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Here are some photographs from a 2024 trip to Prince Edward Island. Plus assorted blurbs because I try to learn something about the species I come across. At the very end are three mystery organisms that have stumped me.

Crustaceans

Atlantic rock crab (Cancer irroratus). It looked sad. Also of minor note: all the tiny little shells in the sand.

Northern acorn barnacles (Semibalanus balanoides) growing on a snail. I wonder how they fare compared to ones that develop on rocks.

Mollusks

As a segue, here are some common periwinkles (Littorina littorea) inside empty barnacle shells. I wonder how often the snails become trapped inside after they add whorls to their shells.

PEI is famous for its Eastern oysters (Crassostrea virginica) so it was no surprise they were growing everywhere. That said, I was surprised. Trillions of them, I suspect, if you count all the babies (spats). Females are said to produce 100 million eggs when they spawn, which is rather impressive.

Blue mussels (Mytilus edulis) were also present in uncountable numbers. This patch seemed to have very prominent growth rings and I wonder whether the farmed ones are smoother. Could just be my imagination, of course.

Northern horse mussel (Modiolus modiolus). These are very large but the word on the street is that they are not good for eating. The alga is Fucus serratus (saw wrack).

Common Atlantic slippersnails (Crepidula fornicata) on the inside of some shell. Unfortunately there’s nothing for scale so you can’t tell how tiny and adorable these are. Approximately the size of a corn kernel.

Three-lined mudsnail (Ilyanassa trivittata). A scavenger, but apparently has a taste for the egg-case of northern moonsnails (below).

Northern moonsnail (Euspira heros). This is a snail of unusual size (SOUS) and uses a mechanical drill and acid to bore into clams and other snails, including other moonsnails. But they also eat algae, as shown by carbon isotope analysis (source). This video is a short and entertaining primer on how they do it. The resulting hole is always countersunk.

Atlantic jacknife (Ensis leei). Despite persistent effort I could not locate a restaurant on Prince Edward Island that served razor clams. Likely because I went in October. I will need to go back.

Tunicates

Chain (or violet) tunicate (Botrylloides violaceus). This invasive is loathed by oyster and mussels farmers on the island because it fouls cages, ropes, boats, etc., all of which need to be blasted clean with high-pressure hoses. And if you don’t, the combined weight of the tunicate is enough to break the mussels’ attachments to the rope that suspends them in the water. They also compete for food. And it gets worse because this is just one of four invasive tunicates in the area. But they are pretty!

Plants

Gutweed (Ulva intestinalis). I didn’t take a close-up but I read that the fronds have hollow parts that trap oxygen and allow it to float when the tide comes back in. Although it’s very green, the reddish rock and combover reminded me of somebody. That’s why I took this photo.

Mermaid’s tresses (Chorda filum) attached to a rock. Fronds can get as long as a school bus. It’s a brown alga.

Furcellaria lumbricalis. This is a red alga and the only member of the genus. Apparently loaded with carrageenan. But apparently not as easy to harvest as giant Irish moss (an asexual, hexaploid variant of Chondrus crispus), a red alga that used to be harvested with horses on Prince Edward Island before the population crashed (invasive green crabs and potatoes are on shortlist of culprits). Even the Irish Moss Interpretative Centre has closed.

Sea wrack (Fucus serratus). Apparently quite tasty, and it’s an invasive so you should.

Dead man’s fingers (Codium fragile), another invasive. Often called oyster thief because it attaches to farmed bivalves, which then get washed away by strong waves. Per one source it causes millions of (CAD) dollars of losses every year.

New York aster (Symphyotrichum novi-belgii). This wasn’t in the intertidal but it was close enough so I wanted to include. I’m a sucker for compact plants that are just barely hanging on.

Insects

Black kelp fly (Coelopa frigida). There were millions of these but it still took probably 100 tries before I could get a decent image. Small, frenetic, and easily spooked. And only 126 observations on iNaturalist for North America, as a likely result. I would like to go back with my real camera and flash setup. Larvae are said to eat the bacteria that grow on decomposing seaweed.

Telmatogeton japonicus. These were even harder than kelp flies to photograph, and that’s my excuse for it being out of focus. And for the sake of full disclosure I’m not positive about the identification. If confirmed, my iNaturalist observation would be the first for Prince Edward Island.

Peryphus sp. This is a subgenus of Bembidion, my father’s favorite carabid. As he often complained, they are really fast and hard to capture. And hard to identify which is probably why my dad liked them.

Black vine weevil (Otiorhynchus sulcatus). This is an invasive agricultural pest and I was surprised to see it on the beach. But it turns out that it has a rather wide host range so I guess not unusual.

For such a beautiful and large wasp I thought somebody on iNaturalist would offer up an identification. After almost a year, nothing. I’m guessing that it was going after some sort of cavity-nesting bee that uses beetle bore holes in driftwood as nests. All the logs had plugs like this so some bee is really utilizing the wood.

Spiders

Thin-legged wolf spider (Pardosa sp.) that was under a rock. I’d wager that it was mainly eating kelp flies. Species identification is only possible with dissection.

Trochosa sp. that has recently molted. This also can’t be taken to species level because the patterns aren’t visible until after the new exoskeleton ages a bit.

Mysteries

I’m assuming this is some sort of venting product made by a sand-dwelling organism such as a clam, worm, or crab. Here’s the iNaturalist observation if you’d like to weigh in.

This sort of looks like a sponge (e.g., Clionaidae, Halichondriidae) but I truly have no idea. Definitely creepy, and I wonder whether those barnacles were victims of something slow moving. Here’s my iNaturalist observation if you can help.

I think this might be some sort of fungus (e.g., Collemopsidium halodytes) or a lichen. It was especially common in depressions in rocks where water might pool. More ideas are on my iNaturalist observation. I would be grateful for suggestions.

As always, if you see a mistake please let me know.

In case you’re a camera nerd, all photographs were taken with an OM TG-7 that I purchased for the trip. It’s waterproof, shoots RAW, does focus-stacking (poorly), and weighs a lot less than the Canon DSLR that I usually lug around with me.

Here are some photographs I took in June at my allotment in town.

First up is a spotted cucumber beetle (Diabrotica undecimpunctata howardi), perhaps the most common insect in my garden every year. In addition to being defoliators, the beetles are important transmitters of the Erwinia tracheiphila, which causes wilting. I think some of my zucchini fruits might be suffering from this wilt, but I’m not positive. The insect can also eat corn roots during their larval phase (hence its other common name, southern corn rootworm). If any of my corn plants lodge (fall over) I’m going to attempt to find and photograph the little bastards. For a beetle with “cucumber” in the common name it’s stunning how many different types of plants this insect can survive on (per one estimate, over 40 different families). More information on the species can be found at BugGuide.

This is a Mexican bean beetle (Epilachna varivestis) next to some of the damage it presumably caused. If you provoke them they apparently “reflex bleed”, and the blood is laced with a toxic alkaloid (Eisner et al. 1986). I haven’t yet seen their larvae (here‘s an excellent pic) but those have a different alkaloid in their glandular hairs (Attygalle et al. 1993). BugGuide has information on identification, distribution, and life cycle.

This is some sort of Phyllotreta, I think, on radish. I spent several hours online trying to identify it to species but got stuck with three options that all are rather similar: Phyllotreta striolata, Phyllotreta zimmermanni, and Phyllotreta liebecki (links go to respective BugGuide pages). But the first option seems the best: “Antennae black, basal 3 segments yellow-brown, 5th segment usually 1/3 longer than 4th, its width 1/4 its length” (BugGuide). Here‘s the iNaturalist observation in the event that an expert is reading this and can help with an ID. These beetles sequester the glucosinolates of their cruciferous hosts (Beran et al. 2014).

Potato stalk borer (Trichobaris trinotata)

This weevil is Trichobaris trinotata, the potato stalk borer. The larvae get inside the stems courtesy of small notches that the female chews prior to oviposition. If any of my potatoes, eggplants, or tomatillo begins to wilt I’m going to dissect the stem in search of the larvae (I’m easily entertained). Adults are easy to ID because of their all-black head and presence of three black spots in between the thorax and elytra. More information is available on BugGuide.

This is one of hundreds of eggplant flea beetles (Epitrix fuscula) in my garden. In addition to defoliating my eggplants every year they are extremely small and thus hard to photograph and identify. And apparently they might be eating my beets, too, as larvae. BugGuide has cursory information on identification but for more extenstive treatments plus excellent photographs see Deczynski 2014 and Deczynski 2016.

Epitrix brevis is even smaller than the eggplant flea beetle, above, and thus really at the limit of my camera gear and patience. They are all over my tomatillo, slowly skeletonizing some of the leaves through hundreds of tiny excavations like the one in the background of this photograph. Pestiferous, but also rather cute due to their small size. BugGuide has a page on the species but doesn’t have any interesting information. Likely too small.

These are the larvae of some sort of coccinellid (lady beetle), still hanging around their eggs and perhaps entertaining themselves by eating each other, as one does. I’m wondering whether they might be Harmonia axyridis (Asian lady beetle), an introduced beetle so common that is often a good guess. I need to go back and check on this location (on pole bean leaf) to find later instars or adults. Here’s my iNaturalist observation.

This menacing insect is a clouded plant bug (Neurocolpus nubilus) and I’ve seen several on my borlotti beans. In perhaps related news, several of my borlotti beans suddenly died this week (early July) and I’m wondering whether this bug is responsible. It’s a known pest of cotton but I can’t find any evidence in the literature that it eats legumes. More details on BugGuide.

This gorgeous leafhopper is a female broad-headed sharpshooter (Oncometopia orbona). Those white spots are chalky deposits (brochosomes) that are often found on females. Females use the substance to coat their eggs, though I’m not sure whether she uses the material from those spots. For the life of me I cannot locate a photograph of eggs protected by this chalk. I gather both males and females of this species (and other leafhoppers and planthoppers) also “anoint” themselves with this goop after each molt to better protect themselves from the elements and from sticky substances (Rakitov 1996). They are really hard to photograph because when they sense your proximity they will quickly move to the other side of the leaf. More on BugGuide.

This is a swift feather-legged fly (Trichopoda pennipes), one of my favorite dipterans. I love it because (1) it’s beautiful, (2) not easily spooked, and (3) is a highly motivated parasitoid of squash bugs. I’ve never seen it in action, but they slap eggs right onto squash bugs (and several related bugs), and they do this all day long, sometimes effectively controlling the pest without any need for pesticides. They are so common that if you scroll through pics of squash bugs you’ll see the fly’s eggs regularly (e.g.). Here‘s a nice summary of its life cycle by Susan Mahr (University of Wisconsin). BugGuide.

This is a male Condylostylus in the sipho group. My garden has thousands of these flies, all of them likely eating the aphids and other small insects that are present in large numbers. They are extremely skittish and hard to photograph. To make things worse, they also take flight when they detect a flash pulse, so 90% of my shots have only a leg or two. Here’s the iNaturalist observation in case you can help me with the identification. Caleb Scholtens has an excellent guide to the Condylostylus groups on iNaturalist .

Finally, here’s an early-instar larva of a squash vine borer moth (Melittia cucurbitae) inside a zucchini stem. I found it by examining leaf stems for surface damage caused by oviposition and early feeding by the larva (see pic #3 on my Inaturalist observation to see the damage). These are horrible pests of zucchini and yellow squash, so I tend to wrap the bases of my plants in tinfoil, plus patrol the leaves and fruit stalks for larval damage. The adult, by the way, is stunningly beautiful. BugGuide has identification help, which I recommend checking just to be sure it’s not Melittia calabaza, which looks very similar.

Finally, here’s a non-macro photograph that shows where all these insects are spending their lives, my little allotment at the Scott Arboretum Community Gardens.

All of the above photographs, plus thousands more, are at https://colinpurrington.smugmug.com.

Colin Purrington's blog

nature photography / natural history / misc

Tag Archives: iNaturalist

Beach finds on Prince Edward Island