Two populations in southern Florida are particularly notable. The more southern of these two populations feeds on the seeds of a native host vine
balloon vine (
Cardiospermum corindum). This vine produces capsules of a fairly uniform size, which adult
J. haematoloma feed on by inserting their
mouthparts (beak) through the capsule's exterior and into the interior seeds. In the mid-1950s, a related
southeast Asian tree, the Taiwanese Flamegold (
Koelreuteria elegans), was introduced as an
ornamental plant. It escaped domestication and naturalized. Significantly, the Flamegold was colonized by
J. haematoloma, though its capsules are smaller and the seeds less deeply embedded than in the balloon vine. In a seminal paper published in the scientific journal
Genetica in 2001, it was shown evolution had taken place in this colonizing population of
J. haematoloma on the Flamegold in a period of only a few decades. They showed that the beak length, which in the
ancestral type was about 70% the length of the body, was only about 50% the body length in the insects that had colonized the
non-native tree, though the size of the bugs themselves had not changed. In addition, they found that: ...derived bugs mature 25% more rapidly, are 20% more likely to survive, and lay almost twice as many eggs when reared on seeds of the introduced host rather than those of the native host. Fecundity is also twice as great as that of ancestral type bugs reared on either host, while egg mass is 20% smaller. ==References==