Hybridization of mouse lemurs: different patterns under different ecological conditions

Area of Science:

• Ecology
• Evolutionary Biology
• Genetics

Background:

• Madagascar's high endemic species diversity may result from secondary contact and hybridization.
• Existing models of diversification do not account for hybridization's role.
• Environmental settings influence secondary contact and hybridization dynamics.

Purpose of the Study:

• To investigate the influence of different environmental settings on hybridization between two mouse lemur species.
• To compare hybridization patterns in a sharp spiny bush-gallery forest ecotone with a gradient hybrid zone.

Main Methods:

• Population genetic analyses using mtDNA sequences and nine nuclear microsatellites.
• Characterization of a contact zone between Microcebus griseorufus and M. murinus in distinct habitats.
• Comparison with a previously studied hybrid zone across a habitat gradient.

Main Results:

• Bidirectional introgressive hybridization was observed in the spiny-gallery system, linked to increased spatial overlap.
• 18 hybrids were identified, with potential underestimation of their true number.
• Environmental factors, such as short-term climate fluctuations and long-term aridification, appear to drive hybridization dynamics.

Conclusions:

• Two distinct mouse lemur hybrid zones in Madagascar are shaped by different environmental settings.
• Hybridization may enhance species adaptability without causing loss of distinctiveness.
• Hybridization could play a significant role in Madagascar's diversification, warranting further research.