Peewee Leggy Bugs--Water Striders

Jesus! A bug type that can walk on water!

A neighbor walking with us spotted a bug he considered a "leggy bug", like several I had written about the last few months. From looking at images and diagrams of proportionally for legs vs. body length, I could agree. However, after peering more into the water strider (aka pond skater), I'd characterize the bug as a peewee leggy bug. These striders' body lengths measure only about 1/2". Their legginess, however, helps them navigate on water surfaces.

From Osborn School site "Water Strider"—"½ of an inch long … sometimes called 'Pond Skater', can run across the surface of the water, very sensitive to movement".

Enchanted Learning's site "Water Strider" has similar information with a descriptive diagram.

The water strider (also known as the pond skater) is a true bug that can run across the surface of water … The underside of the body is covered with water-repellent hair. … Most water striders are over 0.2 inch (5 mm) long. … The long, middle legs move this bug across the surface on the water like paddles. The long hind legs steer them and act as brakes. The short front legs are used to catch prey.

Coincidentally, I wrote about a "true bug" previously—the leaf-footed bug that visited me at one of my porch columns "Leaf-footed Bug Visitor". The commonality—piercing mouth parts: In the case of the water strider in BugFact's "Water Strider (True Bug)" site, using the bug POV, "[I] use my piercing mouth parts to suck the juices primarily from other insects or spiders, alive or dead."

Is the water strider a leggy bug like several I have written about recently? Yep, if considering ratios of body parts. "Water Strider (True Bug)" emphasis on legs—"I am able to slide along the surface of the water by distributing my weight evenly on my long legs. … I have two antenna and six long thin legs. My front legs are shorter than my back legs."

Bugguide.net's "Family Gerridae - Water Striders", shows the size to be a puny (3-16 mm, about .12 to .63 inches)—not as impressive as walking sticks, crane flies, or huntsman spiders.

An informative site, seemingly hostile to water striders, is PestWiki's "Water Strider: 8 General Facts and How to Get Rid of Them". (The descriptive illustration is pretty cool.)

They have short front legs which help them to capture aquatic insects in ponds. They also have wings on dorsal sides. They use their middle pair of hydrophilic legs for propulsion and their hind pairs for steering. The adult water striders come in two species i.e. one with wings n (sic) the other without wings.

How It Works' "How do water striders walk on water?" provides another description of mechanics and water-coping ability of this bug:

Despite being denser than water, a water strider doesn’t doesn’t sink; … The forces of attraction between all the molecules in the water pull the molecules at the surface together so that they lock like a thin elastic membrane of slightly denser molecules.…

The middle pair of legs, lying ?at on the water, are used as oars to ‘row’ over the surface while the rear pair act like rudders for steering. Long, splayed legs enable the pond skater to distribute its weight evenly over a greater surface area, further helping it to float.

Some TouTube Videos About Water Striders with Emphasis on Water-walking Talents

• "Water strider - walking on water"
  Handy succinct description—"Water strider walking on water using surface tension of water. Phylum: Arthropoda, Class: Insecta, Order: Hemiptera, Family: Gerridae."
• "How Do Water Striders Walk On Water?"
  Speeded up whiteboard presentation with diagrams and simple explanation.
• "Shadows reveal how insects walk on water - Headline Science"
  Intriguing study about measuring bugs' shadows and calculating the buoyant force.

A Male Water Strider Species with Captivating Courtship

"Male water striders evolved antennae to grab females by the eyes" describes a study of rheumatobates rileyi species of water strider. The male bug mates with the female, first using his antennae to physically capture her eyes. Besides vivid descriptions, the article includes a video of the couple in action.

Leaf-footed Bug Visitor

My bug visitor was unusually shaped, like a slender, upside-down bell, with muscular-looking, long, rear legs. It was nearly monochrome dark. From preliminary research and images, I settled on it being a leaf-footed bug.

From “Leaf-Footed Bugs, Family Coreidae”—“Many members of this family have noticeable leaf-like extensions on their hind tibia, and this is the reason for their common name.” Another good preliminary resource is the Insect Identification site for “Leaf-Footed Bug - (Acanthocephala spp.)”.

A few days ago (about 8 AM), the intriguing bug was on a porch column, unmoving. I left it alone, but took several pictures. After about an hour, I returned, toting my camera and masking tape-backed measuring stick, to see if it was still there. The bug had moved. I aligned the ruler near it and pressed; took a couple of shots. Bug stayed put.

I decided to return after the house shadow would fall across the column for better pictures (around 3 PM). As I set some blank background nearby, the bug started to move! Upward! Out of range of my backdrop! Aha! I would just RECORD it for a little while! Then it froze. I took more pix, then left. About an hour afterward, I looked to see it had left.

Later, for help in identifying the bug, I posted the ruler-accompanied bug picture to my LinkedIn feed, emailed someone who had blogged about a similar-looking bug, and scoured big-picture bug sites. By poring SLOWLY over the big picture sites, I narrowed down my search. It helped to have an idea of the bug I wanted to ID. Good jumping off (ha) sites:

• Slide show bug lessons in “Subphylum Hexapoda Includes all insects class insecta”
• YouTube video “Taxonomy: An introduction to Insect Orders” that introduces insect categories. An example of bumblebee is around a minute into the video.
• Bugguide.net’s "Overview of Orders of Insects"
• Earthlife.net’s “The Insect Orders An Introduction each to of the 32 Orders of Insects”

I kept encountering the term “true bug”. From ASU School of Life Sciences site:

The key difference between true bugs and other insects is their mouth parts. … true bugs have specialized mouth parts used to suck juices. … The proboscis of a true bug is not retractable. Insects with movable mouthparts allow them to move food from the source to their mouth. The proboscis of a true bug is more rigid and cannot be rolled up.

Poring more into Google site and image searches, I found several sites that showed bugs with strong resemblances to my visitor.

• Bugguide.net’s “Species Acanthocephala declivis” page
• What’s That Bug’s “Leaf Footed Bug: Acanthocephala species”
• iNaturalist.org’s “Giant Leaf-footed Bug Acanthocephala declivis”

Although "What’s That Bug" did not include the species name declivis, I found declivis and three other species names (femorata, terminalis, thomasi) in the Bugguide taxonomy tab. Best match for images is delivis.

*** View my video of the leaf-footed bug that was on my porch column, leaving around mid-day. Includes motion footage, a still of it with accompanying measuring stick for size reference. Additional stills capture a seeming heel click and shadow-illusion pushups. Check out the carapace. As it turns out, I’ve been bugged a long time ago, over the same type of bug … in 2005, when I helped a friend move. I have included some of those stills also.