Beetle in the coconut: Fossil find sheds new light on Neotropical
rainforests
South American fossil reveals earliest evidence of seed beetle predation
in palm fruit

Date:
April 25, 2022
Source:
Penn State
Summary:
Tiny beetles that feed on fruit from the palm family may have
developed their taste for coconuts long ago, according to a team of
scientists studying suspected insect damage in a 60-million-year-old
fossil.



FULL STORY ==========================================================================
Tiny beetles that feed on fruit from the palm family may have developed
their taste for coconuts long ago, according to a Penn State-led team
of scientists studying suspected insect damage in a 60-million-year-old
fossil.


==========================================================================
"We found this remarkable fossil coconut that has clear signs of insect tunneling," said L. Alejandro Giraldo, a graduate student in geosciences
at Penn State. "After studying the damage in detail, we were able to
pinpoint the insect culprit: a group of beetles commonly referred to
as palm bruchines that today still eat lots of palm fruit -- coconuts included." The findings represent the earliest fossil evidence of seed
beetles feeding on palm fruit and shed new light on the Neotropical
rainforests that emerged in modern day South America following the Cretaceous-Paleogene extinction event 66 million years ago that wiped
out the dinosaurs and reshaped life on Earth, the scientists said.

"These were the first Neotropical forests as we know them today," said
Giraldo, whose adviser is Peter Wilf, professor of geosciences at Penn
State. "We know these forests had similar plants compared to today,
and the next step is knowing what was happening to these forests -- for
example how insects were interacting with the plants." Previous studies
have focused on insect damage to fossil leaves, the most abundant plant
parts found in the fossil record, the scientists said. Examples of
insect damage to fruit and seeds are less common, but scientists found
six suspected insect holes on a coconut fossil from a site in modern
day Colombia.

The fossil contained damage to the outer and inner layers of the
fruit, revealing a three-dimensional path that suggests the holes had
a biological origin -- like from larvae eating their way through the
coconut, the scientists said.



==========================================================================
The team analyzed the number, position and size of the holes and the
scar tissue left behind and compared that with damaged caused by modern insects, especially those that feed on plants from the palm family. The
damage was consistent with a sub-group of modern beetles called palm
bruchines, the scientists reported in the journal Review of Palaeobotany
and Palynology.

"There are thousands of different insect species that can feed on seeds,
but not many of them feed on palm seeds, so that was the way to start,"
Giraldo said. "After that it was doing a lot of detective work, really
digging into the literature and studying different morphological features
in terms of how this damage occurs. And it paid off." This kind of relationship between specific plants and insects -- called specialized interactions -- plays an important role in creating and maintaining plant diversity in modern Neotropical rainforests. By eating and destroying
seeds, these highly specialized insects help prevent any one group of
plants from dominating the landscape.

The findings suggest that palm bruchines have consistently eaten palm
fruits for at least 60 million years and that the specialized interactions
that define modern-day Neotropical rainforests have occurred through
geological time, the scientists said.

"This is something that we see 60 million years ago, and it's something
that is still occurring today," Giraldo said. "Our contribution is that
we pinpoint this specific group of insects as the culprit, and that group
is still living today and attacks the same coconuts and same palms as
it did in the past." Also contributing to this research were Mo'nica
Carvalho, postdoctoral fellow at the Smithsonian Tropical Research
Institute and a former graduate student at Penn State, Fabiany Herrera, assistant curator of paleobotany at the Field Museum of Natural History
in Chicago, and Conrad Labandeira, senior research geologist and curator
of fossil arthropods at the Smithsonian Institution.

The National Science Foundation provided funding for this work.


========================================================================== Story Source: Materials provided by Penn_State. Original written by
Matthew Carroll. Note: Content may be edited for style and length.


========================================================================== Related Multimedia:
* Palm_bruchine_tunnels_on_a_fossil_Coconut_fruit ========================================================================== Journal Reference:
1. L. Alejandro Giraldo, Mo'nica R. Carvalho, Fabiany Herrera,
Conrad C.

Labandeira. Ancient trouble in paradise: Seed beetle predation on
coconuts from middle-late Paleocene rainforests of Colombia. Review
of Palaeobotany and Palynology, 2022; 300: 104630 DOI: 10.1016/
j.revpalbo.2022.104630 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220425121126.htm

--- up 8 weeks, 10 hours, 51 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)