Alaus oculatus molted to L4???

[The Mantis Menagerie]

I have been raising this A. oculatus grub, and I have been keeping careful track of its molts. I have had it since it was an L2 grub, and it molted once back in the fall. I went to check on it today, though, and I found it had molted again but was still a larva. The strange thing is that it did not seem to be any larger after this molt, whereas I immediately noticed the size difference when it molted from L2 to L3. I even made sure that the shed exoskeleton I was looking at was indeed the grub's exoskeleton, and it definitely belonged to the grub. How is this possible? I have an adult A. oculatus that I got as an L3 grub at the same time as I got this grub, but that larva did not molt in my care except to become a pupa and then enclose. The adult is currently in hibernation as I am waiting for this larva to become an adult and be ready for breeding, so are there any ways to tell this grub to hurry up?

 

[JKim]

I found it had molted again but was still a larva.

I don't know how many times A. oculatus usually molts, but number of molts can varying per each specimen. Although a certain species of insect is known to molt only 3 times, some specimens can have 4 times or 2 times. This especially occurs in butterflies and moths. I don't exactly know how many A. oculatus or any other Elaterids molt, so I'm just giving you a basic idea of how insect physiology works.

The strange thing is that it did not seem to be any larger after this molt, whereas I immediately noticed the size difference when it molted from L2 to L3. I even made sure that the shed exoskeleton I was looking at was indeed the grub's exoskeleton, and it definitely belonged to the grub. How is this possible?

Each individual feed and grow differently. One can grow smaller/larger than other siblings even in a same container. A larva that did not fed on properly or stopped feeding on properly can molt but not evidently grow in sizes.

I have an adult A. oculatus that I got as an L3 grub at the same time as I got this grub, but that larva did not molt in my care except to become a pupa and then enclose.

If you obtained all your larvae as L3, then it could be an extra molting (that I mentioned up there) or it could be a simple mistake. Each individual grow differently, and some can be quite a large L2 than other regular and average sized L2 larvae, and can be confused as a small L3.

The adult is currently in hibernation as I am waiting for this larva to become an adult and be ready for breeding, so are there any ways to tell this grub to hurry up?

I don't know if it works for Elaterids as well, but in case of scarabs like Dynastinses and Lucanids, if you place fully grown larvae (in container) into the refrigerator (with high temperature = not too cold) for two weeks, and take it out to the room, the larvae tends to construct pupal cell and pupate. This refrigerator trick mimics a cold winter (room temperature → refrigerator), and larvae confuse as it gets extremely warmer (refrigerator → room temperature) afterwards, meaning, it's time to become adults.

 

[AlexW]

Orin’s ult beetle guide notes that clicks and darklings molt many times before maturity, often w no apparent size increases

 

[AlexW]

I suspect your “L3” that pupated may have molted far more times than you think

 

[The Mantis Menagerie]

I looked in the ultimate guide, but I only saw it mention darlings having a variable number of instars. I need to find time actually read the book in its entirety. Since this thing seems fat enough to pupate, I might try to coax it into hurrying up. Is there a max limit on the amount of time a beetle can spend in hibernation?

with high temperature = not too cold

What temperature would you recommend? 

 

[Hisserdude]

Darklings and Elaterids both have an indeterminate number of molts, molting rather frequently and far more than three times... They can often be induced to pupate before they've reach the maximum number of molts, (I assume there is one), and the development of Alaus grubs in particular can be greatly prolonged by substandard pupation conditions... Most Alaus seem to require chunks of wood in order to construct pupal cells in, my half grown, WC Alaus melanops grub waited nearly three years for me to add a chunk of wood in it's setup to make a pupal cell in, and grew very minimally during the last two years.