A strange new holometabolan larva with beak-like mouthparts: Author Interview with Joachim Haug


PeerJ recently published An unusual 100-million-year old holometabolan larva with a piercing mouth cone.

The research describes finding an odd new larva preserved in Burmese amber with beak-like mouthparts, extremely rare among larval forms. Here we talk to author Joachim Haug about discovering the strange critter and why larvae rule his world.

Can you tell us a bit about yourself?

Joachim Haug

My research revolves primarily around larvae as I am fully convinced that not adults, but larvae rule our world. They make up an incredible part of the biomass and possibly well outnumber adults easily. Still, many disciplines in biology focus on adults. So I am merely trying to fill a gap, looking at modern and fossil larvae, especially of insects and various other crustaceans. In diversity research, a more and more important field, we can often not easily deal with larvae; therefore, larvae often do not appear in science. That is something I want to change.

Luckily, I am not alone. Besides the omnipresent colleagues in the common meaning, I have my wife, Carolin, she is my most critical colleague. We have two kids, one still in larval stage, one in the process of metamorphosing, and they are also already supporting our research. When not doing biology we carry the scientific thinking into other fields for fun, hence we have also published on geometry and martial arts (you can find links here).

Can you briefly explain the research you published in PeerJ?

Figure 1: New fossil larva, dorsal view. (A) Composite image under ring-light illumination. (B) Interpretation presented as colour markings; arrow points to constriction. Abbreviations: a1–9, abdominal segments 1–9; ap1–5, abdominal processes 1–5; at, antenna; bk, beak, mouth cone; hc, head capsule; ms, mesothorax; mt, metathorax; mx, maxilla; pn, pronotum; t1–t3, thoracic appendages (‘legs’) 1–3; te, trunk end; ts, terminal structure.

We have found a strange little critter preserved in 100-million-year-old amber. It is clearly a larva of an insect, more precisely a holometabolan (flies, beetles, bees, butterflies). Yet this critter is bizarrely strange: its mouthparts form a single forward projecting stinging type of beak, something that you expect from a bug or an adult mosquito. For a larva, this is extremely unusual. The only known cases for at least comparable types of mouthparts in insect larvae are either backwards directed or paired.

Additionally, the new larva possesses strange prominent paired projections on its posterior trunk appendages that all have a kind of sausage-shaped distal portion. This is also very unusual. So basically we have a very strange, highly specialised larva, and we do not know what it is closely related to? Despite the uncertainty concerning its relationship, it demonstrates the presence of a highly specialised ecological role back in a 100-million-year-old fauna that seems absent in the modern-day fauna.

Do you have any anecdotes about this research?

Figure 2: New fossil larva, ventral view.
(A) Composite image under ring-light illumination. (B) Interpretation presented as colour markings. Abbreviations: a9, abdominal segment 9; ap1–6, abdominal processes 1–6; at, antenna; l?, possible labium; ms, mesothorax; mt, metathorax; mx, maxilla; pt, prothorax; t1–t3, thoracic appendages (‘legs’).

Discovering this larva really led to a rollercoaster of ideas. When we first looked at it, we code-named it as “strange megalopteran larva” as we mostly saw the projections on the trunk, which distantly remind of trunk projections in alderfly larvae (one ingroup of Megaloptera). Yet, while further exploring the details, we found some differences to alderfly larvae. And then, there were some similarities to certain beetle larvae, lacewing larvae, scorpionfly larvae.

This thing is somehow like a Chimera. We have seen other Chimeras in the Cretaceous already, but this one clearly has a mixture of the most distant parts. While that might sound frustrating to someone focussing on taxonomy, I really love that. To quote Sean Carroll: Endless forms most beautiful.

What do you hope your readers take away from the research?

If I could wish for one thing to be taken away by the reader, it is that: “larvae matter”. We really need to understand that for many species, especially among holometabolan insects that are so important to our ecosystems, the majority of their lifespan is not spent as an adult, but in their larval forms. This is very different from most animals we are familiar with.

How did you first hear about PeerJ, and what persuaded you to submit to us?

Well, that was quite some time ago. I think the very first piece of information about PeerJ might have come from one of PeerJ’s editors, Kenneth De Baets, Friedrich-Alexander Universität Erlangen-Nürnberg. He is always keen on spreading good open access ideas in the community. For us, the idea of the life publishing plan was a major factor.

How would you describe your experience of our submission/review process?

PeerJ is quite fast, this is really good. What I am still unsure about is the idea to publish the reviews. Sometimes there are passages in that should not go public, especially when author and reviewer know each other (that is not so uncommon, even in blind and double-blind review systems). I feel it would be an interesting option to publish some parts of the review.

Would you submit again, and would you recommend that your colleagues submit?

We have already submitted two more papers to PeerJ since that one, and these will clearly not be the last ones. I recommend PeerJ to my colleagues.

Anything else you would like to add?

I find it exciting that this little critter is now receiving some more attention. I still cannot foresee which papers have the potential to lure more people to look at them and which ones do not. A life-long learning process, I guess.

Thanks for sharing your research story, Joachim! You can read his full paper here.

You can find more PeerJ author interviews here. View related research in PeerJ’s Paleontology and Evolutionary Science section.

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