Cannibalism

Higher temperatures could trigger an uptick in damselfly cannibalism

damselfly
As youngsters, damselflies sometimes engage in good old-fashioned cannibalism, when larger nymphs make a meal out of smaller ones. A new study shows that rising temperatures could exacerbate this phenomenon.

A warmer climate could put some damselflies in distress, as others get bigger and hungrier.

Because of differences in hatching time, nymphs — the immature form of the insects — vary in size. Sometimes when ponds are overcrowded, other food options are scarce or size differences are…

Giant Cannibal Slugs Invade the UK

Slugs are already the recipients of bad press for ravaging crops and generally being a rather disgusting and slimy presence in dirt—and the general public attitude toward them isn’t about to get any better. The Telegraph reports that a large species resistant to common control methods has invaded the UK, mating with native slugs to create a massive threat to tomatoes and even small rodents.

The species under investigation is Arion vulgaris, an accurate label for the 6-inch gastropod that’s so brazen it feasts on dead mice, dog feces, and even other members of its species, which has earned it the name of “Spanish cannibal…

Wild hamsters raised on corn eat their young alive

European hamster
European hamster

European hamsters in France often live in farm fields, where they may not be getting a balanced diet. That could cause problems. In the lab, hamsters fed a corn-based diet ate their young alive.

People who eat a diet dominated by corn can develop a deadly disease: pellagra. Now something similar has emerged in rodents. Wild European hamsters raised in the lab on a diet rich in corn showed odd behaviors. These included eating their babies! Such behaviors did now show up in hamsters that ate mostly wheat.

Pellagra (Peh-LAG-rah) is caused by a shortage of niacin (NY-uh-sin), which is also known as vitamin B3. The disease has four major symptoms: diarrhea, skin rashes, dementia — a type of mental illness characterized by forgetfulness — and death. Mathilde Tissier and her team at the University of Strasbourg in France never expected to see something similar among rodents in their lab.

As a conservation biologist, Tissier studies species that may face some risk of going extinct and how they might be saved. Her team had been working in the lab with European hamsters. This species was once common in France but has been quickly disappearing. There are now only about 1,000 of the animals left in the whole country. These hamsters also may be on the decline throughout the rest of their range in Europe and Asia.

These animals play an important role in local ecosystems by burrowing. That turning over of the soil as they excavate tunnels can promote soil health. But more than that, these hamsters are an umbrella species, Tissier notes. That means that safeguarding them and their habitat should give benefits to many other farmland species that may also be declining.

Most European hamsters still found in France live around corn and wheat fields. A typical corn field is some seven times larger than the home range for a female hamster. That means the animals that live on a farm will eat mostly corn — or whatever other crop is growing in its field. But not all crops provide the same level of nutrition. Tissier and her colleagues were curious about how that might affect the animals. Perhaps, they guessed, the number of pups in a litter size or how quickly a pup grew might differ if their moms ate different farm crops.

Corn fields
Many European…