The Life Cycle Of A Beetle:The life cycle of a beetle is defined by four stages. Learn more about how long this insect lives.
Beetles, like all insects and other arthropods, go through distinct changes in form throughout their life cycle. This change in form is known as metamorphosis. You may recall other examples of life changes from your biology classes such as the caterpillar changing to the butterfly or a tadpole maturing into a frog. The beetle life cycle is an interesting process, and it begins with mating.
Ground beetles go through “complete metamorphosis”. They hatch from an egg laid in the soil as small larvae and then begin to eat. They will eat and grow in size for up to two years and then “pupate” in the soil. In the spring the adult beetle hatches out of the soil and begins its adult phase where it will feed, mate and lay eggs of its own.
Battle of the fittest
The mating ritual of some beetle species can be compared to battles between Roman gladiators. In certain species, beetles will fight to the death – males against males, and females against females – until only one pair remains. This process, which may seem extreme, ensures that the strongest of their kind will produce offspring. Once the victorious male and female join, the mating process can take a few minutes to several hours.
Four stages of a beetle’s life cycle
The life cycle of a beetle is known as a complete metamorphosis, meaning it has four very different stages: egg, larval, pupal and adult.
Eggs:The female beetle, depending on the species, will lay hundreds of small white or yellow eggs. The eggs can be deposited in decaying leaves, rotten wood and even animal feces. Some beetles keep their eggs inside and give birth to live larvae.
Larval:Beetle larvae are grub or worm-like in appearance and have voracious appetites. It is in this stage that wood-destroying beetles, such as powderpost and Longhorned beetles, do their damage to structures. The larvae of these beetles feed on the cellulose structure of timber, eating the wood from the inside out. As the larvae begin to grow, they need to discard the outer covering of their bodies, known as the exoskeleton, to provide more room. This shedding, called “molting,” may occur between seven to 10 times before the larvae enter the pupal stage.
Pupal:This stage of the beetle life cycle is where the greatest change in form takes place. The worm-like larvae form the pupa or cocoon as it often called, then lay dormant. During this stage, the larva begin to take the shape of the adult beetle. The time period to reach adulthood from the pupal stage varies dramatically among different types of beetles. Some take as little as 30 days while others may take up to two to three years to fully develop. Once adulthood is reached, the fully mature beetle emerges from the cocoon and begins another life cycle all over again.
Adults:The adult stage is the final stage in the life cycle of a beetle. Adults are found in many sizes, shapes and colors. Some adults have large mandibles for catching their prey and for defense from predators. Some species, such as the Cerambycid beetle, resemble wasps to fool predators in to staying away. Other species can emit poisonous or distasteful substances to ward off their enemies.
Understanding the beetle life cycle may help you better identify any that you may find in or around your home. If you have a beetle problem in your home and need help with identification or control measures, call a pest control professional.
Beetles are by far my favourite taxa. The Beetle order (Coleoptera) contains over 350,000 species worldwide. They represent around 40% of all insects. There are so many varietiesof beetles, many of which display incredible colours and patterns for frightening away predators. Many also possess fascinating horn structures for attracting females. The most commonly kept varieties of beetle in captivity are flower beetles (Cetonidae), rhinoceros beetles (Dynastidae) the Stag beetles (Lucanidae). These are the three subfamilies that we will be taking a particular interest in, especially flower beetles, as this is the subfamily we keep and breed the most specimens of. In this care guide we will be explaining the different stages within the beetle life cycles, so you can better understand these magnificent creatures. The beetle life cycle consists of 4 Stages; egg, larvae, pupae and imago. The entire lifecycle will last a different amount of time depending on the species. Here we aim to give you a general overview focusing primarily on flower, rhinoceros and stag beetles.
Stage 1: The Egg
The female, once mated, will begin to find a suitable place for depositing her eggs. This ‘suitable place’ will vary from one subfamily to another. For example, flower beetles will happily lay their eggs in decaying leaf matter. Whereas, the females of stag beetles will burry in search of rotten wood. Upon finding a suitable piece of rotting wood, they chew tiny holes in the side in which they deposit a single egg before packing the whole back up with small fragments of wood. Then the move on and repeat the process all over again. Some may only lay a few dozen eggs. Whereas others are capable of laying hundreds of eggs in their lifetimes. The length of time it takes for the eggs to hatch will vary a lot from one species to another. When the egg does eventually hatch then it has reached the second stage of its life cycle, the larvae.
Beetle’s reproductive season is typically between spring and fall because beetles are usually overwintering during colder months. After mating, beetles will return to the habitat they developed in to lay their eggs. The number of eggs that are laid by a female beetle depends on the species. Most species of beetles lay between several dozen to several hundreds of little white or yellow eggs while some species will carry eggs internally and give birth to live larvae. Most species will lay eggs near ample food sources like rotting wood, dead leaves, animal feces, or underground where they can feed on organic matter found in topsoil. Most eggs will hatch in a matter of a few days but can also lay dormant for a couple weeks while the conditions improve for the upcoming newly hatched larvae.
Stage 2: The Larvae
When the larvae hatches from the egg, this marks the first stage, also referred to as the 1st instar. As beetle larvae develop they must shed their skin in order to grow. Each time they shed their skin they grow a little bit bigger. The larvae then eats and gains weight before shedding its skin for the first time, at which point it becomes a second instar. Then it will continue to eat and gain weight before shedding for a second time into the third instar. This is the longest stage of the larval development and can last just a few months for the simpler, smaller species, to several years for some of the larger more complex species. During the third and final instar the larvae will slowly gain weight consuming as much substrate as possible. The more weight it gains, the larger and stronger it will be when it eventually develops into an adult beetle. The larvae of some of the world’s largest beetles can have a final weight of up to 150g!
A beetle’s larval stage is the most important phase of a beetle’s life. It is usually the longest phase before reaching adulthood and can last between several months to several years depending on the beetle species. During this period, they are typically small, white, grubs without legs or wings. They also have big mandibles that help them excel at their only function, eating. Grubs need to eat constantly to prepare themselves for the next developmental stage of its life. As the grubs feed, their bodies grow in size, and they shed their outer layer in a process called molting. The time between molting, beetle grubs are known as instars. Each instar phase develops a little further than before with most grubs going through 3- 10 instar phases before reaching the pupal stage.
Stage 3: The Pupae
There will come a point when the larvae become a much darker yellowish colour. Shortly after, it will construct a chamber in the soil where it will shed its skin for the last time and develop into the pupae. Some species construct stronger chambers than others. Flower beetles will construct a strong cocoon made of soil in which they pupate. Whereas, stag and rhino beetles make chambers in the soil which are much flimsier, and often collapse if disturbed. During the pupae stage the larvae breaks down and slowly transforms into the different parts of the adult beetle. This process is called metamorphosis and can last several weeks or months depending on the species.
The pupal stage of a beetle’s life is typically the shortest but also the most transformative. This typically takes between a week to several months depending on the species with some species taking several years. During this period, the process of metamorphosis happens, and its body starts to take form. While the beetle larvae lays dormant, the exoskeleton will start to darken, take shape, and harden, the wings will develop, the legs will emerge, and the head will develop its dominant features. After it is done developing, a mature adult beetle will emerge from its cocoon.
Stage 4: The Imago (Adult)
Once metamorphosis is complete the adult beetle will emerge from the pupae. Its wing cases will form properly and harden, which is a process that may take a few days. The adult beetle will then have an inactive stage where it sits and waits inside its chamber/cocoon, sometimes for several months depending on the species. They will then emerge completely when conditions become more favourable. The adult beetle will then make its way to the surface of the substrate where it will find food, mate and the life cycle will then start all over again.
The adult stage of a beetle’s life is the final stage. In their final stage is when most beetles are easy to identify. Adult beetle’s come in a variety of shapes, sizes, and colors. There are species that develop large horns which act as defense mechanisms, others that develop bright colors to help attract mates, others that develop camouflage designed to help blend in to help prevent predators from eating them. Their activity and diets may vary from carrion, to produce, to feces but most beetles share some feature that make them easy to group together. Regardless of the differences, what easily identifies most beetles is the presence of wings along the back of a hard exoskeleton paired with 6 legs. After a beetle has reached maturity, their focus turns to reproduction which starts the beetle life cycle all over again.
Beetle Life Span
Adult beetles’ lifespans vary wildly depending on the species with some beetles living for only a couple weeks before reproducing and dying off, while other species can survive for several years. If you add in the time that it takes to reach adulthood, some beetles can live for several years as they overwinter during critical developmental stages. Some species will even survive long enough to overwinter once or twice as an adult before dying off. Other species of beetles can be very short-lived and survive in total for a couple months before reproducing and then dying. Even though optimal life expectancy maybe a set time, there are often other factors that impact how long a beetle survives. Things like urbanization, habitat modification, pesticide use, predation, and even climate change have all made significant impacts on the life span of a beetle.
Beetle Life Cycle and Lifespan
Beetles are the largest group of insects in the world. Over 400,000 species of beetles exist, and they make up roughly 40% of the insects around the world. They also go through one of the most transformational life cycles as they transition from grubs to adult beetles through a process called metamorphosis. Similar to that of caterpillars and butterflies, beetles experience a pupae period where they become a dormant cocoon while they develop into their mature bodies. Before they reach their pupal stage, the life cycle of a beetle starts with the mating ritual.
Beetle Mating Ritual
There are many conflicts for territory and mates when it is time for insects to reproduce. Beetles are no different and they may have one of the most intense mating periods as males and females of many species will fight to the death to earn their rite to mate. This process helps ensure that the next generation of beetles is the product of the strongest and fittest of their kind. Beetles rely on their strong sense of smell to detect potential mates and the competitors who may be vying for their chance at reproduction. When 2 of the same sex beetles meet each other, they will attempt to defend their territory to earn their place with the beetle of the opposite sex. Once a victorious beetle emerges, the final 2 beetles will mate in a ritual that can last several hours.
