Sunday, March 15, 2015

Nocturnal Floral Visitors

Every day, bees and flies rule the garden. They are by far the most common visitors to most flowers, although beetles are also very common floral frequenters. But, when the sun dips below the horizon, most pollinating insects retreat to their nest, hive, or some other shelter for the night. However, there are many other types of insects that visit flowers, many at night when birds or other diurnal predators are inactive. Here is what I have seen, flashlight and camera in hand.

Narcissus with pincher bug
Earwigs (order Dermaptera) are insects that most people are familiar with, often making the covers of many insecticide labels. They actually play many roles in the garden, besides nibbling on leaves and flowers. They are omnivorous, preying on insects as well as dead or dying plant matter, which is very beneficial but more of a "behind the scenes" task in the garden that many would take for granted. It may be surprising to many to know that they also feed on many floral rewards, including pollen, and potentially serving a role as pollinators as a few grains of pollen may become attached to their bodies to be delivered to a receptive stigma.

Narcissus, spider, beetle.
The large trumpet daffodils attract a variety of insects that use them for both shelter and a food source. While the small cucumber beetle feeds on the pollen of primarily yellow flowers, possibly because the color will camouflage them. Spiders are also attracted to Narcissus for food, but not the flower itself, but the insect visitors. In the insect world, a good predator population is a good indicator that the "food source" (i.e. bees, flies, beetles) is in good shape and strong enough to support the predators. This is also true of parasitic and hemiparasitic species of bees and others.

Chionodoxa with pincher bug
An earwig visits this Chionodoxa flower, completely unaware of my presence. Like beetles, pincher bugs are often seen on flowers to either eat the pollen, nectar, or the flower itself at times. Also, their bodies are shiny and smooth, not adapted to carry pollen. Still, all it takes is a single grain of fertile pollen to make contact with a receptive (compatible) stigma to produce a seed.

Hyacinthus with bug
This insect was interesting, though I wouldn't call it a "floral visitor" because I think it is really some type of benign sap sucker, in the vicinity of the relatively large fragrant flowers incidentally.

Plume moth nectaring on Muscari armeniacum
I watched for ten minutes as this plume moth (order Pterophoridae) nectared on this grape hyacinth. If you enlarge the photo, look closely above its head to see its curved proboscis bending into the floret. It has always fascinated me how dexterous the proboscises of moths and butterflies are. It is amazing to behold, the moth completely still, the proboscis moving erratically and yet carefully into each nearby floret in search of the nectar.

Moth nectaring on Mahonia
Upon approaching a group of small Oregon grape shrubs, I noticed many insects on or around the flowers. A few small moths, beetles, and pincher bugs were apparently attracted to the flowers. The pincher bugs quickly dived out of sight, a tactic they employ to escape percieved predatory threats. 

This moth was the biggest visitor, about an inch long. Look closely to the proboscis. On it you may be able to make out a few grains of pollen that have adhered themselves to it. This is the main way moths transfer pollen, as their bodies are often not in close contact with the plants sexual organs. This is also why many "Lepidoptera plants" have tightly constricted floral tubes with the anthers squeezed inside. This way, short tongued insects are excluded from accessing the nectar, and the proboscis of the moth or butterfly will have to contact the anthers or stigma in order to reach the nectar.


  1. Very interesting. We don't hear much about the night pollinators. (Had to publish using anonymous because none of the others applied to me.)


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