Saturday, August 31, 2019

A-Courting We Shall Go

Out of all insects, butterflies are favorites of humans for their sheer visibility and beauty. Although bees and other pollinators are getting more attention lately as parts of a healthy, functioning ecosystem, it is the colorful, scale-winged lepidopterans that have lit our imaginations for centuries.

What is not to love? They are utterly harmless to us; they are colorful and decorative, and they hang out on beautiful flowers sipping nectar and gently flapping their wings in the sun (we ignore or forgive the less-savory aspects of their behavior, including eating poop and "forced copulation" of females just emerging from their pupae).

The social lives of some butterflies can remind us of birds, with territorial males staking out prime real estate to defend from other males, while females may select mates based not on appearance or song but on their smell, territory, and courtship behavior.

Like a couple of scraps of lace dancing in a breeze, a pair of Black Swallowtails (Papilio polyxenes) engage in a brief courtship flight, swirling around one another and turning up and down before disappearing from sight. A successful dance will result in the butterflies joining to mate for up to 45 minutes before the individuals go their separate ways. 






Sunday, August 11, 2019

An Enchanting World

Sometimes the world can be a bit...overwhelming. So many huge problems, so much hustle and bustle, with a pinch of chaos on top of all the regular joy and suffering of daily life as a piece of humanity.

That's why it is good to take a calming moment and appreciate some of the other lives with which we share our world.

I have an uncomfortable fondness for many of our non-native plants--though I am aware on an intellectual level the ecological disaster they can be, I also admire their tenacity and their persistence, blooming where other plants dare not set root and producing prolific blooms throughout the hot, dry summers.

Birdsfoot Trefoil (Lotus corniculatus) is one of these rugged invaders, roundly reviled as invasive, a "pest" plant, and generally a noxious weed (though not technically classified as such in our state). Its low mounds of compound leaves with small clusters of buttery-yellow flowers are commonly seen along sidewalks and roadsides, sometimes cascading over curbs in decorative masses. Some plants have bright yellow flowers tinged with orange; they have the characteristic 5-petaled flower shape of their bean-family relatives, with their pollen- and nectar-producing organs enclosed in a pair of petals forming a sort of pocket (called the keel).

Because they are non-native, these plants don't participate in the healthy ecosystem as fully as native counterparts, which are usually swarming with bees, beetles, butterflies and other insects with which they have evolved for millennia. Birdsfoot Trefoil, in contrast, is a relatively recent arrival and seldom have I seen any insect visiting its abundant floral arrays.

So when I noticed a single bee diligently visiting one flower after another, I paused to watch. The little bee would alight on a flower, force its way into the enclosed flower with comical enthusiasm, sometimes appearing to rest its abdomen on the keel with hind legs dangling on either side, and then fly to the net flower seemingly at random--but always sticking with the Birdsfoot Trefoil instead of the tempting stands of Cup Plant or Gray-headed Coneflower--each teeming with pollinators--just a few meters away.

Why this bee with this plant? Why didn't other bees find their way to the spoils hidden within the pineapple-hued blossoms? And why did this one bee insist upon foraging on the Birdsfoot Trefoil rather than joining the pollinator party at the abundant native flowers nearby?

It turns out that the bee was an Alfalfa Leafcutter (Megachile rotundata), another non-native (though not as reviled as the aggressive Trefoil and in fact introduced to assist with pollination of crops). These bees specialize in Alfalfa, another non-native that has been grown as a forage crop and of which remnants can be found near the Sycamore Apartments. Alfalfa, as a member of the bean family, has similar flower shapes to the Birdsfoot Trefoil and it is easy to see why the Alfalfa Leafcutter bee might find success on related flowers.

How interesting to see the interaction of two European species, finding each other thousands of miles from their original range and going about their business. They are our kindred, brought to this land for our own selfish purposes. They thrive because they are adaptable and hardy--and we humans possess the same virtues.