use Data::Dumper;

my %islanders;
while (<DATA>) {
        chomp;
        my ($key, $cnt, $fruit) = split / /;
        $key =~ s/://g;
        $islanders{$key}{$fruit} += $cnt;
}
print Dumper(\%islanders);

__DATA__
Gilligan: 1 coconut
Skipper: 3 coconuts
Gilligan: 1 banana
Ginger: 2 papayas
Professor: 3 coconuts
MaryAnn: 2 papayas