The beetle's dilemma

Jun 26, 2007
Carabid Beetle
A carabid beetle inserting its head into a snail shell. Credit: photograph by J. Konuma

Large jaws are efficient in crushing hard prey, whereas small jaws are functional in capturing elusive prey. Researchers have suggested that such trade-offs between “force” and “velocity” could cause evolutionary diversification of morphology in animals such as birds, fish, and salamanders.

Junji Konuma and Satoshi Chiba of Tohoku University found that a new trade-off exists in animal feeding behavior. The team suggests that diversification of carabid beetles could be caused by a “force” and “fit” trade-off.

There are both elongate, small-headed and stout, large-headed carabid beetles that feed upon land snails. Large-headed beetles can readily crush snail shells with their powerful jaws, but cannot insert their oversized heads into the shells. In contrast, small-headed beetles can insert their heads into the shells for direct predation on snail bodies, but poorly crush the shells because of their frugal jaws.

“Crushing and inserting are alternatively effective in feeding on snails,” said Konuma. Carabid beetles that feed on snails tend to have an extremely slender or stout forebody compared with beetles that eat insects and earthworms. Phylogenetic studies show that adaptations for snail feeding led to the diversification of beetle heads.

Interestingly, it has been demonstrated that the same trade-off diversifies shell morphology in studies of freshwater snails, where elongate shells are adaptive in protecting against entry attacks and rounded shells are adaptive in protecting against crushing attacks. “Trade-offs between force and fit have a significant, important role in both morphologies of snails and snail predators in evolution,” said Konuma.

Source: University of Chicago

Explore further: Sheep flock to Eiffel Tower as French farmers cry wolf

add to favorites email to friend print save as pdf

Related Stories

Man pleads guilty in New York cybercrime case

58 minutes ago

A California man has pleaded guilty in New York City for his role marketing malware that federal authorities say infected more than a half-million computers worldwide.

NASA issues 'remastered' view of Jupiter's moon Europa

9 hours ago

(Phys.org) —Scientists have produced a new version of what is perhaps NASA's best view of Jupiter's ice-covered moon, Europa. The mosaic of color images was obtained in the late 1990s by NASA's Galileo ...

Dish restores Turner channels to lineup

10 hours ago

Turner Broadcasting channels such as Cartoon Network and CNN are back on the Dish network after being dropped from the satellite TV provider's lineup during contract talks.

LiquidPiston unveils quiet X Mini engine prototype

15 hours ago

LiquidPiston has a new X Mini engine which is a small 70 cubic centimeter gasoline powered "prototype. This is a quiet, four-stroke engine with near-zero vibration. The company said it can bring improvements ...

Recommended for you

Genomes of malaria-carrying mosquitoes sequenced

13 hours ago

Nora Besansky, O'Hara Professor of Biological Sciences at the University of Notre Dame and a member of the University's Eck Institute for Global Health, has led an international team of scientists in sequencing ...

Bitter food but good medicine from cucumber genetics

13 hours ago

High-tech genomics and traditional Chinese medicine come together as researchers identify the genes responsible for the intense bitter taste of wild cucumbers. Taming this bitterness made cucumber, pumpkin ...

New button mushroom varieties need better protection

17 hours ago

A working group has recently been formed to work on a better protection of button mushroom varieties. It's activities are firstly directed to generate consensus among the spawn/breeding companies to consider ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.