Navigation Links
Switching senses

PASADENA, Calif.Many meat-eating animals have unique ways of hunting down a meal using their senses. To find a tasty treat, bats use echolocation, snakes rely on infrared vision, and owls take advantage of the concave feathers on their faces, the better to help them hear possible prey. Leeches have not just one but two distinct ways of detecting dinner and, according to new findings from biologists at the California Institute of Technology (Caltech), their preferred method changes as they age.

Medicinal leeches, like many aquatic animals, use water disturbances to help them find a meal. Juvenile leeches eat the blood of fish and amphibians, while adults opt for blood meals from the more nutritious mammals. Since it was known that leeches change their food sources as they develop, the Caltech team wanted to know if the way they sense potential food changed as well. Their findings are outlined in a paper now available online in the Journal of Experimental Biology.

The group set up experiments to test how much leeches rely on each of the two sensory modalities they use to find food: hairs on their bodies that can note disturbances in the water made by prey moving through it and simple eyes that can pick up on the passing shadows that those waves make. They monitored both juvenile and adult leeches as they reacted to mechanical waves in a tank of water or to passing shadows, as well as to a combination of the two stimuli. The leeches in both age groups responded in similar ways when only one stimulus was present. But when both waves and shadows existed, the adult leeches responded solely to the waves.

"We knew that there was a developmental switch in what kind of prey they go after," says Daniel Wagenaar, senior author of the paper and Broad Senior Research Fellow in Brain Circuitry at Caltech. "So when we saw a difference in the source of disturbances that the juveniles go after relative to the adults, we thought 'greatit's probably matching what we know.'"

However, the team was very surprised to see that the individual sensory modalities aren't modified during development to help decipher different types of prey. The leech's visual system doesn't really change as the animal matures; neither does the mechanical system. What does change, however, is the integration of the visual and mechanical cues to make a final behavioral decision.

"As they mature, the animals basically start paying attention to one sense more than the other," explains Cynthia Harley, lead author of the study and a postdoctoral scholar in biology at Caltech. She says that the team will now focus their studies on the adult leeches to learn more about how this sensory information is processed both at the behavioral and cellular levels.

Paper coauthor Javier Cienfuegos, now a freshman at Yale, contributed to the study while a high school student at the Polytechnic School, which is located next to Caltech's campus. He ran about half of the experimental trials and was "instrumental in the success of the study," says Harley.


Contact: Deborah Williams-Hedges
California Institute of Technology

Related biology news :

1. Switching to solar
2. Switching off hunger hormone affects desire to drink
3. Switching on the power of stem cells
4. Microbiologists find defense molecule that senses respiratory viruses
Post Your Comments:
Related Image:
Switching senses
(Date:10/29/2015)... YORK , Oct. 29, 2015 ... technology, announced a partnership with 2XU, a global ... to deliver a smart hat with advanced bio-sensing ... and other athletes to monitor key biometrics to ... the strategic partnership, the two companies will bring together ...
(Date:10/27/2015)... 27, 2015 Munich, Germany ... Mapping technology (ASGM) automatically maps data from mobile eye ... , so that they can be quantitatively analyzed ... Munich, Germany , October 28-29, 2015. SMI,s ... from mobile eye tracking videos created with SMI,s ...
(Date:10/26/2015)... , October 26, 2015 /PRNewswire/ ... --> adds Biometrics ... to 2021 as well as Emerging ... research reports to its collection of ... . --> ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... Nov. 24, 2015  Asia-Pacific (APAC) holds the ... (CRO) market. The trend of outsourcing to low-cost ... but higher volume share for the region in ... however, margins in the CRO industry will improve. ... ( ), finds that the market ...
(Date:11/24/2015)... (PRWEB) , ... November 24, 2015 , ... ... maintain healthy metabolism. But unless it is bound to proteins, copper is also ... Health (NIH), researchers at Worcester Polytechnic Institute (WPI) will conduct a systematic study ...
(Date:11/24/2015)... ... 24, 2015 , ... This fall, global software solutions leader SAP and AdVenture ... develop and pitch their BIG ideas to improve health and wellness in their schools. ... to win the title of SAP's Teen Innovator, an all-expenses paid trip to Super ...
(Date:11/24/2015)... , Nov. 24, 2015 /PRNewswire/ - Aeterna Zentaris ... today that the remaining 11,000 post-share consolidation (or ... Warrants (the "Series B Warrants") subject to the ... on November 23, 2015, which will result in ... giving effect to the issuance of such shares, ...
Breaking Biology Technology: