Encontros Scientia Reproductive barriers between two sympatric

Encontros Scientia
Reproductive barriers between two
sympatric beetle species specialized
on different host plants
CBA Researcher (Ciência 2007)
Knowledge on interspecific pre- and post-zygotic isolation mechanisms provides insight into speciation patterns. Using crosses (F1
and backcrosses) of two closely related flea beetles species, Altica fragariae and A. viridicyanea, specialized on different hosts in
sympatry, we measured (a) the type of reproductive isolation and (b) the inheritance mode of preference and host-specific
performance, using a joint-scaling test. Each species preferred almost exclusively its host plant, creating strong pre-zygotic isolation
between them, and suggesting that speciation may occur at least partly in sympatry. Reproductive isolation was intrinsic between
females of A. fragariae and either A. viridicyanea or F1 males, whereas the other crosses showed ecologically-dependent
reproductive isolation, suggesting ecological speciation. The genetic basis of preference and performance was at least partially
independent, and several loci coded for preference, which limits the possibility of sympatric speciation. Hence, both ecological and
intrinsic factors may contribute to speciation between these species.
4ª feira, 3 de Março de 2010
FCUL- Edif. C2- Piso 2- Anf. 2.2.14 - 12:00-13:00h