The larvae of Monarch Butterflies (Danaus plexippus) feed exclusively on plants in the genus Asclepias (Milkweeds) and a few other related genera.
Monarch larva on Butterfly Weed (Asclepias tuberosa)
According to a new study published in the journal Insect Conservation and Diversity (Pleasants & Oberhauser, 2012), overwintering monarch butterfly populations in Mexico have declined by about half since 1999. This is correlated with an estimated 58% decline in milkweed populations in the Midwest and a corresponding decline of 81% in monarch breeding success. These effects are most likely due to the widespread use of Glyphosate on genetically modified crops immune to the herbicide (i.e. Roundup Ready crops).
With the exceptionally warm weather we are experiencing now in the northeast, I decided to take a trip to Little York to see if any plants were blooming. While the spring ephemerals are still at least a few weeks from flowering I did find Daphne and Speckled Alder in full bloom.
The male flowers are in the larger catkins, while the female flowers are in the short reddish ones. Daphne has more showy blooms, with 4 magenta petal-like sepals and a light fragrance. While the speckled alder is a native wetland shrub, Daphne mezereum is native to Europe and parts of Asia. It can be found in some of our rich woodlands, often along trails. The flowers are followed by bright red fruit in May or June.
Not much else was flowering, however the maples and aspens appear to be flowering on the hillsides a few weeks earlier than I’ve seen in previous years.
The European frog-bit (Hydrocharis morsus-ranae) is thought to have been first introduced to St. Lawrence County in New York in 1974. The distribution map from the NY Flora Atlas (below) shows the counties where specimens have been collected.
This map does not appear to reflect the current distribution of this species. I have observed it at Raquette Lake in Hamilton County and at Three Rivers in Onondaga County. It likely spread to the latter area from Oneida Lake via the Oneida River. This species looks like a tiny water lily with 3 white petals. It might be confused with the native Nymphoides cordata, which has 5 petals.
There is an American frog-bit (Limnolobium spongia) that is native further south of New York and is occasionally introduced. It differs from the European frog-bit in having branched (rather than unbranched) roots, petals less than 1.5 times as long as the sepals (rather than more than 1.5 times as long), and one stipule per leaf that is attached below the petiole (rather than 2 free stipules).