My latest YouTube video shows Trigonopeltastes delta (Delta Flower Scarab) and Trichiotinus lunulatus (Emerald Flower Scarab) nectaring on Viburnum dentatum (Arrowwood Viburnum).
This is my first video recorded in 4K which was downsized to HD 1080P for faster upload to YouTube.
A shorter version of this video without titles and credit page can be download from my Wikimedia page at:
https://commons.wikimedia.org/w/index.php?title=Special:ListFiles/James_Leon_Young&ilshowall=1
This video and all the others listed may be used for any purpose you like, as long as you give me a credit line.
The specific license is “Creative Commons Attribution-Share Alike 4.0 International”
Below is the YouTube description of the video.
I hope you like it!
Jim
Description:
Delta flower scarab beetles (Trigonopeltastes delta) and their Trichiotinus cousins from Texas to Maine pollinate a wide variety of native plants like this beautiful arrowwood (Viburnum dentatum.) By successfully pollinating a time series of flowering native plants through spring and summer, the beetles help many other creatures that travel far beyond the beetles’ total range – – for example, migratory songbirds and the Monarch butterfly.
The arrowwood viburnum flowers in this mutualistic relationship attract flower scarab beetles with abundant nectar, pollen, and a place to meet and mate. The female beetle feeds while the male atop lifts his hind legs to protect her and fend off other suitors.
Pollen adhering to the foraging beetles hitches a ride when they fly to flowers of other arrowwood shrubs. This is critical, because arrowwood viburnum is self-incompatible. Cross-pollination occurs only when pollen grains containing male reproductive cells contact a receptive flower’s stigma on another arrowwood that is genetically different from the pollen source plant.
Many other species join the flower scarabs in cross-pollinating arrowwood viburnum. This matters, because if more flowers are pollinated they can produce more of the shrub’s high-fat and high-energy blue berry-like drupes – – a favorite food of migrating songbirds on their long flight south. Seeds defecated by the birds can germinate and produce new arrowwood shrubs, so the cycle continues.
One flower scarab beetle in this video displays a tiny piece of a beautiful perennial plant it visited a few weeks earlier – – the redring milkweed, Asclepias variegata, named for the tiny red ring at the corolla base on each small floret of its showy white flowers.
At 01:55 just after another beetle flies into view over the foraging beetles, the center male lifts his hind legs and a strappy yellow structure appears on his left hind leg tibia. This is a milkweed pollinarium – – a specialized flower structure containing many pollen grains. When a beetle sips nectar on milkweed flowers, it may inadvertently hook a milkweed pollinarium on its leg and later transfer it to a receptive female structure on another milkweed plant of the same species, thus pollinating that second plant. The male beetle in this video failed to transfer the pollinarium before the last local redring milkweed flowers senesced.
To observe more of the flower scarab beetle behaviors described above, please view the video below:
The redring milkweed is one of the first species available for migratory Monarch butterflies to lay eggs in spring as they return to the United States from their wintering territory in Mexico. Its abundant foliage makes it a good “rescue” plant for caterpillars that run out of milkweed resources early in the year.
Timing of flower scarab beetle emergence in early spring impacts the reproductive success of redring milkweeds, because these beetles are among the few pollinators sturdy enough to withdraw and transfer the pollinarium without becoming trapped by the flower’s stigmatic slits. In this woodsy corner of Gadsden Co., Florida, if flower scarab beetles are too few or appear too late in spring, redring milkweed seed pod production may be halved or worse. Over time, that can result in decreased populations of these larval food plants for Monarch and related butterflies.
So, if you would like to encourage flower scarab beetles to settle in to your neck of the woods, and maybe help a songbird or a Monarch butterfly during migration, arrowwood viburnum and redring milkweed would be a beautiful and welcoming addition to your wildlife garden.