After dark, moths, as well as bats, take over the pollinating night shift.
There are some moths that are active by day (diurnal), such as the Hummingbird clearwing (Hemaris thysbe), and visit flowers similar to bees but most moths are crepuscular (active during twilight hours) or are nocturnal (active during nighttime hours).
Moth pollination is more prevalent in the South than other area in the continental USA due to comfortable climates with warm evenings. Heavy with fragrance, nocturnal bloomers produce a strong, sweet scent during twilight, night or early morning. Evening primrose (Oenothera biennis), Madonna lily (Lilium candidum), night-blooming jasmine (Cestrum nocturnum), and some yucca species draw these pollinators to them. Usually, they have white or pale colored flowers that reflect moonlight making it easy for moths to find their flowers from a distance.
Some flowers are designed for hovering moth species and do not have a prominent “landing platform” (labellum) as the moth does not alight on the flower itself. Its flowers tend to be rather delicate, even pendulous, with long tubular spurs facilitating the moth to insert its protracted proboscis (the hollow straw-like tongue) deep into the base of the perianth while rapidly beating its wings, suspended in the air. These moths drink copious amounts of the concentrated sucrose-rich nectar as a lot is needed for their high metabolism. When the moth is sated, it pulls out its proboscis, which is guided along the anther slit of the flower, depositing pollinaria onto the tip and the sticky pollen is then transferred to the next flower the moth feeds from.
There are other moths that fly slower and do not hover. Consequently their need and consumption for nectar is far less. These moths pollinate plant flowers that are smaller, such as the scarlet gaura (Gaura coccinea) or fairy duster (Calliandra eriophylla). The little moths will spend up to twenty minutes perched on a cluster of blooms, taking their sweet time drinking from each flower.
In basic terms, moths go to flowers looking for nectar and by doing so, transfer pollen from one flower to another. Few folks realize that the seemingly nasty hornworms (Manduca spp.), loopers (such as Trichoplusia ni, Autographa precationis, and Pseudoplusia includens), and armyworm caterpillars (Pseudaletia unipuncta or Spodoptera frugiperda) that defoliate crop plants, garden vegetables, and wildflowers eventually morph into lovely nectar-feeding moths, which perform primary pollination to many of the same plants.
Among the more significant moth pollinators is the hawkmoth (Sphingidae spp.). These swift aviators fly upwind following the fragrance of a cluster of pale-trumpeted flowers. Hawkmoths have been compared to hummingbirds as both rapidly beat their wings while hovering when feeding.
Hawkmoths are discriminate pollinators of a group of night-blooming plants including sacred datura (Datura wrightii), tufted evening primrose (Oenothera caespitosa), and sweet four o’clock (Mirabilis longiflora). The mutualistic relationship is evident by these plants providing lots of sucrose-rich nectar that the hawkmoth requires.
Another engaging hawkmoth plant-pollinator relationship is that of Disa cooperi whose white flowers are both nectarous and fragrant. Their scent attracts only two hawkmoths, Basiothia Schenki and Agrius convolvuli, that can effectively pollinate its flower. The moths’ proboscis length and the orchid’s spur length align perfectly with its petals and position of the pollinaria and stigma. Of the two moths, A. convolvuli has the longer proboscis and can simply fly in and out, taking as much nectar as it wants. B. schenki has a shorter proboscis and must fly almost up to the flower and press against it. Either moth then pulls away, taking the pollinaria and carries it to the next flower.
One of the greatest thrills for a naturalist is to see a large hawkmoth unfurl its long proboscis and drink from a trumpet-shaped flower while hovering in place. Who isn’t amused when they watch a small, satin-white yucca moth’s frenzied activities on a yucca plant? The best way to observe these pollinators is to plant a variety of night- blooming, fragrant plants for a moth garden. This way you are providing a nectar “filling station” for beneficial pollinating moths.
Another way to view them is try putting a little day-glo paint powder on a few night bloomers. Wait until twilight, sit quietly and watch their flowers open. Once the scent begins, moths will arrive. After a few moths alight the blooms and move on, scan the yard with a portable ultraviolet lamp to follow these wayfarers.
Beneficials in the Garden & Landscape is an Earth-KindTM program coordinated through Extension Horticulture at Texas A&M University. Earth-Kind uses research-proven techniques to provide maximum gardening and landscape enjoyment while preserving and protecting our environment.
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