I originally chose to visit Bruce Pit in the hope of seeing some darners there – I’d seen none at Mud Lake earlier that morning, and recalled that Chris Traynor had found some Variable Darners late in the season last year (September 18, 2015) along the hydro cut. My plan was to spend some time near the water looking for spreadwings and skimmers, then check out the hydro cut for darners. I didn’t find much around the water – there were lots of Lyre-tipped Spreadwings still present – so I headed up into the field just above the water.
Almost right away I saw this beautiful Black-and-yellow Garden Spider sitting in its web. These large orbweavers – as well as the Banded Argiopes – used to be really common at Bruce Pit and other open grassy fields in Ottawa, but seem to have declined over the past few years. I was happy to see it, though the thought of walking into a web with one in it still gives me the creeps.
Another predator was lurking in a flower close by. The Ambush Bug does not spin a web to catch its prey, but waits patiently among the flowers for small flies and other soft-bodied insects to visit the blossoms for nectar and pollen. When one lands within reach, the Ambush Bug captures it with its thick, powerful forelegs, pierces it with its beak, and devours it.
This Woolly Bear caterpillar found creeping along a plant stem is not a predator. I usually see these in the late summer and fall, moving around in search of food and (really late in the fall) a good place in which to hibernate. The Isabella Tiger Moth – which it will become after metamorphosis – overwinters in the caterpillar stage, and is able to survive our brutally cold winters by producing chemicals called cryoprotectants. These compounds act as an antifreeze, preventing the formation of lethal ice crystals in bodies of overwintering insects. Once temperatures begin to climb above 10°C the following spring, the caterpillar thaws out and becomes active again.
There were quite a few spreadwings still present – more than I had expected after so much time had passed since my first visit. The vast majority were Lyre-tipped Spreadwings, identifiable by their S-shaped paraprocts. The pattern of pale blue pruinosity on the last three segments is also quite distinctive.
A few Spotted Spreadwings were present, too – these are one of the latest-flying damselflies in our region. Their paraprocts are much shorter.
I only saw three dragonfly species – Twelve-spotted Skimmer, Autumn Meadowhawk, and White-faced Meadowhawk. We’re still a month away from the fall equinox, but ode diversity has definitely decreased since my last visit.
As I wasn’t seeing very many odes, I headed to the field on the east side of the pit. I was still looking for darners, and had also seen an American Copper butterfly in the same area several years ago during the month of September. It was clouding over slightly, and darners can often be found perching in tall vegetation when the sun isn’t shining. I started walking through the field and was astonished by the diversity of insects here. The first cool beetle that I found was an Orange-spotted Lady Beetle – a rather pretty beetle that I have only seen twice before. Is Bruce Pit naturally a good spot to find them, or are they particularly abundant this year? I have no idea, but I will definitely have to keep my eyes open for them next summer!
A new beetle for me was this very dark Blister Beetle. When I was here in July, I had found some lighter-coloured beetles that turned out to be Ashgray Blister Beetles; these were similar in shape, but much darker. This looks to me like it is a member of the same genus, Epicauta, but I am not sure which species it is – either Dark Blister Beetle (Epicauta murina) or Black Blister Beetle (Epicauta pennsylvanica) seems likely. However, Bugguide cautions that many common Epicauta species are difficult to identify from photographs – field photos don’t often show the field marks that would need to be seen with the specimen in the hand.
I found two other lady beetle species on the goldenrod, including this lovely Seven-spotted Lady Beetle. Multicolored Asian Lady Beetles were the more abundant species, and I saw several with lots of spots and one with no spots (see top photo).
Bees don’t normally catch my attention unless they are particularly colourful or flashy, so when I saw this pale yellowish-white one land on a leaf in front of me I was intrigued. Some Google searching led me to believe that it might belong to genus Melissodes, and Bugguide confirmed my tentative ID, though so far no one has been able to confirm the species. Bees in this genus are known as long-horned bees, since the males have long antennae. They are small, solitary fees characterized by fuzzy yellow hairs and conspicuous hairy legs. Females are round-bodied, compared to the long-bodied males, and usually have yellow faces. I found this little bee quite striking and wanted to take some close-ups of it, but it flew away after getting only two images.
Fortunately it didn’t take long for my attention to be captured by another bee, this one with rusty red on its abdomen. I was able to follow it around for quite a while, thinking it was the Tricolored Bumble Bee (Bombus ternarius) that I usually see around Ottawa. It wasn’t until I got home and examined my photos that I started thinking it might be something else: there were three red bands, scalloped in appearance, and bordered with black, which is uncharacteristic of the two red bands I’ve seen on the Tricolored Bumble Bee. However, I knew that even among the same species queen bees look different than the workers, so I started looking at different forms of this species. When I realized that the black mark on top of the thorax was round rather than triangular, I knew it was a different species altogether and was able to identify it as a Red-belted Bumble bee.
Native to North America, this species lives in and around wooded areas, urban parks, and gardens. It feeds on the nectar of several kinds of plants, particularly goldenrods, clovers, and asters. When I found it, it wasn’t feeding on the flowers but resting on a leaf; from there it landed on a mullein stalk.
A few butterflies were also present, including an unknown skipper (these butterflies are not usually seen this late), a Common Wood-nymph, a Northern Crescent, an Eastern Tailed Blue, a few Clouded Sulphurs, and a few Common Ringlets.
From there I headed over to the milkweed field where I found all the Gray Treefrogs (see previous post). There were several lady beetles on the milkweeds, as well as two different milkweed specialists. The first was the Red Milkweed Beetle, an insect whose entire life cycle depends upon Common Milkweed. The eggs are laid by the female at the base of a milkweed stem, either within the stem itself or on a piece of grass close by. After the larvae hatch, they will travel down to the roots of the Milkweed, either by burrowing into the tissue of the stem or moving directly through the soil. The milkweed roots sustain the larvae all through the fall, although once winter comes the larvae remain in the soil but do not feed. Once spring arrives the beetle larvae build a small chamber in which they pupate, emerging as adults a month later.
In the summer, the leaves, flowers, and buds of the milkweed plants sustain the adult Red Milkweed Beetles. The milky sap of the milkweed is quite sticky, and can often glue the beetle’s mouth-parts shut, so the beetles avoid the sap but making a small cut into the leaf vein above the site where they are feeding, allowing the sticky sap to drain out. This reduces their exposure to the sap considerably.
Small Milkweed Bugs are also quite common on milkweed, and can be recognized by the black heart over the red “X” on its back. I have quite a few in my yard this year, and suspect they were the ones feeding on all the Swamp Milkweed blossoms, leaving no flowers for any butterflies. While I wasn’t happy with the destruction of my milkweed flowers, they are considered a beneficial insect because they help control the spread of the invasive Common Milkweed – in the fall they are often found on the milkweed’s seed pods, piercing the wall of the pod to feed on seeds within.
I walked over to the hydro cut from there, hoping to see some darners flying around. The sun had come out by then, and I saw few darners high up in the sky – the tinted wings looked more like Common Green Darners to me than the Variable Darners Chris had found in this area. Even though I didn’t find the species I was looking for, I still had a great time and found more than enough beetles, bugs, bees and butterflies to keep me enthralled. I hope to get back there again next year earlier in the season; who knows what may be lurking among the flowers in June when biodiversity is even richer!