Scientists say an ancient bee extinction which occurred about 65 million years ago – at the same time that the dinosaurs were wiped out by an unknown event – could shed some light on the current decline of the bee population.
Sandra Rehan, an assistant professor of biological sciences at the University of New Hampshire, and a team of researchers including Michael Schwarz of Flinders University in Australia and Remko Leys of the South Australia Museum, worked to create a model of a mass extinction of Xylocopinae (carpenter bees) which occurred at the end of the Cretaceous era and the beginning of the Paleogene era, a time known as the K-T boundary. This time period is associated with the extinction of all non-bird dinosaurs.
Previous studies have led scientists to believe that, in addition to land dinosaurs becoming extinct during this event, there were also a widespread extinction of flowering plant species during this time. Because of this extinction, they believe that bees must have also experienced a mass extinction. Unfortunately for scientists, there is not a good fossil record of bees so it is difficult to confirm this theory.
In order to get around this lack of a fossil record, the research team working on the current study used a technique called molecular phylogenetics. What they did was they analyzed the DNA sequences of four different “tribes” containing 230 different species of carpenter bees in order to try to understand their evolutionary relationships. When they did this, they began to see patterns from which they could infer a mass extinction.
According to Rehan, their data showed them that something big was happening in the four different groups of bees at the same time. And, this event coincided with the K-T boundary, when the extinction of the dinosaurs took place.
When they combined this information with existing fossil records they were able to gain a further understanding not just of how the bee species are related, but also of how old each particular species is.
Rehan says that if we can understand what happened during this ancient bee extinction, it will help us understand what is going on today with declining bee populations, a problem which is often called Colony Collapse Disorder (CCD). With CCD, large numbers of adult bees are disappearing from hives for unknown reasons. And, when this occurs, it has the potential to create many problems.
First of all, bees play a crucial role in agriculture. They help move pollen from the male part of one plant to the female part of another plant so that the plant can be fertilized and produce fruit. Without insects such as bees, which are very efficient in this process, crop yields would not be great enough to support human needs.
Secondly, the die-off of bee species has important implications as far as biodiversity. There is a complex interplay between all of the different species that exist on the planet; and, when species disappear, it can have important effects on other parts of the ecosystem.
If people could understand the importance of bees, they might be more careful about protecting them, Rehan believes. It is her hope that the findings of the bee extinction study can help us gain a better understanding of why bee populations are now in decline.
The study appears in the October 23, 2013 edition of PLOS ONE.
Written by: Nancy Schimelpfening
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