Even if you are sessile (latin "to sit") rather than motile (latin "to move") you can still be vagile (latin "wandering") by having mobile (latin "moveable") seeds blowing in the wind. Curiously, Asclepias syriaca is both sessile and not: plants can't walk so botany uses "sessile" to refer to leaves that grow directly from the stalk without a stem.
2022-10-22 I-270 Frederick Overlook, Frederick County, MD
New word: vagile. Free to move about. Being world travellers V. cardui mix it up a bit, so they have diverse genetics.[1] North American and Eurasian populations are separated by 5 M generations but are still considered the same species.[2] The Australian population is separated by 30 M generations and is now considered its own species (V. kershawi). Unlike V. cardui its wing spots have blue centers (though if you stress V. cardui during metamorphosis they too will develop spots with blue centers).[3]
2022-10-22 I-270 Frederick Overlook, Frederick County, MD
[1] DOI:10.1111/j.1365-3113.2010.00566.x [2] DOI:10.1111/mec.16770 [3] DOI:10.2108/zsj.24.811
Frequent flier miles rack up. Vanessa cardui are continuously migrating, from the tropics in the winter to the arctic in the summer, in a multigenerational travel epic spanning many thousands of kilometers. They even cross oceans, appearing on islands such as Iceland and Madagascar. They can fly fast and high (25 kph) or close to the ground. Apparently insect radar is a thing, allowing them to observe flocks at an altitude of 2000 m. DOI:10.1111/j.1600-0587.2012.07738.x
2022-10-22 I-270 Frederick Overlook, Frederick County, MD
Agnorisma badinodis, also known as the spotted-sided cutworm. The caterpillars emerge from the egg in late fall and hibernate throughout the winter. By spring they are ready to feast on the tender young seedlings (mostly chickweed and docks), coming out at night to chomp through the stems at ground level. Kind of wasteful, but it keeps them safe from predators. By mid-April they cocoon themselves underground for the hot summer, emerging as moths in the fall.[1,2]
2022-10-15 Bethesda, MD
[1] Walkden, H. H. (1937). Life-history notes on the Spotted-Sided Cutworm (Agrotis badinodis Grote). Journal of the Kansas Entomological Society, 10(1), 20-26.
[2] Crumb, S. E. (1929). Tobacco cutworms (No. 88). US Department of Agriculture.
Despite the name she isn't blue because she is a she. A "free love" species (multiple partners in the same day) the latest beau scoops out the previous sperm and injects his own, then hovers nearby as she dip-dip-dip lays eggs one at a time in the pond scum (see video from Wikipedia).
2022-08-20 Patuxent Research Refuge - North Tract, Laurel, MD
[1] Sherman, K. J. "The adaptive significance of postcopulatory mate guarding in a dragonfly, Pachydiplax longipennis." Animal Behaviour 31.4 (1983): 1107-1115. DOI:10.1016/S0003-3472(83)80018-9
[2] Artiss, T. "Structure and function of male genitalia in Libellula, Ladona and Plathemis (Anisoptera: Libellulidae)." Odonatologica 30.1 (2001): 13-27.
Cirsium vulgare, another Eurasian native that not even the deer will eat. Fortunately they are susceptible to many of the insects that feed on native thistles so they are not completely out of control.[1] They also feeds many pollinators.[2] Not a good thing if this interferes with native plant reproduction, but in this study area they flower a month later so not a problem.
2022-08-15 Bethesda, MD
[1] DOI:10.1007/s00442-013-2876-4 [2] DOI:10.1007/s00442-013-2876-4
Securigera varia (latin: multicoloured axe-bearer), a European invasive banned in several states. It is used for erosion control and for ruminant forage (cattle growth: 1 kg/day vs. 2/3 kg for alfalfa).[1] Not so good for other animals: Without fermentation in the rumen its neurotoxins are poisonous.
2022-08-20 North Tract, Putuxent Research Refuge, Laurel, MD
Abaeis nicippe. The long brown smudge on the wing is characteristic.
2022-08-20 North tract, Putuxent Research Refuge, Laurel, MD
... because their eye spots are closed? They certainly weren't sleepy while we were watching. The male has glands on his forewings, so he will hover near a female and buffet her with his seductive perfume. Abdomen "up" says she is not interested. The glands are hidden between the wings (in the "friction" area) so we can't identify sex from photographs. [DOI:10.1155/1978/78397] The paper includes SEM images of the scales. To protect them from vacuum and provide a conductive surface they first coat the wings in gold. Somewhat disturbing, they used either "freshly-killed males, live males, or males killed and stored at −5°C."
2022-08-20 North Tract, Putuxent Research Refuge, Laurel, MD
A fancy cloak to wear to the ball. Mostly it is the males that fly, with females staying put and emitting pheromones in the breeze. It is not clear why they fly toward the light, but it creates a statistical challenge when you are surveying populations: The number of individuals in your light trap varies with temperature, cloud cover and the phase of the moon. [DOI:10.1093/ee/26.6.1283 DOI:10.48550/arXiv.2101.00074]
Throwing camouflage to the winds, Carolina grasshoppers are highly visible when flying. Their escape strategy follows an economic model, balancing the cost of escape against the risk of staying. They have a tendency to escape sideways, which allows them to ignore risks that are not directly targeting them with a single flight.[DOI:10.1163/156853906778691595] During hours of pursuit I inadvertently fell into a good strategy: Approach slowly and they won't fly as far on escape. Not enough for a good photo, but at least I captured something.
2021-08-22 McKee-Beshers WMA, Poolesville, MD
Hiding in plain sight, breathing quietly.
Breathing? Yes! Sort of... No lungs, and no oxygen exchange to hemoglobin carried by a circulatory system to every organ. Instead, they have complex ductwork connected directly to the environment through 10 pairs of tracheal tubes,[1] carrying oxygen throughout the body where it can diffuse through the walls and into the muscles. Rhythmic abdominal contractions and pulsing from the heart pump the bellows, forcing old air out and letting new air in.[2]
2022-08-20 North tract, Putuxent Wildlife Refuge, Laurel, MD
[1] https://www.jstor.org/stable/25003832
[2] DOI:10.1146/annurev-ento-011019-025003
A typical leafhopper in a not-so-typical location. Its camouflage doesn't work so well when it is not on a leaf.
2022-09-02 Bethesda, MD
The Potomac River forms a constantly evolving series of swirls and fractals, made visible by surface scum. The Great Falls rapids beat air into the water and surfactants turn it into a foam. Contaminants such as dust, salts and metals can stabilize it so that it lasts for hours. The components are natural (soil, decaying plants, bacteria) but foaming can increase with industrial runoff (fertilizer, treated wastewater, pesticides). The foam leaves the remaining water a little cleaner and provides cover for fish while providing concentrated nutrients for the aquatic food web. DOI:10.1016/j.watres.2011.06.004
2022-11-19 C&O Canal near Great Falls, MD
These bugs are kind of fun. Despite advertising how awful they taste (milkweed is a poison), they will still crawl behind the stem if they see you coming. To get a picture you need to move one hand behind the plant so they scoot to the near-side. Adults are good fliers, migrating from the northern states down to the gulf. [DOI:10.1126/science.175.4028.1327] They can only sustain flight for a couple of hours at a time,* so it takes them a while.
2022-08-20 North Tract, Putuxent Research Refuge, Laurel, MD
* Bug treadmills: tie a tether to them and see how long they fly. No IRB required for invertebrate studies (or anything before 1974).