Ancient insects preferred warmer climates

Nov 23, 2010

For millions of years, insects and plants have coevolved—leaf-eaters adapting to the modifications of their hosts and plants changing to protect themselves from herbivory. The abundance and diversity of both insects and plants have varied depending on changes in climate.

However, according to a study published in the November issue of Ecological Monographs, a journal of the Ecological Society of America, abnormally high global temperatures have historically lead to a greater diversity and abundance of , separate from plant diversity and adaptations.

Ellen Currano formerly from Pennsylvania State University and colleagues examined a total of 9071 fossilized leaves at nine sites of the Bighorn Basin in Wyoming that had fossils dating back 52.7 to 59 million years ago. This particular location contains fossils created during a period when global temperatures gradually warmed to the greatest sustained highs of the last 65 million years. In addition to this gradual rise, there was also a temporary spike in temperature and partial pressure, similar to the weight, of carbon dioxide in the atmosphere and a subsequent cooling period.

From the fossils during this six million year span, the researchers identified 107 plant species and recorded multiple types of insect feeding damage. They paid special attention to variations of insect feeding on one leaf, indicating the presence of multiple species of insects. By comparing these findings with the established temperature records, Currano and colleagues found that a rise in global temperature—both gradual and abrupt—led to an increase in insect populations. Surprisingly, the increase in insect diversity and abundance was not necessarily correlated with changes in plant diversity or abundance, suggesting that warmer temperatures directly affected insect numbers.

This relationship, said the authors, can be attributed to insect migration: As temperatures rose, insects could move northward and to previously uninhabitable altitudes. These climate shifts, then, may have also caused insect migration over higher latitude land bridges connecting North America, Europe and Asia.

"Our findings indicate possible changes to come as a result of anthropogenic climate change," said Currano. "As temperatures rose some 60 million years ago, tropical and subtropical insects were able to migrate northward to Wyoming. It is likely that present-day anthropogenic warming will lead to similar distributions of insect populations and cause an increase in herbivore damage."

Explore further: Call for alternative identification methods for endangered species

More information: "Fossil insect folivory tracks paleotemperature for six million years" from ESA's journal Ecological Monographs is available open-access at www.esajournals.org/doi/pdf/10.1890/09-2138.1

Provided by Ecological Society of America

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Six times more insects in tropical mountains

Sep 06, 2010

How many species of insects exist? Umea University researcher, Genoveva Rodriguez-Castaneda, found that in tropical mountains there are six times more insects than shown in global calculations. The insects ...

Eating like a bird helps forests grow

Apr 05, 2010

Lions, tigers and bears top the ecological pyramid -- the diagram of the food chain that every school child knows. They eat smaller animals, feeding on energy that flows up from the base where plants convert ...

Recommended for you

Scientists tether lionfish to Cayman reefs

2 hours ago

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

India's ancient mammals survived multiple pressures

22 hours ago

Most of the mammals that lived in India 200,000 years ago still roam the subcontinent today, in spite of two ice ages, a volcanic super-eruption and the arrival of people, a study reveals.

User comments : 0

More news stories

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

Deadly human pathogen Cryptococcus fully sequenced

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

Leeches help save woman's ear after pit bull mauling

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

Venture investments jump to $9.5B in 1Q

Funding for U.S. startup companies soared 57 percent in the first quarter to a level not seen since 2001, as venture capitalists piled more money into an increasing number of deals, according to a report due out Friday.