Ecology & Zoology
In the animal world, if several males mate with the same female, their sperm compete to fertilize her limited supply of eggs. And longer sperm seem to have a competitive advantage, but even when it comes to sperm the size of the animals matter. The larger the animal, the more im-portant the number of sperm is relative to sperm length. That's why elephants have smaller sperm than mice.
Sperm are probably the most diverse cells in terms of size and shape and have been a continual source of fascination since their first discovery nearly 350 years ago. But why are sperm so incredibly…
The United States Food and Drug Administration has approved the AquAdvantage salmon, a genetically modified Atlantic salmon that expresses a gene from a Chinook salmon to grow faster, after reviewing it since 1996.
The additional gene added by AquaBounty Technologies enables it to grow year-round instead of only during spring and summer, so it grows twice as fast. Since 95 percent of Atlantic salmon is currently imported, and fish is promoted as part of a healthy diet, a faster-growing fish makes sense to stave off depletion of wild salmon and to boost locally-grown, sustainable farming.
The…
Researchers have discovered several new species of marine fungi inhabiting previously undescribed branches of the tree of life. Though there is always talk about what little we do know going extinct, little is known about species on land, now or in the past, much less about the fungi flourishing in the world's oceans.
It turns out that many marine fungi are very different from those found on land.
The research, published in Proceedings of the Royal Society B, used large-scale DNA sequencing to describe the diversity of fungal microbes in a wide range of marine environments.
The study found a…
As the American media continues to speculate, analyze and in some cases choose the Republican and Democratic nominations for U.S. President, researchers in the journal Trends in Ecology&Evolution review the nature of leadership - at least in a set of small-scale mammalian societies, including humans and other social mammals such as elephants and meerkats.
"While previous work has typically started with the premise that leadership is somehow intrinsically different or more complex in humans than in other mammals, we started without a perceived notion about whether this should be the…
From the Biblical plagues of Egypt to a major infestation in Madacasgar two years ago, locust swarms have caused chaos throughout history. Just one swarm can cover 20% of the land surface of the Earth, affecting the livelihood of 10% of the world’s population by consuming up to 200 tons of vegetation per day.
Understanding how swarms form and what can break them apart, then, is of great importance.
But how many locusts does it take to make a swarm? It sounds like the start of a bad joke, but understanding and controlling locust plagues is something we’ve been striving to do for thousands of…
One day a few years ago, while working on wasps in a rainforest in Costa Rica, entomologist Kevin J. Loope, a postdoctoral researcher at the University of California, Riverside, began reading about the enigmatic matricidal behavior of some social insects. In most social insects, such as bees, ants and wasps, the workers, which are all female, work their whole lives to help the queen produce new offspring. Yet, in the literature Loope found anecdotal reports of workers killing their queen, presenting a fascinating evolutionary puzzle.
"The observations of queen-killing seemed paradoxical to me…
Nature reserves and national parks play a crucial role in sheltering wildlife, such as African elephants, from hunting and habitat destruction, but they have no problem at all exhausting the wildlife around them.
Researchers have examined the effect elephants have on the woody plant life in Kruger National Park, the largest protected area in South Africa, and found that elephants are the preserve's leading causes of fallen trees.
"National parks and nature preserves will serve as biodiversity arks as we move into the future," said Carnegie Institution's Greg Asner. "But to manage them…
Horses need help when it comes to insect pests like flies but many horse owners are in the dark about how best to effectively manage it.
A new overview of equine fly management in the latest issue of the Journal of Integrated Pest Management, an open-access journal that is written for farmers, ranchers, and extension professionals.
One fly-management method that is gaining ground is the use of wasps that are parasitoids of fly pupae. The female wasp inserts an eggs into the fly puparium, and when the egg hatches, the wasp larva eats the fly pupa.
The authors conducted research on two wasp…
When flowering plants are surrounded by a large number of insects, usually both sides profit from the encounter. Feasting on the plant juice and pollen, the insects pollinate the flowers and thus secure the survival of the plants. However, sometimes the insects - in this case a certain species of leafhoppers - can bring disaster to the plants, which they are not able to overcome.
"The insects transmit bacteria, so-called phytoplasmas, which destroy the life cycle of the plants," says Prof. Dr. Günter Theißen of Friedrich Schiller University Jena (Germany). Instead of blossoming, the…
Like seeds, pollen loses most of its water during maturation, entering a state of suspended animation. This allows it to survive its journey from male to female organs of a flower, where it is rehydrated by sugary fluids secreted by the female organ, and springs into life again.
But rehydrating is a dangerous process, one that can kill the pollen grain before it can fertilize the egg if not properly controlled.
New research from the lab of Elizabeth Haswell, PhD, associate professor of biology in Arts&Sciences at Washington University in St. Louis, shows how pollen survives the…