Stink Bugs Preying On Insects
Shield-shaped stink bugs (Pentatomidae) are fairly distinctive looking and smelling. Their common name comes from the presence of scent glands that open on their thorax, discharging pungent compounds over a wick-like surface near the bug’s hind legs. These compounds serve as a chemical deterrent for would-be predators, and also as an alarm for other stink bugs.
About a third of the 200 North American species of stink bugs are predaceous – they actively hunt and kill their prey. (The other two-thirds are plant feeders.) After spearing the prey with its piercing mouthpart, or beak, the stink bug injects digestive enzymes into its victim. These enzymes help liquefy tissues in the body of the prey and a muscular pump in the head of the stink bug enables the bug to suck nutrient rich liquid from its prey. Many predaceous stink bugs are major predators of webworms, tent caterpillars, Colorado Potato Beetles and a number of other insects that are considered garden pests. Unfortunately, non-pest species, such as the monarch caterpillar (see photo) are also subject to stink bug predation.
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Hackberry Nipple Galls
If you look on the underside of the leaves of a Common Hackberry (Celtis occidentalis) tree at this time of year, you often find light-colored, raised bumps, commonly referred to as Hackberry Nipples Galls. The creatures responsible for these growths (through chemical interactions with the leaves) are a group of small insects called jumping lice, or psyllids, which resemble miniature (1/6 “ long) cicadas, with their large eyes and wings held roof-like over their backs.
Adult Hackberry psyllids emerge in September and October from the galls they have formed and seek shelter for the winter, often in the cracks and crevices of tree bark. Because they are attracted to lights and can often fit through the mesh of window screens, these insects also seek shelter in houses. Although considered a nuisance by some, Hackberry psyllids do not sting, nor do they carry disease. They pass the winter as adults and when they break dormancy in the spring, the psyllids exit houses, tree bark fissures, etc. and lay eggs on the emerging leaves of Hackberry trees. After the eggs hatch, the young psyllids start feeding, stimulating abnormal growth in the leaves, forming small pockets, or galls, surrounding the insects. The psyllids spend the rest of the summer sucking on tree sap safely within the protective galls before exiting in the fall. As a rule, these insects do not cause serious damage to their Hackberry tree hosts.
Ambush Bugs Patiently Waiting To Pounce
Ambush bugs, a type of assassin bug, are true bugs, in the order Hemiptera. (Although insects are often referred to as “bugs,” technically only insects in this order are classified as bugs by entomologists.) All true bugs have piercing and sucking mouthparts, and wings which are membranous and clear at the tips, but hardened at the base.
Ambush bugs are usually brightly colored (yellow, red or orange) and have thickened front legs which are used to capture prey up to ten times their own size. They live up to their name, patiently lying in wait for unsuspecting prey, often in goldenrod flowers where they are very well camouflaged. An ambush bug, upon sighting an insect, suddenly seizes the prey in its powerful forelegs and quickly dispatches it with a stab from its sharp beak. It then injects digestive enzymes into its prey, after which it drinks the resulting liquid innards.
Dog-day Cicadas Emerging, Courting, Mating and Laying Eggs
Adult annual cicadas, including the pictured Dog-day Cicadas, have emerged from their subterranean dwellings. High up in trees most males are vibrating their abdominal tymbals (drum-like organs) in order to woo female cicadas with their “song.” Thanks to an abdomen that is relatively hollow, the sound is intensified, and very audible to human ears as a high-pitched whining drone, somewhat resembling a buzz saw. We associate it with the hot, humid “dog days” of July and August.
Annual cicadas emerge from the ground (where they have been feeding off of the sap of trees through the trees’ roots for two to four years) every year as nymphs. They climb a tree, split and emerge from their exoskeleton, or outer skin, and pump their wings full of fluid. After their exoskeleton dries, the adult cicadas (also called imagoes) head for the canopy, and males commence “singing” to attract a mate. Within two weeks mating takes place, eggs are laid in slits of live branches and the adults die. After hatching, the nymphs will drop to the ground and burrow into it with their shovel-like front legs. (Thanks to Wallie Hammer for taking and providing today’s photograph. Mating usually takes place in the canopy, and therefore rarely seen.)
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Ants “Milking” Treehoppers
Certain species of treehoppers (a type of true bug) release a sugary liquid called honeydew, made mostly from excess plant sap that they consume. Ants farm these treehoppers, much as they farm aphids, for their honeydew. An ant grasps a treehopper and strokes it with its antennae, causing a droplet of honeydew to appear at the tip of the treehopper’s abdomen, which the ant then consumes. Both insects benefit from this mutualistic arrangement. The ants get honeydew, and in return, provide protection for the treehoppers from predators. The plant indirectly benefits from the ants, as well, for if the ants were not there, the treehoppers’ honeydew would fall onto the plant, causing mold growth on fruits and leaves. Eggs, nymphs and adult treehoppers can usually all be found in one location. (Photo insert: a treehopper nymph on left, adult treehopper on right) To see a video of ants farming a type of treehopper called a thornbug, go to https://www.youtube.com/watch?v=HoeJn3Imss4.
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Spittlebugs Feeding
This strange-looking insect is none other than the nymphal stage of a true bug called a froghopper. During its immature stage, it is referred to as a spittle bug, due to the fact that while feeding on the sap of a plant it pumps excess water out of its abdomen (up to 150-300 times its body weight every 24 hours) and this water, combined with body secretions, turns into sticky bubbles which fall down over the nymph (it feeds upside down). The spittle provides thermal protection and prevents the nymph from drying out while it feeds for days in the sun. While seemingly drawing attention to the nymph’s presence, the spittle has a very bitter taste that would-be predators find unappealing. As an adult, the froghopper earns its name by being able to jump 100 times its length.
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