Larval cannibalism

[jamesd]

While rearing a lepidoptera species, I noticed that there were mysterious disappearances of some of the eggs, enclosed in the same container as older larvae, as well as disappearances of younger larvae. Why is this happening?

I thought maybe the larvae could be eating the eggs. Do insects ever do this? I was thinking it would be plausible - extra nutrition and less competition for food.

If this is not the case, what is?

[nomihoudai]

Zygaenidae are known to perform cannibalism during the first 24 hours after eclosion. There can be losses up to 50% of the new born larvae. The strange thing is that when you separate the eggs they will always not eat anything during the first 24h hours, it seems like if they were frustrated that they cannot get a good bite of their siblings. Afterwards cannibalism is not happening anymore. Caterpillars that performed cannibalism have a serious advantage in size compared to their peers.

On the other hand there is also some Noctuidae species which are known to be "carnivorous" and eat other lepidoptera larvae in any size and stage, if they also eat their own species or not is unknown to me.

So far my knowledge on cannibalism in Lepidoptera,

Rgds Claude

[wolf]

i've also heard some lycaenidae can be cannibalistic in early stages.

[africaone]

yes cannibalism in the Miletinae (Lycaenidae) of which a lot of species are carnivors.
I had also accidental cannibalism in other purely phytophagous genera.

[bobw]

Many common European Lycaenidae are highly cannibalistic in the larval stage, e.g. C. argiolus, L. boeticus, C. minimus, C. rubi etc. Another common European butterfly that's very cannibalistic is A. cardamines, that's why the eggs turn orange soon after being laid - to warn the female not to lay on the same plant; if you find two eggs on the same plant they were almost certainly laid within a short time of each other, so that the first one hadn't turned orange when the second was laid. A. cardamines larvae particularly like to eat freshly formed pupae.

It seems to me that most cannabalistic larvae are flower and seed feeders, whereas leaf eaters tend not to be cannibalistic.

Bob

[papiliotheona]

Danainae, Anthocharinae of the Pieridae, some Papilioninae (particularly Heraclides), sometimes assorted Nymphalidae (such as A. vanillae when crowded). M. yuccae larvae are very bad with this and will go out of their way to eat a neighboring larva if next to each other.

Hesperiids, most sulphurs, and pretty much any communal species don't seem to be cannibalistic.

[wingedwishes]

I've had accidental cannibalism when later instars have eaten leaves which had ova on them. I had an Actias luna in the 3rd instar eat 30 polyphemus eggs in a 1/2 hour.

[Adam Cotton]

Pachliopta aristolochiae larvae will eat other smaller larvae or soft pupae when there is a shortage of Aristolochia to eat (ie. especially in captivity). I expect this also happens with other Papilionidae too.

Adam.

[admin]

I have had mysterious things happen when rearing early instars of Papilio rutulus together in the same container. Namely: they disappear! For example, I start out with 10 hatchlings and a week later I will only have 6 larvae in there with no signs of what happened to the other four. No dead bodies, nothing! Same thing with early instars of Anthocharis sara. It is strange. It's gotta be cannibalism. Do you think?

[Adam Cotton]

Clark,

Sounds like cannibalism, especially likely in Anthocharis sara, as the British Anthocharis is known to be a cannibal.

Adam.

[jamesd]

Yes. The reason I ask this is because I am rearing Papilio anactus, and I noticed at least 2 of the younger larvae had vanished, when placed in the same container as a much older larva. I also noticed the same thing happening to some eggs last summer. I now separate them, and so far I haven't noticed any missing larvae.

Thankyou everyone, for your helpful answers.