Everlasting love from Yarrow

You’re almost at Bobcaygeon Road! Take a moment at this bench on Water Street and admire the large patch of White Yarrow (Achillea millefolium). With fern-like leaves and lots of clusters of white flowers, this native perennial also has several cultivars with different coloured flowers. It will bloom consistently from late spring into the fall, making it a nice addition to a garden. Take a small piece of a leaf stem and smell it – what do you think? Do you see any butterflies, moths or bees on these umbel-shaped flowers? This shape of flower is preferred by many insects – no wonder the “flower meaning” for yarrow is “everlasting love”.

A large number of Syrphid or hoverflies were found at this location. The Eastern Calligrapher (Toxomerus geminatus), is just one of dozens of different species of syrphid flies found along the Riverwalk. They have a long season from April to October so you should be able to spot some. You might mistake them for a bee or a wasp. They’ve evolved the look of a wasp as a clever way to ward off predators but they’re really quite harmless. They like Boneset (Eupatorium perfoliatum) and Meadow sweet (Spiraea alba), two flowering plants that are found here in addition to that large patch of white flowered yarrow we spoke about already. They feed on the nectar and pollen found in the flowers. The female fly will lay eggs on the leaves. The maggots that emerge from the eggs love to feed on aphids and other soft bodied insects. They keep the numbers of aphids in check thereby preventing them from stripping the plant of all its leaves. So next time you see a Syrphid fly remember all the good things it is doing in all its life stages to benefit the environment and ultimately you.

U-Links Species Profile:

Eastern Calligrapher, Toxomerus geminatus

This Syrphid fly will be a difficult species to find while you walk along the riverwalk, but if you look carefully, you may notice the Eastern Calligrapher flying to and from various plants, feeding on nectar and pollen and also looking for ideal plants to lay their eggs. Toxomerus geminatus is one of the smaller species of syrphid, ranging from 6.1-7.6mm in length (Skevington et al., 2019). An up close look displays large, bright red eyes, and a small mouth piece that they use for gathering nectar. They will commonly be seen out flying in April to October.

The Eastern Calligrapher however, has an even larger impact in the ecosystem beyond pollination as it is an avid hunter in its larval stage (Sampson et al., 2002). Aphids are one of the most common prey for many syrphid species and the Eastern calligrapher is no exception. The larvae will hunt for aphids that are present on their host plant, providing protection to the plants that they host (Sampson et al, 2002). It has been noted however that the larvae of T. geminatus are a more opportunistic hunter, attacking aphids that come within its proximity, rather than proactively hunting, however, despite there sluggish hunting techniques, they are thorough when consuming their prey, leaving almost not remains of anything they catch (Sampson et al., 2002).

The range of habitats of this insect is very diverse, as they can be found in forests, savannas, bogs, fens marshes, meadows and fields (Skevington et al., 2019). They also have a range of plants that they will host and feed from, varying with both fruit producers and flowering plants alike. The common plants to find them on are brambles (raspberries, blackberries etc.), Bonesets, goldenrods, hogweeds, cranberry, and many more (Skevington et al., 2019).

Researcher: Caleb Brown, Trent University