We, humans, sleep periodically. Those who have trouble with it risk facing numerous health problems. All mammals sleep too — you can easily observe this in your cat.
Reptiles, amphibians, and birds also enjoy a nap, although it’s not always obvious whether these creatures are asleep. Many don’t close their eyes or change their posture when resting; they simply become still.
But can simpler creatures like insects sleep?
On the internet, you might come across claims such as “sleep is a brain function, and bugs and ants don’t have brains.” However, that is pure myth.
Insects have a brain composed of three lobes — the protocerebrum, deutocerebrum, and tritocerebrum. Of course, it’s not as sophisticated as a human brain. But calling insects “brainless” is not only disrespectful to them but also scientifically incorrect.
The average cockroach has around 200,000 neurons, while a human brain has roughly 86 billion. Moreover, the brain isn’t as vital for an insect’s survival as it is for mammals.
For instance, you could cut off a cockroach’s head, and it would still live for some time due to the activity of its nervous system in the rest of its body.
Nevertheless, an insect without a head wouldn’t fare well. It would only be capable of performing the simplest actions — like standing, crawling, and reacting to touch.
However, it wouldn’t be able to properly hunt or search for food. It would lack even a basic brain to make decisions, no sensory organs to navigate, and, quite frankly, no mouth to eat.
So, insects do indeed need their heads. And for their brains to function properly, they need rest. Insects are quite capable of sleeping, though not in the same way mammals do. They don’t need to lie down, nor can they close their eyes. Still, sleep is crucial for them.
Deprived of the ability to sleep, insects suffer from overexertion — just like us.
For example, researchers at the Institute of Neuroscience in California and scientists at the University of Pennsylvania conducted independent experiments on sleep deprivation in fruit flies (Drosophila). Poor flies that were kept awake for ten hours perished, while those left undisturbed restored their sleep patterns and returned to normal.
Most Drosophila prefer to rest in darkness and stay active in the light. After a sleepless night, they extended their sleep by 50% when allowed.
Overworked flies slept deeply and barely responded to external stimuli.
Drosophila are the most popular laboratory subjects. However, entomologists have studied the sleep of other insects as well — including cockroaches, bees, New Zealand wētā, and monarch butterflies.
For example, it is known for sure that cockroaches sleep.
These nocturnal creatures seek food in the dark and avoid light. During the day, they hide and doze off. The circadian behavior of cockroaches is controlled by a complex hormonal system, but the brain also plays a role in this. Scientists haven’t yet fully understood how.
In an experiment, researchers removed a piece of brain from one cockroach and implanted it into another. The new host adopted the donor’s sleep schedule.
The circadian rhythms of bees are also well-studied. Bees can adjust their sleep schedule based on the time flowers, which provide their pollen, open. During this time, the insects work, and when food is unavailable, they rest.
When bees were deprived of sleep for a long period, they lost coordination in their dances used to signal their hive mates. Tired insects simply couldn’t communicate properly with the rest of the colony. Moreover, bees that researchers woke up too early in the morning tried to catch up on their rest during the day.
In conclusion, insects can sleep just as well as we do and strive to maintain a sleep schedule, even if disturbed. Let’s follow their example and go to bed early tonight.
An ant mill is a phenomenon where a group of migrating ants loses their pheromone trail, becoming separated from their colony. In their search, they create their own trail, resulting in a circular movement. Eventually, the majority of ants in such a circle die due to exhaustion. This phenomenon is rare in nature but has been replicated in laboratories and appears in simulations of ant colonies. Similar occurrences have been observed in processionary caterpillars and fish.
Discovery of the ant mill
In 1910, the American myrmecologist William Morton Wheeler described a case he observed in the laboratory of a spontaneously formed ant circle that lasted for 46 hours. However, the first documented description of an ant mill dates back to 1920 by William Beebe. While exploring the Guyana jungle for the New York Zoological Society, later known as the Wildlife Conservation Society, Beebe encountered a group of wandering ants.
Upon seeing the ants, belonging to the genus Eciton, the next morning, he followed their trail and discovered it formed a closed circle, sometimes as wide as six rows. Beebe was astonished by this revelation and retraced the trail to confirm it. The circle measured 1210 feet (370 meters) in circumference, and by measuring the ants’ average speed, Beebe estimated it took them about two and a half hours to complete the circuit.
American animal behavior scientist Theodore Christian Schneirla (1902–1968) explained the phenomenon in 1944. Drawing from prior research on ant behavior, Schneirla concluded that the circular movement resulted from the chemicals left behind by ants, later identified as pheromones, which caused the ants to follow each other. A circular motion occurs when the leading ants lose the trail of the column and then rediscover the followers’ trail, akin to a tracker following their own footprints.
Schneirla also noted that a similar phenomenon was described as early as 1896 by Fabre, who observed a similar circular motion in the caterpillars of the silkworm.
The presumed explanation for the ant mill phenomenon is the pheromone trail that ants of certain species, engaged in group food gathering, mark on the soil surface during foraging expeditions. The goal is to facilitate a quick and efficient journey to the food source and back to the ant nest.
Using their antennae, located close to the ground, ants perceive the direction and intensity of the odor and strictly follow the pheromone trail.
At some point, due to various reasons, a malfunction occurs in the ant’s algorithm, causing it to start walking in a closed circle, leading its fellow ants into a deadly procession when they encounter its trail. A possible reason for the malfunction is that the food raid, in some cases, lasts too long, and by the time the ant returns home, the scent of the pheromone trail has dissipated.
As a result, halfway through the journey, the ant deviates from its course and turns several times, only to immediately encounter its own trail again. Newly emitted pheromones have the strongest scent, and the ant repeats the cycle along the recently created trajectory.
Small “whirls” occur in terrain of almost any type and are most common where two ant trails pass close to each other or intersect. However, a phenomenon similar to the one described at the beginning of the article occurs only in a large open area without particularly significant irregularities.
Evolution
Kinship
The occurrence of ant mills is known only to migrating ants. In the 20th century, it was assumed that the species exhibiting this behavior did not share a common ancestor where this behavior could have originated. It involved three lineages: Aenictinae and Dorylinae in the Old World and Ecitoninae in the New World, and it was believed to have independently evolved in each of these lines. From 2003 onward, it became evident that the kinship between these lines traced back much further, up to 105 million years ago. Therefore, there could indeed have been a shared ancestor before the complete separation of the Gondwana continent. As of 2023, all three groups are classified under Dorylinae.
In their natural habitat, ant mills are rare due to variations in terrain, where migrating ants occasionally lose their trail, breaking the circle. When such natural obstacles are absent, for example, in a laboratory or on a sidewalk, the formation of an ant mill is almost inevitable.
Because ant mills are infrequent in nature, there is not much evolutionary pressure to eliminate this phenomenon. However, it is noteworthy that an evidently harmful behavioral pattern could persist for over a hundred million years. Explanations lie in two behavioral factors and the reproductive strategy:
The nomadic lifestyle and food-catching habits of migrating ants create a strong evolutionary pressure toward unconditional collective behavior. An ant isolated from the migrating column is nearly doomed, and an individual can hardly secure food alone, as migrating ants primarily hunt prey much larger than themselves.
Additionally, there is the reproductive strategy: unlike many other ants, migrating ants have queens that do not fly, resulting in slow evolution. Due to this combination, there are few evolutionary opportunities and little pressure to eliminate the detrimental collective behavior.
Social insects, such as bees and termites, refer to insects that form colonies and exhibit a hierarchical structure similar to human societies, with a queen and worker ants (or bees). These colonies are essentially family units, differing significantly from human societies in content. The opposite of social insects is solitary insects. Historically, the determination of whether an insect is social relied on the presence of hierarchical divisions within the group.
However, contemporary assessments emphasize the existence of infertile castes. From this perspective, insects exhibiting true social behavior are referred to as genuinely social. Research in this direction has led to the discovery of several insect groups demonstrating true social behavior beyond the mentioned classic groups. Presently, social insects are considered to possess true social characteristics. Nevertheless, due to the considerable differences in their nature, these newly recognized groups are often treated separately. This article focuses on social insects in the classical sense mentioned above.
Some insects, although not forming large colonies or exhibiting hierarchical divisions, are considered subsocial when parents and offspring cohabit. Additionally, the term “parasocial” is used when unrelated individuals form a group. These aspects are significant in considering the evolution of social insects.
Sociality
Most insects do not care for their hatched offspring. While some insects are known to engage in parental care, many abandon their offspring before they mature. In contrast, certain bees and ants not only care for their offspring but also continue to live together even after the offspring have grown, forming large colonies. Insects with such behavior are termed social insects.
In vertebrates, temporary family formations, where parents and offspring form families and engage in social relationships within a population, are common. The term “sociality” is used when a group, including multiple individuals or families, exhibits more complex structures and interactions than a mere gathering. Although challenging to precisely define, sociality generally refers to relationships resembling human societies.
Even compared to social structures in vertebrates, bees and ants forming large colonies appear remarkably similar to human societies. For instance, the presence of classes such as queens and worker bees, each with specific roles, resembles aspects of human societies.
This has led to comparisons between insect and human societies. However, upon closer examination, differences emerge, such as morphological variations based on caste differences, reproduction limited to queen individuals, and the majority of colony members being siblings. These aspects distinguish insect societies significantly from vertebrate societies.
The social lifestyle of social insects has proven highly successful. Social insects constitute a significant portion of the animal biomass in terrestrial ecosystems. In the tropical rainforests of Brazil, for example, bees and termites make up 80% of the insect biomass, with bee biomass reaching nearly four times that of all non-fish vertebrates. Despite comprising only 2% of insect species globally, estimates suggest that social insects occupy 50% of the current biomass.
As a result, these insects play a crucial role in natural ecosystems. Bees serve as pollinators for flowering plants, wasps act as predators of insects, and termites play a vital role in decomposing plant matter, especially in tropical regions. Ants, with their diverse diets and lifestyles, contribute to various ecological aspects, including predation on small animals, seed dispersal, symbiosis with other organisms, and soil improvement.
Superorganism
In social insects, where members depend on each other for survival, and individual survival is challenging, as reproduction occurs within the group and involves the creation of a new colony, some consider the entire colony as equivalent to a single organism, terming it a superorganism. The concept was first proposed by the ant researcher William Morton Wheeler, who extensively studied social insects. He referred to these insect colonies as superorganisms. Although criticized by some, such as Kinji Nishinow, who disregards the existence of male bees, there is still recognition of the colony as a unit corresponding to an individual.
Various Social Insects
Sociality in Bees
Within the order Hymenoptera (including ants, where ants belong to the family Formicidae and taxonomically fall under Hymenoptera), there exists a variety of social behaviors, ranging from highly social to subsocial and solitary. Examples of traditionally considered social insects include ant species, potter wasps, hornets, and honeybees.
The societies of social bees and ants are run exclusively by females. From fertilized eggs, females (queens) and males are born. The queen, after mating with a male bee, constructs a nest alone. Male bees die after mating with the queen and do not contribute to nest-building. The queen continues to lay eggs while caring for hatched larvae.
Once the larvae mature into adult worker bees, they stay in the nest to assist the queen with tasks such as childcare, foraging, and nest construction, without participating in reproduction. In most bee species, queens and male bees are born in autumn, after which they leave the nest and mate, and while the queen overwinters, the rest of the colony perishes. Consequently, many bee colonies last only one year (although honeybees and certain ants can maintain nests for multiple years).
Ants, with very few exceptions, are fundamentally social insects. For instance, the trap-jaw ant exhibits subsocial behavior without a queen, but this is considered a secondary adaptation. Some ant species develop soldier ants with well-developed mandibles.
Sociality in Termites
All termites exhibit social behavior. When winged termites leave the nest and mate, the resulting male-female pairs construct a nest. These individuals become the king and queen, engaging in repeated mating and egg-laying.
The offspring initially resemble their parents and, upon reaching a certain stage of development, transform into worker termites, assisting the king and queen with nest construction and other tasks. Some of their offspring develop into soldier termites as they grow. Soldier termites do not engage in reproduction.
The remaining worker termites, including some becoming winged termites, venture out of the nest. Many termite colonies endure through the year.
Colony Management
10 feet high termite mound in Botswana.
In many social insects, reproductive individuals (bee queens, termite kings, and queens) solely handle reproduction, while all other tasks are performed by workers (worker bees or worker ants). However, in species like hornets, where only reproductive individuals can survive the winter, reproductive members initially handle all tasks, from nest-building to foraging.
After worker emergence, they stay in the nest and focus exclusively on reproduction. In termites, some colonies build nests within wooden materials, while others, particularly in tropical regions, forage outside for food. In such cases, numerous individuals use pheromones as markers to navigate between the nest and food sources. In honeybees, the well-known figure-eight dance is performed to communicate the location of food sources to other colony members. Worker roles include carrying food and maintaining and managing the nest, as well as caring for larvae and reproductive individuals.
In species where a single individual (or pair) serves as the reproductive entity within a nest, there are instances where candidate reproductive individuals emerge from larvae within the nest if the reproductive members die. These are known as replacement reproductives.
When one of these becomes a new reproductive, the others are killed. Reproductive individuals release pheromones that suppress the appearance of other reproductive individuals. Many of these insects engage in behaviors like trophallaxis, the sharing of food mouth-to-mouth and facilitating pheromone transmission. Notably, species like the polygynous Myrmecina nipponica create large colonies with multiple reproductive individuals (multiple queens) and multiple nests, numbering in the tens of thousands to hundreds of thousands.
Evolution of Sociality
Charles Darwin himself faced difficulties explaining the treatment of social insects. Worker bees do not reproduce, and since traits are not passed on to offspring without reproduction, this posed a challenge.
One proposed explanation was the “queen manipulation” theory. It suggested that the queen, through pheromones, transforms offspring into worker bees. This trait, making one’s own offspring into worker bees, was selected through the queen, making childcare easier and allowing for the production of many offspring. However, this theory couldn’t dismiss the possibility of rebellion among worker bees. If a spontaneous mutation occurred in worker bees, rejecting the queen’s dominance, they could autonomously cease producing their own offspring.
This dilemma was resolved by Hamilton’s kin selection theory. This theory begins with the idea that in natural selection, it is not the individual but the traits expressed by the individual that are selected. An individual survives because it possesses certain traits, and the genes underlying those traits are selected. Therefore, the perspective shifts to the standpoint of individual genes, considering kinship.
Explaining this using the example of humans: when a parent has a child, from the parent’s perspective, the child carries half of the parent’s genes. Considering sibling relationships, the probability of one gene existing in the other is also 1/2. Thus, the gene responsible for caring for one’s daughter and the gene responsible for caring for one’s sister have similar chances of success.
In insects like ants and honeybees (Hymenoptera), where fertilized eggs become females and unfertilized eggs become males, the probability of one gene existing in the other between sisters born from the same parents is 3/4. In this case, the gene responsible for caring for one’s sister becomes more likely to be passed on to future generations than the gene responsible for caring for one’s daughter.
With this perspective, it becomes apparent that in Hymenoptera or any animal with a typical sex determination system, in groups with close kinship, supporting parents and increasing siblings without having one’s own offspring aligns with the goal of preserving one’s genes. If there are genes that induce behavior to assist parents in childcare instead of producing one’s own offspring, and if this behavior allows for a greater chance of preserving genes than producing one’s own offspring, and if it succeeds, those genes will survive through natural selection.
In this way, the existence of worker bees in social insects can be explained through the theory of natural selection. This led to the idea that the characteristic of social insects involves the presence of an infertile hierarchy. Kin selection theory has become a foundation for the development of sociobiology.
The New Meaning of Social Insects
In this way, the existence of an infertile hierarchy was shown to be a significant characteristic of social insects. This is unique even when compared to the social structures found in mammals. Consequently, this type of sociality is referred to as “eusociality.” Among previously known social insects, only some bees (and ants) and termites exhibit eusociality. E.O. Wilson defined eusociality as having:
The presence of an infertile caste.
Multiple generations living together.
Cooperative care of young individuals.
With the foundation for eusociality now apparent, it became conceivable that there might be other eusocial insects. Due to the operation of kin selection, creating groups and maintaining high relatedness within those groups is crucial. Consequently, new instances of insects with infertile castes were discovered. In aphids, for example, soldier aphids were observed.
Aphids, after settling on plants through winged females and reproducing asexually, establish large colonies. Some aphids born in these colonies have sharp mouthparts and scythe-like front legs. They cling to attackers and defend the colony. However, these individuals do not survive to maturity. Since these aphids are clones born through asexual reproduction from the same mother, the relatedness is higher than in termites or bees, making the development of true eusociality more likely.
Subsequently, true eusociality was discovered in other insects, as well as in non-insect species such as shrimp-like creatures and mammals like naked mole rats. These organisms do not disperse, and high relatedness among individuals is maintained through inbreeding.
True eusociality is not exclusive to insects but is collectively referred to as “eusocial animals” or “eusocial organisms.” However, in biology, when “sociality” is mentioned without distinction, it may refer specifically to eusociality. In this context, humans are not considered eusocial animals. Currently, the naked mole rat is the only mammal known to exhibit true eusociality.
Ants, Bees, and Termite Nests
Some of these insects build massive nests, creating new environments and harboring diverse ecosystems. While they cultivate fungi and domesticate small animals such as aphids and scale insects in special cases, various small animals, similar to rodents or cockroaches in the case of humans, or freeloaders, food guests, or brazen burglars, inhabit their nests. In plants, the accumulation of food and excrement around the nest can increase soil nitrogen levels, and ants eliminate insects around the nest, resulting in selective sightings in the vicinity of the nest. These phenomena are described by terms like “myrmecophily” or “termitophily.”
Development of Sociality
Among bees, there are various stages of life, from solitary living to family living, and even true eusociality. Comparing these habits provides insights into how sociality evolved. There are two lineages of social bees. Some have species of subsociality where parents and offspring coexist, and it is suggested that true sociality evolved from such species. This was proposed by Wheeler, and the research by Kojiro Iwata also supported this theory.
Examples include predatory species like longhorned bees and hornets. The ancestors of these were apparently predatory wasps like bee wolves and mud daubers. Predatory wasps anesthetize insects or other prey to feed their larvae. While many close their nests after laying eggs, some add additional prey midway. From such practices, family life involving childcare evolved, leading to the development of advanced sociality as seen in honeybees.
Species like honeybees, which feed on flower pollen and nectar, have various solitary relatives among the bee family, such as carpenter bees and small carpenter bees. Many solitary bees store pollen and nectar in their nests and close the nest after laying eggs. From such solitary habits, they evolved through small-scale family group living, similar to mason bees, to the large-scale advanced sociality seen in honeybees.
On the other hand, the evolution from communal nesting to cooperative nesting and from such side-societal species to true eusociality is also discussed. This was proposed by C.D. Michener, suggesting that reproductive females gather to form nests, and then, through some means, all but one female loses reproductive ability, leading to true eusociality. In reality, in social bees and ants in temperate regions, groups mostly begin with a solitary female.
However, in tropical social bees, nest formation with multiple females is more common. In some cases of longhorned bees, within a group founded by multiple females, there is a clear linear hierarchy among females, and only the top female lays eggs. This hierarchical system was anticipated to contribute to the advancement of comparative sociology by allowing comparisons with the flocking behavior observed in birds and others. However, the subsequent progress seems to suggest otherwise.
Termites are all eusocial. Unlike bees, termites do not perform direct feeding for their offspring, as termite larvae feed themselves. Therefore, there is a completely different history compared to bees. It is unclear how termites developed this way, but they possess symbiotic microorganisms capable of cellulose decomposition, enabling them to feed on wood. Born offspring need to obtain these microorganisms through mouth-to-mouth feeding from their parents, possibly leading to the development of family life. Furthermore, the abundance of inbreeding due to enclosed living in materials like wood may have increased relatedness, although this is debated.
Perillus bioculatus is an insect that belongs to the family of stink bugs (Pentatomidae), specifically the subfamily Asopinae. In common language, this insect is also known as a two-spotted stink bug or a double-eyed soldier bug. The Danish zoologist Johan Christian Fabricius described this animal in 1775 and gave it its Latin name. Like other stink bugs, they are known for their distinctive stench, but they are also predatory.
Latin is the source of the species name, bioculatus. The prefix bi signifies “two” or double,” and the name oculatus means “with eyes.” The genus name Perillus means “full of danger or risk.”
Together, the name Perillus bioculatus can be translated to mean “two-eyed perilous bug.” However, these animals are not dangerous to humans but are actually beneficial.
Perillus bioculatus undergoes color alterations in response to its diet. They get carotene from the animals they hunt. At temperatures between 88 and 90°F (31 and 32°C), carotene is oxidized and excreted. As a result, the bug looks all black and white.
However, at mild temperatures, carotene is deposited beneath the cuticle, and the animal appears black and yellow.
Carotene accumulates heavily beneath the epidermis at around 70–75°F (21–24°C), causing more melanin to be produced and giving the insect a red appearance.
The size of Perillus bioculatus varies from 0.4 to 0.5 inches (10 to 12 mm). They also vary in coloration but have a quite characteristic pattern. The two-spotted stink bugs often seem to be black, dark brown, or even red and yellow.
The two black dots on these bugs’ pronotum—the area directly behind the head—make them pretty simple to identify.
On the scutellum, there is a triangular marking surrounding a black Y-shaped pattern. This is the large, triangular, shield-shaped part on the back of the animal.
The front pronotum (chest) and scutellum (back) patterns are often a fiery red or orange on a Perillus bioculatus. However, there is also a cream-colored variation.
Distribution
(Photo by Ioan Alexandru Rădac and Maximilian Teodorescu, CC BY 4.0)
Historically, the only place you could find Perillus bioculatus was in the Nearctic realm (most of North America, including Greenland, Central Florida, and the highlands of Mexico).
Today, the geographic distribution of two-spotted stink bugs includes southern Canada, all of the United States (east-to-west coast), and all of Mexico.
For the purpose of biological plant protection, this species was introduced to many European nations. But so far, it has only taken root in Turkey and the Balkans.
Originally from North America, they have now made their way to Eastern Europe and North India, thanks to human intervention.
Perillus bioculatus’ diet mostly consists of arthropods. They specifically eat beetles and beetle larvae because these are their favorite foods.
The Colorado potato beetle (Leptinotarsa decemlineata) is an example of a valuable agricultural pest that falls victim to the two-spotted stink bug. That is why they are known as ‘predator stink bugs’ and considered a ‘beneficial organism.’
Eggs
Perillus bioculatus often lays between 100 and 300 eggs in a clutch. There are five nymphal stages in their life cycle. After an egg is laid, a total of 25–30 days are required for its development.
Typically, there are two to three generations every year for this species. In other words, they manage to go from egg to adult and then to egg again two to three times a year.
In the wild, the species hibernates as an imago, the last stage an insect attains during its metamorphosis, and reaches maturity.
The Perillus bioculatus larvae are phytophagous (herbivore) in their initial nymph stage, sucking the sap from potato plant stems for food. There is gregarious activity or social grouping in their first four nymphal stages.
Is Perillus bioculatus Dangerous?
The answer is no; Perillus bioculatus poses no threat to humans. In fact, there are advantages to having them around. Native to North America, these bugs are expert predators of Colorado potato beetle eggs and larvae. In high numbers, they help control insect populations.
Perillus bioculatus in My House
These bugs belong to the family Pentatomidae, or stink bugs. There is no need for alarm if you have discovered Perillus bioculatus in your house. These insects pose no risk to human health.
Frogs have to remove insects like flies and crickets from their sticky tongues before they can ingest them. The process by which cane toads accomplish this feat has recently been determined by scientists. As the research shows, sophisticated tongue gymnastics are necessary to get the victim far enough into the pharynx to be gutted. The hyoid bone, which has never before been linked to swallowing, is also crucial.
Frogs will stick their lengthy tongues out of their mouths while pursuing flying insects. Insects often attach to this and then fall into the amphibian’s mouth if the strategy is successful. The specifics of how frogs extend their tongues and utilize them to grab prey have been studied extensively. Studies have shown, for instance, that frog tongues are not sticky until they are in touch with food.
However, according to Rachel Keeffe of Mount Holyoke College, whose team has investigated what occurs following prey acquisition, almost everything that occurs after the mouth shuts has remained a mystery.
What’s Happening Inside
Keeffe and her colleagues videotaped cane toads eating to get insight into the process by which frogs remove food from their tongues before swallowing it. Because of their size (cane toads may grow to be as long as 5.9 inches or 15 cm), the inside workings of their mouths are easily studied. Keeffe and her colleagues kept the animals in a Plexiglas enclosure and fed them crickets during the research.
The tongues of cane toads can grow to be as long as 80% of their heads.
They used a high-speed camera and X-ray footage to capture the action on film. They were able to see what was happening inside the toads. Metal beads were placed in strategic places in the toads’ mouths to enhance the visibility of the necessary structures under X-ray.
The resultant video material was then recreated by Keeffe into 3D animations so he could examine the movement patterns more closely. She used the animations to create a detailed flow chart that describes the whole feeding cycle of a cane toad, from the time it first spots the cricket until the time it dies in the toad’s stomach and the toad returns to its original condition.
The Hyoid Retracts Into the Neck
The results surprised researchers because they revealed a more complex system than anyone had imagined for how a frog prepares its prey before placing it in its throat. The hyoid bone plays a crucial role in this system. The frog’s tongue is attached to the hyoid bone, a cartilaginous plate located near the floor of the mouth. When the frog lunges at its target with its tongue, the hyoid bone retracts into the neck, bringing the tongue and prey back into the mouth.
Some of the hyoid muscles, seen here with the tongue outstretched. The color blue describes the hyoid cartilage. (Credit: Oxford Academic)
Records have shown that during this recovery movement, the tongue moves much further into the throat than during prey capture. This process involves a network of cartilage and muscle that extends so far back in the frog’s throat that it touches the organ that pumps blood throughout the body. The next movement involves the tongue bone thrusting forward, causing the tongue to be pushed against the hard palate of the mouth and pulled back from the pharynx.
In this way, the esophagus encloses the prey that is stuck to the tongue. Keeffe thinks that frogs’ palatal grooves, or extra rows of teeth, help with the frictional action necessary to remove prey from the frogs’ sticky tongues. This is a very interesting development, considering that until this discovery, the purpose of the grooves and small teeth was a mystery. He also mentions the hyoid bone, which was not previously linked to swallowing.
It Takes Less Than Two Seconds
It takes less than two seconds for the toad to go from seeing the cricket to its original form. This is still far longer than was anticipated. The time it takes to acquire prey is much less than two seconds.
It was also intriguing to see the toad’s intricate swallowing process in action, both when it successfully caught the cricket and when it failed to do so.
Keeffe suggests that future studies should investigate whether or not the swallowing technique of cane toads is shared by other frogs, or whether or not they use other methods of digestion.
In the evening, with pleasant weather, it doesn’t take long until you find yourself relaxing on the patio, taking in the sun, or enjoying a BBQ. But then, you are startled by a painful sensation on your arm, which is immediately followed by severe itching. The blood was drawn out by the lengthy proboscis of a mosquito that just bit you. Throughout the spring, summer, and autumn, it is almost impossible to get rid of mosquitoes, even with the use of pricey mosquito repellents. But, during the winter, you never see or hear anything about them. Where do mosquitoes go in the winter? And what do they do at this time of year?
Unlucky Males
The mosquito, like other insects, is a cold-blooded species. They have no control over their body temperature, which is always the same as their environment. The optimal temperature for mosquitoes is around 78 degrees Fahrenheit (25ºC), and at 60 degrees Fahrenheit (15ºC) the insects slow down, and anything below 50 degrees Fahrenheit (10ºC) makes them almost dead.
The thing is, the male mosquitoes can’t survive the winter. In fact, they already die away by fall. Males do not feed on blood, and their proboscis is not powerful enough to puncture your skin and bite you.
They consume nothing other than nectar and the fluids of plants. Blood is one of the several nutrients that only females are required to provide for their kids. It is specifically these female mosquitoes that are able to endure the dip in temperature during the winter.
Mosquitoes Craft Their Own Anti-Freeze
Aedes aegypti mosquito larvae.
The female mosquitoes may find the best chance to survive throughout the winter months in locations like basements, caverns, cow barns, and buildings since these areas are cool, wet, and sheltered. There, the insects enter a state of inactivity, also known as torpor, caused by the dropping temperatures.
For the mosquitoes to be prepared for this, during evolution, they have created an odd adaptation mechanism: they begin by eliminating a fluid from their bodies via excretion. After that, sugar is added to this liquid which together acts like an antifreeze covering the mosquito’s body. The females emerge from their torpor when the weather begins to warm up again in the spring and start laying their eggs.
Mosquito Eggs Survive in the Mud
The frost very rarely kills adult female mosquitoes or their egg clutches that have already been laid in water bodies such as lakes, ponds, or rain barrels in the autumn. As long as the mud does not freeze, the mosquito eggs survive the winter in the mud on the bottom of a body of water without any issues.
The conditions throughout the spring and summer are what ultimately determine whether or not there will be a mosquito infestation. For instance, prolonged periods of rainfall provide the larvae with optimal breeding grounds. If warm temperatures are coupled with this, the conditions become ideal for a mosquito invasion.
However, it is possible to be bitten by a mosquito even during the wintertime. Because if a mosquito is able to find its way into a heated home, then that is where it will continue to live for a while. Yet, there is a good chance that it will die over the winter season while in there.
Thunderstorm creatures, also known as thrips or fringed-wing insects, are often little, black, and very unpleasant. They are often called thunderflies, thunderbugs, storm flies, thunderblights, or storm bugs. These tiny insects, which rarely exceed 0.12 inches (3 millimeters) in length, seem to arrive en masse if the weather is hot and humid and a rainstorm is on the horizon. Although there are over 6,000 different species of thrips, their tiny size means they are often overlooked.
When Thrips Cluster in Thousands
(Image: Fort Valley State University)
They cluster together in the thousands, resembling dark clouds, which are unpleasant for anybody who is caught in them because the thrips fall on any exposed skin and also in the nasal passages, oral cavity, and eyes, producing a crawling, itchy sensation. But may the reason for their mass hording be the approaching thunderstorm? Are they really suitable as thunderstorm indicators? If that’s the case, then how can thrips anticipate the arrival of a thunderstorm?
On hot, humid summer days, several species of thrips are known to engage in swarming flights. Temperatures over 70 degrees Fahrenheit (20 degrees Celsius) and stable, unchanging climatic conditions trigger the huge swarming of thrips. Thrips may rapidly become a nuisance when they emerge in masses, landing on humans and being drawn to all bright colors. When it’s hot and steamy outside, humans sweat, and thrips lick this perspiration off their skin and sometimes even bite through it. This causes irritation and, in really sensitive individuals, skin inflammation.
Humans as Landing Pands
But the thunderstorm is not the cause of the thrips’ mass presence. Instead, the little insects, which are normally dispersed across the skies, settle on the ground in a coordinated effort when a storm is approaching. So they cluster around the places where people like us go and even utilize us as landing pads.
Thus, an increase in the number of thrips in the lower levels of the atmosphere may actually be an indicator of an approaching thunderstorm.
Electric Field as a Thunderstorm Indicator
However, how can thrips know when a storm is about to hit the area? This is more related to a physical phenomenon than the weather itself. This is because electrically charged thunderclouds also alter the atmospheric electric field. Thunderstorms may produce electric fields as strong as 15 kilovolts per foot (kV/ft) (50 kilovolts per meter), compared to the typical 0.03 kV/ft (0.1 kV/m).
Research on fruit flies and other insects demonstrates that strong electric fields may cause thrips to lose control of their flight and become disoriented. For instance, British thrips researcher William Kirk believes that tiny insects like thrips, in particular, are impacted by variations in electric field strength and are no longer able to fly at roughly 2.4 kV/ft (8 kV/m) and beyond. So, this electric charge might also be responsible for the sudden swarms of thrips that arrive near the ground just before a rainstorm. In most cases, though, it appears that thrips swarms are indicators of an impending storm.
Some of nature’s most eye-catching displays of color may be seen on the wings of butterflies. They have spots that are green, blue, or red, and they appear to change color as they move. Morpho rhetenor is a butterfly native to tropical regions with a brilliant blue coloration that can be seen from more than half a mile away. The work of British physicist Peter Vukusic has led to this conclusion. But where does this brilliant glow exactly come from?
Pigments are what give flowers, fur, and most other common items their colors. They seem to be different colors because they reflect just part of the visible spectrum. But butterflies and the ones that glisten in the sunlight are different from other insects. Most of the time, they lack any visible pigments. But what causes them to glow in the first place?
The famous scientist Isaac Newton began to suspect something was amiss as early as 1672. As far as he could tell, insects use small physical structures to influence light. We now know that the anatomy of a butterfly’s wing holds the key to understanding the iridescent colors it displays.
Reminiscent of Roof Shingles
Butterflies have thousands upon thousands of tiny, overlapping scales covering their wings. These scales are 1–3 micrometers thick and laid out in a pattern reminiscent of roof shingles. Each scale is constructed from a number of very thin layers of keratin. The protein keratin is also found in hair and fingernails. There is a minimal amount of space between each keratin layer.
The topmost of these transparent layers reflect some of the light that penetrates them. Keratin is penetrated by the rest. Another portion of the light is reflected from its underside as it travels through the air. Light waves that are reflected from the wing undergo a little redistribution as a result of this offset reflection. The two reflected waves no longer have parallel troughs (dips) and crests (peaks).
Scientists liken it to the action of waves on a small channel between two harbors: Sometimes a bigger wave is formed when the crests of two waves collide. And sometimes a crest and trough cancel each other out.
The nanostructure of the scales on a butterfly wing makes some colors and wavelengths of light more intense than others.
Butterfly Colors Change Due to Directional Reflection
However, the wing scales are capable of doing more, since each individual layer selectively emits the reflected light. That’s why the butterfly wing might seem brilliant blue one moment and subtly green the next time you look at it.
Generally speaking, pigment colors don’t shine very brilliantly due to their inefficient light reflection. By reflecting light in a specific fashion, structural colors like the ones seen on butterflies may achieve extremely high and varying intensities. Thanks to these, the male butterfly in the morphed form can still attract females from hundreds of feet away with its dazzling blue display.
Biologists have estimated that there are at least 20 quadrillion ants in existence on Earth, or around 2.5 million ants for every human being. This means that the total dry biomass of all ants exceeds that of all birds and wild animals put together. The subtropical and tropical areas have the highest ant density, yet the ant world map still has a lot of blank spaces.
Ants are common in practically every environment, including forests, gardens, and cities. While scientists have documented and named over 15,700 different species of social insects, they suspect the number is really closer to 30,000. Ants are crucial in the breakdown of organic matter because they are aphid or fungus producers as well as a source of food for a wide variety of birds, arthropods, and mammals.
Ant Population Count
But how many ants exist on a global scale? So far, estimates of ant population size have been made only on a rough scale, using methods such as local sampling or the fact that ants account for just a fraction of the world’s insect population (1%). Estimates have varied greatly in the past because of the large number of unknown variables involving the frequency and variety of insects. As a result, the “census” of the world’s ant population was conducted in a novel way by a group headed by Patrick Schultheiss of the Universities of Hong Kong and Würzburg.
The scientists looked at information from 465 studies from all around the globe that counted ants by taking soil litter samples or by using ground traps. The second technique was examined independently from the former since it represents activity rather than absolute numbers of ants in a region. Also included were results from 24 research that sprayed whole tree canopies with pesticide to determine ant populations.
Worldwide, There Are Around 20 Quadrillion Ants
It is estimated that there are three quadrillion ants in the world’s ground litter. The ants in the litter are only a small sample of the whole ant population. The overall number of ants, including those in various environments, is estimated to be roughly 19.8 quadrillions (that makes 19,800,000,000,000,000). That means there are around 2.5 million ants for every human being on Earth.
Even though each ant weighs almost nothing, the total dry biomass of all ants adds up to around 12.
3 megatons of carbon, according to the study’s authors. This represents almost 20% of the total human dry biomass and is comparable to the total dry biomass of all wild birds and animals.
Especially In the Tropics
Ants, however, are not uniformly dispersed throughout all temperate zones and ecological zones: Remarkably, just two biomes—tropical rainforests and tropical savannas—are home to more than half of the world’s ant population.
Results from the scatterplots show that the abundance of ants is two times as high in subtropical and tropical ecosystems as it is in temperate ones. Ant activity in tropical and subtropical regions could be three to four times greater than in temperate regions. This demonstrates how crucial tropical areas are to the worldwide quantity and biomass of ants.
Omnivorous Ant-Eaters From All Corners of the World
A large number of mammalian species, particularly in the tropics, have adapted to rely on ants as a primary food source. The anteaters of South America, the pangolins of Southeast Asia, and the aardvarks of Africa have all separately acquired specialized adaptations that allow them to dig up ant nests and gather the ants with their insensate, long tongues.
To escape being eaten by ants or to be able to feed on them directly, more arthropods copy ant behavior or morphology in the tropics since ants are more prevalent there and mimicry is thus more successful there.
The Real Figure Is Significantly Higher
Indeed, the new study has improved our understanding of the staggering magnitude of the ant population on Earth. However, the group emphasizes that these numbers represent a cautious assessment. The number of unreported instances is likely considerable since there are numerous habitats and biomes for which very little data is available. Examples of such biomes and habitats include subterranean habitats, mangroves, and boreal woods.
There is also a lack of data from Africa and Central Asia.
For this reason, the estimated global ant population likely understates the genuine amount by a significant margin. To acquire a fuller understanding of ant diversity and patterns of global biodiversity, their causes, and their implications, there is so much more work to do.
In many different countries, mosquito infestations occur at various times of the year. The ones that occur throughout the summer originate from the ideal breeding conditions, which end with an explosion in the mosquito population. The itching and discomfort caused by mosquito bites are indisputable. When you scratch the bite, you irritate the surrounding tissue, which leads to the development of a red, raised lump on the skin. If you are bitten by a mosquito, does it mean that you are also at risk of contracting a disease?
The Rise in Animal Transmitted Diseases
The incidence of diseases transmitted by animals is growing at an alarming rate around the world, especially in the Far East. In the past, residents of Central Europe have been diagnosed with malaria despite having never left the area where they live. But veterinarians and other specialists believe that there is currently no cause for concern in this region for mosquito infection.
Researchers discovered a few cases of virus transmission in the previous year, despite the unusual nature of the transmission. The Sindbis virus is a mildly dangerous virus that can occasionally result in meningitis. It is carried by the common Culex pipiens mosquito.
However, the population of the Asian bush mosquito, also known as Aedes japonicus, is increasing at an alarming rate, especially across Central Europe. Throughout the past few years, areas that encompass a land area of approximately 2,000 square kilometers have been plagued by an extremely active vector of diseases such as the West Nile virus. It wasn’t until the year 2012 that researchers were able to prove that a breeding population of this particular species of mosquito had indeed been established in Europe.
The Asian tiger mosquito, scientifically known as Stegomyia albopicta, has already established a breeding population in the area. The bloodsucker known to carry exotic diseases has been linked to the transmission of viruses, including West Nile and tropical dengue fever. In recent years, the mosquitoes that are responsible for transmitting the dengue and chikungunya viruses to people have been discovered in southern Europe.
Dog Tapeworm Is Carried by Mosquitoes
The larvae of the canine tapeworm, Dirofilaria repens, were found for the first time in Europe. This part of the world did not have any previous encounters with the parasite until very recently. Although mosquitoes are the most likely vector for transmission of these parasitic worms to humans, dogs continue to be the most common hosts for them. As of yet, there have been no reports of human illnesses acquired in the area.
Researchers have detected larvae of the dog skin worm Dirofilaria repens in mosquitoes for the first time in Central Europe. The parasite was previously not native to the land. Parasitic worms are found in dogs, but in rare cases, mosquitoes also transmit the infection to humans. So far, however, no human infections acquired in the area.
So, people are still relatively safe for the time being. However, if global temperatures continue to rise this may change in the future.
Sources:
Johnson, N., de Marco, M. F., Giovannini, A., Ippoliti, C., Danzetta, M. L., Svartz, G., Erster, O., Groschup, M. H., Ziegler, U. (2018, December 7). Emerging Mosquito-Borne Threats and the Response from European and Eastern Mediterranean Countries. PubMed Central (PMC). https://doi.org/10.3390/ijerph15122775
The bee colony lives under the slogan “All for one, one for all.” There are between 30,000 and 80,000 individual bees in a hive, and none of them could survive on their own. The only thing that assures the insect population will continue to exist is the perfect division of work inside the hive. The queen bee is primarily responsible for reproduction at all times.
On the other hand, the worker bees are responsible for all of the other tasks, including the care of the young, the collection of food, and the protection of the nest. However, the male bees, often known as drones, do not seem to contribute much to the common good and would rather have their needs met. The only duty they have is to mate with the queen, and this happens over and over again. But should we really believe that? Are drones as lazy as they seem?
When considering the number of forays they make each day, bees as a species might be characterized as “lazy.” On the other hand, the honey bee colony functions as a superorganism that is very hardworking. Every day, bees are responsible for pollinating several million flowers.
The Main Role of Drone Bees
But what exactly are drones responsible for in a bee colony? It is not possible for drones to gather nectar and pollen, construct honeycombs, or feed babies.
A bee colony uses drones to spread its genetic material. The physical effort drone bees make during their multiple mating flights is extraordinary. That’s why they are actually diligent. That’s why drones cannot eat themselves and must be fed by workers throughout their lives.
Temperature Control and Communication
Simply by being in the hive, drones perform an essential role in the process of temperature control. Their bodies provide insulation, and they have the ability to create heat via the use of their flight muscles. But there is little doubt that the drones also played some part in the intricate communication system that the bees used.
They Die From Not Being Fed
Drone bees seem to be employed not just as sperm banks, but also for a variety of other important hive tasks. Despite this, they do not get a lot of appreciation for doing what they are doing. Drone bees face a hasty demise after the conclusion of the mating season, which occurs in August and September at the very latest.
After then, they have fulfilled their purpose and are no longer fed by the workers; the drones are destined to perish from hunger. They often pass away within the hive, and their bodies are then removed.
Even more, worker bees regularly stab drones that are still living.
