Re: Jurassic insect leaf-mimicry to fool predators (pterosaurs, theropods (proto-birds?)) (free pdf)

[Tim Williams <tijawi@gmail.com>]

Ben Creisler <bcreisler@gmail.com> wrote:

> A new online open-access paper. Not strictly dino-related, but what
> predators were these Jurassic bugs trying to fool?

Excellent question.  According to the authors: "This insect
had a comparatively large body size of >30 mm in length
compared with other contemporaneous mecopteran taxa,
resulting in easy detection by the diverse predator fauna at
Daohugou, including larger predaceous insects, mammals,
pterosaurs, and small arboreal dinosaurs (27–30)."


Curiously, the _Epidendrosaurus_ paper isn't included among references
27-30: There's two papers about mammaliaforms, one about lizards...
and one about prosauropods! (by Galton).  Surely an innocent mistake
on the part of the authors.


AFAIK there is no known insects preserved as stomach contents in any
Mesozoic theropods - even though there's no doubt that many theropods
targeted insects.  We have direct evidence that certain theropods ate
fish, lizards, mammals, and birds - based on the preservation of bones
or scales inside specimens.  But no insect bits.  (_Eoalulavis_ is
reported to have exoskeletal fragments of crustaceans preserved in its
thoracic cavity; but O'Connor et al. [2001] dispute that these remains
were found *inside* the bird skeleton.)


Some of the Messel proto-bats (stem-chiropterans) and have insect
remains preserved as stomach contents (such as moths, beetles and
caddis-flies), as does the Messel proto-pangolin _Eomanis_
(Pholidota).  But I don't know of any avian or non-avian theropods
(including the specimens from Liaoning that preserve soft tissue) that
have insect remains inside them, even though many of them must have
fed on arthropods.  My guess is that in general it's very rare for
theropods to have remains of the "last meal" preserved inside, and
arthropod cuticle is dissolved faster than bones or teeth inside
stomach acid, so the chances are even lower.






Cheers

Tim