Greater Fritillaries are a genus of butterflies that are also known as “silverspots” due to the silver spots many of them have beneath their hind wings. Greater Fritillaries in New England include the Great Spangled Fritillary , the Aphrodite Fritillary and the Atlantis Fritillary. It can be challenging to tell these three orange-dappled species apart. The black margins on the upper side of the pictured Atlantis Fritillary’s wings help identify it. This fritillary is named after Atlantis, a legendary island first mentioned by Plato. While adult Atlantis Fritillaries favor the nectar of milkweed, thistle, burdock and boneset, the brown and black-speckled larvae feed on violets.
According to the Vermont Center for Ecostudies, this spring and summer there’s been an estimated drop of 90% in the overall monarch population in eastern Canada – the most dramatic decline ever recorded. Vermont (and most likely New England in general) is experiencing much the same situation. The low numbers of monarchs are due to several factors that they have encountered along their migratory routes the past couple of years, including extreme temperatures, record drought, low nectar production by flowering plants and a scarcity of their host plant, milkweed. The cold temperatures and record amounts of rain this spring undoubtedly added to their stress.
Of all the insects I’ve found in milkweed patches over the years, the Hummingbird Clearwing is one of my favorites. It is a species of sphinx moth, named for its habit of hovering at flowers while it gathers nectar with its proboscis in a manner similar to that of hummingbirds. In fact, they are often mistaken for hummingbirds. The transparent wings, light brown thorax and dark chestnut abdomen are the field marks to look for. A diurnal moth, the Hummingbird Clearwing can often be found during the day in milkweed patches.
Milkweed is in full bloom right now, presenting the perfect opportunity for young and old alike to discover the multitude of butterflies, beetles, bees and other insects that are attracted to these magnificent flowers. If you visit a milkweed patch, don’t leave before getting a good whiff of the flowers’ scent – one of the sweetest on earth. How many of the insects you find are carrying milkweed’s yellow pollen “saddlebags” on their feet? You might want to check out my children’s book, MILKWEED VISITORS, which I wrote after spending the better part of one summer photographing the various insects I found visiting a milkweed patch. ( http://basrelief.org/Pages/MV.html )
This time of year you can often find many orange and black bugs on milkweed leaves. If they are black with an orange “X” on their forewings, they are small milkweed bugs (Lygaeus kalmii). This combination of colors, which many insects that feed on milkweed have, warns predators that, due to ingesting milkweed toxins, red and orange insects may be bad for their health. Adult small milkweed bugs feed mainly on milkweed seeds, but they also consume the nectar of a variety of flowers. In addition, they occasionally prey on insects, such as the ant in the accompanying photograph.
We think of monarch larvae as being impervious to the ills of milkweed, but they are very vulnerable when it comes to the sticky latex in the sap of their host plant. The mandibles of young monarch caterpillars are often glued together by this latex, preventing them from eating. Research shows that about 30 percent of monarch larval loss results from miring in this glue-like substance. One strategy young larvae use is to chew a near circle in a milkweed leaf, blocking the flow of latex to the enclosed surface area, which they then eat. If a monarch survives the first few stages, or instars, of its larval life, it uses yet another strategy to circumvent the latex. Older, larger larvae often cut through the midvein of a leaf they wish to consume, which dams the latex flow to the entire leaf beyond the cut. Look for limp leaves as you peruse a milkweed patch. If you find one, you may be rewarded with the nearby presence of a monarch caterpillar.