What Is That … on the daisy?

Waddells

This summer the roadside near our cottage has been awash with ox-eye daisies.  This sea of yellow and white is pleasant in its own right but when we stop to examine individual blossoms we were surprised by the diversity of beasties we found.  Daisy blossoms fulfill four functions for beasties.  They attract pollinators by providing nectar and act as a platform from which predators may stalk prey, most often nectar-harvesting insects. Also, parts of the flower are eaten by beasties.  In some cases the daisy simply provides a platform to rest upon.

Before looking at some of the daisy’s visitors, let’s talk a bit about the plant.  The ox-eye daisy is a perennial, flowering plant found throughout Lanark, along roadsides, and in fields and abandoned areas.  This member of the aster family grows to 80 centimeters tall producing a single blossom at the end of each stalk.  Each flower has 15 to 35 white petals radiating from a yellow disk that can be 10 to 20 millimeters wide.  They bloom from June to early August.

We start this short survey with three pollinators.  First, the green soldier fly.  Apart from the bright green of its abdomen, the markings and body shape of the individual in the following picture mimic a bee and wasp.  But soldier flies do not sting. This specimen was 15 millimeters long.  Soldier flies feed on nectar from by a variety of flowers.

Next, flower chaffers, sometimes called hairy scarab beetles, are found during the late spring and early summer, feeding on a daisy’s nectar.  This member of the scarab beetle family can grow as long as 10 to 12 millimeters and in this picture may about to be supper for a spider.

Thirdly, the black and white eight-spotted forester moth, which can grow to 16 to 20 millimeters, is active during the day in the summer months.  Adult moths feed on flower nectar.  This individual’s visit to a daisy for some food resulted in it becoming a meal for the goldenrod crab spider that has firmly captured the moth by its head.

The goldenrod crab spider, also called a flower spider, can be found most often on white or yellow flowers where they lay in wait to ambush insects which land on flowers to feed or rest.  They are small arachnids, with the females growing to eight millimeters and the males to only three.  Individuals can vary their colour from white to yellow to light green.  Such colour changes take several days, but allow the spider to blend in with the colour of their host flower.  Waiting with their two front pairs of barb-laden legs extended, ready to capture prey, they take on a crab-like appearance.  They are capable of capturing and feeding on a variety of insects including ones that are much larger than the spider including dragonflies, moths and butterflies. (Look closely, crab spiders show up in four of the seven pictures in this article.)

Many of our friends despise earwigs even though they only grow to 12 millimeters.  Many old wives’ tales persist about the much-maligned earwig … they are filthy or they can pinch their cerci hard enough to attach themselves to a person’s ears.   And while earwigs are omnivorous, they especially like to feed on flowers.  On close examination you can see the damage this earwig has caused by feeding on the yellow center of the daisy.

The common field slug can grow to a length of 60 millimeters. We often see them on damp days feeding on animal feces and decaying plants and animals along the roadside.  Occasionally we have observed smaller slugs feeding on leaves and ox-eye daisy blossoms.

Robber flies are small, 25 millimeters long, agile aerial predators who catch other insects in flight. While they are related to horse flies, having similar mouthparts, they only feed on insects, not humans.  Once they capture their prey, including insects as large as and including bees, they return to the ground to consume their meal.  They can be found on the ground or perched on vegetation looking for prey.  In this instance we observed these individuals resting on a daisy while/after ensuring the continuation of their species.

These are a few of the beasties we have observed and photographed while enjoying summer displays along the roadside near the cottage.  As we move deeper into August the white and yellow daisies are being replaced by Queen Anne’s lace, goldenrod and various purple flowers.  We look forward to seeing out more wildlife on other colourful flowers, as fall approaches.

Field guides that we relied on in preparing this article included: Timothy Dickinson et al’s The ROM Filed Guide to Wildflowers of Ontario; Larry Weber’s Spiders of the North Woods; John Acorn and Ian Sheldon’s Bugs of Ontario; Peterson’s Field Guide to Moths of Eastern North America; Arthur V. Evans’ Beetles of Eastern North America; and Stephen A. Marshall’s Flies – The Natural History and Diversity of Diptera.