Insects that disappeared in the cold came out again during last week’s warm weather. On Wednesday I found a western conifer-seed bug on my front porch.
Formerly restricted to the western U.S., the western conifer-seed bug (Leptoglossus occidentalis, WCSB) has spread across North America, to Europe and South America. At 1/2 to 3/4 inches this “true bug” sucks the sap of developing pine cones and the pulp of pine seeds.
Travel is a tonic for seeing the world in new ways. This month my husband and I spent a week with his sister at Cape Cod where we had new weather, new scenery and new looks at plants I might have seen at home.
Our timing was pretty good. We missed the October 12 nor’easter but were on hand for the October 17 “bomb cyclone.” We didn’t lose power, but it was still very windy on the 18th when I visited Fort Hill, pictured above.
Birds were hard to find that day so I noticed plants such as this European spindle-tree (Euonymous europaeus) with puffy, pink, four-sided fruits.
The puffballs are actually a casing that holds orange fruit within. This ornamental has probably been planted in Pittsburgh, though I’ve never noticed it.
My favorite discovery was a hole in a leaf.
Who ate it? Perhaps this caterpillar did. I found him elsewhere on the plant.
And finally, the sun touched translucent red berries and made them glow at Bell’s Neck.
The small plants have a single leaf midway up the stem (lefthand photo) and were growing among pine needles. I wonder if they are orchids … Perhaps green adder’s mouth (Malaxis unifolia)? Please leave a comment to tell me what they are.
(photos by Kate St. John except where noted in the captions; click the captions to see the originals)
So many woolly bear caterpillars have crossed my path this fall that, fearing they’d be trampled, I have carefully moved each one across the trail.
“Woolly bears” are the larva form of a common North American moth, the Isabella tiger moth (Pyrrharctia isabella). Since she is not dependent on only one host plant, Isabella is found in many habitats.
She even lives in the Arctic, surviving the winter because she has natural anti-freeze in her cells. Wikipedia describes how she does it:
The banded woolly bear larva emerges from the egg in the fall and overwinters in its caterpillar form when it literally freezes solid. First its heart stops beating, then its gut freezes, then its blood, followed by the rest of the body. It survives being frozen by producing a cryoprotectant in its tissues. In the spring it thaws.
The orange oakleaf butterfly (Kallima inachus), native to tropical Asia, is well named. The underside looks exactly like a leaf when the butterfly closes its wings, and it has wet and dry season forms that mimic the leaves of each season.
The butterfly stands out when its wings are open.
Watch it become a leaf as it flutters in place.
We have leaf-like butterflies in North America, too. Click to see the ventral and dorsal sides of the goatweed leafwing (Anaea andria). It ranges from southeastern Arizona to southern Ohio.
Though it’s nearly mid October I saw monarch butterflies migrating through Pittsburgh on Thursday and Friday October 10 & 11. Their timing seems late, but they were given a boost by August-like weather early this month.
While writing about the worldwide spread of Asian ladybeetles (Establishing a Bridgehead) I learned another amazing fact. These insects are cannibals when they need to be, but they’re careful about it. They avoid eating close relatives.
Asian ladybeetles (Harmonia axyridis) are insect carnivores, preferring aphids above all else. Their population surges when aphids are plentiful and goes hungry when aphids crash. Rather than starve, ladybeetle larvae eat eggs and smaller larvae of their own species. The strong ones survive, indirectly regulating their own population.
However, they also make sure that their own family survives …
Interestingly, H. axyridis recognize their kin and are less likely to cannibalize a sibling than a non-related individual (Michaud, 2003). If normal prey becomes scarce, larval mortality can be very high, with in excess of 95% of larvae failing to survive to adulthood, and in such circumstances cannibalism can be essential for survival.
Now that the weather has changed unwelcome insects will invade our homes including Asian ladybeetles (Harmonia axyridis) that resemble native ladybugs but don’t act like them. Also called “harlequin ladybirds,” they overwinter indoors, make a stink, and bite when frightened.
A hundred years ago we thought this bug was a great idea and repeatedly introduced it to the U.S. to control aphids. The introduced ladybeetles never made it in the wild until a population was found thriving near New Orleans in 1988. After that they spread like wildfire across the eastern U.S. and into Canada.
Thirteen years later they became established in South America and Europe(*). By 2004 they were in southern Africa. They hadn’t been introduced. How did they get there?
A 2010 study of their genetic markers revealed that those three continents were invaded by the eastern North America population. In a move called the bridgehead effect, Asian ladybeetles in the U.S. used our continent as a jumping off point to colonize Europe, South America and Africa.
Comb-footed spiders (Anelosimus studiosus) have a lot of personality. These social cobweb spiders live in colonies of 40-100 individuals, build their webs around branches, and hunt cooperatively to capture large prey.
The spiders exhibit either aggressive or docile personalities. If you know what to look for you can tell the difference. In the evening aggressive A.studiosus attack each other and then retire to opposite corners of the web; docile spiders rest side by side. Aggressive spiders come out to attack when their web is disturbed, the docile ones stay inside.
What happens to these spiders when they’re hit by a tropical storm or hurricane? Is there a difference in which spiders survive?
A 2018 study led by Jonathan Pruitt of U.C. Santa Barbara tracked 240 Anelosimus studiosus colonies in seven states including Florida, Alabama and the Carolinas. For baseline data they recorded the locations and personalities of the spider colonies. Later they searched for spider webs after a tropical storm or hurricane had passed.
You might think it’s futile to look for cobwebs after hurricanes, but individual spiders do survive, stay on their home territory, and rebuild. While humans are picking up the pieces, the spiders are too.
The study found that the storms always wiped out the docile spiders but the aggressive ones survived.
The relentless pressure of weather and nature is changing the spider population. Among comb-footed spiders, only the strong personalities survive.
Northern snakeheads (Channa argus) are predatory fish native to China, Russia and the Koreas. They prefer shallow stagnant freshwater and can survive in low oxygen locations because they can breathe the air. In fact they can live out of water for days where it’s moist and cool and are known to wriggle overland from pond to pond, earning them the nickname “walking fish.”
This top-level predator eats crustaceans, amphibians and other fish and can double its population in only 15 months. If you find one, watch out! They look like this.
All Snakeheads are distinguished by their torpedo shaped body, long dorsal and anal fins without spines, and toothed jaws. Northern Snakeheads are typically distinguished by a flattened, pointy head with long lower jaws.
They have teeth …
… and they can get really big! According to Wikipedia, a record 19.9 pound northern snakehead was caught — actually shot at night with a bow and arrow — at Mattawoman Creek in Charles County, Maryland in May 2018.
How did they get here? People release them. They’ve been kept in aquariums or raised on fish farms in the past, but it’s illegal to keep a live one now in North America. Not everyone knows this.
The first encounter with northern snakeheads in the U.S. did not go well. A breeding population was found in a pond in Crofton, Maryland in 2002. Officials were so worried about this species that they drained the pond and poisoned three adjacent ponds to kill every fish. A man later admitted to releasing an adult pair in the original pond, but the fish was out of the bag. It already had spread in the watershed.
Since then northern snakeheads have been found in Virginia, Florida, New York, Pennsylvania, Massachusetts, California, North Carolina, Arkansas, and B.C, Canada. New isolated discoveries always begin with someone releasing a fish. If the fish become established they spread throughout the watershed. When deemed appropriate, wildlife officials may poison newly infested ponds and kill all fish.
Fortunately Lance Mroz knew what to do. He identified the fish, killed it, froze it and reported it to the PA Fish and Boat Commission. If you ever catch one,
In some plant species, bees must vibrate the flowers to shake pollen loose. The technique is called buzz pollination or sonication.
Buzz-pollinated plants have anthers with very small openings so the pollen stays inside unless the anther is shaken. To collect the pollen bees grab the flower and vibrate their flight muscles. This makes a buzzing sound.
In the photo above, a halictid bee is releasing yellow grains of pollen as she shakes. She collects it on her legs for delivery to the hive.
Most species in the Solanum genus, including potatoes, eggplants and tomatoes, have to vibrate to release their pollen. Strong wind can do the trick outdoors but greenhouse tomatoes are out of luck. That’s how bumblebees get an indoor job.
(photo from Wikimedia Commons; click on the caption to see the original)