Tiny shot hole borers want our guacamole!

The Asian shot hole borer has a name longer than it is. This tiny bug has a big appetite, though, and a new favorite food: avocado trees.

The little beetles are native to southeast Asia, but traveled to Los Angeles in 2003. More than a dozen years later, they’re expanding into other areas of Southern California.

Among those areas are the avocado tree orchards of Ventura County.

“Shot hole borers will bore into almost everything, including avocado trees, which is why they are getting a lot of attention,” graduate student Shelley Bennett said in a press release. “But these beetles also affect many native tree species.”

Bennett works in the Riparian InVasion Research Laboratory at the University of California, Santa Barbara. The lab studies invasive insect species, among other topics. One team has been tracking Asian shot hole borers in California.

The two species of shot hole borer seen in the state are tiny – usually less than a tenth of an inch. They have a big appetite, though.

Worse, both species of beetle carry a pathogenic fungus that causes a disease called Fusarium dieback.

For the beetles, the fungus is vital. It’s carried by pregnant females, who plant it beneath a tree’s bark before laying their eggs. The eggs hatch into larvae, which eat the fungus as they grow to adulthood.

Once they’re adults, each females collects some fungus of her own before heading out into the world.

But for trees that are susceptible to Fusarium dieback, the fungus that causes it is devastating. The disease affects the vascular systems of more than 130 tree species, cutting off the flow of nutrients that keep them alive.

Aside from the avocado trees, the beetle has been spotted in oak and sycamore trees in Santa Barbara County, and along the Santa Clara River which runs through parts of Southern California.

The spread of the invasive insects could lay waste to Southern California’s avocado groves, valued at more than $400 million.

Worse, they could cause damage to the state’s riparian habitats – natural areas along rivers that offer habitat for native animal and plant species.

The UC Santa Barbara researchers are working with scientists from the UC Cooperative Extension, the California Department of Food and Agriculture, and other agencies to come up with a solution.

By Kyla Cathey / Earth.com staff writer

New study sheds light on gender in gynodioecious plants

A team of researchers wanted to learn more about how and why gynodioecious plants change their sex, so they shone some light on the question. Literally.

Scientists from the University of Lincoln found that it’s the amount of light they receive that triggers sex changes in the relatively rare plants.

Gynodioecy in plants is a system of reproductive behavior in which plants can either be female or hermaphrodites. Female plants have all of their reproductive parts intact, but hermaphrodites do not produce pollen.

The new study shows that at least some plants express as female when light conditions are good. When conditions are poor, they become hermaphrodites.

Gynodioecious plants are comparatively rare. Most plant species are dioecious – they produce both male and female plants, and both participate in reproduction.

Scientists have known for some time that dioecious plants can switch gender from female to male and back due to environmental triggers. However, sex changes in gynodioecious plants have not been well studied before.

The researchers hoped to change that, so they conducted a study of 326 Geranium sylvaticum specimens.

“We conducted a transplantation experiment in the field where plants with different sex expression were reciprocally transplanted between high light and low light habitats. We measured plants’ reproductive output and sex expression over four years,” the scientists wrote.

They found that, regardless of each individual plant’s origin, those that received more light expressed their sex as female. Those that grew with less light were hermaphrodites.

“This study shows that sex expression in Geranium sylvaticum is [liable to change] and related to light availability,” the researchers wrote.

Because plants may live in light conditions that don’t change much from year to year, they might not change their sexes frequently. That means more species of gynodioecious plants may swap their genders than we thought, the scientists said – but no one has observed them yet.

The study was published in the journal American Journal of Botany.

Your world: top Instagram feeds from plant non-profits

Here at Earth.com, we always like to highlight some of the incredible work being done by nature and wildlife non-profit organizations all around the world. Today, in our regular “Your World” feature, we celebrate the top Instagram feeds from plant non-profits.

Arbor Day Foundation


Trees For Cities 


Woodland Trust 




Fruit Tree Planting Foundation

Famous sequoia tunnel tree takes final bow

If a tunnel tree falls in the forest…

The “Pioneer Cabin Tree,” of Calaveras Big Trees State Park in Northern California, has been toppled by a powerful winter storm. The ancient sequoia had been carved into a living tunnel over a hundred and thirty years ago, allowing horses, and eventually cars to pass through. In recent years, passage through the base of the towering tree had been restricted to hikers.

The Associated Press reports that last weekend’s storm may have been the largest to hit California and Nevada in over ten years, leading to flooding and mudslides in some regions. At over 150 feet tall and with a base of approximately 33 feet in diameter, the iconic tunnel tree was not able to withstand the storm.

A post on the Calaveras Big Tree Association’s Facebook page stated, “The storm was just too much for it.”

It was reported on Sunday by state park volunteer Jim Allday that Pioneer Cabin had fallen. SFGate spoke with Allday to confirm that local flooding was likely the cause of the tree’s demise.

“When I went out there [Sunday afternoon], the trail was literally a river, the trail is washed out,” Allday said. “I could see the tree on the ground, it looked like it was laying in a pond or lake with a river running through it.”

Jim’s wife. Joan Allday, added that the tree had been weakening for several years.

“It was barely alive, there was one branch alive at the top,’ she said. ‘But it was very brittle and starting to lift.”

While sequoias can live for more than 3,000 years, it’s unclear exactly how old the iconic tree was. According to the Los Angeles Times, trees in Calaveras Big Trees State Park are estimated to be more than 1,000 years old.

In the 1800s, tunnel trees were created to promote tourism. Cutting through a living sequoia can do damage to the tree and most of the tunneled-through sequoias in California are dead. Wawona Tree in Yosemite National Park, the most renowned at an estimated 2,100 years old, was felled by a winter storm in 1969. Many of the remaining sequoia tunnels are fallen trees – logs on their sides carved through for passage.

“Tunnel trees had their time and place in the early history of our national parks,” the National Park Service has written. “But today sequoias which are standing healthy and whole are worth far more.”

Image: Tom Purcell-flickr

Earth news daily: January 9, 2017

What’s going on in the world today? Plenty. In your daily dose of Earth news for January 9, 2017, you’ll find a new nature miniseries, tips on algae growth, potential uses for earwax, and more.

Earth news for January 9, 2017:

BBC launches ‘Spy in the Wild’

With “Planet Earth II” over, nature fans are looking for their next fix. “Spy in the Wild” aims to provide it. The new BBC documentary conceals cameras in lifelike robots, and sends them to watch animals in their natural habitats.

Maybe they’re a little too lifelike. In the first episode, a robot disguised as a langur monkey successfully infiltrates a group in India. When the robot was dropped from a height, the monkeys began mourning, producers said.

The miniseries airs in the UK beginning Thursday. In the U.S., the first episode will run February 1 on PBS Nature.

Could earwax be the next big tech innovation?

Scientists at the Georgia Institute of Technology have taken on a new – and sort of disgusting – project: figuring out a technological use for earwax.

The project was inspired after her boyfriend had water trapped in his ear by an earwax plug, doctoral student Alexis Noel said. She wondered how the earwax was able to allow the water in, then trap it so effectively, and mentioned it to Dr. David Hu. They decided to take on the problem.

Using earwax from pigs, sheep, rabbits, and dogs, they began testing its properties and trying out different uses. They’ve found that earwax is made up pretty consistently across species.

They also found that it has excellent filtering properties. As earwax collects dust, it traps it. When too much dust is trapped, the earwax crumbles and falls away, and new wax is formed.

While they’re still studying exactly how earwax is formed, the researchers already see potential uses in tech. One idea would be to create a biomimetic adhesive surface for ventilation systems in robotics and other machinery.

Colorful new flatworm species discovered in Brazil

Scientists have found three new land-based species of flatworm in the Araucaria forest of Brazil. Flatworms are invertebrates, and also predators that hunt other invertebrate species.

The Araucaria is part of Brazil’s Atlantic Rainforest and is considered to be a hotspot of flatworm diversity, the scientists wrote in their article in ZooKeys, an open access journal. The three new species belong to the genus Cratera.

In forests, Missouri bees prefer darker flowers

Bees prefer darker colors in cool climates, at least when it comes to flowers. That’s what scientists at St. Louis University discovered while observing how native bee species interact with birds foot violets.

In most cases, the bees prefered the concolor morph, in which all five petals of the flower are light in color. In sunny locations, the concolor morph far outnumbers the bicolor morph, which has two dark purple petals and three light ones.

But in shady, wooded areas, the bicolor morph makes up about half of the flower population. Bees in these areas always land on the darker petals to feed, the researchers found. Testing revealed darker petals were warmer.

Scientists at UC Irvine find a new method for recycling greenhouse gases

A team of researchers from University of California, Irvine has discovered a new method for dealing with carbon dioxide: using it to help produce biofuel.

The bacterium Azotobacter vinelandii can be used to convert carbon dioxide into carbon monoxide. Though toxic in enclosed spaces, carbon monoxide can be used to produce biofuels and chemical products. Their findings were published in the journal Nature Chemical Biology.

Biodiversity of algae is important in biofuel production

University of Michigan researchers studying algae-derived biocrude have found that when raising algae, biodiversity is important. They found that growing a wide variety of algae reduced crop failure and gave a better return on investment. While their research was conducted indoors in tanks, that will be true in outdoor tanks or ponds, too, the researchers said.

The research is being funded by a $2 million, four-year grant from the National Science Foundation.

Scientists explore link between rainfall in West, Rocky Mountain air quality

When the western U.S. suffers from a drought, Rocky Mountain air quality suffers, too, scientists at the University of Utah found.

That’s because drought sparks more wildfires, which creates haze in the Rockies, the scientists said. Haze can be evaluated with instruments that measure aerosol optical depth – the amount of aerosols between the sensor and the sun.

Aerosols in the Rockies went up when the west was in a drought, according to the study published in the journal Environmental Research Letters.

— January 9, 2017

City life may influence plant and animal evolution

The story of the city mouse and the country mouse may be truer than we thought. A new study has found that plants and animals that live in urban areas are being changed by city life.

The analysis, led by Dr. Marina Alberti of the University of Washington, looked at 1,600 cases around the world. They found that animals and plants living in cities showed changes in body size along with changes in behavior and reproduction habits compared to their country cousins.

“Humans challenge the phenotypic, genetic, and cultural makeup of species by affecting the fitness landscapes on which they evolve,” Alberti and her co-authors wrote in the analysis. “Recent studies show that cities might play a major role in contemporary evolution by accelerating phenotypic changes in wildlife, including animals, plants, fungi, and other organisms.”

For example, one 2008 study found that wildlife and plant populations exposed to human activity – especially activity in which humans alter the natural world, such as overharvesting or pollution – show faster rates of evolutionary change.

The researchers looked at another study that recorded changes in the behavior of crows and ravens in response to human behavior. That 2005 study found that social species with the ability to create and evolve their own “culture,” such as crows, can adapt and change that culture to take advantage of city life.

Alberti and her fellows used their “meta-analysis” to try to piece together the role that urbanization as a whole, rather than just individual human behaviors, plays in plant and animal evolution. That included widespread habitat modification like paved roads, street lights, and tall buildings; social interactions among species and between animals and humans; and disturbances of the natural ecosystem like flooding (though flood prevention or damming rivers) or pollution.

“By explicitly linking urban development to traits that affect ecosystem function, we can map potential eco-evolutionary implications of emerging patterns of urban agglomerations and uncover insights for maintaining key ecosystem functions upon which the sustainability of human well-being depends,” they wrote.

The analysis was published in Proceedings of the National Academy of Sciences.