Hornets, Yellow Jackets, Paper Wasps. Being true social insects, these critters have a well-developed caste system. In a typical mature wasp nest there are many workers and one or more kings and queens. Unlike some of the other social insects discussed in this CD, there are fewer differences in the appearance of each caste.
Hornets, yellow jackets and paper wasps all exhibit the same general life cycle. Their nesting cycle is annual, with only mated queens surviving the winter in a variety of protected locations--including under bark and in attics. In early spring the queen emerges and may reoccupy an old nest, or construct a new one. Regardless of which condition prevails, the queen initially deposits a few single eggs-one to each cell. Upon hatching, the larvae are fed a variety of insect larvae (mainly caterpillars) that are captured and brought back to the nest by the adult queen wasp.
The adult wasps feed primarily on nectar, ripe fruit and other substances that are high in sugar. They do require a certain amount of protein in their diet which is typically acquired from the larvae. As adults wasps are feeding their larvae, the larvae exude a protein based material from their mouth that is quickly consumed by the adult. The majority of these larvae will develop into adult workers, which take over the duties of expanding the nest, collecting food and feeding the young. The queen continues to lay more eggs; this results in several generations with the colony continuing to increase in size into the fall. In the late fall, new kings and queens are produced, mating occurs, and the newly mated queens overwinter, completing the annual cycle.
Biological Control. Wasps are quite beneficial from the standpoint of biological control, as they are predatory on different pest species. Besides feeding on caterpillars and other insects and spiders, these insects are attracted to any meat source, a phenomenon, which is frequently observed much to the displeasure of campers, clients of or participants in restaurants, snack bars and backyard barbecues
The nests of hornets, yellow jackets and paper wasps are constructed out of cellulose, which is collected by the adult workers from a variety of sources, including old newspapers, cardboard, weathered wood, and bark. Once collected, these materials are chewed, saliva is added and they are formed into cells basically appearing like those in honey bee comb.
With paper wasps the nest is a single layer that is suspended upside down by a short stalk. Around the home, paper wasp nests typically are found under eaves, along fences, or can be found attached to trees and plants. Hornet and yellow jacket nests may exist above or below ground; their nests are much larger than those of paper wasps, and are constructed of many layers of cells that are surrounded by a capsule-like structure.
Left. A Paper Wasp Nest with a Dozen or So Workers. Image Courtesy Dicklyon CC BY-SA 4.0 InternatuinaL Right. Right Large Hornet Nest. Image Courtesy CDC Healthwise Photo Library-Dr. Gary Alpert.
Since paper wasp nest are single-layered it follows that mature colonies of these insects are much smaller than those of the multiplayer nests of hornets and yellow jackets. The nest of a paper wasp typically contains a few dozen adults while the nests of hornets and yellow jackets may number in the thousands.
Paper wasp colonies although common under the eaves of houses do not typically pose a threat to the homeowner unless the nest is disturbed. If disturbed they will readily defend the nest and sting is similar to that of a bee although unlike that of a honey bee these insects can sting repeatedly.
I was once asked in class how to remove a paper wasp nest from the eves of a home. Although not in the position to recommend such a task there are sprays available at garden centers that provide an instant knock down a subsequent kill of wasps and bees. One of the students in the class said she used hair spray which upon drying prevented the wasps from flying. Another student immediately added that she uses hair spray but lights it! Both seem quite unacceptable and possibly dangerous!
Students frequently ask me what is the worst sting-bite that I personally have experienced. I have been stung by many scorpions, many species of ants, exotic caterpillars and hundreds of bees at one time and bitten by large beetles, giant waterbugs, assassin bugs, various tarantulas and black widows but the worst encounter was by a colony of yellow jackets. The sting of a yellow jacket or hornet is considerably worse than that of a honeybee. I was once called to remove a honeybee nest from a property. When I got there it was a yellow jacket nest in the ground. Even though, I was only prepared for honeybees (a veil and hat) I decided to continue. After about 15 stings (over a period of 20 minutes) I decided to retreat and get some better protective clothing. By the time I got back to my vehicle most of my body had turned bright red with hives and large red welts. Besides the initial pain I itched for several days. I once received a single sting from a large hornet in Mexico. The initial pain was so strong and painful that it put men down on the ground.
Electron Microscopic Close up of German Wasp. Image Courtesy Secret Disc-GNU Free Documentation.
Paper Wasps. With paper wasps the nest is a single layer that is suspended upside down by a short stalk. Around the home, paper wasp nests typically are found under eaves, along fences, or can be found attached to trees and plants. Hornet and yellow jacket nests may exist above or below ground; their nests are much larger than those of paper wasps, and are constructed of many layers of cells that are surrounded by a capsule-like structure.
Because paper wasp nest are single-layered it follows that mature colonies of these insects are much smaller than those of the multiplayer nests of hornets and yellow jackets. The nest of a paper wasp typically contains a few dozen adults while the nests of hornets and yellow jackets may number in the thousands.
Paper wasp colonies although common under the eaves of houses do not typically pose a threat to the homeowner unless the nest is disturbed. If disturbed they will readily defend the nest and sting is similar to that of a bee although unlike that of a honey bee these insects can sting repeatedly.
I was once asked in class how to remove a paper wasp nest from the eves of a home. Although not in the position to recommend such a task there are sprays available at garden centers that provide an instant knock down and subsequent kill of wasps and bees. One of the students in the class said she used hair spray which upon drying prevented the wasps from flying. Another student immediately added that she uses hair spray but lights it! Both seem quite unacceptable and possibly dangerous!
Western Yellow Jacket. V. pensylvanica is a predatory species that feeds on a wide range of invertebrates (and occasionally even on slugs) and this has great potential for negative impact on the native fauna in isolated habitats. In its genus, it is one of the few species that also has a scavenging habit as opposed to being strictly a predator and is thus considered a major pest to humankind. Along with two other species — the "common wasp" or "yellowjacket" (Vespula vulgaris) and the "German wasp" or "European wasp" (Vespula germanica) this species is part of the "Vespula vulgaris group" which together are the most abundant and bothersome of eusocial wasps species. With a preference for scavenging carrion that attracts it to the human food and garbage, V. pensylvanica is the most significant pest yellow jacket in western North America.
Left. Western Yellowjacket. Image Eugene Zelenko GFDL.
Vespula pensylvanica shares its basic yellow and black pattern with other species of wasp in genus Vespula and its sister genus Dolichovespula which are collectively known in North America by the common name "yellowjacket." V. pensylvanica; however, is the only member of its species group that has a complete yellow eye ring around each compound eye. This eye ring is also visible in queen wasps of this species. The length of this specie’s fore wing is 8.5–10.5 mm in workers, 12.5–14.5 mm in queens, and 12.5–14.0 mm in males.
Even though the specific name is "pensylvanica", this species is actually native across the western half of North America, in temperate zone climates. More precisely, individuals have been identified in Canada from Manitoba to British Columbia. The easternmost record for V. pensylvanica is a single record from Ontario but it is apparently not established in that province as a species. In the United States the eastern edge of its range is in Wisconsin, Nebraska, Colorado, and Texas. In Mexico it is known from Baja California Norte, México, and Michoacán.
The most common social wasp found in the Western United States is the western yellow jacket. This species typically nests underground, but occasionally is found in wall voids and other protected locations. As with other members of this group these insects are predatory in nature but when their natural food is scarce they are attracted to any type of meat or sweets. Certain years these insects become extremely common and are major pests around campgrounds, restaurants and even backyards. One major factor relating to larger numbers during certain years is previous mild winters. Under these conditions the nests may not totally die out during the winter months.
Asian Giant Hornet-Vespa mandarinia. This includes the subspecies Japanese giant hornet (Vespa mandarinia Japonica), locally known as the yak-killer hornet, is the world's largest hornet, native to temperate and tropical Eastern Asia. Its body length is approximately 2 inches with a wingspan of about 3 inches. It can be found in the Primorsky Krai region of Russia, Korea, China, Taiwan (where it is called 虎頭蜂; "tiger head bee"), Indochina, Nepal, India, and Sri Lanka, but is most common in rural areas of Japan.
Left. Asian Giant Hornet. Courtesy Yasunori Koide GFDL.
The stinger of the Asian giant hornet is about ¼ inch in length, and injects potent venom that contains, like many bee and wasp venoms, a component that can damage tissue by stimulating phospholipase action, in addition to its own intrinsic phospholipase. Masato Ono, an entomologist at Tamagawa University near Tokyo, described the sensation as feeling "like a hot nail being driven into his leg."
An allergic human stung by the giant hornet may die from an allergic reaction to the venom, but the venom contains a neurotoxin which can be lethal even to people who are not allergic if the dose is sufficient. Each year in Japan, the human death toll caused by Asian giant hornet stings exceeds that of all other venomous and non-venomous wild animals combined, including wild bears and venomous snakes (60 to 70 people a year).
A few interesting notes on Vespa mandarinia's venom and stinger: The venom contains at least eight distinct chemicals, some of which damage tissue, some of which cause pain, and at least one which has an odor that attracts more hornets to the victim; the venom contains 5% acetylcholine, a greater concentration than is present in bee or other wasp venoms. Acetylcholine stimulates the pain nerve fibers, intensifying the pain of the sting; Vespa mandarinia uses its large crushing mandibles, rather than its sting, to kill prey; the venom of the Asian giant hornet is not as toxic as some other bees or wasps, and is less toxic than honey-bee venom, but because of the large quantity of venom, this species has one of the greatest toxicities per sting; the enzyme in the venom is so strong that it can dissolve human tissue.
As bad as this is for humans, it is much worse for the European honeybee, Apis mellifera, the most common honeybee found around the world. These wasps will fly many miles looking for beehives to raid. They can fly as far as 60 miles in a day at 25 miles per hour. A searching hornet may actually follow a foraging bee back to its hive. Once finding the hive it attacks giving off the alarm pheromone attracting other hornet in the vicinity. Ultimately they typically attack in force with a relatively small but very effective army of 30 or more. You wouldn’t think such a small army would be that successful as a beehive can have upwards of 80,000 bees. However, one hornet can kill 40 bees a minute. Unfortunately, honeybees have relatively small stingers that are of minimal use in penetrating the thick exocuticle of the invading hornets nor do they defend in mass. The hornets descend on the hive and systematically one by one cut the bees in half. In the interest of efficiency, they typically cut off the defending bees heads. After a few hours the hive contains few if any adult bees but there are piles of heads, limbs and various other body parts. At that point the hornets gorge on the honey and rip the bee larvae (young) and pupae from their cells and carry them back to their nest to feed to their young.
However all is not totally lost. There is different species of honeybee which naturally occurs in Japan that has a defensive tactic it uses against these invaders. When a single hornet in search a beehive is detected, hundreds of the worker bees gather at the hive entrance but readily allow the hornet to enter. Once in the hive the bees immediately surround and totally cover the hornet with a ball-like mass of up to 500 individuals. They prevent the hornet from moving and begin to vibrate their wings muscles. This action produces heat raising the temperature in the center of the mass (where the hornet occurs) to around 117 F. This temperature is not lethal to the bees but the hornet cannot tolerate temperatures above 113 F and subsequently dies. Of course action prevents the “scout” hornet from releasing its pheromones which would normally attract other hornets in the vicinity to mass attack the hive.
Honeybee Thermal Defense. Image Courtesy of Takahashi CC BY-SA 3.0.
In the mountains of Japan where these hornets are commonly encountered villagers eat them deep fried. Recently, several companies in Asia and Europe have begun to manufacture dietary supplements and energy drinks which contain synthetic versions of secretions of the larvae of Vespa mandarinia, which the adult hornets usually consume. The manufacturers of these products make claims that consuming the larval hornet secretions (marketed as "hornet juice") will enhance human endurance because of the effect it has on adult hornets' performance. Because these products are marketed as dietary supplement rather than pharmaceuticals, they do not have to support their claims. Some studies, however, have suggested that the vespa amino acid mixture itself may influence animal performance in minor ways.
Organ Pipe Mud Dauber-Trypoxylon politum. These are fairly large wasps, shiny black to blue with white hind tarsi. The male remains with the nest and protects against theft of prey or nest materials, as well as warding off parasites, while a female seeks and collects spiders. They typically build their nests in protected locations. Large aggregations can formed by dozens to hundreds of nests located in small areas. The shape of their nest is the basis of the common name.
As with other parasitoids these wasps are also an exceedingly docile and generally should be of no concern to the homeowner. And possibly of benefit as they serve to keep spider populations down-of course depending on how you feel about spiders. Human stings are exceedingly rare, bordering on non-existent; however if squeezed, or otherwise threatened they will sting in self-defense. There are many other species in the genus Trypoxylon (over 700 of them worldwide), mostly smaller in size and less abundant. All form this type of nest.
Control of solitary wasps is rarely if at all needed. These species are not aggressive such as the yellow jackets, hornets and paper wasps. They are also beneficial as biological control organisms controlling various lepidopterous and spider pests. Regardless some home owners or business owners do not like the nests built on the outside of their structures. In this case chemical control in not necessary. They can easily be removed with a scraper or other device and cleaned up with a vacuum cleaner. Once removed the residue can be washed and if needed can be treated with a residual insecticide to prevent reestablishment of the wasps.
Sand Wasps-Bembix spp. Although similar in appearance to predatory wasps (Vespidae), they belong to the family Sphecidae. As their name implies, these wasp are commonly found in areas with sandy soil. As a consequence, they typically occur in schoolyards and other areas with sandy play areas. They can be of concern in such areas. However, because they are solitary and not aggressive they generally do not cause a problem due to stings. These are parasites on various groups of insects. The type of prey captured tends to be rather consistent within each genus, with flies being the most common type. Nests are typically short, simple burrows, with a single enlarged chamber at the bottom. Once the nest is constructed the burrow is provided with prey for the developing larva. It is common for numerous females to excavate nests within a small area where the soil is suitable. This can result in large, dense nesting aggregations. Such aggregations tend to attract various species of parasitic flies and wasps, many of which are cleptoparasites; in some cases, the sand wasps will prey on their own parasites, a surprisingly rare phenomenon in the animal kingdom. Sand wasps vary considerably in coloration including yellow and black, black and white with bright green or red eyes.
Sand Wasp. Image Courtesy of Muhammad Mahdi Karim GNU Free Documentation License 1.2
Mutillidae-Velvet Ants. This family contains more than 3,000 species of wasps (despite the names) whose wingless females resemble large, hairy ants. Their common name velvet ant refers to their dense pile of hair which most often is bright scarlet or orange, but may also be black, white, silver, or gold. Their bright colors serve as a warning to potential predators that “I am bad, don’t mess with me”. They are known for their extremely painful stings, hence the common name cow killer or cow ant. Unlike true ants, they do not have drones, workers, and queens and are solitary.
The exoskeleton of all velvet ants is unusually tough (to the point that some entomologists have reported difficulty piercing them with steel pins when attempting to mount them for display). This characteristic allows them to successfully invade the nests of their prey and also helps them retain moisture. Like related families males have wings. They exhibit extreme sexual dimorphism where the males and females are so different, it is almost impossible to associate the two sexes of a species unless they are captured while mating.
In mutillids, as in all Hymenoptera, only the female is capable of inflicting a sting because the stinger itself is a modified ovipositor (egg laying apparatus). Female velvet ants have unusually long and maneuverable stingers. Their sting is extremely painful, hence the name cow killer. In both sexes, a structure called a stridulitrum on the metathorax is used to produce a squeaking or chirping sound (called stridulation) when the wasp is harmed or threatened. Adult mutillids feed on nectar. Although some species are strictly nocturnal, females are often active during the day. Females of some species parasitize (lay eggs on) the larvae of pupae of ground inhabiting bees or wasps such as bumblebees or or wasp nest.
Spider Wasps. These are one of the better known groups of large Hymenoptera. Most of the spider wasps are orange and black, black and grey/white markings or just black. These colorations are very strong warning colors. Many have opaque or colored wings and a smooth, shiny body. Their hind-legs are long and always have 2 prominent spurs located at the distal end of the tibia. The antennae of many are coiled at the terminal end. Spider wasps are best distinguished from other similar appearing wasps by the presence of (in most species) a transverse groove dividing the mesopluron into halves. This can be seen on the below image on the plate located between the base of the wing and attachment of the middle leg.
All species are solitary, and most capture and paralyze prey; a few species are cleptoparasites of other pompilids, or ectoparasites of living spiders. Sexual dimorphism is not marked although females are often larger than the males. They paralyze spiders with a venomous ovipositor. Once paralyzed, the spiders arer dragged to where a nest will be built – some wasps having already made a nest. A single egg is laid on the abdomen of the spider, and the nest – or burrow – is closed.
Spider Wasps Collecting Prey. Images Courtesy I, Tony Wills CC BY 2.5.
The female wasp has the capability of depositing an egg that will eventually turn into a male or female adult. If an egg is not fertilized, it will be a male: however, if the egg is fertilized, it will eventually develop into a female adult. The size of the captured host can influence if the female deposits an egg that will develop as a male, or into a female. Larger prey typically yields (larger) females. When the wasp larva hatches, it begins to feed on the still-living spider. After consuming the edible parts of the spider, the larva spins a silk cocoon and pupates, Adults typically emerge as adults the next summer. Some species of these wasps lay their eggs on still-active (unparalized) spiders. In this case. the hatching larvae feed externally on hemolymph (blood) of the hsot. In time, that spider will die and the mature wasp larva will then pupate. Adults usually hunt on ground exhibiting a characteristic wing flicking movement.
Tarantula Hawk-Pepsis spp. This is a well-known species of spider wasp which hunts tarantulas as food for it larvae. With up to a 2 inches long black body with and bright rust-colored wings, tarantula hawks are among the largest of wasps. As with other brightly colored insects, the coloring on their wings warns potential predators that they are dangerous. Their long legs have hooked tarsal claws for grasping their victims. The stinger of a female tarantula hawk can be up to 1/3 inch long, and delivers a sting which is rated among the most painful in the insect world.
Tarantula Hawk Dragging Prey to Nest. Image Courtesy Charlesjsharp CC BY-SA 3.0. Feeding on Milkweed Nectar. Image Courtesy of Astrobradley Right Image Courtesy Davehood at English Wikipedia Public Domain.
These wasps are relatively docile and rarely stings unless threatened or injured. The sting of Pepsis formosa is among the most painful of any insect, but the intense pain only lasts for about 3 minutes. Commenting on his own experience, one researcher described the pain as "…immediate, excruciating that simply shuts down one's ability to do anything, except, perhaps, scream. Mental discipline simply does not work in these situations”. In terms of scale, the wasp's sting is rated near the top of the Schmidt Sting Pain Index second only to that of the bullet ants from Costa Rica and is described by Schmidt as "blinding, fierce [and] shockingly electric". Because of their extremely large stinger, very few animals are able to eat them; one of the few animals that can is the roadrunner.
Carpenter Bees. Carpenter bees are large, hairy bees with over 500 species distributed worldwide. Their name comes from the fact that nearly all species build their nests in burrows in dead wood, bamboo, or structural timbers.
Carpenter bees are traditionally considered solitary bees, though some species have simple social nests in which mothers and daughters may cohabit. However, even solitary species tend to be gregarious. There are 2 very different mating systems that appear to be common in carpenter bees, and often this can be determined simply by examining specimens of the males of any given species. Species where the males have large eyes are characterized by a mating system where the males either search for females by patrolling, or by hovering and waiting for passing females. In the other type of mating system, the males often have very small heads, but there is a large, hypertrophied glandular reservoir in the mesosoma, which releases sex pheromones while it flies or hovers. The pheromone advertises the presence of the male to females.
These bees come in a variety of sizes, although most are slightly larger than a honey bee. One of the most common species is the valley carpenter bee that is characterized by solid black females and golden males. They are as large as or larger than bumblebees.
Female and Male Valley Carpenter Bees. Image Dr. Kaae
As previous indicated these bees nest in wood. Their colonies consist of a series of tunnel-shaped burrows. As do other bees, carpenter bees collect pollen to feed to their young. Once collected, the pollen is formed into a ball about the size of a small marble. A single egg is then deposited on each ball, which subsequently is compartmentalized within the burrows. Their life cycle is completed in a few months as the larvae develop on the pollen balls.
Tunnel of a Carpenter Bee with Developing Larva and Pupa. Image Courtesy Univar Corporation.
Carpenter bees are not true social insects as there is no division of labor, but many bees may occupy the same nesting burrow. The burrows typically are used year after year and can become rather extensive. Even though these are wood infesting insects, rarely do they do any significant damage to homes. Occasionally they can be bothersome to the homeowner because the males are especially aggressive and will fly up to and buzz in a person’s face; however, they are totally harmless, as male Hymenoptera do not have stingers. The sting of the female is quite painful, but she is much less aggressive.
In the telephone industry, these bees are referred to as pole bees because they frequently nests in telephone poles. Even though they typically do not sting, they buzz linemen and in some cases this has resulted in injuries as a result of the workers’ attempts to avoid their harassment. I am aware of more than one case where linemen have fallen from poles due to “bee attack”.
Ant Wars. Ants are among the most aggressive and war-like of all animals. If ants had a policy of life it could be summarized as restless aggression, territorial conquest, and total annihilation of neighboring colonies. These insects use any of a number of strategies and weapons to reach these goals. Chemical warfare is used in many ant species including spraying a variety of toxic chemicals (mainly formic acid) in order to repel, confuse, immobilize or even kill their rivals. The soldiers of many species frequently assume a kamikaze role in order to “win skirmishes” between rival colonies. Of course this is not a true kamikaze behavior as ants do not think but merely react to given stimuli. One of the most dramatic of these sacrifices is exhibited by a carpenter ant from SE Asia. These ants act as walking bombs. There is a huge internal gland that occupies much of their body that is filled with toxic chemicals. If one of these ants is hard pressed by a rival ant or predator it contract some large abdominal muscles that bursts open the abdomen violently (like a bomb) releasing the chemicals.
The availability or more significantly the limited availability of food frequently is important in colony survival. As a result rival colonies frequently develop strategies and plans to maximize the chance of finding food. There is a small fast moving ant in the deserts of Arizona that use toxic secretions to intimidate and confuse the large honey ants (10 time larger) as they steal food from the honey ant colonies. In addition these tiny ants will on occasion block honey ants from leaving their nests by releasing toxins down the hole or nest entrance thus keeping the former below ground. This of course allows the smaller species to forage for food without competition from the larger ants. An additional form of nest entrance blocking is performed by a smaller species. In this case they gather in mass at the nest entrance of their rivals and release toxic chemicals down the entrance. However in addition they collect pebbles, twigs and other small objects and drop them down the vertical shaft entrance.
Without a doubt the most elaborate of all aggressive strategies in social insects has been recorded in battles between s tiny woodland ant and the red imported fire ant, one of the most aggressive of all ants. These ants are major enemies of the woodland ants with colonies 100 times larger than the latter. Even though fire ants are much more powerful than these tiny ants both species successfully survive living in the same area. The secret of woodland ant survival depends primarily on a specialized soldier (major) and a three-fold strategy to defend against fire ant attack. These specialized in many ants) but quite utilize their huge mandible to snip off legs, heads and other body parts of the fire ants. Unless attacked the majors remain in their colony. However, as the minor caste forage for food they are always on the alert for the scout of fire ants that are looking for colonies to attack. If a foraging woodland ant minor encounters a fire ant soldier near its colony, a violent but preprogrammed response unfolds. The minor immediately rushes to the fire ant in a mock attack but instead touches the potential invader in order to acquire some of its odor. She then retreats toward her nest. As she retreats, she lays down a pheromone trail by periodically touching her abdomen to the ground. On her way back to the nest she rushes up to any other minor alerting them to the presence of the fire ant scout. Once in the nest she continues to alert soldiers plus many other of the minors to the presence of the soldier scout (by its smell on the minor worker). As a result all subsequently rush in mass along the establish pheromone trail that leads to the enemy. Once encountered the soldier they surround the fire ant and attack relentlessly pulling of its led and other parts and destroy it due to their great superiority in numbers. Of course the idea is to kill the fire ant scout before it can alert other fire ants as to the presence of a woodland ant colony. Once accomplished the soldiers search for any additional fire ant scouts in the area.
Of course fire ants mount a full scale attack of a woodland ant colony: as a result the defenders have an alternate and equally effective but sacrificial strategy for survival of the species. If fire ants arrive in great numbers the entire force of woodland soldier ants are rush to battle. Soon the ground is littered with the destroyed bodies of the smaller species plus many of legs and other body parts of the fire ant soldiers. As the battle continues any remaining woodland ant minors retreat to the nest. As more enemy soldiers arrive and the woodland ant soldiers are greatly out-numbered they also retreat, close ranks and form a dense perimeter around the entrance of the colony. As doom appears eminent that the fire ants will soon break through the protective barrier and ravage, steal and consume the woodland ant’s brood the activity of the minors in the colonies is erratic but still well programs. They gather the egg, larvae and pupae in their mandibles and rush out though the colony entrance, through the battle field and beyond to safety. The woodland ant soldiers remain true to their programmed behavior and fight to the death. Once the fire ants abandon the now partially destroyed colony the minors return with the young and reestablish colony life. Over time new soldiers develop in the colony preparing for the possibility of another raid. .
Honey Ants. Honeypot ants, also called honey ants, are ants which have specialized workers ("repletes") that are gorged with food by workers to the point that their abdomens swell enormously, a condition called plerergate. Other worker ants in the colony ants then extract nourishment from them. They function as living larders. Honeypot ants belong to any of five genera, including Myrmecocystus. They were first documented in 1881 by Henry C. McCook.
Ants vary tremendously as to their food preferences, size and colony locations. Normally they live in arid desert regions of the world; their primary diet is honeydew, which they collect from aphids and other homopterous insects. In such dry areas, honeydew-producing insects are common during the rainy season only when host plants prevail. Because in most areas this season only lasts a few months, honey ants have developed a means of ‘storing’ honeydew from season to season.
Many insects notably honey bees and some wasps collect and store liquid for use at a later date. However, these insects store their food within their nest or in combs. Honey ants are unique in using their own bodies as living storage, but they have more function than just storing food. Some store liquids, body fat, and water from insect prey brought to them by worker ants.
They can later serve as a food source for their fellow ants when food is otherwise scarce. When the liquid stored inside a honeypot ant is needed, the worker ants stroke the antennae of the honeypot ant, causing the honeypot ant to regurgitate the stored liquid. In certain places such as the Australian Outback, honeypot ants are eaten by aboriginal people as sweets and are considered a delicacy.
Some worker ants turn into honeypots right from their emergence from pupa stage. The young ants stay in the nest, and the worker ants who collect food feed them. As the workers feed them with more food than they need, the surplus nutrients get stored in their abdomens. As their abdomens expand, the ants lose their mobility.
These ants can live anywhere in the nest, but in the wild, they are found deep underground, literally imprisoned by their huge abdomens, swollen to the size of grapes. They are so valued in times of little food and water that occasionally raiders from other colonies, knowing of these living storehouses, will attempt to steal these ants because of their high nutritional value and water content. These ants are also known to change colors. Some common colors are green, red, orange, yellow, and blue.
Honeypot ants such as Camponotus inflatus are edible and form an occasional part of the diet of various Australian Aboriginal peoples. Papunya, in Australia's Northern Territory is named after a honey ant creation story, or Dreaming, which belongs to the people there, such as the Warlpiri. The name of Western Desert Art Movement, Papunya Tula, means "honey ant dreaming".
Myrmecocystus nests are found in a variety of arid or semi-arid environments. Some species live in extremely hot deserts, others reside in transitional habitats, and still other species can be found in woodlands where it is somewhat cool but still very dry for a large part of the year. For instance, the well-studied Myrmecocystus mexicanus resides in the arid and semi-arid habitats of the southwestern U.S.
Some repletes also hoard water, fats and body fluid from insect prey. The repletes engorge on food that is collected outside the nest and brought to them by normally-proportioned worker ants. Deep in underground chambers, the repletes hang quietly in clusters, literally imprisoned by their abdomens ballooned to the size of small grapes.
Honey ants are highly social insects. They live in efficiently organized colonies or groups of cooperating individuals. Their societies are matriarchal or female-dominated families. A typical honey ant colony contains a single fertile queen and thousands of sterile female workers. The queen is the mother of the colony and is specialized for egg production, while the workers, the queen's daughters and hence all sisters, are responsible for colony labor.
Protein sources also are necessary, particularly for the growing larvae. Foraging honey ants search for live or recently dead invertebrates, predominantly arthropods; small soft-bodied insects like termites and caterpillars are especially fair game. Individual workers head homeward with pieces of food clasped within their mandibles, while groups of workers may cooperate when retrieving large or struggling prey items.
Like all formicine ants, honey ants lack stingers: rather, they spray fine droplets of formic acid from their abdominal tip. The caustic acid is used, along with pinching mandibles, to help subdue uncooperative prey or to deter colony enemies. Grappling with prey or facing off against their foes, attacking honey ants spread and brace their legs, rapidly curl their abdomens underneath pointing forward, aim and fire. Their chemical weaponry is most effective against small targets; it is useful against mammals or other large animals only if sprayed into highly sensitive tissues like eyes or nostrils.
Given an abundance of sweet repletes, it is not surprising that badgers and other desert creatures sometimes burrow into and plunder honey ant nests. Even some honey ant colonies will raid one another, stealing not only repletes but also brood, that when mature, is "enslaved" as part of the pirating colony's worker force.
As recently as early this century, various Native American tribes and Mexicans regularly excavated honey ant colonies to obtain the savory morsels stockpiled therein. Sweet-toothed human predators typically hold a replete's head and thorax with the fingers, bite off or rupture the fragile abdomen, then suck its contents into the mouth. The so-called "honey" tastes somewhat like molasses, while the ants' bodies, being bitter, are discarded. Perhaps fortunately for honey ants, this practice seems to have fallen by the wayside due to the advent of commercially available candies. These not only taste better but are much less work to procure.
In the presence of excess food, repletes can develop from any newly emerged worker, apparently before its exoskeleton and intersegmental membranes harden and become less flexible. In young colonies, it is not uncommon to find small workers serving as somewhat ineffective repletes, with their tiny abdomens distended to the bursting point. However, on an individual basis, major workers make the most efficient honeypots. Hundreds to a thousand or more large repletes can be found in mature honey ant colonies, each patiently hanging and waiting to serve up dinner when called upon by its nest mates.
Argentine Ant. Linepithema humile.
Argentine Ant Tending Soft Scale for Honeydew. Image Courtesy Penarc. CC BY-PA 4.0 International,
The Argentine ant is a single node, relatively small, brown ant with monomorphic workers. These are typically about 1/12 to 1/8 inch long. The queen ants are considerably larger, sometimes reaching 1/4 inch. They nest outdoors under logs, concrete slabs, debris and mulch. Argentine ants build very large colonies and can move rapidly. During winter months, this ant will move indoors.
Biology. This ant is successful and hard to control because:
Different Argentine ant colonies in same general locations are not enemies. Even the many queens in a single colony or separate colonies are friendly to each other.
These ants are not too "picky" when selecting a site to infest or colonize. They frequently move their nests during the changing seasons and other environmental conditions.
They are omnivorous feeding on a wide variety of food.
Each colony of Argentine ants contains a multitude of workers.
They are extremely aggressive towards other species of ants and harder worker than mos. Creatures that attempt to prey on Argentine ants are confronted with an army of stubborn insects that never runs from a fight!
The queens of most ant species are typically lay large number of eggs. The queenS of Argentine ants actually helps in the care, grooming and feeding of her young.
Most species of ants mate and reproduce by swarming; the Argentine mates in the colony and therefore not exposed to predators such as birds, frogs, lizards, predator insects and extreme weather conditions. It is estimated that swarming reproductive (as seen with fireants and carpenter ants) has about 1 chance in 1,000 of surviving and successfully reproducing.
The worker ants are about 3 millimeters (0.12 in) long and can easily squeeze through cracks and holes no more than 1 millimeter (0.039 in) in size. Queens are two to four times the length of workers. These ants will set up quarters in the ground, in cracks in concrete walls, in spaces between boards and timbers, even among belongings in human dwellings. In natural areas, they generally nest shallowly in loose leaf litter or beneath small stones, due to their poor ability to dig deeper nests. However, if a deeper nesting ant species abandons their nest, Argentine ant colonies will readily take over the space.
According to research published in Insectes Sociaux in 2009, it was discovered that ants from three Argentine ant supercolonies in America, Europe, and Japan, that were previously thought to be separate, were in fact most likely to be genetically related. The three colonies in question were one in Europe, stretching 6,000 km (3,700 mi) along the Mediterranean coast, the "Californian large" colony, stretching 900 km (560 mi) along the coast of California, and a third on the west coast of Japan. Based on a similarity in the chemical profile of hydrocarbons on the cuticles of the ants from each colony, and on the ants' non-aggressive and grooming behavior when interacting, compared to their behavior when mixing with ants from other super-colonies from the coast of Catalonia in Spain and from Kobe in Japan, researchers concluded that the three colonies studied actually represented a single global super-colony. The researchers stated that "enormous extent of this population is paralleled only by human society", and had probably been spread and maintained by human travel.
They have been extraordinarily successful, in part, because different nests of the introduced Argentine ants seldom attack or compete with each other, unlike most other species of ant. In their introduced range, their genetic makeup is so uniform that individuals from one nest can mingle in a neighboring nest without being attacked. Thus, in most of their introduced range, they form super-colonies. "Some ants have an extraordinary social organization, called unicoloniality, whereby individuals mix freely among physically separated nests. This type of social organization is not only a key attribute responsible for the ecological domination of these ants, but also an evolutionary paradox and a potential problem for kin selection theory because relatedness between nest mates is effectively zero." In contrast, native populations are more genetically diverse, genetically differentiated (among colonies and across space), and form colonies that are much smaller than the supercolonies that dominate the introduced range. Argentine ants in their native South America also co-exist with many other species of ants, and do not attain the high population densities that characterize introduced populations.
In a series of experiments, ants of the same colony were isolated and fed different diets. The hydrocarbons from the diet were eventually incorporated into the cuticle of the subjects. Those that had the same diet appeared to recognize one another as kin. Those who had at least some overlap in dietary composition also appeared to react non-aggressively to one another. These interactions contrast drastically with the groups that fed on completely different sources, such as those who lived off flies and those that fed on grasshoppers. The groups appeared to have incorporated hydrocarbons that were not similar to the others and created an unfamiliar identity cue. These groups reacted violently towards each other. This suggests that dietary factors affect the recognition cues for colony members.
Like workers in many other ant species, Argentine ant workers are unable to lay reproductive eggs but can direct the development of eggs into reproductive females; the production of males appears to be controlled by the amount of food available to the larvae. Argentine ant colonies almost invariably have many reproductive queens, as many as eight for every 1,000 workers. The queens seldom or never disperse in winged form. Instead, colonies reproduce by budding off into new units. As few as ten workers and a single queen can establish a new colony.
The seasonal low occurs in mid-winter, when 90% of a representative colony consisted of workers and the remainder of queens, and no reproductive activity and minimal birthing. Eggs are produced in late-winter, nearly all of which hatch into sexual forms by May. Mating occurs after the females emerge. Worker production increases steadily from mid-March to October, after which their numbers are not replenished; thus, their numbers drop steadily over the winter months.
Colonies in the Argentine ant’s native habitat are kept within a range of ten to one hundred meters by colonies of interspecific and intraspecific rivals. As the colonies expand, they appear to form fluctuating territory borders, which contract and expand on a seasonal and conditional basis. There is an expansive push outward in the summer months, with a retreating motion in the winter. This has to do with soil moisture and temperature conditions. At the edges of these borders are either rival Linepithema humile colonies or other obstacles that prevent further expansion, such as an inhospitable environment for nesting.
These ants are ranked among the world's 100 worst animal invaders. In its introduced range, the Argentine ant often displaces most or all native ants. This can, in turn, imperil other species in the ecosystem, such as native plants that depend on native ants for seed dispersal, or lizards that depend on native ants for food. For example, the recent severe decline in coastal horned lizards in southern California is closely tied to Argentine ants displacing native ant species on which the lizards feed.
Argentine ants sometimes tend aphid colonies, and their protection of this plant pest can cause problems in agricultural areas by protecting plant pests from predators and parasitoids. In return for this protection, the ants benefit by feeding off an excretion known as honeydew. Thus, when Argentine ants invade an agricultural area, the population densities of these plant parasites increases and so too does the damage they cause to crops.
Leaf-cutting Ants. These are commonly found in many New World tropical areas. In such areas, columns of these ants frequently can be seen crawling up the trunks of trees and cutting small discs from the leaves. In some areas these insects are so common that they become major agricultural pests.
Leaf Cutting Ants Carrying Leaf Discs. Courtesy Adriab Pingstone-Public Domain. Right. Courtesy Bandwagonman at English Wikipedia CC BY-SA 3.0. Right. Bottom. Queen and Workers in Fungal Garden-Blew Me Away-Courtesy Christian Linder-CC BY-SA 3.0
Some of these ants exhibit polymorphism (different form within a caste –in this case the workers) to an extreme. There are 4 different forms within the worker caste, namely the minima, minors, media and maxima. The minima are the smallest form of the adults and function to care for the brood (larvae and pupae) and fungal gardens. Media workers forage for and carry the leaf discs deep into their nests, where they are licked, cut into smaller pieces, dampened with an anal secretion and finally formed into a bed of moist pulp. The newly formed beds are then planted with fungi from established beds. As a fungal garden grows, it is harvested and fed to the larvae. Most leaf cutting ants are quite particular and typically cultivate and harvest only one species of fungus. Media workers continuously ‘weed out’ any alien species of fungi that infest their gardens. It is believed that a few species actually produce fungicidal substances from their salivary glands, which is used to aid in the weeding process. In some species, when the swarming queens leave the colony, they carry the strands of fungi with them in pouches below their heads. Once new colonies are begun, the strands are ‘planted’ to assure a new garden of the correct species of fungi. The maxima are the largest of the forms with enlarged heads and protruding mandible. These of course are the soldiers of the colony and function to protect the colony against intruders.
In a few species of leaf-cutting ants, the minor caste performs a rather specialized function. There are some smaller workers that frequently accompany the larger foraging leaf-gatherers; they do not assist in leaf cutting; but ride back to the nest either on the leaf portion or on the thorax of the media. Their sole function is to protect the media by snapping their mandibles at a species of parasitic fly that attempts to lay eggs on the media’s head.
Army Ants. The most spectacular and well-known ants are the legionary, or army, ants of the humid tropical forests. These ants do not construct nests, but form temporary clusters called bivouacs in the shelter of fallen trees or in other partially exposed situations. The workers form a solid mass up to a yard wide, which consists of layer after layer of individuals hooked together by their tarsal claws. The queen, larvae, pupae, and eggs are located in the center of this mass.
Top. African Driver Ants on the Hunt. Image Mehmet Karatay CC BY-SA 3.0Middle. Soldier and Workers-Image Courtesy Alex Wild CC0 1.0 Universal Public Domain Dedication. Botttom. Ant Moving Their Brood to New Location. Image Courtesy Geoff Gallice from Gainesville, FL. CC BY SA 2.0.
The night is passed in a tight cluster, but at the first sign of light the cluster dissipates and hoards of workers fan out from the bivouac in all directions. Soon, one or more columns form and begin to search for food. The workers lay down a pheromone trail for others to follow while the soldiers guard the perimeter of the trail. Workers form numerous columns; changing positions behind the advancing hoards of ants—flushing out large numbers of prey (arthropods, small reptiles and rodents). The prey is stung, killed and transported to the rear as food for the larvae. At the end of the day the cluster is reformed. When the food supply is depleted around the area of the bivouac, the colony relocates.
Some colonies of army ants may number as high as one million individuals. Because of the spectacular size of their colonies and ‘raiding’ nature of these insects, they have been used repeatedly by the motion picture industry. Actually army ants pose no threat to humans or other large animals.
The authors recently had the opportunity to observe army ant behavior in Costa Rica. One morning we were walking down a dirt road with several students collecting insects. Collecting was not that good but suddenly hoards of insects, spiders and even a few scorpions and lizards started pouring out from the underbrush across the road we were on. After a few moments of excellent collecting, we decided to investigate the reason for this windfall. And, as you might suspect, there was a column of army ants moving through a gully to the side of the road. Of course all the animals in its path were attempting to flee. On the following evening a column of army ants raided the students' cabin. The students were not awakened, but the following morning they were very disappointed to see that the army ants had stolen most of the several thousand insects they had collected and mounted on pins over the past week. Shortly thereafter, I decided to test the reports that army ants pose no threat to humans. There was a column moving through our pension grounds--so I placed my foot directly in their path. They merely ignored this obstacle and marched over and around it.
While the army ants are primarily found in the New World tropics the driver ants are found in the tropics of Africa. Both types are very similar as far as their behavior and biology is concerned. One distinct difference is that while large colonies of army ants may number one million colonies of driver ants can reach 200 million. With such huge numbers they present more of a threat to humans and other animals. There have been human deaths recorded from the raids of these critters (mostly infants). In these cases death has typically occurred from suffocation as a result of the ants entering and filling the lungs.
The mating behavior of these ants is especially strange. The males are to drawn to the foraging columns supposedly looking for a mate. Instead of finding a queen the sterile workers quickly swarm the males and immediately tear their wings off. Then they carry them off and basically imprison them until a potential new queen is available.
Bullet Ants.This ant is primarily found in rainforests ranging from Nicaragua to Paraguay and Australia. This huge (1 inch) beast is called the bullet ant because its sting feels like being shot by a bullet. On the Schmidt Sting Index bullet ants rate as the number one most painful sting found in the arthropods. When defending their nest, they swarm out, release a strong odor and stridulate an audible sound (said to sound like a shriek) and then grab and impale their intruder. In Central-South America they are referred to as the 24-hour ant, referring to the pain described as “of burning, throbbing, all-consuming pain” that may last a day or more.
A One-inch Costa Rican Bullet Ant. Image Dr. Kaae.
As with many other arthropods bullet ants play a ceremonial role in some tribes of the rainforests. The Satere-Mawe people of Brazil use this ant in the right of passage of boys into manhood. In this case live bullet ants are woven into a sleeve made of leaves with the stingers pointing inward. Once the sleeve is place on the arm the goal is to leave it on for 10 minutes without crying due to the stings. When finished the boys arms are temporarily paralyzed and they may shake uncontrollably for days. To fully complete the initiation, however, the boys must go through this ordeal a total of 20 times over a several months period or years.
Steve Backshall Participating in Bullet Ant Ceremonial. Image Courtesy Geckochasing. Public Domain.
Harvester Ants. These (Pogonomyrmex spp.) are commonly thought as the large red or black ants that form rather large nests in open fields, schoolyards, along railroad tracks, alleys or other similar situations. Of the 23 species that occur in the United States 22 occur west of the Mississippi River. Beside their large size and color these ants can be distinguished by fringes of long curved hairs on the back, underside margin of the head. These hairs are used to clean the ant’s antennae and legs, carry water and remove sand during excavation of their nests. The nests are typically quite large consisting of one or more holes surrounded by a low flat crater (up to 8 inches across). This crater in turn is surrounded by a rather large vegetation free area. These are the ant species that are common used in ant farms.
Black Harvester Ant. Returning to Nest with Dinner. Image Courtesy Jeff Turner CC BY 2.0
Harvester ants feed primarily on seed. In agricultural areas they are considered beneficial as they remove weed seeds from crops. The main reason they are found along railroad tracks is due the grain that is lost during transportation. Harvester ants readily sting but typically are not aggressive unless defending the nest. If disturbed, they will swarm from the nest and readily sting. Their venom is extremely powerful resulting in considerable pain that may last for several days. Harvester ant venom is the most toxic venom found in arthropods although there is considerably less than in black widows and consequently the sting of the ant is much less dangerous than the bite of the spider.