical tests exploring the extent of morphological convergence in the Geoscapheinae on forelegs adapted for burrowing. We then generated environmental niche models for members of both subfamilies using presence-only data and abiotic variables related to temperature, precipitation, and soil composition.An existing phylogenetic framework was used to reconstruct ancestral niches and compare environmental niche models, and tests for niche overlap and phylogenetic signal were also performed.
We found that soil burrowing behaviour is consistently correlated with thirteen abiotic factors associated with aridity, including a wider range of temperatures and lower precipitation levels. Evidence for convergence in leg morphology and body dimensions across soil burrowers was found. Overall, we find that the onset of aridity in Australia – and therefore the shrinking of available mesic habitats – likely contributed to the repeated and independent acquisition of soil burrowing behaviour in geoscapheine cockroaches.
The ways in which abiotic factors contribute to parallel evolution – the evolution of similar, derived phenotypes in independent, closely related lineages – remain understudied. Australian blaberid cockroaches of the subfamilies Panesthiinae (‘wood feeders’) and Geoscapheinae (‘soil burrowers’) are two closely related groups that provide a striking example of parallel evolution of burrowing behaviour. The ancestral wood-feeding panesthiines migrated from Asia ~20 million years ago before soil burrowing was independently acquired multiple times in the derived geoscapheines.
We investigated whether specific abiotic factors were associated with the parallel evolution of soil burrowing behaviour, and whether divergence events of geoscapheines from panesthiine ancestors are consistent with niche conservatism or diversification. These analyses were paired with statistical tests exploring the extent of morphological convergence in the Geoscapheinae on forelegs adapted for burrowing. We then generated environmental niche models for members of both subfamilies using presence-only data and abiotic variables related to temperature, precipitation, and soil composition.An existing phylogenetic framework was used to reconstruct ancestral niches and compare environmental niche models, and tests for niche overlap and phylogenetic signal were also performed.
We found that soil burrowing behaviour is consistently correlated with thirteen abiotic factors associated with aridity, including a wider range of temperatures and lower precipitation levels. Evidence for convergence in leg morphology and body dimensions across soil burrowers was found. Overall, we find that the onset of aridity in Australia – and therefore the shrinking of available mesic habit ...
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