Premium
Confrontation of cryptic diversity and mate discrimination within G ammarus pulex and G ammarus fossarum species complexes
Author(s) -
Lagrue Clement,
Wattier Remi,
Galipaud Matthias,
Gauthey Zoe,
Rullmann JeanPaul,
Dubreuil Christine,
Rigaud Thierry,
Bollache Loic
Publication year - 2014
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/fwb.12453
Subject(s) - biology , sympatric speciation , gammarus pulex , pulex , zoology , mating , amphipoda , sympatry , ecology , evolutionary biology , crustacean , daphnia
Summary Freshwater amphipods G ammarus fossarum and G ammarus pulex are widespread in Europe, with some evidence of cryptic diversity in the former. We used DNA barcoding to assess genetic diversity within and among amphipod populations and examined mate discrimination and pre‐copulatory pair formation between genetically divergent individuals. Eight distinct G . fossarum and four distinct G . pulex molecular operational taxonomic units (MOTUs) were detected. Among the 33 amphipod populations sampled, 11 contained a single MOTU , 11 had two and 11 were composed of three sympatric MOTU s. Genetic divergences between sympatric MOTU s ( G . fossarum and G . pulex MOTU s combined) ranged up to 28% (Kimura two parameter estimates). In amphipod populations containing sympatric MOTU s, pre‐copulatory pair formation was random between MOTU s diverging by <4%. However, pre‐copulatory pairs involving amphipod individuals from MOTU s diverging by >4% were rare, suggesting mate discrimination between sympatric, highly divergent MOTU s. Although the likelihood decreased with genetic distance between partners, pre‐copulatory pair formation in the laboratory can occur between MOTU s diverging by c . 16% and led to successful mating: most female amphipod carried viable, fertilised eggs 48 h post‐mating. Data showed high cryptic diversity in the G . fossarum / G . pulex groups, even at a small spatial scale. Mate discrimination between genetically divergent amphipods in natural populations suggests that some of the MOTU s found in G . fossarum and G . pulex may be separated into (sub)species. However, amphipods from different MOTU s can still form pre‐copulatory pairs and females produce viable eggs. Overall, data suggest that cryptic diversity is common in the G . fossarum / G . pulex groups and that pre‐zygotic isolation through mate discrimination, rather than post‐zygotic incompatibility, is likely to drive cryptic speciation.