Navigation Links
Insects are scared to death of fish

TORONTO, ON -- The mere presence of a predator causes enough stress to kill a dragonfly, even when the predator cannot actually get at its prey to eat it, say biologists at the University of Toronto.

"How prey respond to the fear of being eaten is an important topic in ecology, and we've learned a great deal about how these responses affect predator and prey interactions," says Professor Locke Rowe, chair of the Department of Ecology and Evolutionary Biology (EEB) and co-principal investigator of a study conducted at U of T's Koffler Scientific Reserve.

"As we learn more about how animals respond to stressful conditions whether it's the presence of predators or stresses from other natural or human-caused disruptions we increasingly find that stress brings a greater risk of death, presumably from things such as infections that normally wouldn't kill them," says Rowe.

Shannon McCauley, a post-doctoral fellow, and EEB professors Marie-Jose Fortin and Rowe raised juvenile dragonfly larvae (Leucorrhinia intacta) in aquariums or tanks along with their predators. The two groups were separated so that while the dragonflies could see and smell their predators, the predators could not actually eat them.

"What we found was unexpected - more of the dragonflies died when predators shared their habitat," says Rowe. Larvae exposed to predatory fish or aquatic insects had survival rates 2.5 to 4.3 times less than those not exposed.

In a second experiment, 11 per cent of larvae exposed to fish died as they attempted to metamorphose into their adult stage, compared to only two per cent of those growing in a fish-free environment. "We allowed the juvenile dragonflies to go through metamorphosis to become adult dragonflies, and found those that had grown up around predators were more likely to fail to complete metamorphosis successfully, more often dying in the process," says Rowe.

The scientists suggest that their findings could apply to all organisms facing any amount of stress, and that the experiment could be used as a model for future studies on the lethal effects of stress.

The research is described in a paper titled "The deadly effects of 'nonlethal' predators", published in Ecology and highlighted in Nature this week. It was supported by grants to Fortin and Rowe from the Canada Research Chairs program and the Natural Sciences and Engineering Research Council of Canada, and a post-doctoral fellowship awarded to McCauley.

Contact: Sean Bettam
University of Toronto

Related medicine news :

1. Diet of contaminated insects harms endangered meat-eating plants
2. How pest insects might adapt to climate change, affecting agriculture and health
3. Insects that deter predators produce fewer offspring
4. Premature Death Could Await Obese Kids
5. Most maternal deaths in sub-Saharan Africa could be avoided
6. Cleveland Medical Malpractice Attorney Obtains Settlement in Wrongful Death Case
7. American Stroke Association Late-Breaking Science Report: Surgery, Stenting to Open Blocked Neck Arteries Similar in Safety, Efficacy, But Show Differences in Stroke, Heart Attack and Death Rates at Certain Ages
8. Hormone thought to slow aging associated with increased risk of cancer death
9. Some Parents Consider Hastening a Sick Childs Death
10. New tool to predict early death or hospital readmission
11. Death After Discharge Rates Higher in Elderly ICU Patients
Post Your Comments:
Related Image:
Insects are scared to death of fish
(Date:6/27/2016)... ... June 27, 2016 , ... ... its strategic partnership with Connance, a healthcare industry leader providing predictive analytics ... proprietary technology combine to provide health systems, hospitals and ambulatory surgical centers ...
(Date:6/26/2016)... PLAINSBORO, N.J. (PRWEB) , ... June 27, 2016 , ... ... same sources, yet in many ways they remain in the eye of the beholder, ... Oncology (EBO), a publication of The American Journal of Managed Care. For the full ...
(Date:6/26/2016)... ... 26, 2016 , ... PawPaws brand pet supplements owned by Whole ... enhance the health of felines. The formula is all-natural and is made from Chinese ... PawPaws Cat Kidney Support Supplement Soft Chews are Astragalus Root Extract and ...
(Date:6/25/2016)... (PRWEB) , ... June 25, 2016 , ... ... health policy issues and applications at AcademyHealth’s Annual Research Meeting June 26-28, 2016, ... work on several important health care topics including advance care planning, healthcare costs ...
(Date:6/25/2016)... ... June 25, 2016 , ... "With 30 hand-drawn hand gesture ... said Christina Austin - CEO of Pixel Film Studios. , ProHand Cartoon’s package ... Final Cut Pro X . Simply select a ProHand generator and drag it ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... Mass. , June 24, 2016   ... Spaulding Rehabilitation Network,s Dean Center for Tick ... Physical Medicine and Rehabilitation, MIT Hacking Medicine, University ... for Innovation, today announced the five finalists of ... for Lyme disease.  More than 100 scientists, clinicians, ...
(Date:6/24/2016)... BEIJING , June 24, 2016 Dehaier ... or the "Company"), which develops, markets and sells medical ... China , signed a strategic cooperation agreement with ... as "Hongyuan Supply Chain") on June 20, 2016, to ... Under the strategic cooperation agreement, Dehaier will leverage Hongyuan ...
(Date:6/24/2016)... 24, 2016   Pulmatrix, Inc ., (NASDAQ: ... inhaled drugs, announced today that it was added to ... its comprehensive set of U.S. and global equity ... an important milestone for Pulmatrix," said Chief Executive Officer ... of our progress in developing drugs for crucial unmet ...
Breaking Medicine Technology: