Beetles make the most numerous group of insects. They form the order Coleoptera ("sheathed wing") because of their elytras (thickened outer pair of wings). 25% of all species on Earth are beetles and they make for 40% of all described insects but there may be at least 5 million undescribed beetle species. They live all over the world, from the sea to the polar areas, so no wonder they have a varied biology.
1.The world's largest beetle, and insect, is Titanus giganteus, from the Cerambycidae (longhorn beetles) native to the Amazonian forest in South America. It can reach 18 cm (7.2 in) in length. The larvae are wood borers and the adults can inflict painful bites to a human and even cut flesh with their powerful mandibles.
2.The Hercules beetle (Dynastes hercules), a rhinoceros beetle found in the tropical forests of South America, can reach 6.75 in (170 mm) in length, but is bulkier than the previous species. Still, much of its length is given by the horns. The Hercules beetle is the strongest creature on earth given its size, able to carry 850 times its own body weight. Such a beetle can drag a wood piece of tens of kilograms! At a weight of 60g, this beetle is as big as a mouse.
3.Also in the forests of South America the elephant beetles (Megasoma) live, being closely related to the Hercules beetles. They too are very large (up to 12 cm (4.8 in) in length) and mainly nocturnal. Elephant Beetles can maintain high body temperatures when temperature decreases, a rare performance amongst insects, whose body temperature usually fluctuates with that of the environment (only bees have a complicated group method of doing something similar).
4.Beetles do have their giraffe variant: the species of the genus Colliuris, which lives in the wet areas.
5.Mustard gas may have killed thousands of soldiers but the chemical war has no secrets for the bombardier beetle. There are over 500 species, included in the Carabidae family - tribes Brachinini, Paussini, Ozaenini, or Metriini. They can fire a mixture of chemicals from special glands in their posterior. High speed images showed that the beetles use a pair of deflectors located in the tip of their abdomen and they can point a jet of chemicals with high precision towards a possible enemy, drowning it in a fraction of a second.
Bombardier beetles store two chemicals (hydroquinone and hydrogen peroxide) which are mixed only when they are attacked. These chemicals are released through two tubes, together with catalytic enzymes (catalases and peroxidases), resulting a violent heat releasing chemical reaction, with the final product p-quinones. The hot foul smelling liquid turns 20% into a gas, causing a loud popping sound. The shot is deadly to insects and other small animals and painful to human skin. As these beetles are immune to p-quinones, they can also defend themselves by splashing it over their body parts, like the back, when attacked by groups of small insects, like ants. The shots can be repeated 12 times, but after that the beetle needs one hour to recover its "bomb" supply.
This mechanism is older than 100 million years, as a bombardier beetle was found preserved in amber dating from that age, while employing chemicals to repel an attacker and an oozing flow of sap permitted the preservation of this scene forever. The amber was found in 2006 in the Hukawng Valley in Myanmar. The small beetle, about 0.25 inch (0.6 cm) long, was attacked by a giant cockroach or other big bug of about 2-3 inch (5-8 cm) long, these measurements being based on the length of an antenna from the attacker also trapped in the amber piece. The attacker either escaped the sap or was embedded in a different amber piece.
6.If you thought only men buy women a drink to win their favors, you were wrong. There are beetle females that will mate just for quenching their thirst. It's the case of the bean weevil Callosobruchus maculatus, which feeds on stored pulses that may contain a maximum of 10% water. With such a dry diet, the male's ejaculate is a precious water source for females. Females kept on beans and lacking water sources mate with more males, to get the water in the seminal fluid. They are more likely to mate if they are thirsty. Males invest 10% of their body weight in semen. It buys them time before the females mate again and their sperm have to compete with that of other males.
7.Beetles can be aphrodisiacs. Many boys dream of parties where they slip cantharidin to girls an then end up in an orgy. This chemical obtained from the beetle named Spanish Fly, indigenous to southern Europe, is in fact an irritant of the animal tissues. It has a disagreeable scent and bitter flavor and is often given to farm animals to incite them to mate. The cantharides excreted in the urine irritate the urethral passages, triggering inflammation in the genitals and subsequent priapism. For this reason, Spanish fly has been given to humans for seduction purposes.
It is a dangerous game, as the amount required is very small and the line between the effective dose and the harmful dose is quite thin. Cantharides cause painful urination, fever, and sometimes bloody discharge and even permanent damage to the kidneys and genitals. The victims are usually women who are unaware that they had the powder slipped in their drink. In 1772, a trial was intended to Marchis de Sade, under the charge of having poisoned some women. He offered them sweets with cantharidin, but instead of sexual arousal, they got sick. Ancient Greeks and Romans also knew about the cantharidin.
8.Moreover, beetles lead nasty sex wars. The male wants to be sure the offspring are his, while the female is looking for the best male to father her progeny. The tougher the war, the more extreme the weaponry. Sometimes, this can reach the absurd: the genitals of male seed beetles are extremely spiny, enabling males to anchor inside the females, as they try to fertilize them. But this is too much, as the spikes can damage the females and compromise the breeding process. The female counteract by growing genitals that are even tougher than the spinier male genitals. The speed of the "weaponry" shifts in this battle of the sexes leads to new species. Some seed beetle species display over 100 spikes on male genitals, while others none. As male penises became spikier and more harmful, females grew tougher genitals to protect themselves.
9.Despite their name, fireflies are not flies but beetles. Their light is "cold light", with no infrared rays, and a wavelength varying from 510 to 670 nanometers, pale yellow or reddish green in color, with a lighting efficiency of 96%. Fireflies produce bioluminescence on their own, without using bacteria, like deep sea animals do (fishes, squids and shrimps).
There are more than 2000 species of fireflies, measuring from 0.5 to 2 cm (0.2 to 0.8 inch) included in Lampyridae family and encountered in temperate and tropical areas around the world. Many species can be found in marshes or in wet, wooded areas where their larvae have more abundant sources of food.
Males can fly but females do not have wings and signal their position by glowing. In European firefly, males glow only very weakly and intermittently. But in Malaysia, all year round you can witness a scene that looks like in a fairy-tale: trees that turn on and off. Indeed, those are firefly clouds (from the genus Pteroptyx) that cover the trees. The phenomenon of a tree "functioning" in unison may be rare, but it does occur.
The researchers discovered that the male firefly emits 12 signals per second, while the female lights on continuous current. When a male approaches a female, his signal changes turning irregular in order to "personalize" it. But usually, there are more males attracted to the same female, that's why they can imitate the "serenade" of the favorite male, all at once, like an orchestra following the conductor's signaling.
During the sunset, a firefly on a branch turns on its lantern and the others respond soon while the whole tree starts lighting up. This phenomenon can be encountered, but weaker, in other parts of the world, too, like in the mountains of southeastern US or Jamaica (Photinus species).
The females of the American fireflies belonging to the genus Photuris use their flashlight to attract the males of other firefly species in order to eat them! All firefly larvae glow, but they do it in order to warn predators as they are usually toxic or distasteful. Maya people even associated fireflies with the stars and had a firefly god!
In ancient China, fireflies were sometimes captured in transparent or semi-transparent containers and used as short-term lanterns. In fact, the light emitted by several large fireflies is enough to allow you to read a book! In Malaya, they can be used as hair adornments.
The enzyme that inflicts bioluminescence, luciferase, is used by forensic investigators to detect blood traces at crime scenes but it is also used to detect the presence of pathogen bacteria in biological liquids, in studies of protein denaturation or studying cell populations in live animals.
In the Americas, from Canada to Chile, there is another family of bioluminiscent beetle, named Phengodidae. Both larvae and females look like worms, hence the name "glowworms", but these insects are much larger than real fireflies: up to 7 cm (2.8 inch) long!
Males are winged and do not eat, but the larvae and females are carnivorous and possess luminescent organs in every segment of their body, looking like little glowing trains. The light is produced in the same way like in the firefly: luciferine oxidation in the presence of luciferase can be red, orange, yellow and green. The lanterns help larvae find their prey, millipedes and warn predator, like ants, frogs and spiders that they are distasteful.
10.There is even a ghost beetle: the ghost tiger beetle (Cicindela lepida), from a group of fearsome carnivore beetles endowed with huge jaws. The species gets its name from its whitish color.