“A small group of insects,” earwigs, have cylindrical bodies that are slightly flattened. They have long abdomens that end in long forceps. These forceps are called cerci and are utilized for protection and mating. The cerci in males are curved and lengthier than females. Besides the pincers, a male earwig has ten sections in his abdomen that are visible. Females only have 8. When it comes to wings, there are some species that do not have them and others do. Those who are winged use one set for defense and the other to fly.
Earwig Breeding- Starting With The Organs
Found mostly in tropical environments with Britain being the limit, earwigs have diverse reproductive organs.
Some earwigs have one “male intromittent organ” while others have two penes. The species that have one functional reproductive organ are:
- Eu Dermaptera
In earwigs where there are two penes, both function but only one is employed in a single mating. There is no set rule for the usage of the two paired reproductive organs. It is seen that “laterality of the penis-use pattern is not related to the direction of rotation of the male abdomen to establish genital coupling.”
The vagina of a female can hold only one male reproductive part at a given moment. It is the sperm theca, a storage body organ with numerous setae, where the sperms are deposited by the male earwig. The opening of the sperm theca is sometimes wounded by the spined section of the male organ during mating. If the female is damaged, it decreases the chances of re-breeding and initiates “terminal reproductive output.”
Earwig Mating Season And The Battle Of Dominance
The earwig mating season starts in autumn and lasts till winter. They use pheromones to attract each other. The odor of the pheromone is detected using the receptors present on the antennae. To communicate during the copulation, they use cerci. Both genders tend to have more than one mate. In some species like Forficula auricularia, it is the female’s choice if she wants to mate with a courting male earwig or not.
- The Competition:
The cerci are used by male earwigs to compete for courtship of a female. The forceps are utilized to fend off rivals.
- The Courting:
A male earwig will tap and stroke a female using the cerci on the abdomen. He will then present the forceps to the other gender. The female nibbles on cerci to determine whether to accept or reject through a chemosensory input. A courtship can take as long as 10 minutes because females take their time to decide.
- The Acceptance:
It is thought that the length of the forceps factors in the decision. Thus, males with longer cerci are more likely to be accepted for mating. Once approved, the female earwig takes the mating position where her pincers are closed, and abdomen is raised. Now the male turns his abdomen by 180 degrees to start the coupling. In this position, the bottom of the male earwig abdomen is faced up.
How Often Do Earwigs Reproduce?
The first mating can be as short as a few minutes and last up to thirty-eight minutes. After this, the male keeps on courting the female. The female earwig, on the other hand, escapes the male and accepts the “initiation of sperm” after a set period. It is noted that large earwigs have a higher chance of copulation success. Insemination tends to happen when mating is repeated within 8 to 24-hour interval – more the duration of copulation, more the probability of insemination.
Good To Know
- The cerci are used by the earwigs to hold on to each other while coupling.
- Earwigs can spend hours mating.
- Some females stay un-inseminated even after protracted coupling.
- The female will find a safe place that is free of light after insemination. These are generally below rocks and in cracks.
How Many Eggs Do Earwigs Lay?
A female can lay:
- 30 – 55 eggs
- 20 – 40 eggs
The quantity depends upon the season. The former happens when winter is about to end, or spring has just arrived. The latter number is laid during winters. They keep the eggs inside the soil to tend over them. The earwig breeding season starts in September and ends in January. Most earwigs breed just once per year, but some can do so twice.
Development From Egg To Earwig
There are three life stages in earwigs, i.e., they perform an “incomplete metamorphosis.”
- Nymph –This is the larval stage. The only physical difference from the adult is lack of fully formed wings, reproductive organs, and cerci. It lasts for 10 weeks.
- Adult – In late summer, the nymph matures with long and developed cerci. After they reach 3 months of age, they can reproduce in the coming breeding season. An adult lives for 8 to 10 months.
The entire lifecycle from hatching to death is for one year.
Truly Nature’s Wonders
The process of earwig reproduction and mating is not only highly unusual but also not complicated. The patience the insect show, the insemination process and even the care a mother provides to nymphs is remarkable and worthy of study.