Final answer:
Wolves in Italy faced a genetic bottleneck due to population decline by the 1970s. Afterward, as the population recovered and wolves spread to France, an increase in haplotype diversity is expected due to new genetic variations and the natural processes associated with the establishment of new populations.
Step-by-step explanation:
The question focuses on the explanation for the number of haplotypes in wolves that have spread from Italy to France. During periods of population decline, such as when wolves in Italy dwindled to fewer than 100 individuals by the 1970s, the level of genetic variety within the population would have been significantly reduced due to the effects of genetic bottlenecks.
However, since the 1980s, as the number of wolves has increased and individuals have dispersed to new habitats, including France, we would expect to see an increase in haplotype diversity. This is due to the promotion of genetic diversity through the founding of new populations by a few individuals, followed by population expansion which can lead to the occurrence of new genetic variations or the spread of existing variant haplotypes in the wolf population.
As such, the wolves that spread to France could be expected to have a variety of haplotypes due to their recent history of population expansion and the natural increase in genetic variations that comes with it. This increase can occur through mutations, natural selection, migration, and genetic drift during the establishment of new populations.